f. r * F Plant Guide Washington Park Arboretum Hours: Dawn to dusk, 365 days a year The Arboretum Foundation 2300 Arboretum Drive East Seattle, WA 98195 (206) 325-4510 FAX: (206) 325-8893 UW programs: (206) 543-8800 Gift Shop: (206) 543-8800 The Arboretum Foundation Officers Steve Garber, President Vice Presidents: Deborah Andrews, Administration Gretchen Hull, Special Events Phil Wood, Planning Gail Donohue, Secretary Don Close, Treasurer Duane Kelly, Immediate Past President Staff Susan Hebert, Executive Director Cindy Jackson, Administrative Assistant Pam Tharl, Bookkeeper Contractors Jan Silver, Editor, Arboretum Bulletin Elliott Bronstein, Editor, Ground Work Regen Dennis, Public Relations Editorial Board Washington Park Arboretum Bulletin Jan M. Silver, Editor Tom Berger Jeannine Curry Valerie Easton, Book Review Editor Daniel J. Hinkley, Advisor Arthur R. Kruckeberg, Ph.D. Steven R. Lorton, Advisor Bill Mackay, Arboretum Foundation liaison Sue M. Nicol Jan Pirzio-Biroli, Advisor Mary Robson Richard Walker, Ph.D. John A. Wott, Ph.D. Brian O. Mulligan (1907-1996) University of Washington John A. Wott, Ph.D., Director of Arboreta Curatorial/Management Staff: Tracy Omar, Assistant Curator and Recorder Christina Pfeiffer, Horticulturist Dana Kirley, Education Coordinator Barbara Selemon, Propagator Center for Urban Horticulture Clement W. Hamilton, Ph.D., Director City of Seattle Department of Parks & Recreation Ken Bounds, Acting Superintendent Woodland Park Zoological Gardens This publication is dedicated to the outstanding gardeners , both professional and volunteer, who have transformed Woodland Park Zoo into a botanical as well as a zoological garden. Hours: 9:30 a. m. to 6:00 p.m. March 15 to Oct. 15 9:30 a.m. to 4:00 p.m. Oct. 16 to March 14 5500 Phinney Avenue North Seattle, WA 98103-5897 Information: (206) 684-4000 TDD: (206) 684-4026 FAX: (206) 233-2663 Horticultural program: (206) 684-4803 ZooStore: (206) 548-1535 (for single or bulk pur- chases of this guidebook) ZooDoo: (206) 684-4828 About Woodland Park Zoological Society: 601 N. 59th St., Seattle, WA 98103-5858 Membership: (206) 789-6000; FAX (206) 789-1937 Woodland Park Zoological Society was founded in 1965 to assist the zoo with volunteers and finan- cial support. A wide range of programs and activi- ties has been undertaken that benefit Woodland Park Zoological Gardens. Today, the Society is the zoo’s partner organization in marshalling public support for this nationally acclaimed attraction. Woodland Park Zoo is committed to the goals of conservation, education, research, and recre- ation. It has received international acclaim for its naturalistic exhibits, species conservation efforts, and portrayal of major ecosystems from around the world. For more information on zoo horticulture, visit the Elisabeth C. Miller Library, University of Wash- ington Center for Urban Horticulture, 3501 NE 41st St., Seattle, WA 98195. Partners in Horticulture & Conservation The publishers of this guide are Washington Park Arboretum (a fund-raising arm of the Univer- sity of Washington) in partnership with Woodland Park Zoological Society, Woodland Park Zoo’s sup- port organization. The idea for this issue came from discussions with Sue Maloney Nicol, zoo horticulturist, a mem- ber of the editorial board of the Washington Park Arboretum Bulletm. The Washington Park Arbore- tum, Woodland Park Zoological Gardens, and Seat- tle Aquarium are the three public living museums of the Seattle Department of Parks and Recreation. How can I support the zoo’s horticulture program? Donations to Woodland Park Zoological Soci- ety’s Horticulture Fund are designated for all plant-related activities. Money in this fund helps support conservation projects as well as buying special rare plants, reference books, plant labels, and much more. Send donations to the Woodland Park Zoological Society Horticulture Fund, 601 N. 59th St, Seattle, WA 98103-5858. Printed on recycled paper Welcome to the Garden of Animals . . . and Plants elcome to our garden. The Arboretum Foundation and Woodland Park Zoo have produced this guidebook as an issue of Washington Park Arboretum Bulletin , to explore the unique way the zoo has merged the plant and animal kingdoms into award-winning naturalistic exhibits. The zoo exhibits create landscape habitats within animal displays instead of using concrete cages. This is the result of a type of urban horticulture, which started at Woodland Park Zoo in the late 1970s. At that time, the first naturalistic exhibits were designed by Jones and Jones, landscape architects. Since then, you have been able to experience savanna, tropical rain forest, and taiga without leaving Seattle’s Woodland Park. Use this guidebook as you tour the zoo. You will see how Seattle’s mild climate allows zoo gardeners to use a wide variety of plant species to emulate exotic wildlife habitats. The Gorilla exhibit, for example, is created entirely outdoors using temperate plants that mimic a tropical rain forest. Other exhibits, such as the Northern Trail, re-create the plant communi- ties of south-central Alaska accurate to almost the last species. nter through the gates of Woodland Park Zoo into a unique green gar- den. Stately old trees planted during the early days of the twentieth cen- tury still tower over state-of-the art exhibits. Quiet spots for picnicking are nestled amongst landscapes that immerse you in exotic natural worlds. Let this plant guide accompany you on walks through the zoo to learn about the plant life among the animals. Come often to the zoo: You will be transported to regions of the earth where you can learn about the world’s plants and animals without ever leaving Seattle. David Towne , Director Sue Nicol , Grounds and Pacilities Supervisor Woodland Park Zoo Woodland Park Zoological Gardens Seattle , Washington Plant Guide Woodland Park Zoological Gardens Contents Welcome to the Garden of Animals... and Plants 1 Crossing the Zoo Boundary 3 Travel the African Savanna 6 Experience the Tropical Rain Forest 10 Zoo Bamboo The Tropical Rain Forest 16 The Elephant Forest 17 Trail of Vines 19 On the Northern Trail 21 Feigning Foreign Flora 27 Our Backyard to Your Backyard: Creating Wildlife Havens 30 Woodland Park Rose Garden 33 Volunteer for Zoo Horticulture 33 Enjoy the Outstanding Trees 34 Conserving Plants and Animals 37 ZooPlant Facts Back cover This guidebook is an issue of the Washington Park Arboretum Bulletin, published in cooperation with Woodland Park Zoological Gardens and Woodland Park Zoological Society. COVER: Two siamangs swing through the Trail of Vines, in the Tropical Asia zone. Tree is Lirioden- dron tulipifera. Gerry Ellis. The Washington Park Arboretum Bulletin is published quar- terly as a bonus of membership in The Arboretum Foundation, Seattle, Washington. This guidebook is volume 58:3. ©1996 The Arboretum Foundation. ISSN 1046-8749. The Washington Park Arboretum is administered coopera- tively between the University of Washington, its Center for Urban Horticulture (CUH), and the City of Seattle Department of Parks and Recreation. The programs and plant collections are a responsibility of CUH. The Arboretum Foundation is a non- profit organization that was chartered to further WPA develop- ment, projects, and programs through volunteer service and fund raising. The Arboretum Foundation mission is to ensure stewardship for the Washington Park Arboretum, a Pacific Northwest treasure, and to provide horticultural leadership for the region. This stewardship re- quires effective leader- ship, stable funding, and broad public support. The Washington Park Arboretum is a living plant museum emphasizing trees and shrubs hardy in the maritime Pacific North- west. Plant collections are selected and arranged to display their beauty and function in urban landscapes, to demonstrate their nat- ural ecology and diversity, and to conserve important species and cultivated varieties for the future. The Arboretum serves the public, students at all levels, naturalists, gardeners, and nursery and land- Top: Flaming red Berberis thunbergii ‘Atropurpurea’ is a backdrop to the gorilla. Carol Beach. Middle: Peeking through the Pinus densiflora is a red panda. Woodland Park Zoo. Bottom: Vines against artificial buttress tree in the Trail of Vines. David Selk. Crossing the Zoo Boundary by David Hancocks TXZhen I became director of Woodland Park Zoo in the early 1970s, I noticed that Parks V V maintenance crews, like itinerant barbers, descended each month with clippers, mowers, and rakes to give everything a crew cut: They came, they clipped, they quit. Zoo keepers tend- ed the few plants that survived,. usually inside certain animal enclosures. This situation was not aesthetically appealing. Philosophically, it was unacceptable. A young gorilla in one of the original zoo exhibits: a concrete cage. Woodland Park Zoo. We wanted to create exhibits in which sim- ulated wild landscapes flowed across bound- aries of the animal enclosures, so that both zoo visitors and zoo animals shared the same type of environment. The term for this design technique, “landscape immersion,” was coined by landscape architect Grant Jones, senior partner of Jones & Jones, Seattle, and is now universally used. To achieve this, we had to develop expertise in plant maintenance beyond that which we had. Historically, zoos have presented their ani- mal collections in taxonomic groupings, segre- gated by genus or species. This is an artifact of the eighteenth and nineteenth century way of looking at nature; it is why zoo visitors tradi- tionally had to go to one part of the zoo to view all the bears, then to other parts separate- ly to see pachyderms, monkeys, birds, reptiles, and so on. Taxonomy is the most convenient way to maintain a living collection but is of no value in depicting animals in their habitats. The other type of zoo layout is done occa- sionally, in which animals are arranged accord- ing to their continents of origin: zoogeo- The lowland gorillas of the Tropical Rain Forest are sur- rounded by plants that simulate their original environ- ment. Gerry Ellis. graphic zoning. Toronto Zoo is the largest modern example. Again, such displays tell nothing about the natural homes of animals. In such a zoo’s South America zone, for exam- ple, you might find llamas, which are moun- tain animals, living with tapirs, which are for- est dwellers, living with mara, which are plains animals. This arrangement doesn’t make sense. The inadequacy of arranging animals by continent is revealed as soon as plants are added to the exhibit. Traditionally, zoos have only presented plants as decorative back- drops, inconsequential to animals. But to tell visitors something about animals other than what they look like — especially to tell some- Vol. 58:3 3 thing about behaviors and habitats — zoo plants must become as important as animals. Faced with an exhibit containing South American llamas, tapirs, and maras, a zoo would need to decide what plants can repre- sent their homes. Should species be used from mountain, plains, or forest? As long as zoos persist in focusing on nothing but animals, they avoid this dilemma and thus fail to see its inadequacies. The names we give to things dictate what we expect of them. In zoological gardens, for example, we confine activities to matters zoo- logical. So, when I went before the Seattle City Council in the mid-1970s to request funding for horticulturists, several Council members found it incomprehensible. One of them asked, “Why do you want horticultur- ists? You’re a zoo!” Several other zoos have had gardeners on staff for many years. In Europe, especially, there is a long tradition of presenting immac- ulate, colorful flower beds as part of the zoo- logical gardens. But Seattle wanted to be among the first where horticulturists played an integral role in shaping the landscape — where as much attention was devoted to plants as to animals in creating naturalistic replicas of wild habitats for both people and animals. After a lot of lobbying we got our first horticulturist. Fortuitously, we started with one of the world’s best, Sue Maloney Nicol. Grant Jones is as much a poet as a land- scape architect. He not only coined the term “landscape immersion,” he also introduced me to the concept behind it. I once asked Grant if we could lay out Woodland Park Zoo to display all animals in their natural sur- roundings— pine forests, grasslands, and so on; in effect, if we could display animals along with flora representing their native climates. “Ah,” he said. “You mean bioclimatic zon- ing!” “Oh,” I said. “Do I?” Jones & Jones prepared a long-range plan for Woodland Park Zoo in 1974. The plan called for the zoo to develop bioclimatic zones to demonstrate the relationship between cli- mate and living matter. This new way of creat- ing a zoo had never before been attempted. At Woodland Park, the bioclimatic zones selected for replication are the ones you see today: savanna, tropical rain forest, temperate forest, steppe, taiga, and temperate forest montane — a very wide range. Ideally, we would have limited the scope, especially to conform to local climatic conditions. Howev- er, we had to fit the concept around the exist- ing collection of animals, most of which came from tropical rain forests. Grant Jones and I toured the Puget Sound region looking for plants with the appropriate look and character for tropical rainforest ex- hibits. “Simulators,” he called them. We scoured Washington Park Arboretum, parks, private gardens, roadsides, and vacant lots. This yielded a gratifyingly diverse number of species that would grow in Seattle yet resemble foreign plants we wanted to represent. At first, however, the creation of naturalis- tic landscapes in Woodland Park Zoo almost back-fired. People were not used to seeing wild landscapes there. When visitors wrote to the City Council complaining that the zoo was looking unkempt, I was afraid that funding for our horticulturists was in jeopardy. We had to install signs saying, “These Are Not Weeds!” Fortunately, enough Seattle residents under- stood and liked the change. Woodland Park Zoo now has many and various simulated habitats that allow visitors to gain a bet- ter understanding of the natural environ- ments in which the animals evolved and thrive. In addition, how- ever, we recently have become aware of the need for natural history institutions, such as zoological and botanical gardens, to become more directly and actively involved in conser- vation. This creates an abundance of serious problems. Zoos, for example, are set up principally for exhibition. Conservation centers, however, require lots of spaces for holding optimum numbers of pairs or groups, and these are just not available in a zoo. Some zoos are making good progress in breeding and conserving some endangered species; there are about 70 “ Traditionally , zoos have only presented plants as decorative backdrops, inconsequential to animals. ” “Zoo horticulture is still a new profession, mainly confined to institutions in North America. ” 4 Washington Park Arboretum Bulletin species survival pro- grams in a coordinat- ed effort nationwide. But the species receiving attention are, almost without exception, the charis- matic animals such as large predators that are more important to zoos than to nature. In the wild, it is typically the little things such as insects and arthropods that have the greatest biomass, that are most important, and run the world. Zoos, however, typically ignore these small life forms, as they do botan- ical life forms. Plants and animals are interdependent, a fact rarely revealed in zoological or botanical gardens, which highlights the widespread need to understand this basic phenomenon and its vital importance. Plants and animals are also being lost at an accelerating rate, often by linked extinctions in which one species disap- pears because a plant or animal important to its survival has gone. One thing zoos can do about the threat of extinction is to upgrade the status of their hor- ticultural efforts: Every zoo should have a curator of botany. This would greatly help the more accurate development of habitat exhibits. Another obvious endeavor would be for zoos, despite the limiting factor of their name, to become involved in plant conserva- tion, if at no other level than education and the dissemination of knowledge. This is where we run into a fundamental dilemma. Today, many zoos are pursuing landscape immersion exhibits and replicating the images of natural habitats with simulator plants or, sadly, with concrete and plastic trees. To go beyond this step and do what zoos should be doing with animals, anyway — accurately inter- preting the plants, their evolutionary tactics, and the role plants play within their ecosys- tems— means growing and maintaining authentic species. For most of the world’s zoos that is simply impossible. Even Seattle, with its mild and wonderful growing climate, cannot sustain enough diversity to do that. The best way to conserve species would be to develop a center or “garden” to not only show the beauty of nature but to interpret its complexity to ever increasingly urbanized audiences. Such a center would reveal the importance of ecosystems and the connections between all living things and, most important- ly, explain how we all can do something about conserving nature. This requires inventing something different from a zoo or an arbore- tum — a Garden of Ecology. It would not be sensible, however, for such a garden to try to maintain living things from all over the world. It is true that exotic animals and plants from all of the planet’s biomes are represented in zoos and botanical gardens nationwide, in climate-conditioned buildings. The expense, however, is enormous and is not, I believe, justifiable. There is a simpler, more useful approach. The best solution is for gardens of ecology to focus on regional interpretations; for Seat- tle, that would mean Cascadia. In such a gar- den, native plants and animals could be main- tained and displayed together, with mini- mal cost and maxi- mum effectiveness. Here, the total rich- ness of natural ecosystems could be interpreted fully. Vis- itors would better understand the diversity and com- plexity of the world around them. Conserva- tion messages would be brought home, direct and meaningful. Zoo horticulture is still a new profession, mainly confined to institutions in North America. It has grown well during its short life and brought immeasurable benefits to zoos. Perhaps its greatest and most enduring contri- bution, however, will be the following: By introducing horticulture into the zoo the basic flaw in the zoo concept is revealed and brings into our field of vision the possibility for the next evolutionary leap by zoological gardens — their transformation into ecologi- cal gardens. David Hancocks is former director of Woodland Park Zoo. He currently is executive director of Ari- zona-Sonora Desert Museum, a living museum in Tucson, Arizona. “Plants and animals are interdependent , a fact rarely revealed in zoological or botanical gardens. . . * 4 \ff “ ... the next evolutionary leap by zoological gardens — their transformation into ecological gardens. ” ^4 Vol. 58:3 5 Travel the African Savanna by David Selk Tou are walking down a dusty path of red soil, surrounded by dry grasses and thorny bushes. You come to a refreshing water hole, and up rise two huge heads. Hippo! You raise your eyes to look past them and just ahead are herds of zebra, giraffe, and springbok. To the left, weaver birds in a grove of thorn trees busily create pendulous homes from dried grass. From off to your right comes the roar of a lion answered by anoth- er. Welcome to Africa? Welcome to Woodland Park Zoo’s African Savanna. Most people will never be able to travel to Africa and see these animals in their native habitat, but here in Seattle you can come as close as you can get to expe- rience the thrill of that part of the world. Some may think of a savanna as a flat, treeless grassland. That is cer- tainly true, but it is also more com- plex than that. Savannas have vast stretches of open grassland, and on the edges are many types of deciduous, semi- deciduous, and evergreen wood- lands; scrubby bushlands; grasslands; and combinations of all of these. There are even wetlands. The plant communities mix various degrees of density and height, depending most- ly on rainfall. The zoo’s savanna emphasizes animals. To see them in their habitat, however, the savanna habitat needs plants. Although most African savan- na plants cannot be grown outdoors in Seattle because of Northwest win- ters, the zoo has planted trees, shrubs, and grasses to simulate the look and feel of such plants. As you go, you will learn about the savanna habitat and the fascinating adapta- tions plants have developed to flour- ish there. 6 Washington Park Arboretum Bulletin Touring the Savanna 5 tart at the public pathway around the savanna. It runs between two of the plant communities — the open grassland, where you will view many of the animals, and the scattered woodland edge. The individual plants discussed appear many times along the savanna path, and you will find many of them on the map. Plants Challenged by Water Many challenges face plants on the African savanna, and they have many strategies to cope with these challenges. Water is one of the crit- ical limiting factors in that climate. Months can pass with no rain and very high tempera- tures. Plants have many adaptations to prevent water loss, and savanna plants incorporate most of them. One common adaptation is to develop a thick and waxy or leathery cuticle, which minimizes water loss through the leaf surface. You can see this demonstrated throughout the savanna in broad-leaved ever- green plants such as thorny elaeagnus (Elaeagnus pungens) and silk-tassle bush (Garry a elliptica). Wintergreen barberry (Berberis julianae) also has a thick cuticle as well as thorns that serve as added protection against browsing. Good examples of thorny elaeagnus are at the hippo viewpoints. The silk-tassle bush is south of the giraffe house, and the wintergreen barberry can be seen near the west patas monkey viewpoint. Another way to reduce water loss is by reflecting the strong equatorial sun. Plants do this by developing leaves with light coloration. In African forest margin areas you can find native olives (Olea spp.) that have dull gray- green leaves with an almost white underside. On the zoo’s savanna you will see good simu- lations of this with Russian olive (Elaeagnus angustifolia), which is near the lion overlook across from the Patas monkeys, and with autumn elaeagnus (E. umbellata) in the area behind the Jimi Hendrix Memorial. Prickly Situations Giraffes of the savanna eat hay from bags in a dead tree, which allows them to eat at the normal level without damaging existing trees. Opposite page: Springboks in the elms. Woodland Park Zoo. minimize being eaten; one way is to modify branches into thorns. This is very common in African savannas, and probably the best- known examples are the acacias. At least thir- teen species of acacia trees and several small bushy species are found in Serengeti National Park alone. Acacia thorns often stick out farther than their small leaves. On the zoo’s savanna the black locust (Robinia pseudoacacia ) substi- tutes for acacia. Even its scientific name gives a hint as to how similar the locust is to acacias. Both are large woody members of the Pea family (Leguminosae) and have thorns, a pod for fruit, and compound leaves, which reduce surface area and water loss through the leaves. During times of drought, most of the savanna’s water is stored in plants, so herbi- vores will be trying to get at all that water and nutritious food. Plants have developed ways to Fire for Plant Health The locust trees are scattered throughout the savanna, but the best and most interesting example dominates the lion exhibit and can be Vol. 58:3 7 Left: Black locust are used here to sim- ulate African acacias. Toxic trees such as these can only be used in an exhibit of carnivorous animals such as the lions. Sue Nicol. Above: Dried grass goes into the weaver bird’s nest. Woodland Park Zoo. Below: Another acacia simulator, Phellodendron amurense, frames the view across the hippo pond to the savanna. seen from many parts of the zoo. The large center sec- tion that has died gives it a very natural, authentic look and is purposely kept as it is. Notice the thick, corky bark on this tree. This rep- resents a way to withstand fires that periodically race through savannas. Inside the rail at the hippo view- points are more examples of fire resistance. These trees (Phellodendron amu- rense) have glossy com- pound leaves and a thick, corky bark. Periodic fire plays a very important role in the vitali- ty of many plant communities, and this is espe- cially true in grasslands such as the savanna. Fire keeps woody plants from encroaching into the open grasslands and releases vital nutrients back into the soil. It also rids the ground layer of old dried grass allowing light to penetrate to the new shoots. Plants Defend Themselves from Animals Several other examples of both compound leaves and thorns grow on the savanna. As you are standing at the Patas monkey viewpoint, notice the tree with the large compound leaves and very spiny trunk and branches. This is a Japanese angelica tree (Aralia elata), which is a good example of defense with spines, even on the leaf stalk. Other examples of thorny trees are the hawthorns. You will notice two dominant species as you walk around the savanna; they can be seen together on the path just south of the giraffe barn and are easily distinguished by their habit. The Carriere hawthorn (Cratae- gus x lavallei cCarrierei’) is more upright, usu- ally with a single trunk and large, leathery, dark green leaves. The cockspur thorn (Crataegus crus-galli) is a wide-spreading, multi-stemmed tree with glossy green leaves and vicious three-inch thorns. Shrubs also need protection from brows- ing, and a good representation of this is the 8 Washington Park Arboretum Bulletin r . a ■ Spanish broom Silk-tassle bush I, • .1 _ . . Variegated manna Cockspur thorn qrass Water canna Cockspur thorn Zebras graze on pasture grasses planted to simulate savanna grasslands. Russian olive is in the background. Woodland Park Zoo. Spanish broom (Genista hispanica). See it just west of the patas monkey viewpoint. This reduced leaf size also shows an adaptation to limit water loss. The leaves are so small that most of the photosynthesis is done through the green stems. Water! Water isn’t always in short supply on the African savanna. Rivers and lakes can be found scattered throughout, and there you will sometimes find hip- popotamus. The northeast corner of the savanna has seasonal wet areas and a permanent pool where hippo and African waterfowl are found. The large compound leaves and exotic look of staghorn sumac (Rhus typhina) along the east side of the savanna give a lush feel to this area. East of the hippo view- points are water-loving plants to enhance this feeling of a cool, wet spot in the often dry savanna. One water-loving plant is a clump of the tall bamboo-looking giant reed, Arundo donax. This grass can get up to eighteen feet tall, and in parts of the world where it is common, its stems are used for fence material and musical instruments. Another is water canna, Thalia dealbata , which can grow to ten feet and blooms with pale blue flowers in summer. Also look at the manna grass (Glycera maxima ‘Variegata’), a creeping perennial grass that has striking green- and cream-striped foliage. As you walk through the African Savanna exhibit, enjoy the amazing wildlife you see. They represent a significant ecosystem in a spectacular part of the world. But take the time to experience all this exhibit has to offer. The glare from the summer sun off the dry grasses might make you squint. Listen to the zebra calling and the lions roaring. Stop and feel the thick leaves of the thorny elaeagnus and the formidable thorns of the hawthorn. As you walk the paths, notice the smell of the red dust from the dry soil. When you look across the wide grassland at the herds, monkeys, birds, or lions, you are not just looking at wild savanna animals and plants that simulate their native flora — you are in Africa. David Selk is a horticulturist on the zoo staff. The African Savanna won the 1 991 Exhibit Award presented by the American Zoo and Aquarium Association. Plants of the Savanna Wintergreen barberry Black locust Russian olive Carriere hawthorn Japanese angelica tree African Savanna Giant reed Thorny elaeagnus Cork tree Staghorn sumac Autumn elaeagnus Vol. 58:3 9 Experience the Tropical Rain Forest by David Selk Tropical forests cover only six percent of the earth’s land surface yet hold two-thirds of all plant species. They have more diversity of species and more complex relationships than any other bioclimatic zone on earth. Upper left: Paphiopedilum barbatum, an endangered orchid. Lower left: Ring-tailed lemur eats haws from a hawthorn. Karen Anderson. Upper Right: Poison dart frogs deposit their eggs in water stored in bromeliad rosettes. Woodland Park Zoo. Lower right: Neoregelia, a bromeliad, holds water and is a life-support system for birds, reptiles, amphibians, insects, and mammals. Karen Anderson. 10 Washington Park Arboretum Bulletin Upper left: Epiphytes grow on the branches of an artificial tree in the rainforest canopy. Karen Anderson. Upper right: The Canopy exhibit is a free-flight aviary. Thunbergia grandiflora grows near staghorn fern. Carol Beach. Middle left: Children enjoy open- ing day of the Tropical Rain Forest. Asian ferns are planted on the wall behind them. Carol Beach. Lower right: Wrinkled horn- bills are cavity nesters. Here a female exam- ines the cavity of an artificial tree. Ian Dewar. Bottom: Live plants and animals intermingle with an artificial stilt-root palm and an artifi- cial tree of the forest floor. Karen Anderson. Vol. 58:3 11 mw Dark areas indicate the world’s tropical rainforest zones. All of the significant rain forests have equa- torial climates, which is the key to their diver- sity. They sustain relatively constant tempera- tures and high rainfall throughout the year, due to ocean currents and prevailing winds. Being on the equator, they are not subject to devastating climatic shifts, such as glaciation, and in some regions have evolved unimpeded for more than seventy million years. The earth’s three major tropical rain forests are spread over three continents: Africa, Asia, and South/Central America. In Africa, a large rain forest is centered on the Zaire River basin and continues west through Cameroon to Liberia. In southeast Asia, rain forests extend from the northeast coast of Australia through Indonesia, Malaysia and the Philippines, and into Thailand. The largest rainforest region is known as the neotropics: the Amazon Basin of South America, reaching north through Cen- tral America to eastern Mexico and parts of the West Indies. Enter the Tropics t’s hot in here!” You will hear this often as children enter the vestibule of the Tropical Rain Forest exhibit at Woodland Park Zoo. Yes, it is hot... and humid... and there’s water dripping all over. It feels, well, tropical. The Entry Vestibule The entry vestibule has no animals in it, but here you can acclimate to the warmth and humidity of the exhibit. More importantly, the vestibule introduces the rich diversity of trop- ical plants and the prominent role they play in our everyday lives. Many tropical plants are used by native peoples for medicinal purposes; important medicines used by Western society also have their origins in tropical species. The potential is enormous for further uses of these plants, from food to pharmaceuticals, but each day the likelihood diminishes as tropical rain forests are destroyed and rich ethnobotanical knowledge about their uses are lost. Immediately to your left is a shiny-leafed 12 Washington Park Arboretum Bulletin coffee tree (Coffea arabica). To your right, leaning over the pond, is a small tree with large, leathery, simple twelve-inch leaves. This is cacao ( Theobroma cacao ) whose fermented and roasted seeds are the source of chocolate. Below the cacao is a vine with small heart- shaped leaves growing on the large trunk of a fallen tree — pepper (Piper nigrum), which yields black pepper from the unripe fruit. Behind and to the left of the pepper are the large leaves of the banana (Musa spp.), which originated in the Old World tropics. Other plants in the vestibule important to humans are papaya (Papaya carica), vanilla (Vanilla planifolia, the fruit of an orchid), and tapioca (Manihot esculenta ) . Overhead, notice branches that have plants growing on them, known as epiphytes. Though epiphytes grow on other plants, they do not take nourishment from them. Most of the epi- phytes in this area are of two families. The ones with stiff leaves coming from a center rosette are bromeliads. The others with shinier leaves are orchids. In the tropics, many other plants have taken to the trees, including numerous ferns, pitcher plants, and rhododendrons. The Exhibit Next, go through the doors to the main exhibit. Tropical rain forests support organ- isms growing in many microhabitats. This results in complex, floristic diversity and a dis- tinct layering of the forest. The different for- est layers blend into each other but are often conveniently referred to as forest floor, under- story, and canopy. The Tropical Rain Forest exhibit is exactly this way. Start on the Forest Floor Enter the main exhibit on the forest floor. Very little light penetrates to the forest floor, so plant life is sporadic. What you will see are scattered woody and herbaceous plants as well as trunks of trees extending far up into the canopy. Immediately to your left is an artificial strangler fig (Ficus sp.), which houses the leaf- cutter ant exhibit. Strangler figs often start as epiphytes and then extend their roots to the ground as they grow. They eventually encircle the host tree, choking it off to light and new growth — hence the name “strangler.” Live strangler figs of the species Ficus aurea can be found in the entry vestibule where they are still well-behaved. Strangler figs are common- ly found in rain forests, and their fruit is rel- ished by any number of animal species, such as the toucans, who then act as important “seed dispersers.” At this level, the first two exhibits are sepa- rated by an artificial tree representing Ceiba pentandra. It has many large flanges extend- ing from the trunks, known as buttress roots, which are vital to the tree’s ability to stand up. Because of the high level of biological activity, tropical soils never have the chance to build up in depth or nutrition. Buttresses allow the tree to extend its roots farther, thus having access to more food as well as support in the dense, shallow soil. Another way plants overcome the problem of low light is to attach to tall straight trunks and climb to light as vines do. Woody vines, known as lianas, are abundant in the tropics, and you will see them throughout this build- ing. In lowland rain forests, one in six species are climbers. Philodendron is a well-known example, and most of these exhibits have them taking advantage of tree trunks. Climbing the back wall of the Sunbittern exhibit is a vine with spotted, heart-shaped leaves, Piper crocatum. Behind you, hanging down from the window top of the Ocelot exhibit, are the aerial roots of the curtain vine, Cissus sicyoides. An important timber tree of neotropical forests grows in the center of the Ocelot exhibit. Mahogany (Swietenia mahagoni) is native to the West Indies. Recognize it by the pinnately compound leaves, arranged along a central axis like a feather. This species has largely been replaced as a source of timber by Swietenia macrophylla , which is much more widespread in lowland tropical America. Because of its timber value, mahogany has been completely harvested from large parts of its natural range. Further along on the left, find an exhibit situated between the plush-crested jays and the emerald tree boas. In the future this exhib- it will display many plant/insect coadapta- tions, but currently it is dedicated to orchids. Orchids comprise the largest plant family (Orchidaceae) on the planet, with at least 25,000 species. Most of them are epiphytes and have developed incredible adaptations. Vol. 58:3 13 Certain orchids go so far as to have flowers that mimic female insect species in order to trick the male to pollinate it. Others, such as some species of Dracula , mimic fungi that attract gnats, which then serve as pollinators. Many tropical orchids have evolved to attract very specific pollinators; for example, a single bee species. In turn, that species of bee depends on the specific orchid species to pro- vide food. These strategies have led to fantas- tic diversity, yet such adaptations also make them vulnerable when their habitat is dis- turbed. If either one is destroyed, the other also disappears. This is known as “linked extinction.” Move to the Understory At the boardwalk, you enter the understo- ry. At this level of the rain forest, the larger trees start branching out and more light pen- etrates. Here, branches and tree trunks are not only highways for animals but a great place for plants to grow as well. Also, you will see more epiphytes, such as many of the bromeliads. In the tropics, there is enough rain and humidity that if a plant has a thickened cuticle, as bromeliads do, it can do very well by attaching itself to a tree branch. The Bromeliad family, with more than two thousand species, has a long history of coevo- lution with animals in the tropics. For an example, look at the poison dart frog display. The frogs climb trees and deposit their eggs in the water stored in bromeliad rosettes; there the eggs hatch and tadpoles mature. But the frogs are not alone in their use of these plants. Entire mini-ecosystems exist here, supporting spiders, insects, mollusks, and even crabs. Since bromeliads hold water in their cups, they are seen as arboreal water holes visited by lizards, snakes, mice, and monkeys. Predators hide to prey on the creatures who stop to drink. Near the top of the boardwalk, the tan- ager display is a lush example of a bromeliad community that covers branches. Look into the rosettes and watch the tanagers come for a drink from time to time. Reach the Rainforest Canopy Next, go through the glass doors and enter the world of the rainforest canopy of South- east Asia. Here you are on a boardwalk at tree- top level. Many plants and animals spend their entire lives up here. The eleven bird species in this exhibit represent birds native to the rain forests of Southeast Asia. Included are fairy bluebird, lesser green broadbill, gold crested mynah, red-billed leiothrix, Victoria crowned pigeons, and others. Notice at this level that the trees have spread out to take advantage of high light lev- els, and many vines and epiphytes have found their way up here for the same reason. For example, take a look at the heart-shaped leaves of the large Hibiscus tiliaceus leaning over your head from the left. Often, leaves of trop- ical plants such as this one are leathery with a thick cuticle. Here in the rain forest there is so much water and humidity that thick cuticles help prevent bacteria and fungi from invading the plant tissue. This leaf is also a good exam- ple of how plants shed excess water. The leaf margin is smooth and not jagged, so droplets don’t accumulate on the edges. Instead, mois- ture goes directly to the exaggerated drip tip where water is easily shed. Look up on the planted walls, where you will see a never-ending variety of forms, colors, and textures. In places, you will notice sec- tions of cane-like stalks with long, pointed leaves, such as those growing in front of the windows to your left. These are members of the Ginger family (Zingiberaceae). Several genera of ginger have many commercial uses including spices, condiments, dyes, perfumes, and medicines. Included in this collection is the common cooking ginger (Zingiber offici- nale) from southeast Asia, cardamom (Elet- taria cardamomum) from India, and red gin- ger (Alpinia purpurata), native to the Pacific Islands and common to US flower shops. On the large tree arching over the center of the boardwalk are some very unusual examples of ferns. Ferns are part of a highly diverse group of plants in the tropics. One interesting genus of fern has wide, leathery fronds that often branch to look like the antlers of a deer. They are known as staghorn ferns (Platyeerium spp.), all of which are epiphytes. Staghorn ferns have two types of fronds, sterile ones that are roundish and serve to hold the plant to the tree, and fertile ones that usually branch and give these ferns their name. Look on the underside of the frond, and find dense, brown patches. These are the sporangia, the reproductive part of the 14 Washington Park Arboretum Bulletin Leaves of philodendron, which is native to the neotropics, camouflage an emerald tree boa in the Tropical Rain Forest’s understory. Woodland Park Zoo. fern. Around the planted wall are located many genera of ferns, such as Adiantum, Pel- laea, and Bleehnum, that have counterparts such as maidenhair fern and deer fern in the Northwest. Walk to the center of the boardwalk. Sever- al species represented here in the Asian canopy are on the endangered species list. Look straight up at the large tree branch extending over your head for an epiphyte with a stout stem enveloped by the base of closely spaced, opposite-laying leaves that are hanging down towards you. This is the endangered Vanda coerulea, a beautiful blue -flowering orchid from Burma and Thailand. Several species of tropical pitcher plant (Nepenthes spp.) are also endangered. To your left, one is climbing the trunk of the tree. Note its leathery leaves with elongated midrib curled into a tendril. Some of these tendrils will develop into water-holding pitchers that lure and entrap insects and occasionally small vertebrates, which the plants digest to supple- ment their nutrition. Many tropical pitcher plants live only on single islands in Southeast Asia, so they are very vulnerable to extinction. Tropical rain forests are extremely diverse and unendingly complex ecosystems. Because of this diversity, they are vitally important sources of foods, medicines, and other prod- ucts that we use every day. Even more so they are indispensable sources of biodiversity — bio- logical and cultural knowledge that needs to be retained. This exhibit gives you a taste of the richness tropical rain forests contribute to life on this planet. David Selk is a horticulturist on the zoo staff. The Tropical Rainforest received the 1993 Exhibit Award presented by the American Zoo and Aquarium Association. Vol. 58:3 15 Zoo Bamboo by James Clever The Woodland Park Zoo’s bamboo collection is probably one of the largest in the Pacific Northwest. Over 40 species, both temperate and tropical, are grown in the exhibits and sur- rounding areas. Everyone knows that giant pandas love the fresh-cut canes, with their branches full of tasty leaves. At the zoo, other bamboo-eaters include red pandas, gorillas, orangutans, sia- mangs, macaques, and elephants. In addition to a food source, bamboos play other important roles within the zoo’s ecosystem. They help create natural and simulated habitats by screening off one exhibit from another; define access paths, roads, and maintenance work areas; and provide ornamental growth around many buildings. Even though bamboo can be seen in many areas, the most impressive plantings can be viewed in three exhibits: the Elephant Forest, Trail of Vines, and the Tropical Rain Forest. Bamboos of the Tropical Rain Forest Jn the Tropical Rain Forest exhibit, you will see only one tropical bamboo growing in the main building but a variety growing along the outdoor pathways. All of these plantings help give the feeling of being in a very special place. Once you have walked through the en- trance of the building, follow the rainforest trail to the canopy. Near the exit, look for one of the most beautiful bamboo species, Bambusa vulgaris cVittata’. This Southeast Asian timber bamboo has bright yellow canes marked by broad to narrow green vertical stripes. Just outside the canopy’s west windows behind the Bambusa vulgaris ‘Vittata’ is a temperate bamboo, Phyllostachys viridis ‘Robert Young’, with bright yellow canes and green stripes; it gives the appearance of con- tinuing the landscape from the exterior to the interior. Exit the building. Stay to the left, and follow the path across the bridge. On the right, you will see golden bamboo (Phyllostachys aurca ), which is common to the Northwest and to the rest of the US. The gold-toned canes with sev- eral short internodes make excellent fishing pole handles. Continue down the path, and on the right, next to the south De- Brazza viewpoint, is a small planting of Pleio- blastus variegata (dwarf white stripe). This is the most desirable dwarf var- iegated bamboo and probably one of the most easily available of all bam- boos. The leaves tend to keep their green and white stripes throughout the year. Turn left with the path toward the Colobus exhibit to see the timber Bamboos of the Tropical Rain Forest Exhibit Gorillas iX Phyllostachys flexuosa Pseudosasa ★ japonica ★ Ph. nigra 'Megurochiku' — s _» BE, Tropical Rain Forest Ph. viridis 'Robert Young' if * . w Bambusa vulgaris Vittata Ph. nigra 'MMurochiku7 ★ Sinobambusa sp. i m Ph. aurea Pleioblastus variegata UIIIWWJU ■ m ■ • • | in r Fargesicnnunelae ^ if Fargesia nitida if 1 i | ★ Pl. chino vaginata vari|gata Ph. nigra ’Henon' 16 Washington Park Arboretum Bulletin bamboo, Phyllostachys nigra ‘Henon,’ and another variegated dwarf bamboo, Pleioblastus chino vaginata variegata. Further along the path find two different types of hardy clumping bamboos on either side: left is umbrella bam- boo (Pargesia muriclae) and right is blue fountain bamboo ( Pargesia nitida), which are the hardiest bamboos and good for planting in filtered shade. Umbrella bamboo grows above 10,000 feet in China where it is important food for the giant panda. Further down the path approaching the gorilla exhibit, large plantings of Phyllostachys nigra ‘Megurochiku’ form a tunnel. This hardy timber bamboo can grow fifty feet tall with culms three and one-half inches in diameter. Bamboos of the Elephant Forest A short distance before the entrance to the -ZClElephant Forest, on the right, is the grove of yellow groove (Phyllostachys aureosulcata) . This upright bamboo is hardy to -10 degrees F and can reach twenty- five to thirty feet with a maximum culm diameter of at least one and one-half inches. Young canes are dark green and have a distinct yellow stripe on alternative sides, extending from node to node. Occasion- ally, canes have a distinct zig-zag within the first couple of feet. This bamboo is native to tem- perate East Asia, as are all of the bamboos used at the zoo to simulate tropical exhibits. Above: The demonstration yard of the Elephant Forest. David Selk. Right: Phyllostachys vivax, a timber bamboo, and Phyllostachys nigra ‘Henon’ can be seen in the Elephant Forest. James Clever. The growth habit of the bamboo is unique. All new growth comes from an underground network called a rhizome, either running or clumping. Running bamboo can send out rhizomes the equivalent to its height from the main plant or its current existing space in one season. Clumping bamboo spreads slowly, one to two inches per year forming tight clumps. Most bamboos at the zoo have running rhi- zomes. The diameter of culms (stems known as canes) can reach up to four inches in the Pacific Northwest climate. Vol. 58:3 17 Just inside the southern entrance to the Elephant Forest exhibit on the left and right you will also see a low- growing variegated running bamboo, Pleioblastus varies at a. Con- tinue down the path on the right to another low-growing runner, Sasaella masamuneana albostriata , which is variegated with thick leaves and a cream-colored stripe. Behind it more Phyllostachys aureosulcata can be seen. On the small berm dividing the path, a clump of Phyllostachys aurca flavescens-inversa is located at the front forward area across from the Sasaella masamuneana albostriata. It is a golden bamboo with green-colored culms and a yellow groove, and can reach up to twenty- seven feet tall with a 1/4- inch diameter. On the opposite side of the berm in front of the viewpoint rail is a generous planting of Pleioblastus viridi-striatus. During the spring when all the new leaves unfurl, this bamboo, which only reaches two to three feet, presents a lush color of golden yellow with green stripes. Stay on the main path to the left. Many plantings of medake (Pleioblastus simonii) can be seen on either side all the way down to the bathing pool for the elephants. The grassy wild look helps to define the natural feel of the area. Medake, as it is called in Japan, reaches up to twenty feet high with 1- 1 /2 inch culms. Behind the elephant bathing pool on the berm above the viewing area is a very un-bamboo-looking bamboo, Shibataea kumasaea. It has short, broad leaves that give it a unique shrubby appearance. The slender canes bear a multitude of these leaves with just as many canes from the root stock. Shibataea kumasaea is native to Japan. Continue on the path as it gently slopes up, and on the right you will see a grove of Phyllostachys flexuosa. It grows to about twenty feet, creating a nice open feeling as the canes tend to come up a few inches apart. The cane sometimes has a slight ziz-zag and thus the name flexuosa. Pass the saddle shed on your right and the tack shed on your left. These are examples of domestic Thai architec- ture, using thatch for roofs and split bamboo for siding. Because bamboo species each grow canes of different diameters, matu- rity determines cane size. There are hundreds of different uses for bamboo canes in Asian cultures. Just past these two buildings are the beginnings of many scattered plantings of Semiarundinaria fastuosa viridis, which is planted almost exclusively throughout the Thai logging camp work area. Fastuosa grows up to thirty feet high, and its 1 /4-inch-diame- ter canes are multibranched. Foliage covers it top to bottom, making it a favorite for hedges and screens in the zoo, as well as home gar- dens. Continue down the path until you reach a T. On the left is Phyllostachys nigra cBory\ This unique cultivar of black bamboo pro- duces canes that can grow to fifty feet tall and three inches in diameter. Farger than the type (black bamboo), the young green canes devel- op scattered spots of brown to light black in a couple of years. Bamboos of the Elephant Forest PI. argenteostriatus Ph. nigra 'Megurochiku' Ph. nigra 'Henon' ^ c Indocalamus tessellata Sasa veitchii Ph. vivax Ph. nigra 'Bory' * Ph. bambusoides Ph. viridis Sasa palmata Semiarundinaria fastuosa viridis Elephant Forest Ph. flexuosa ♦IH Shibataea kumasaea Ph. bisetii PI. simonii Pleioblastus variegatus Sasaella masamuneana albostriata Ph. aurea flavescens-inversa PI. viridi-striatus Phyllostachys aureosulcata All maps in this issue courtesy of Woodland Park Zoo. 18 Washington Park Arboretum Bulletin Join us in supporting the Washington Park Arboretum , a living museum, a garden of discovery and an outdoor classroom. Bambusa vulgaris Vittata’ in the Tropical Rain Forest canopy. James Clever. On the right of this junction is tropical- looking Sasa palmata; it will reach about sev- en feet in height. The Jungle path, which is small and non-wheel chair accessible, parallels the main path heading to the right through it. On your left find a grove of Phyllostachys vivax, probably the largest bamboo species that grows in the Northwest, both in diameter (four inches) and height (fifty feet plus). Just as you exit this short path, on your right is a small planting of Phyllostachys viridis, which can get up to forty-seven feet tall. The shoots are eaten by humans, primates, elephants, and many other animal species, and culms produce good quality wood. Again on the main path, a large, long grove of Phyllostachys nijyra ‘Henon’ extends from the main zoo loop to the viewpoint for the Tapir exhibit. This timber bamboo is native to southern China, reaching up to fifty feet high and 3/2 inches thick. Once at the Tapir exhibit, you can see two different bamboos. On your left, growing against the building, is a bamboo similar to cHenon’, called Phyllostachys nijjra cMegu- rochiku.’ The difference is that ‘Megurochiku’ grooves turn black after the culm is a year or two old. On the right side of the Tapir glass view- point, a planting of Phyllostachys bambusoides , commonly called Japanese timber bamboo, is bravely trying to make a go of it at the zoo. It is one of the two most used bamboos in the East for its strong, large, long canes and edible shoots. In Japan, it reaches seventy feet tall and six inches in diameter; in the Northwest climate, expect about half of these dimensions if your microclimate is favorable. Continue on the main path. Go right and follow it down the incline towards the ele- phant house, to see a five-foot-high planting of Sasa veitchii. This bamboo, distinctive for large green leaves with parchment-like fringe, is most notably used in Japanese gardens. On the planting berm on the elephant house side see the bamboo with the largest-sized leaves (up to two feet long), Indocalamus tessellata. Bamboos of the Trail of Vines oop around the planting space as you leave the elephant house, and go back up the hill on your right to the newest exhibit, the Trail of Vines. Look for the very promi- nent planting of Phyllostachys dulcis (forty feet tall, 2/4-inch-diameter culms). This attractive plant is noted for arching canes and shoots that are particularly free of any acrid taste. Phyllostachys dulcis is planted on the right side of the viewpoint for the macaque. On the left side of this viewpoint is a young planting of Phyllostachys aurcosulcata ‘Spectabilis’, a very rare cousin to yellow groove, with all the same growth characteristics. This plant is vigorous, hardy, straight, sometimes has a few zig-zag- ging culms, and is upright twenty-five to thir- ty feet. The only difference that the ‘Spectabilis’ has is a yellow cane with a green vertical stripe on the internode. It is a very attractive plant. Continue down the path and straight ahead to the Siamang exhibit, which contains an island. On it are plantings of Phyllostachys aureosulcata cAlata’ and arrow bamboo (Pseu- dosasa japonica), distributed to create a quick- growing and hopefully durable jungle for the siamangs. Because bamboo has an effective habit of binding the soil and stopping erosion, this should prove helpful on the small island. Arrow bamboo canes are thick and very erect, commonly used for the shafts of arrows Vol. 58:3 19 Bamboos of the Trail of Vines Tropical Asia Ph. rubromarginata ^ PI. simonii ^ Ph. meyeri A ^Ph. nigra Ph, heterocycla ^p|. viridi-striatus Ph. purpurata pubescens /er...\ , I ^ Ph. aureosulcata Solidstem fiHly 'Alata' ★ I ^ ^ ^ Pseudosasa japonica ^ mm Kseuao sasa |aponica Ph. congesta L L » . „ 3 W Sasaella ramosa $ Ph. aureosulcata^ ± dl. j,!- *Pn. dulcis 'Spectabilis' because of their strength, straight form, and light-weight features. The masses of dark green large leaves that are up to a foot long and llA inches wide form the semi -erect branches at the upper nodes. The culm sheaths (parch- ment-colored husk-like protective covering) are often as long as the internodes and are quite persistent. It is very common in the US, good for hedges and wind breaks. Continue up the path. On the right behind and below the rocks, are plantings of the gold- en bamboo (Phyllostachys aurea). When full- grown, it will help mask the wire mesh enclo- sure; the lower few feet of the culms are solid. Straight ahead, in a raised planting bed, is Phyllostachys purpurata ‘Solidstem,’ which can reach eighteen feet and have solid %-inch diameter culms. In two separate raised planting island beds is the popular and common black bamboo (Phyllostachys nigra). The striking black canes reach thirty feet and are quite elegant in appearance. Cut canes are used in fine cabinet work. Both Phyllostachys purpurata, with a sol- id stem, and Phyllostachys nigra are used in this area to screen off the exterior of the exhibit and cut down the sunlight that could reflect off the windows. Opposite the indoor Orangutan exhibit is the Research Station. Note the walls covered by split bamboo poles. It shows that the cut canes can be useful and attractive as fencing or siding. Walk past this area and move onto the outdoor orangutan exhibit area on your left. There, many plantings of Pleioblastus simonii are scattered throughout the forest floor. The wild, rough quality helps emulate a tropical forest, and with luck it will thrive under the attention of orang- utan families. In the background on the tops of the parapets (cliffs), see plantings of Phyllostachys meyeri, which are dis- tributed here to create the effect of another level or plateau. The plant- ings help screen off the building’s many skylights. When the plants attain some height, they will visually make the cliffs look larger. Continue down the path at the end of the raised wooden walkway, and on the right you will see Phyllostachys rubromarginata. Its dark green canes have the internodes as long as six- teen or more inches and smooth nodes; they are a favorite of musical instrument and basket makers. In its native China, the shoots are prized for their taste. On the planting island just ahead is Pleioblastus viridi-striatus, which gets up to three feet tall. New leaves are golden with green stripes. As you exit, on your left is a young grove of moso (Phyllostachys heterocycla pubescens) . Moso is the largest of the hardy bamboos at seventy-five feet with seven-inch diameter culms. In the Northwest, however, the largest moso reaches thirty feet in height. James Clever is an amateur botanist and has been a member of the American Bamboo Society since 1986. He was president of The Pacific Northwest Chapter of the American Bamboo Society from 1990-1992. James owns Bamboo Gardener, a small business that specializes in hardy bamboo plants. 20 Washington Park Arboretum Bulletin On the Northern Trail by Michael Pope Jmagine yourself in the interior of Alaska, slowly walking through a dense, white spruce for- est, looking for trails of moose, bears, and wolves to follow. A movement through the trees has your heart pounding, and you immediately shout, “Bear!” Soon you sense another move- ment: Your stare is met by that of a wolf through the spruce trees, and you freeze in your tracks. Above: The grizzly yearling travels on the Northern Trail’s braided stream. In the background are mountain goats as well as white spruce and paper birch. L. K. Sammons. Vol. 58:3 21 Right: Forget-me-not, Alaska’s state flower. Above: The Taiga Interpretive Center building simulates a landslide. L.K. Sam- mons. Prickly rose (Upper Right) and yellow potentilla (Lower Right) are found throughout Alaska and in the Northern Trail exhibit. Karen Anderson. Bottom: White spruce frames the gray wolf. Karen Anderson. 22 Washington Park Arboretum Bulletin The Northern Trail exhibits the flora and fauna of the Alaskan boreal forests. The Russ- ian word for this region is taiga, meaning “land of little sticks.” These vast, dense forests of spruce or pine stretch around the world at high northern latitudes. The zoo chose to simulate the dense white spruce forest of the interior of Alaska, starting north of the Alaska range near the world-renowned Denali National Park and Preserve, traveling south over the Alaska range, and ending along the coastal areas of the Kenai peninsula south of Anchorage The horticultural goal in planting the Northern Trail was to use species native to the taiga forests of Alaska, though simulator plants were also used where natives could not be obtained. The zoo wanted to be as correct as possible in representing the seven distinct plant communities of south-central Alaska. The land of the midnight sun is an extremely harsh climate for plant growth. Limiting factors include a very short growing season (June 1 to August 15), extreme cold temperatures, a wide range of high and low annual temperatures, and low mean soil tem- peratures. However, during the growing sea- son, sixteen to twenty-two hours of daily sun- light enable astonishing growth spurts, especially of perennial wildflowers and fruiting shrubs. These forests explode in the short growing season of the north! Hiking the boreal forests of the north can bring great excitement. So can Woodland Park Zoo’s exhibit of Alaska’s natural habitats. Whet your appetite for the adventure of a life- time— the Northern Trail. Starting the Northern Trail White Spruce Forest Tou start the Northern Trail in a closed forest of white spruce (Pice a jylauca). Find clumps of paper birch (Betula papy- rifem) in areas opened where trees have fallen. In summer, look for prickly rose (Rosa acicu- laris) and shrubby yellow- flowered cinquefoil (Potentilla fruticosa), two Rose family mem- bers that add soft, long-lasting flowers to the forest. In spring and summer, a colorful forest floor is painted by mountain cranberries (Vac- cinium vitis-idaca minus) and low- bush blue- berries (Vaccinium ‘North Sky’), pink bunch- berry (Cornus canadensis ), white twinflower (Linnaea borealis), blue lupine (Lupinis albi- caulis), white foamflower (Tiarella trifoliata), and Alaska’s state flower, blue forget-me-not (Myosotis alpestris). The abundance of berry- producing flowers and shrubs provides food to many migratory bird species and resident small mammals during the very active warmer months in the Alaskan taiga. Fire Succession Round the bend to the first wolf viewpoint, and the white spruce forest opens to a grove of quaking aspen (Populus tremuloides) . These slender trees with light- green bark have leaves that flutter in the breeze, hence the term “quaking.” Quaking aspen is the tree that recolonizes spruce forests after wildfires. It is also the widest-ranging tree species in North America and thrives from Mexico to the Arc- tic. You can see evidence of wildfire if you stand at the wolf viewpoint. In addition to the aspen planted here, the roots of flreweed (Epilobmm anjyustifolium ) were collected and sown into the ridge before you. In summer, spike-like racemes of rose- colored flowers give way to slender capsules that burst open. Cottony seeds float on the wind to disperse over wide areas and colonize newly cleared land. The gray wolves move freely on and around this ridge. Soapberries (Shepherdia canadensis) are often found in these burned aspen stands as well as along stream courses in Alaska. They are a favorite food of bears and also used by native Athabaskan people in the Interior. From the wolf viewpoints, also see more berry bushes along the opposite hillside. Saskatoon serviceberry (Amelanchier alnifo- lia) is another species that contributes to an abundant summertime food supply in Alaska. Black Spruce Forest Move to the small mammal exhibits, and observe members of the unique black spruce (Picea mariana) forest community. Interest- ingly, if classified based on low annual rainfall, the interior north of the Alaska range could be considered a desert. But in many low-lying areas, especially those underlain by per- mafrost, there is enough standing water to call them true wetlands. Vol. 58:3 23 Black spruce forests support fascinating black spruce plant communities, which are represented here. Often slanted and always stunted, see the skinny black spruce which provide a deep green background for tamarack or eastern larch (Larix laricina). This is a deciduous conifer known for its splendor, because the needles cast yellow blazes across a dark green forest before dropping in the fall. Also notice the rich, thick carpet of moss and lichens that coats the forest floor. Bog birch (Betula glandulosa) and scat- tered clumps of Labrador tea (Ledum groen- landicum) grow in association with yet another berry-producing shrub, crowberry (Empetrum nigrum). The presence of these species are good indicators of the wetness of these black spruce forests, which are often associated with permafrost conditions. Flat, low-lying areas and north-facing slopes are almost always underlain by permafrost north of the Alaska range. Permafrost Bank The permafrost bank is located next to the Tundra Interpretive Center and in front of the snowy owl exhibit. The bank was also planted to represent the black spruce forest communi- ty. Mosses in this planting were collected from the Verlot area on the Darrington Ranger Dis- trict, Mt. Baker-Snoqualmie National Forest, with permission from the US Forest Service. Feathermoss (Hylocomium splendins ), sphag- num moss, and Pleurizium schereberi are all found both here in the Washington Cascade range and throughout Alaska. The taiga forest near Denali National Park and Preserve was one of the areas studied as the zoo attempted to recreate the natural habitat of the taiga for- est. Denali is a magnificent place to see an actual moss-rich black spruce community. Shrub Tundra Continue to the triangular bed just to your right of the entrance to the Tundra Interpre- tive Center building. Two dwarf Arctic birch (Betula nana) are planted here to represent part of the shrub tundra. Here, the zoo is dis- playing species common to a type of tundra community that is found in abundance in inte- rior Alaska — not the kind of tundra that is associated with the mountainous regions. Shrub tundra, unlike the low growth of dry alpine tundra, consists of waist- to head-high shrubs including a variety of willow (Salix) species and many dwarf Arctic birch (Betula nana) and bog birch (Betula glandulosa) . Bog birch and dwarf Arctic willow ( Salix purpurea ‘Nana’) are planted all across the face of this building to represent shrub tundra. Dwarf- Willow Shrub Tundra Turn north to view the habitat of the brown bears, and observe species representa- tive of a dwarf- willow shrub tundra communi- ty, which is another type of tundra found in the North. Salix yezo-alpina and S. lindleyana , al- though not native to interior Alaska, are two willow species that demonstrate the prostrate growth habit that is characteristic of at least eight species of willow native to Alaska. With thirty-eight species, the Willow family com- prises almost one-third of all woody species in Alaska. Adding the Heath family (thirty species) and the Rose family (twenty-one species), these three families comprise about two-thirds of all woody species in Alaska. Of the twelve willow species in this exhibit, half are native to the Interior. The others were chosen for similar appearance and growth habit. The terrain at this brown bear viewpoint also contain plants commonly eaten by the interior grizzly bear, which is one type of brown bear in Alaska. Another brown bear, the world-famous Kodiak bear, lives on the coast where an abundant salmon diet allows much larger growth than the mainly vegetari- an interior grizzly. From late spring to early summer, interior grizzly bears eat fermented berries left on the shrubs from the previous fall and fresh grass shoots like the clumps of polargrass (Areta- grostis latifolia) planted at this viewpoint. In mid-summer, the bears shift their diet to include some of the starchy roots of the legume, Hedysarum , which grows in abun- dance along gravelly river and stream bars. At the viewpoint, look for Hedysarum alpinum with its gray-green, pinnately compound leaves. The bears’ preference for this legume and others, such as blackish oxytrope (Oxytro- pis campestris ), gives hikers in the North some bear warning signs to look out for. As the bears dig these legumes for their roots, they 24 Washington Park Arboretum Bulletin leave the tundra and river bars with gouges and tears noticeable from some distance. In the fall, the bears’ attention turns to fresh berries. Soapberries (Shepherdia cana- densis) seem to be the most preferred, so much so that, when the soapberries ripen in Denali National Park, certain stretches of the popular Toklat River are closed to hiking as a precaution to encounters with hungry berry- eating bears. Also at this viewpoint see other ripe patches of low-bush blueberries that sig- nal to hikers that bear are nearby. They are represented in this collection by Vaccinium ‘North Sky’ and ‘Top Hat’ and mountain cranberries (V. vitis-idaea minus). These bear favorites allow the zoo to interpret for visitors changes in the mostly vegetarian diet of the interior grizzly, during the relatively short, snow-free season in the north. It also allows you to see some of the differences between the two types of brown bears native to Alaska. At the second bear viewpoint, catch sight of the braided stream, a replica of the many braided streams and rivers found in interior Alaska. These streams are animal highways of the North. Not only is travel much easier than in a dense white spruce forest or in five-foot- high shrub-like tundra, but important food plants grow in abundance along these gravel stream bars. These include willows for moose and soapberries, blueberries, and legumes for bears. Notice how the bears move with ease and great curiosity as they travel up and down this stream. Paper Birch/White Spruce/ Poplar Forest Continue toward the Taiga Interpretive Center but facing away from it, and you will notice an increasing number of paper birch ( Betula papyrifera). Large tracts of paper birch dominate the landscape on the south side of the Alaska range and into the paper birch/white spruce/poplar forests of the Up- per Susitna valley. White spruce grows in patches, and large poplars or cottonwoods crowd the river and stream banks. Mountain alder (Alnus crispa) and tall willows grow in thickets in forest openings and colonize land- slides. Enter the Taiga building, “buried” under a simulated landslide. Here you can experience fabulous views of the brown bears and the underwater aerobics of the playful river otters. The otter habitat is planted with the willow Salix scouleriana , red-flowering dogwood ( Cornus sericea), and other species common to coastal areas on the Kenai peninsula. After leaving the Taiga building, notice the cliffs of the mountain goat exhibit. It is hard to tell, but they are actually carved out of con- crete that was designed and constructed to portray columnar basalt, a geologic phenomena that is found both in the Pacific North- west and in Alaska. And all the lichens were painted by artists. These cliffs give vis- itors a realistic view into the rugged mountain homes of the regal mountain goats. Vol. 58:3 25 Coastal Forest At the end of your journey down the Northern Trail, stop at the eagle viewing shel- ter. There lives the majestic symbol of the Alaskan wilderness and the national bird, the bald eagle. The mature bald eagle has the well- known white head and tail feathers, which they develop in their fourth or fifth year of life, while the immature bald eagle is mostly brown with a mottled white chest and belly. This exhibit, like the river otter habitat, was planted with species common to the coastal areas of Alaska. Notice the slender, almost scraggly, Alaska yellow cedar (Chamaecyparis nootkatensis), which exhibits an unusual growth habit to deal with the heavy snow of coastal Alaska. The foliage of these trees hangs perpendicular to the ground. This adaptation, combined with springy branches that bend down until the snow sloughs or melts off, allows this species to withstand the heavy wet snows of coastal Alaska. In the spring, look for shooting stars ( Dodecatheon pulchellum) and wild iris (Iris tenax) along the stream. These wildflowers, along with ferns, sedges, and an abundance of willows and red-flowering dog- wood, were planted to recreate the lush coastal forest of south-central Alaska. Come again with friends and enjoy the Northern Trail. It is one of the finest exhibits in the world and gives you a glimpse into the taiga forests of Alaska. Michael Pope helped design, plant, and maintain the Northern Trail exhibit, first as a consultant and then as a member of the horticulture staff. The Northern Trail exhibit won the 1995 Exhibit Award presented by the American Zoo and Aquarium Association. Plant Communities of the Northern Trail Coastal forest nr Coastal forest Dwarf willow shrub tundra Shrub tundra t Paper birch/White spruce/Poplar forest Permafrost bank Black spruce forest Fire succession Closed white spruce forest WKBBm fff Northern en- closed white spruce forest mi* 11m, 26 Washington Park Arboretum Bulletin Tropical Temperance for the Pacific Northwest by Daniel J. Hinkley Hydrangea anomala x petiolaris, as seen in Washington Park Arboretum. Joy Spurr. Jn the heart of Puget Sound, dominant masts of needled evergreens provide a familiar, though somewhat monotonous, signature to the landscape. Beneath them, gardeners frequently cultivate a rather lim- ited array of ornamental understory shrubs. This assemblage of commonly used landscape exotics and natives reflects that which is home and familiar. Though I am generally content with the landscape style that fits the region, some landscape situations validly call for exotic plant materials whose effect can transport the human participant to another time or place. The best justification for this approach is at Woodland Park Zoo. Throughout the exhibits, design- ers ingeniously use a wide palette of hardy ornamentals to produce vignettes that simulate raw nature. The permanent residents react to the simulation of their original haunts with a corresponding naturalness in behavior that further enhances the visitors’ experi- ence. Plant shapes, leaf sizes, and landscape composi- tions unfamiliar to the eye are the most effective in evoking the emotions of separation from the Northwest environment. Within a short distance, visitors can suc- cessfully transition from Asia to Africa and South Amer- ica. Using this acute understanding of form, shape, and ecology, you too can successfully fabricate the essence of the tropics. Tropical Forest Simulators Though it is virtually impossible to reconstruct a liv- ing tropical forest in the Pacific Northwest, horticultur- al trompe l’oeuil is accomplished by paying attention to those common threads that link all equatorial wood- lands— vines and lianas, large-leaved plants, and a diver- sity of flora. Tropical forests can be simulated by recog- nizing the vertical delineation that exists in nature — with life forms becoming more and more abundant as one rises higher into the trees. Colorful, Tenacious Vines The easiest way to impart a tropical effect is by use of vines and lianas, dozens of which are suitable for the Pacific Northwest. Feigning Foreign Flora Vol. 58:3 27 Akebia quinata is found in the Trail of Vines and in the Tropical Rain Forest exhibit near the gorillas. Joy Spurr Wisteria floribunda and W. sinensis are two vines that will quickly rise into the crown of a sizable native or non-native tree. Deciduous pinnate foliage unfolds just as the long pen- dent racemes of fragrant purple flowers are produced. The flowers of W. sinensis open col- lectively on the vine, providing a shorter-lived but bolder floral effect than W. floribunda , whose flowers open consecutively over a longer period of time. Select host trees that are strong enough to accommodate these vines: physically, to support the added weight, and in vigor, to withstand the added stress of reduced light for photosynthesis. Grape species are invaluable for coaxing up trees to provide extremely bold foliage with spectacular color in autumn. Best for this effect is the well-known Vitis coignetiae. With leaves expanding up to fifteen inches across and rich autumn tints, they add an aerial chain of color not unlike a flock of macaws in the distance. The fruit is generally considered inedible, being small and acrid. Vitis davidii , from China, is the only grape species with thorny stems, providing a distinc- tive addition to the list of Northwest tropical simulators. The large, glossy green leaves are arranged along stems studded with succulent reddish spines; when back-lit by late evening sun, these spines provide a dazzling effect. It has proven to be somewhat tender above ground, however the vigor it possesses readily replaces wood lost during the winter. Unable to climb a limbless tree trunk, both grapes mentioned must be provided means of sup- port to get them to the first limbs. In our gar- den, we suspended a rope in the Douglas-firs, which the grapes have now climbed. They are nearing the first branches from which they will be able to explore unaided the canopy of the Northwestern forest. Hydrangea petiolaris var. anomala and Schizophragma hydrangeoides are two vines that also perform remarkably well at adding tropical flair to the Northwest. With vigorous- ly upright stems hugging the main trunk of the tree, they will not swamp the outer canopy of their host, yet provide a summer showing of white flower clusters surrounded by white bracts. Akebia quinata, on the other hand, does not share the polite demeanor of the afore- mentioned vines. The five-leaved akebia, with tiny clusters of black-purple stars in early spring, clambers through, over, and under any support, living or otherwise, that is provided. Aptly coined the “kudzu of the north,” it con- vincingly portrays the vigor of tropical vines. Any thought of marriage between vine and tree provokes an often-asked question of suit- ability and danger to the supporting plant. Although in the tropics, vines truly can con- quer and kill, this process is unlikely to happen in the Pacific Northwest as long as the host is vigorous and large enough to house the intruder. This is not to say it is appropriate in all instances; case-by-case pairings should be well thought out. Large Leaves Through film, fiction, and fact, inhabitants of the northern climes have come to associate immense leaves with the exotic. Adapting to the rigors of a fast-growing canopy and instan- taneous shade, tropical plants produce large leaves to maximize the capture of electrons that pierce the upper for the creator of a tropical exhibit or garden, tender tropi- cal flora do not hold a monopoly on folial massiveness. Many hardy species exist in the Puget Sound area that perform remarkably well in this regard. Gunnera mani- cata and G. chilensis (syn. G. tinctoria) produce Jurasically large clumps of sur- realistic-sized leaves canopy. Conveniently Find gunnera at the entrance to the Elephant Forest. David Selk. 28 Washington Park Arboretum Bulletin as well as three-foot cone-shaped inflores- cences. These South American species perform exceptionally well for Northwest gardeners when ample moisture and protection from severe winter cold is provided. Simply cut the leaves at season’s end and pile them over the crowns for sufficient protection. Though cer- tainly adapted to full sun conditions, their massive rosettes are somewhat more appropri- ately sited in partial shade as an understory herb. Gunner a manicata possesses the larger leaves of the two, with long, nodding branch- es extending from its massive upright inflores- cence. G. chilensis is relatively more compact and has a narrower flowering spike. Better for smaller settings are the orna- mental rhubarbs found in the genus Rheum , with several species being superb in foliage and flower. Rheum palmatumw^x:. tanpfuticum sends forth wrinkled reddish leaves in early spring that expand to boldly cut leaves with a reddish cast even when fully mature. The white flowers are produced on substantive six- foot panicles in mid-spring. Even more strik- ing in foliage and flower is R. palmatum var. atrosanpfuineum with dark-toned leaves and red flowers that theatrically unfurl from rising globular buds of unparalleled anticipation. Nurture the rhubarbs with adequate mois- ture and well-amended soils, and they will eas- ily hold their own against a modestly sized Gunnem. The foliage of rhubarbs tends to be short-lived after flowering occurs, however. Rejuvenate the plants by cutting everything to the ground, then enjoy the fresh regrowth of foliage for the remaining months of summer. Another herbaceous perennial that is well known among Northwest gardeners is Cmmbe cor difolia. Unlike the succulent, kale- like foliage of its cousin, C. maritima, this species produces quite large rounded leaves and a six-foot-high flowering stalk cloaked in fragrant, white, four-petaled flowers during June and July. Best in conditions of full sun, C. cordifolia provides remarkable contrast in the form and size of leaves and flowering stalk whether growing in the mixed border or fully herbaceous garden. Canna delivers a tropical punch to any landscape in the Northwest. Oddly, however, it is used more on the US eastern seaboard where it dominates herbaceous borders from New England to Florida. In the Pacific North- west, the banana-like leaves reach six feet or taller, and showy blossoms of orange, red, or yellow are produced above the foliage in late summer or early autumn. However, if banana foliage is the effect you hope to achieve, then why not the real McCoy? Musa basjoo is con- sidered one of the hardiest species of banana that exists; with limited protection, it flourish- es and flowers outdoors throughout the Pacific Northwest, ultimately spreading to become a multi-stemmed clump that rises to eight feet by summer’s end. Mulch heavily as good insurance against damage to the root system during extremely cold winters. A Multiplicity of Flora The immense number of different species inhabiting an equatorial forest is yet another hallmark of the tropics that can be exploited in its re-creation. Traveling northward or south- ward from the equator, species diversity is replaced by species density. At the extreme opposites are both poles, which support vast numbers of very few species. In the Puget Sound area, we have less diversity of native flora. However, a virtual mishmash of leaf types, colors, and textures can excite our visu- al nerves. The doctrines of good landscape design espouse the use of repetitive themes of identi- cal plants. When simulating the tropics, how- ever, this would deflate the overall effect. While there are certainly large numbers of the same plant used in many of the plantings at Woodland Park Zoo, a deliberate attempt is made to reduce the appearance of order or pattern. Having used Woodland Park Zoo for sev- eral years as a teaching site for plant identifica- tion classes, I have come to fully appreciate the accomplishments of the horticultural and design staff in brilliantly evoking and main- taining different floral regions of the world. With each visit, I leave with the experience of again having drunk from the cup of travel while sensing the profound impact that plants can play on the human emotions. Daniel Hinkley is the co-owner of Heronswood Nursery, Ltd., and the author of Winter Ornamen- tals. He lectures and teaches throughout the United States. Vol. 58:3 29 Backyard to Your Backyard: Creating Wildlife Havens by Cathy Miller photos by Karen Anderson A canopy of green is ahead as you approach Woodland Park Zoo’s South Entry Gate. Huge -ZXoaks and tall European beech — the beech of Robin Hood’s Sherwood Forest — form a spreading canopy over zoo plantings. On your left as you approach the entry booth are large boulders that appear to have been deposited by the last glacier. Among the boulders you recognize a tree with the peeling bark of paper birch. Quaking aspen also grows above a shrub layer of native rose, hardhack, salmonber- ry, and thimbleberry. You also may notice the songs of native birds, who nest and feed in trees, shrubs, and ground covers throughout the zoo. The zoo is a haven for native wildlife that is not in cages. It has what they need — food, water, and layers of plant cover. To see more native flora and fauna visit “Our Backyard.” i At /i if iiWrTr Vi r * 30 Washington Park Arboretum Bulletin Penstemon (left) and santolina. Karen Anderson. Welcome to Our Backyard ollow the paved path toward the old water tower at the zoo’s far west bound- ary. On your left, as you leave the entry plaza, are serviceberry and Indian plum, both spring- blooming native plants that produce nectar and berries that are food for wildlife. There are also western red cedar, Douglas-fir, and west- ern hemlock. These familiar native trees, along with shrubs and ground cover, provide natur- al cover for wildlife. On your left, pass the monolith that marks the entry to the Temperate Forest exhibit and take a diversion by following the inviting grav- el path that disappears into a nook among the shrubs. There you will find benches facing a stream planted with sword fern, deer fern, rhododendrons, and red-flowering currant. Older, non-native trees provide structure as well as beauty along the stream. This is the Talking Bench nook where bench voices speak very quietly when you sit down. A part of Seattle’s project to put art in public places, the benches “speak” in poetic and narrative form with wildlife themes chosen by the artist. As you sit, listen for the soft “whirr” of hummingbirds at the red-flowering currant, a spring nectar source for them. Female hum- mingbirds use spider silk to bind together moss and lichen to make tiny nests on a tree branch. Chickadees also use moss for their nests. The moss on the rocks next to the stream may be just right for these small birds. You begin to realize that there is more wildlife at the zoo than elephants and lions! Leave the bench nook and continue west on the paved pathway. Follow the wavy brick wall past the old Family Farm entry on your left and the new Tropical Rain Forest on your right. Our Backyard is just ahead. You will recognize this garden when you see the trellis forming a canopy of clematis over the wrought-iron garden benches. An unobtrusive sign on your left confirms it. In Our Backyard there is no lawn; mowed lawn is a sterile monoculture having little benefit for wildlife. Instead of lawn there is ground cover as well as an herb and shrub layer. Water is available in a bird bath. Food is provided by many lands of berry- and nectar-producing plants. Canopy is supplied by established trees in neighboring areas, much as the trees in your neighbors’ yards might provide canopy for your yard. While the trees here are typical birch, maple, and sycamore, the neighbors who live in these yards are seriema, cranes, and red pandas. The bed south of the garden’s trellis takes sun, a good location for flowering plants that provide summer nectar for hummingbirds as well as butterflies and other insects. On the far Vol. 58:3 31 right are butterfly bush ( Buddleia davidii ), possibly the number one nectar plant for but- terflies, and a white-flowering variety of spirea. Ground cover is sword fern, wild strawberry, rock rose, columbine, snowberry, and penste- mon. Insects, which are pollinators as well as a source of protein for birds, are attracted to the summer blooms of penstemon, while snow- berry provides white fruit that birds and mam- mals eat in fall and winter. The plants in this bed have features that make them drought-tolerant. Many bloom early, and with their reproductive work done, are able to shut down in the typical Seattle summer drought. Senecio greyi, for example, is a low mound of silver-gray fuzzy leaves. The fuzziness is produced by tiny hairs that help slow down and direct the air that circulates over the leaves. This reduces moisture loss from the leaves, a good adaptation for times when moisture is scarce. Santolina is another low mound of silver- gray foliage, but more lacy than the senecio. Cornelian cherry, Cor- nus mas , blooms in early spring to attract insect pollinators, while red-hot poker (Kniphofia) in this bed blooms in summer, and its red flowers attract hummingbirds. Behind the Our Backyard sign, planted on an island between the garden walkway and the main paths, is highbush cranberry (Viburnum opulus). This tall plant produces red berries in the fall, but you might still see the berries in the spring, since they have a bitter taste and birds seem to eat them only as a last resort. However, the berries do provide emergency food for wildlife in a harsh winter. Growing under the highbush cranberry is Oregon grape, a good ground cover in shade. The dark blue berries are food for wildlife. Native Americans used Oregon grape to make dried berry cakes to last over the winter. Several oaks grow north of the highbush cranberry. Plants can lose moisture through their leaves. But the leathery leaves of ever- green oaks such as deer oak (Qiiercus sadler- ana) and huckleberry oak (Q. vacciniifolia) that grow here help retain moisture and re- duce moisture loss, making them drought tol- erant. The bark of oaks and other trees are home to a variety of insects. Watch for birds, such as nuthatches, creepers, and chickadees, that search for insects in the bark. Along the north border of the garden is pyracantha (firethorn), which you will recog- nize by bright orange summer berries that per- sist through the winter, as well as red huckle- berry, sword fern, and lingonberry. Huckleberry or blueberry is a good wildlife plant. Many varieties are available to garden- ers. Lingonberries are good ground cover and provide berries appreciated by humans as well as wildlife. Hardy Fuchsia majyellanica , straw- berry bush (Arbutus unedo), native dogwood (Cornus nuttallii ), and blueberry provide structure in the garden understory. Other low- growing ground covers are barren strawberry (Waldsteinia frajjarioides) and ajuga (Ajujja reptans), which has leaves tinted with purple and tiny blue summer flowers. In the back- ground are vine maple (Acer circinatum )3 a springtime source of seed, and Indian plum (Oemleria cerasiformis ), often called “the har- binger of spring” by hikers as well as garden- ers because of its beautiful white flower sprays that are an early pollen source for wildlife. Moss that you see is welcomed by animals who use it for nest and den lining. It is anoth- er ground cover that is thought to deter para- sites in bird nests. Zoo gardeners periodically remove ground litter, but this debris provides necessary shelter for insects. The insects are important food for ground-feeding birds such as rufous-sided towhees and northern flickers. Our Backyard is generally a quiet place at the zoo where you can enjoy the garden, rest, eat a peaceful lunch, and watch for visitors of the wildlife variety. Look up! You may see a bald eagle circling overhead. Not only Our Backyard but the entire zoo is a valuable wildlife habitat. The zoo has food, water, and cover planted in layers throughout the grounds. Just as the zoo provides wildlife habitat, any neighborhood can provide the features needed by wildlife. Start with your backyard. To obtain a packet on backyard wildlife planting, call or write the Washington De- partment of Fish and Wildlife, 16018 Mill Creek Blvd., Mill Creek, WA 98012: (206) 775-1311. The packet provides information on plants and garden designs as well as bird feeders and bird nesting boxes. Cathy Miller is a volunteer and former staff mem- ber at the zoo. 32 Washington Park Arboretum Bulletin Woodland Park Rose Garden A horticultural trip to Woodland Park wouldn’t be com- plete without a stroll through Woodland Park Rose Garden near the main entrance. In 1995, it was voted the outstanding rose garden in the US. The two and one-half acre formal garden lies in vivid contrast to the wild and natural plantings of the zoo. It opened to the public in 1924 and has been lovingly maintained by Robert Lasser for three decades. As one of 26 All American Rose Selection Test Gardens in the United States, almost 5000 roses can be seen at their peak during the first week of July. The Rose Garden is open daily until dusk and is free of charge. It is across the parking lot from the zoo’s South entry at 50th and Fremont Avenue North. Volunteer for Zoo Horticulture Plant lovers and dirt gardeners will find many opportunities to volunteer with WPZG’s internationally aeelaimed horticultural program. Docents Zoo docents are volunteers who present educational programs to the public on behalf of the zoo. Once a docent has completed a twelve - week training course, that person can choose a variety of activities to support the zoo. These women and men lead tours; take zoo programs to libraries, preschools, community centers, and nursing homes; participate in research pro- jects; and support zoo special events. Since 1966, docents at the zoo have been invaluable in communicating the message of wildlife conservation to thousands of children and adults each year. As a Woodland Park Zoo docent, you will have the opportunity to edu- cate and inform the public, not only about Woodland Park Zoo’s animals, plants, and world-class exhibits, but also about the vital role that Woodland Park Zoo and other zoos play in worldwide conservation of endangered species and habitats. Docents make a service commitment to the zoo for two years, thirty hours/year minimum. They often put in many more hours and stay many more years. If you enjoy public contact and have a back- ground in botany or horticulture, Woodland Park Zoo is interested in having you help form a small group of docents that specialize in plant- related programs and tours. To receive more information about the training class, con- tact the docent coordinator: (206) 684-4827. Gardener Aides Gardener aides are the volunteers with the tan work shirts and volunteer patches. They assist the zoo horticultural staff in planting and cultivating flowers, trees, and shrubs, as well as with landscape maintenance. You must be at least 16 years old, available on weekday morn- ings for a minimum of three months under all weather conditions, and able to perform stren- uous work. We also have a variety of other vol- unteer positions, including office aide/recep- tionist. Contact the volunteer coordinator for an information packet: (206) 684-4845. Vol. 58:3 33 Enjoy the Outstanding Trees Ton will find interesting tree specimens along zoo pathways as well as in exhibits. by Arthur Lee Jacobson photos by the author To discuss a zoo without mentioning animals is like talking about restaurants while ignoring the subject of food. But the zoo is so refreshing in plant life that even if all of its colorful, howling animals were to suddenly disappear, gardeners and tree -watchers would still enjoy a worthwhile visit. More than 5000 trees (200 species) grow throughout exhibits and open spaces as though the goal is to ensure that the place live up to its name, Woodland Park. More than two-thou- sand young trees have been planted in recent years, a model of ecologically aware installa- tion— high diversity, organic practices, and encouragement of exhibiting wildlife in more naturalistic exhibits. To those who recall the zoo as high and dry, open and sunny, and windswept with barren, sandy soil, this trans- formation into a lush, diverse forest is thrilling. Shirotae cherry is north of the Trail of Adaptations. Zoo trees, if viewed collectively, are a patchwork of different origins. Woodland Park once consisted of hundreds of acres packed with towering old-growth Douglas-firs. Guy Phinney, an Englishman who amassed a for- tune by running a sawmill on Lake Washing- ton, bought the tract and transformed it into an amazing estate. Phinney opened the 200- acre park to the public in 1889. His vision was vast, and he had the money to make his This deodar cedar is at the south entrance to the zoo near the Education Center. dreams come true. The nucleus of a zoo, rose garden, ballfields, and many other embellish- ments was created. After Guy Phinney died, Seattle bought the land just before the turn of the century, and soon enough the Seattle Department of Parks and Recreation was busy planting. Virtually none of the old-growth Woodland Park natives still exist, except maybe a bigleaf maple over one-hundred years old remaining near Aurora Avenue North. During the gradual, redevelopment of the zoo, an important component has been the special effort to preserve trees. Some zoo species are on the Washington State Big-Tree list, meaning that a designated specimen is either taller or stouter in trunk or spreads its branches wider than any other like specimen known in Washington State. Numerous other trees, though not of surpassing size, offer col- or, shade, sculpted silhouettes and — in one word — life. 34 Washington Park Arboretum Bulletin Tour of Zoo Trees M any zoo trees deserve to have their stories told. If I had to show an out-of-town tree lover just six of them, however, they would be the following: 1 . Deodar Cedar ( Cedrus deodar a ) Of landmark stature at the south entrance near the Education Center, is an especially ver- dant and limby Deodar cedar, which bears sharp one- to two-inch needles.The lemon- sized cones disintegrate at maturity, thereby reserving energy for foliage. Notice its gently drooping aspect, like that of hemlock, yet how massive it is. The name Deodar is from San- skrit, devadaru (deva, deity, and daru, timber), timber of the Gods. Though this Himalayan native is common and thrives in Seattle, the zoo specimen is spe- cial. Stout, low limbs invite children to climb. It is sited so as to be the center In some respects, black locust is high on the “world’s greatest hits” of treehood. Native to a small region in the central and eastern United States, it was widely cultivated begin- ning in 1635. Since then, black locust has nat- uralized in many places on earth, including the Pacific Northwest. A member of the Pea fam- ily, you will notice its long, dry pods in fall; this tree is able to thrive even in poor dry sites. Rapid growth and the ability to either reseed or spread by root suckers ensures that this species and its many cultivars will remain com- mon. English of attention. Being evergreen, grand in size, and long-lived, the zoo’s specimen is well suited to such an honored place. There is something about evergreens that arouses admiration. The dig- nity of age, as well as great breadth, only add to the favorable impression. We are fortunate that this tree is a Deodar, because many other species would be inferior in longevity, health, or safety. 2. Black Locust (Robinia pseudoacacia) The lions, in both a geographic and roman- tic sense, are at the heart of Woodland Park Zoo in the savanna — the zoo’s glory. It is fit- ting that the king of beasts should hold court in the midst of everyone else. Who can gaze upon the broad expanse of waving grasses without admiring the achievement here? Find the hippos in their pond and zebras on the plain, giving you a glimpse of another world: a bit of sunny Kenya in a Northern metropolis! The landmark black locust trees in the lion exhibit are fine substitutes for African acacias, being in the same family and similar in appear- ance. These dark and rugged- trunked, craggy - limbed trees deck themselves in delicate, rich green foliage. From May into early July they are loaded with small but numerous fragrant white flowers beloved by bees. 3. English Elm (Ulmus minor var. vulgaris; syn. U. procera) Fourteen English elms adorn the zoo grounds. They tower above and shade a spacious lawn south of the concert stage. Three envelop the Giraffe House, and five shade the west woodland playground at 59th and Phinney Avenue North. They are at their height of stately form, being at that ideal age where juvenility is far behind and senescence yet to come. These are superb trees to gaze up into. Elms have traditionally been valued more for their looks than for their timber or other properties. The Dutch elm disease more than chestnut blight brought home the urgency of planting diverse trees along streets and in land- scapes, not relying too much on one kind. Now that this fatal scourge of elms is in Puyallup and Tacoma, we fear it won’t be long before Seattle elms begin to be infected and die. The zoo specimens are reasonably well isolated, howev- er, so don’t hurry to write them off as doomed. They might live another one hundered years, although they will shed branches with increas- ing frequency, no matter what. 4. Bigleaf Magnolia (Magnolia macrophylla) West of the gorilla-viewing shelter are plantings that suggest humid tropical jungles. These simulators are broad-leaved evergreens Vol. 58:3 35 including Mahonia ‘Arthur Menzies’, wax- myrtle (Myrica ccilifornica ), and Portugal lau- rel (Primus lusitanica). But the ultimate trop- ical motif in this area is supplied by the deciduous bigleaf magnolia, the zoo’s largest; find smaller examples elsewhere (e.g., in the Pheasantry and Trail of Vines). The large leaves are magnificent, commonly two feet long, sometimes reaching more than three feet. From May into early July, it bears white flowers of celestial fragrance and immense size, eight to twenty inches wide. A native of the southeastern United States, this species grows in woodland there. It does very well in Seattle but becomes a bit sunburnt and wind- blasted if too exposed. 5. Empress Tree (Paulownia tomentosa) More than fifty empress trees have been planted at the zoo, and many exuberantly add six to eight feet of growth yearly. The only mature specimen is north of the Trail of Adap- tations (formerly the Feline House), flanked west by blue spruce, east by incense cedars. Native to China and Korea, this tree is stout; though smooth-barked, overall it suggests catalpa, with coarse heart-shaped leaves. The leaves are also reminis- cent of those of the sunflower: late to flush, huge, dull green, fuzzy, and dropping without fall color. Sometime from March into May, before the leaves emerge, it bears spectacular terminal clusters of trumpet-shaped pale violet- to sky-blue flowers, sweetly scented. Both the flower buds and seed capsules are conspicuous. Paulownia is a weed of sorts in parts of the eastern US, because it naturalizes conspicu- ously and copiously along interstates. In Seat- tle, however, it is restrained, though the pow- erful root system makes short work of paving. The wood is highly prized in Japan, where it is called Kiri. Paulownia was named for Anna Paulownia (1795-1865), daughter of Czar Paul I of Russia and hereditary princess of The Netherlands. 6. Chilean Fire Tree (Embothrium coccineum) Explosive floral display from trees is the more glorious if borne by a species that would be quite the ugly duckling except for its blos- soms. Chilean fire tree is usually a spare, leggy, and small tree of graceless, irregularly upright form, with semi-evergreen foliage. If it did not bloom, no one would want it, but because of the blooms, it is irresistible: Anytime from mid-April into mid- June this little tree pre- sents intense scarlet flowers. Being a hardy South American native, Chilean fire tree was planted with Antarctic beech (Nothofajyus antarctica) across from the prairie dogs. Younger and thriftier specimens are near the bench in the Pheasantry. In ideal sites, Chilean fire tree grows very fast, but it may be short-lived like pussy wil- low. It blooms when very young, and hum- mingbirds love the flowers. The tallest record- ed specimen was sixty- five feet tall and the stoutest trunk, six feet around. Most are fif- teen to fifty feet tall and slender. Other trees at Woodland Park Zoo are, in Sorbus their own way, equally worthy as the a u cup aria six just singled out. Several are champions for size, such as mountain ash (Sorbus aucu- paria), sweet birch (Betula lenta), black cherry (Prunus serotina), Shirotae or Mt. Fuji cherry (Prunus ‘Shirotae’), Sar- gent crab apple (Malus sarjyen- tii ), and chinquapin oak (Qiter- cus muhlenberpfii) — all are on the Washington State Big Tree List. A few tree specimens at the zoo are very rare in the Northwest region, such as Kalopunux, which is at the entrance to the Elephant Forest, and Maackia , in the Family Farm Habitat Discovery Loop. Several have been planted in combinations or quantities perhaps never seen before (e.g., find six hun- dred boreal spruces in the Northern Trail). At any given time of year, some species are show stoppers, with blossoms or bright fall color, or because of winter presence. Seattle is truly fortunate to have a first rate zoo that also serves as a horticultural mecca. The whole world of plants and animals is brought together in one place. Arthur Lee Jacobson is author of Trees of Seattle , Purple leaf Plums, Trees of Green Lake, and Land- scape Trees of North America. 36 Washington Park Arboretum Bulletin Conserving Plants and Animals by John A. Wott Often the consequences of human actions to nature are understood only after they are irreversible. That is why one of the main responsibilities of living museums, such as Woodland Park Zoological Gardens and The Washington Park Arboretum, is to help con- serve plants and animals. Many Species Are Threatened More than 30,000 species in the world are now threatened with extinction, according to the Global Biodiversity Assessment. A Decem- ber 1995 report by the Nature Conservancy found that one-third of the 20,000 native American species of plants and animals are list- ed as “rare or imperiled.” A high proportion of flowering plants and freshwater species head the list. “In many respects,” says the doc- ument, “this is not a report card on how they’re doing but how we’re doing.” The Woodland Park Zoo has 60 species (both plants and animals) on the endangered list of the International Union of Conserva- tion of Nature — 18 are endangered plants, including 12 species of orchids and six species of pitcher plants. Washington Park Arboretum has 120 distinct plant types on the list. While many of these plants are from other areas of the world, specimens of brisdecone pine and Monterey pine are West Coast endangered species. How Living Museums Can Help Museums were once for the rich or learned. For years, they merely collected objects, usual- ly at the whim of a single curator. It was easi- Center for Wildlife Conservation The CWC is a coalition of Northwest organi- zations dedicated to the preservation and enhancement of wildlife diversity, with an emphasis on native Northwest species of plants and animals, as well as habitats. For informa- tion: Center for Wildlife Conservation, 5500 Phinney Ave. N, Seattle, WA 98103. est to display similar things together. Unfortu- nately, this does not work for displaying plants or animals in living collections. It is not easy to modernize an older insti- tution. As living collections of plants and ani- mals age and die, they must be replaced in ways that reflect and protect their disappearing ecosystems. When living museums modernize, they must also become more accessible and useful to a large and diverse audience. Modern plant and animal exhibits must show how they are related to each other and to the habitats from which they originated. Conserving Together Seattle’s living museums have compatible conservation goals. Modern zoos frequently concentrate on conserving animal germ plasm, because male animals are difficult and expen- sive to maintain. Usually, participating zoos focus on specific animals. Public botanical gardens concentrate on conserving specific plant collections. They can no longer afford to plant every species that can grow in that climate. For example, several of Washington Park Arboretum’s collections — mountain ashes, pines, and hollies — are very large and expensive to maintain. In the future, both the zoo and the arboretum may also con- centrate more on conserving local species. The zoo as the keeper of wildlife and the arboretum as the keeper of the plants should start more conservation programs evolving around their collections. For example, native trees could be introduced back into Woodland Park Zoo or other city parks with help from the Arboretum in a program to preserve our native flora — a partnership of living museums. All living museums must emphasize con- servation through ecologically aware displays and an emphasis on maintaining diverse species. The future of both the natural and human-made world depends, in part, on living museums talcing the lead. John A. Wott is director of arboreta, Washington Park Arboretum. Vol. 58:3 37 ZooPlant Facts What is that plant with the purple berries ? This is our most frequently asked plant question. In die fall and winter, the normally inconspieuous beautyberry (Callicarpa spp.) erupts in tiny purple fruit. Beautyberry, a native to eastern Asia, can be found next to the Trail of Adaptations (formerly the Feline House) and in the Tropical Rain Forest exhibit. How old are the oldest trees in the zoo ? The City of Seattle purchased the zoo property in 1899 from the widow of Guy Phinney. Even then, many of the original native forest trees had already been removed from the property. None of today’s zoo trees Are plants grown and fed to the animals ? Two sources of zoo plants are fed to the animals. First, the zoo grows bamboo in what is called a “browse garden.” The browse gar- den is not on public display, but is used by keepers as a source of food for certain plant- eaters, such as elephants. The second living plant source is the many trees and shrubs that are pruned by zoo gardeners. Only the edible, non-toxic prunings are hauled to the animals to eat. How can exotic species grow here ? Plants from all over the world can grow outdoors in Seattle if they originate from habi- tats with similar rainfall, summer drought, sea- sonal changes in day length and temperature, and soil characteristics. Gardeners can grow more kinds of plants in Seattle’s maritime cli- mate (with mild winters and summers) than in many other parts of the United States. Where can I get favorite plants that I see at the zoo ? Most can be found in local nurseries. Look for a label to obtain the correct name, and then ask at your local nursery. What is that plant with the giant leaves ? m Though several plant species at the zoo have large leaves, probably the most eye-catching is the gunnera found at the ntrance to the Elephant Forest. Gunnera is native to Mexico and Central America, and it survives as a perennial in Seattle. The eaves can reach six feet across. Gunnera is grown in a swale at the zoo, because it seems to thrive in damp areas. How important are plants to wildlife ? Plants are as important to wildlife survival as wildlife is to plant survival. In other words, all of life is interconnected. Animals need plants for food, shelter, and nesting material. Many plants need animals to pollinate them, and they must have that animal or insect part- ner to survive. were alive at that time. However, muc ing was done during the first de of the twentieth century, when the zoo was a popular, city park. Probably the oldj est zoo trees are its beeches still found just north of south entry towering over a popular picnic area. This issue of the Washington Park Arboretum Bulletin was published as a partnership between Woodland Park Zoological Society and The Arboretum Foundation. The Arboretum Foundation Washington Park Arboretum University of Washington Seattle, Washington 98195 (206) 325-4510 A zoological garden is a living museum of animals and plants. An arboretum is a living museum of woody plants for education , conservation, research, and display. Nonprofit Org. U.S. Postage PAID Seattle, WA Permit No. 126 Beautyberry, Callicarpa japonica. Joy Spurn