Historic, Archive Document

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Forestry

Research

West

Forest Service

U.S. Department of Agriculture
March 1981

Forestry

Research

West

Forest Service
U.S. Department of
Agriculture

March 1981

In This Issue

Page

Understanding the habitat needs

of anadromous salmonids 1

Studies show strength of tree
roots 6

Giving the land back to nature 10

Leafy spurge — Scourge of the
West 13

New publications 16

Cover

Researchers at the Pacific North¬
west Station are studying the habitat
needs of anadromous salmonids
along the West Coast. This scientist
is recording water temperature near
a net that collects drifting insects.
Over the years, populations of these
fish have declined due to increased
harvest and destruction of habitat.
The Forest Service and several
other cooperators are hoping to turn
the tables. Read more about it on
the facing page.

To Order Publications

Single copies of publications referred
to in this magazine are available
without charge from the issuing
station unless another source is
indicated. When requesting a
publication, give author, title and
number.

Each station compiles periodic lists
of new publications. To get on the
mailing list write to the director at
each station.

Subscriptions

Subscriptions to this magazine will
be sent at no charge. Write To:

Forestry Research West
240 West Prospect Street
Fort Collins, Colorado 80526

To change address, notify the
magazine as early as possible. Send
mailing label from this magazine and
new address. Don’t forget to include
your Zip Code.

Permission to reprint articles is not
required, but credit should be given
to the Forest Service, U.S.D.A.

Mention of commercial products is
for information only. No endorsement
by the U.S.D.A. is implied.

A report for land managers on
recent developments in forestry
research at the four western
Experiment Stations of the Forest
Service, U.S. Department of
Agriculture

Western Forest
Experiment Stations

Pacific Northwest Forest and Range
Experiment Station (PNW)

809 N.E. 6th Ave.

Portland, Oregon 97232

Pacific Southwest Forest and Range
Experiment Station (PSW)

P.O. Box 245
Berkeley, California 94701

Intermountain Forest and Range
Experiment Station (INT)

507 25th Street
Ogden, Utah 84401

Rocky Mountain Forest and Range
Experiment Station (RM)

240 West Prospect Street
Fort Collins, Colorado 80526

Understanding
the habitat
needs of
anadromous
salmonids

by Dorothy Bergstrom,
Pacific Northwest
Station

A researcher collects terrestrial insects that
have dropped into a floating trap.

Along the West Coast of North
America, from California to Alaska,
the many rivers and streams that
empty into the Pacific Ocean are
habitat for a unique and valuable
resource — the famous sea-run
salmon and trout — or anadromous
salmonids.

This region produces eight species,
including five salmon — Chinook,
coho, chum, sockeye, and pink; two
trout — steelhead and cutthroat; and
one char — Dolly Varden. These
migratory species have evolved a
complex reproductive process that
requires two habitats — fresh water
streams and lakes and the Pacific
Ocean. Some fish travel hundreds or
even thousands of miles and spend
virtually their entire lives in instinc¬
tive migration from fresh water
tributary to salt water and back
again.

But over the years, fewer and fewer
fish have made the journey. In¬
creased harvest of fish and destruc¬
tion of habitat have reduced the
yield dramatically. Both the size of

catches and the size of fish have
become smaller. The weight of con¬
cern about habitat loss rests heavily
on managers of forests and range-
lands — since the freshwater rivers
and streams that flow through these
lands provide important habitat for
spawning and rearing. And because
streams ultimately reflect everything
that happens in watersheds, all
management activities have the
potential for affecting fish habitat.

Providing information that will help
resource managers predict the ef¬
fects of management activities on
the welfare of fish is the purpose of
a new series of publications collec¬
tively titled “Influence of Forest and
Rangeland Management on Anadro¬
mous Fish Habitat in Western North
America.’’ The report series is one
of the products of an interagency
program established in 1976. Three
Forest Service Experiment Stations
and five Forest Service Regions are
cooperating with several federal and
state agencies, universities, and
private industries in a program to
coordinate research concerning fish
habitat and report results to
managers.

Fisheries Biologist Bill Meehan of
the Pacific Northwest Station’s
Forestry Sciences Laboratory in
Juneau, Alaska, is coordinator of the
program. “While we have learned a
good deal about anadromous salmo-
nids,’’ he says, “the knowledge has
been scattered in scientific publica¬
tions and has not been readily
available to resource managers.

One of the goals of the program is
to pull together results of research
concerning habitat needs and the ef¬
fects on habitat of forest and
rangeland management.” Four
reports have now been published.
Ten more are planned.

Habitat needs

The first report lays the foundation
for the series. It defines the range of
conditions that allow the 8 major
species of anadromous salmonids to
thrive, thereby providing standards
against which the effects of
management activities on habitat
can be measured.

Western anadromous salmonids are
adapted to a variety of habitat con¬
ditions within their range. Most
species have distinctly different life
histories and habitat requirements.
Certain conditions, such as water
temperature, velocity, turbidity, and
the amount of dissolved oxygen in
the water are important at all life
stages. Other requirements are im¬
portant at certain life stages. For ex¬
ample, migrating adults making the
journey to their birth streams from
the sea need streams that are free
from barriers. After the adults arrive
in their home waters, they need
hiding cover during the weeks or
months while they look for satisfac¬
tory places to build their redds
(nests). While the eggs are in¬
cubating, conditions within the
stream bed gravels determine
whether fry will hatch successfully.
After the fry emerge from the gravel,
their greatest needs are for food,
cover, and space.

Water temperature

Salmonids are cold water fish and
prefer a rather narrow range of
temperatures. Tolerances and
preferences of the species vary
somewhat, but scientists working in
laboratories and artificial streams at
research facilities along the Pacific
Coast now have good information
about temperature requirements.

Salmonids have successfully
migrated upstream in temperatures
ranging from 3° to 20°C.
Temperatures above 20°C have
been found to stop migration, alter
the timing of migration, accelerate
or retard maturation, and lead to
outbreaks of disease. Spring
Chinook salmon tolerate the lowest
range. They migrate best in water
that is between 3.3°C and 13.3°C.
Summer Chinook salmon are at the
other end of the scale, doing well in
a range from 1 3.9° to 20°C.

Celsius

Temperature

Comparisons

Farenheit °

0

32

5

41

10

50

15

59

20

68

25

77

30

86

Anadromous salmonids spawn
successfully in water temperatures
ranging from 3.9° to 17.2°C. The
range is lowest for steelhead (3.9°
to 9.4°C) and highest for cutthroat
(6.1 ° to 1 7.2°C). A sudden drop
in temperature may cause all
spawning activity to cease.

The eggs of most species incubate
during the winter months. In the
past it was believed that 4.5°C was
the lower limit. Research has now
found that pink and Chinook salmon
eggs can tolerate long periods of
low temperature if spawning and in¬
itial embryo development occurred
at temperatures above 6.0°C. The
recommended range of incubation
temperatures for chum, coho, pink,
and sockeye salmon is 4.4° to
13.3°C; for fall, spring, and summer
Chinook salmon, 5.0° to 14.4°C.

The time young fish spend in their
home streams before migrating to
sea varies with species but is also
influenced by water temperature.
The growth rate, the ability to swim,
capture and use food, and withstand
disease are all affected by temper¬
ature. Temperatures above 25.8°
are lethal for Chinook, pink, sockeye,
chum, and coho salmon. Under cer¬
tain conditions steelhead trout can
tolerate temperatures up to about
24°C. In general, all cold water fish
stop growing at temperatures above
20.3°C.

Turbidity or sediment
content

Although migrating adults will persist
in swimming toward their home
streams through turbid water, they
will stop when silt loads get too
high. One study reported that salmo¬
nids would not move in streams
where sediment was more than
4,000 milligrams per liter. This is
water that looks like soup or a mud
puddle. (People usually stop fishing
when silt reaches 50 milligrams per
liter.) Turbid water also absorbs
more radiation than clear water, and
this may be an indirect cause of in¬
creased water temperatures that
may stop migration. During the
juvenile rearing period, high levels
of suspended solids may abrade and
clog gills, reduce feeding, and cause
fish to avoid areas.

In general, scientists have found
that streams with silt loads aver¬
aging less than 25 milligrams per
liter will support good freshwater
fisheries.

Dissolved oxygen

Although tne requirements for con¬
centrations of oxygen dissolved in
the water vary with species and
developmental stage, concentrations
at or near saturation are recom¬
mended for all salmonids, with tem¬
porary reductions no lower than 5.0
milligrams per liter. Dissolved
oxygen and water temperature are
closely linked; the higher the
temperature the less oxygen the
water will hold, and the higher the
temperature the more oxygen fish
need.

Fish populations are estimated by using
electric shocks to bring the fish temporarily
to the surface.

Low amounts of dissolved oxygen
may stop migration. In one study,
the swimming speed of both adults
and juveniles decreased sharply
when levels dropped to 6.5 milli¬
grams per liter.

Concentrations of dissolved oxygen
in intragravel water must average 8
milligrams per liter to insure high
survival of coho salmon and steel-
head embryos. Embryos receiving
less oxygen are likely to have longer
incubation periods, and the resulting
fry are apt to be smaller and weaker
than fry incubated with high oxygen
concentrations. A study using three
concentrations of dissolved oxygen
indicated that the juveniles tested
functioned well with 7.75 milligrams
per liter of oxygen. When oxygen
was reduced to 6.00 milligrams per
liter the fish developed initial symp¬
toms of distress.

Water depth

Requirements for water depth are
fairly well documented. For
upstream migration, adults require
minimum depths ranging from .12
meters for trout to .24 meters for
the larger salmon. Measurements
near active redds indicate minimum
depths from .06 to .30 meters are
selected for spawning.

Depth is particularly important dur¬
ing the juvenile rearing period
because it influences production of
aquatic organisms that are impor¬
tant food for salmonids. Most of
these organisms are found in
shallow areas typical of riffles. In
one study, several species were
found in water less than 0.3 meters
deep. If other conditions are
suitable, the areas that produce the
greatest number of invertebrates are
usually 0.1 5 to 0.9 meters deep.

Water velocity

Under certain conditions of channel
constriction during snow melt and
storm runoff, water may flow faster
than migrating adults can swim — ap¬
proximately 2 to 4 body lengths per
second. Water velocities of 3 to 4
meters per second may retard
upstream migration.

During spawning, preferred
velocities range from a low of 1 1 to
72 centimeters per second for cut¬
throat trout to a high of 32 to 1 09
centimeters per second for summer
Chinook. Many salmonids prefer to
spawn at the interchange between
pool and riffle, where a downwelling
current may help a fish maintain its
position with a minimum of effort.

During rearing, stream velocity plays
an important role in the distribution
of aquatic invertebrates that are
primary food for juveniles. Most in¬
vertebrates live in a thin layer of
water 1 /4 to 1 12 inch deep just
above the bottom of the stream.
Velocities there are near zero, but
these invertebrates depend on water
flowing immediately above the
lowest layer for oxygen and other
environmental needs. There,
velocities of 0.1 5 to 1 .22 meters per
second are needed.

Streambed

The streambed or substrate provides
the gravels which are essential for
spawning, incubation, and the pro¬
duction of food during juvenile rear¬
ing. When adult fish select sites for
redds, they are often selecting the
incubation environment. The size of
gravel chosen by different species
depends to a large extent on size of
the fish. Researchers have deter¬
mined the particle size preference
of different species by running
samples of gravel from active redds
through a series of sieves. When
offered a choice of gravel size in ar¬
tificial spawning channels, pink,
coho, and spring Chinook salmon
select gravel from 2 to 1 0 centi¬
meters in diameter. Sizes accept¬
able to all salmon species range
from 1 .3 to 1 0.2 centimeters. For
smaller trout the range begins at
.6 centimeters.

3

During incubation, permeability of
gravel is vital. This factor deter¬
mines subsurface water velocity,
which is the single most important
factor in delivering oxygen to the
eggs and removing metabolic waste
products. Researchers have con¬
cluded that fish production is
greater in gravels with high
permeability. Permeability is high
(velocities up to 24,000 centimeters
per hour) when sand and silt that
can pass through an 0.833
millimeter sieve make up less than 5
percent of the bottom material. It is
low (velocities less than 1 ,300 centi¬
meters per hour) when fine sedi¬
ment makes up more than 1 5 per¬
cent of the stream bottom.

Even though embryos may hatch
and develop in gravel with excessive
sand and silt, fry will not survive if
they cannot emerge from the gravel.
In one study fewer Chinook salmon
and steelhead fry emerged when
sediments smaller than 6.4 milli¬
meters made up 20 percent or more
of the substrate.

The size of streambed material is
also important. Areas with coarse
gravel and rocks up to about the
size of grapefruit provide a diversity
of cover for streambed invertebrates
that are food for fish. With larger
rocks there are fewer invertebrates.
The size of material on the stream
bottom is also related to velocity;
large rubble and boulders are asso¬
ciated with fast current, silt and
sand with slow moving water.

Protective cover

Protective cover is important for
adults waiting to spawn and
especially for juvenile fish.

Overhead cover and shade near
stream margins are provided by
riparian vegetation, turbulent water,
undercut banks, and shadows cast
by large debris and rocks in
streams. Submerged cover is pro¬
vided by aquatic vegetation, large
rocks, and partially submerged logs
and root wads incorporated in the
streambed.

Some anadromous species enter
freshwater streams months before
they spawn, and since spawning
areas are often on relatively open
parts of streams, the fish are vulner¬
able to disturbance and predation.
The availability of cover nearby may
be a factor in the selection of
spawning sites by some species.
Researchers have speculated that
the early spawners and large domi¬
nant fish may select areas by cover
and that as these areas are taken,
the late spawners and smaller fish
are forced to use unprotected sites.

Overhanging vegetation and partly
submerged togs provide cover for fish.

Juveniles are susceptible to preda¬
tion from other fish and terrestrial
animals and need places to hide.
Newly emerged salmonids and
some overwintering juveniles tend to
hide under stones or among rocks
and rubble on the stream bottom.
Studies have shown that removing
cover reduces juvenile populations
and adding cover increases them.

Food sources

While the stream bottom produces
the invertebrates that are the prin¬
cipal food for juvenile salmonids, the
surrounding land is also important.
Bits of vegetation that fall into
streams provide food for the aquatic
invertebrates. Terrestrial insects
also fall from or are blown off
shrubs, grass, and other vegetation
into the water to become part of the
drift that also provides food for fish.

4

Processes that shape
habitat

Natural events like storms, fire,
earth movements, and outbreaks of
insects and disease on vegetation
can make drastic changes in water¬
sheds and streams. Sometimes
these events improve habitat, as
when heavy rainfall swells streams
and flushes fine sediment from the
gravels. Whether the effect is
beneficial or detrimental depends
somewhat on timing. For example,
flushing and gravel redistribution
that occurs while eggs are incu¬
bating can bury an entire generation
or grind up eggs and newly hatched
fry. The effects on habitat of natural
events are the subject of the second
report in the compendium.

An understanding of ways natural
events modify habitat, combined
with knowledge of habitat re¬
quirements — the subjects of the first
two reports — together provide a
foundation for predicting the effects
of human activities on fish.

“We already know a good deal
about the effects of removing
streamside vegetation,’’ Meehan
says. “Streams exposed to sunlight
will have higher water temperatures
in summer, and lack of insulating
canopy may lower them in winter.

We have recently begun to quantify
the importance of large woody
debris in providing rearing habitat
for juveniles, including pools they
need for cover and the material that
provides food for aquatic organisms.
We have also learned that the very
small headwater streams that dry up
in summer provide spawning areas
for thousands of salmon and
steelhead in winter.”

Since management activities— un¬
like natural events — can be planned
to minimize adverse effects on
habitat, the other 12 reports in the
compendium will summarize present
knowledge about the effects of
specific management activities and
suggest guidelines for protecting
fish habitat.

Small streams and side channels provide
important rearing habitat for juvenile
salmonids.

The effects of forest roads on fish
habitat are discussed in the third
report of the series. The publication
includes suggestions for designing,
constructing, and maintaining road
systems with minimal adverse ef¬
fects on fish habitat. The primary
adverse effects are increased
sedimentation, changes in stream
velocity, and obstructions to fish
passage posed by bridges, culverts,
and other structures. For example, a
migrating adult is often near exhaus¬
tion after surmounting a difficult
obstacle. If there is no resting area
upstream the fish may be swept
downstream and have to spend
energy overcoming the obstacle a
second time.

The effects of log processing mills
and camps on fish habitat are
reviewed in the fourth report. These
effects are primarily the discharge
of toxic effluents from pulp and
paper mills and a reduction in the
amount of dissolved oxygen in the
water, resulting from decomposition
of wood sugars in mill wastes. Tox¬
icity and low levels of oxygen
reduce the growth of fish and their
ability to swim. In one study re¬
searchers found that when fish were
exposed to sublethal concentrations
of kraft effluent they reversed the
flow of water past their gills. This
activity, which researchers called
“coughing,” increased when con¬
centrations of effluents were
increased.

“It is important to realize,” Meehan
says, “that stresses on fish are
cumulative and that relieving them
may involve adjustments in many
forest management activities.” Fie
expects the research program to
continue to define more closely the
habitat requirements of fish and the
influences of land management on
habitat. Ways to enhance and
restore damaged habitat are also
being studied.

Publications available

The first four publications in the
planned compendium series, “In¬
fluence of Forest and Rangeland
Management on Anadromous Fish
Habitat in Western North America,”
are now available from the Pacific
Northwest Station. They are:

Habitat Requirements of
Anadromous Salmonids by D. W.
Reiser and T. C. Bjornn, General
Technical Report PNW-96.

Impacts of Natural Events by
Douglas N. Swanston, General
Technical Report PNW-104.

Planning Forest Roads to Protect
Salmonid Habitat by Carlton S. Yee
and Terry D. Roelofs, General
Technical Report PNW-109.

Processing Mills and Camps by
Donald C. Schmiege, General
Technical Report PNW-1 1 3.

Studies show
strength of
tree roots

by Marcia Wood,
Pacific Southwest
Station

Along the Pacific Coast, from north¬
ern California to Alaska, some of the
most productive forest land occurs
on some of the least stable slopes.
On many of these sites, the strong
roots of trees and shrubs add
strength and stability to the soil, and
help prevent the soil mantle from
sliding down the mountainside.

Research at the Pacific Southwest
Station’s Redwood Sciences
Laboratory in northwestern Califor¬
nia is showing how rapidly the rein¬
forcing properties of tree roots can
deteriorate after a site is clearcut.
Further, the research is determining
how long it takes planted tree seed¬
lings or invading brush to rebuild the
soil-root matrix that existed before
logging. And, the studies are com¬
paring the strength of the roots of
different species of trees and
shrubs. The work is underlining the
importance of root strength as a fac¬
tor that must be considered in
assessing landslide risk and in
evaluating any forest management
activity — such as logging — that
would alter the soil-root matrix.

In charge of the studies is Robert R.
Ziemer, research hydrologist at the
Redwood Sciences Laboratory in

Areata. Ziemer says plant roots can
play “a critical role in maintaining
the stability of steep slopes that
have shallow, cohesionless soils.”
He explains, “Vertical roots can
anchor a shallow soil mass to frac¬
tures in the bedrock. Horizontal
roots provide long, fiberous binders
that can interlock and tie the hillside
together laterally. When the forest
cover is removed, these roots
deteriorate, and much of the soil
strength is lost.”

International studies

One of Ziemer’s collaborators,
Geologist Doug Swanston of the
Pacific Northwest Station, Juneau,
Alaska, says root strength is
something that has been largely
ignored in the U.S. He points to
practices in Czechoslovakia and
Hungary, where foresters use differ¬
ent tree species “to get a degree of
control over landslide occurrence.”
Researchers in Russia, Canada,
New Zealand, and Japan are also in¬
vestigating the soil-binding proper¬
ties of tree roots. At the Redwood
Laboratory, Ziemer has worked with
translators to prepare English-
language summaries of some of the
most important research reports
from Japan.

6

Although other researchers in the
U.S. are studying the role of tree
and plant roots, Ziemer probably
has the most comprehensive data
on this topic. Over the past several
years, his field crews have worked
at sites ranging from the Six Rivers
National Forest in northwestern
California to the Tongass National
Forest in southeastern Alaska. They
have excavated more than 500 tons
of soil and, from this, have extracted
more than 5 tons of roots. The roots
have been shipped to the Redwood
Laboratory, where they have been
washed, sorted into diameter and
age (years since logging) classes,
oven-dried, and weighed. By com¬
paring the measurements from
cutblocks of various ages, Ziemer
has shown how the amount of roots
in the soil changes in the years
following logging.

Other roots have been sheared with
a laboratory machine that Ziemer
designed and built. These measure¬
ments indicate the strength of roots
of various forest species.

And, to examine yet another aspect
of root strength, soil blocks — which
include roots — have been sheared
in the field, using a portable shear
box that Ziemer developed. These
measurements show the strength of
the soil-root matrix.

All of these data will be used to
develop a model of how slope
strength changes in the years
following logging. The model can be
used — along with other guides — to
predict how logging might affect
root strength and the stability of
fragile, slide-prone slopes.

Ziemer's contributions to date have
been to provide preliminary informa¬
tion on root strength in various
forest types — encompassing some
30 different tree and brush
species — in California, Oregon, and
Alaska. He has presented work¬
shops for foresters, engineers,
geologists, hydrologists, and others
in California and the Pacific North¬
west. His findings have been used,
along with other data, to modify
timber management plans on Na¬
tional Forests and privately owned
timberlands on the West Coast. And,
he has redesigned and improved
equipment used to shear roots in
the laboratory and in the field.

The laboratory shear device measures the
amount of force it takes to shear individual
roots.

Preliminary results

Although much of his data is still
being analyzed, Ziemer has some
preliminary results from several of
the areas he has studied. One of
these areas is the vicinity of Staney
Creek on the Prince of Wales Island
in Alaska. There, Ziemer and
Geologist Swanston compared
western hemlock and Sitka spruce
roots in uncut areas to roots in
areas that had been clearcut either
2, 4, 6, or 1 0 years before the study.

The researchers collected root
segments, each approximately 12
centimeters long, from the mineral
soil. The roots were grouped into 6
diameter classes of 2, 5,10,1 7, 25,
and 50 millimeters (without bark),
and were then sheared in the
laboratory.

For hemlock, spruce, and red
elderberry (a shrub that invades
cutover sites), Ziemer and Swanston
found that the smaller roots lost
strength very quickly in the first 2
years after logging. Hemlock roots
were more resistant to loss of
strength than the Sitka spruce roots:
2 years after logging, hemlock roots
smaller than 25 millimeters in
diameter lost only about one-third of
the average strength, while Sitka
spruce lost about one-half the
average strength. The large hemlock
roots (50 mm in diameter) didn't
lose any strength during the first 6
years after cutting. However, over
the next 4 years, these roots lost 50
percent of their strength. The pat¬
tern was similar for the large Sitka
spruce roots. Roots 50 mm in
diameter retained their strength for
the first 6 years after logging, then
lost 87 percent of their strength over
the next 4 years.

Surprisingly, red elderberry shrubs
contributed to soil strength.

Although the smaller elderberry
roots, such as those that were 2
mm in diameter, were much weaker
than Sitka spruce or hemlock roots
of the same diameter, the larger
elderberry roots (1 7 mm in diameter)
were comparable in strength to the
spruce and hemlock roots in this
size class.

Mixed-conifer sites

At cutover mixed-conifer sites in the
Klamath Mountains of northern
California, Ziemer’s work showed
that invading brush species can help
keep a fragile slope from falling
apart after logging. These results
were based on laboratory and on¬
site tests of roots sifted from 1 03
soil blocks. The soil blocks were ex¬
cavated from cutover sites that had
been logged anywhere from 3 to 24
years before the study. Roots from
an uncut, old-growth stand were
measured for comparison.

Ziemer found that two of the com¬
mon hardwoods, golden chinkapin
and Pacific madrone, and two
shrubs, Pacific red elder and
snowbrush ceanothus, had stronger
roots than the conifers (white and
red firs, sugar and ponderosa pines,
and incense cedar). The snowbrush
roots, which were a major compo¬
nent of the cutover sites, were
about twice as strong, on the
average, as pine and fir roots. For
example, snowbrush roots 2 milli¬
meters in diameter were about 1 .35
times as strong as conifer roots; the
50 millimeter brush roots were
about 3.76 times stronger than fir or
pine roots.

By comparing the strength of roots
that remained on the various ages
of cutblocks, Ziemer determined
that, within 2-3 years after logging,
about half of the original reinforcing
strength of the roots was gone. After
8 years, three-fourths of the strength
was lost. After 25 years, essentially
all of the reinforcement by dead
roots was lost.

When brush began to invade the
cutblocks, the site recovered much
of its original reinforcement. “Brush
can bring a site back up to a level
that is equal to 70 percent of the
reinforcing strength of an uncut
stand,’’ Ziemer explains. “But, as
the brushfield ages and the decay of
the conifer root progresses, root
reinforcement will decrease.” He
points out, “If the transition from a
cutover site, to a brushfield, to a
conifer forest, is gradual, the rein¬
forcement by roots will slowly return
to that of an uncut forest. If brush is
killed in an attempt to establish the
conifers more quickly, however, the
strength of the soil-root matrix will
probably drop rapidly. It may be
several years before the dead roots
of the brush are replaced by the
small roots of young conifers. Thus,
from the standpoint of soil and slope
stability, invasion by brush may be
desirable.”

Equipment modified

The laboratory and field equipment
that Ziemer designed for the root
strength analyses represents
modifications of models developed
by others. Ziemer’s portable shear
box measures the amount of force
that it takes to break the soil-and-
root fabric. An earlier model
measured the shear resistance of
the soil and of those roots that grow
down through the soil profile.
Ziemer’s version gauges shear
resistance of the soil and the
horizontal roots. Ziemer believes
that these horizontal roots are
“probably more important than the
vertical ones.” He explains, “the
horizontal roots can connect weak
areas to stable portions of the slope,
and can strengthen unstable slopes
in other ways, as well.”

The laboratory shear device that
Ziemer designed measures the
amount of force it takes to shear in¬
dividual roots. The stress is applied
to each root at the rate of 3.6 cen¬
timeters per minute. These shear
strength measurements can be con¬
verted into measurements of tensile
strength, using a formula that
Ziemer developed.

Tensile strength is an indication of
how much force it takes to pull a
root apart, from both ends. This ap¬
proximates the tearing action that
occurs in nature when a slope
begins to give way. In developing
the conversion formula, Ziemer
worked with a tensile strength
machine that was built by Edward R.
Burroughs of the Forest Service and
Byron R. Thomas of the Bureau of
Land Management. The major draw¬
backs with this and other tensile
strength machines are that they are
limited in the size of the roots that
they can accommodate, and that
they are time-consuming to use.
Currently, tensile strength machines
can’t measure roots larger than 1 5
millimeters in diameter, while
Ziemer’s machine can accom¬
modate roots up to at least 50
millimeters. It can take as long as
1 5 minutes to test a root on a ten¬
sile strength machine; the shear
stress machine only takes about 30
seconds.

Ziemer believes that the combina¬
tion of the shearing machine and
conversion formula offers the best
of both approaches, and provides
“excellent predictions of root tensile
strength.”

Limits to concept

The concept of root strength does
not apply to every acre of forest
land on every naturally unstable
slope. Instead, it is most applicable
to sites where the soil is shallow
and lacks cohesion. Thousands of
square miles of forest land from
Alaska to California fit this descrip¬
tion. Contributing further to the in¬
stability of this region is the fact that
it is located at the margins of con¬
tinental and oceanic plates. The
plates are continually colliding, shift¬
ing and grinding, and uplifting the
land. “This activity, combined with
rapid erosional processes, has pro¬
duced a steep and youthful
topographby,” Ziemer says. “Many
of these steep slopes are landslide-
prone. The landslides may take the
form of shallow-seated mantle
slides — failures in which the soil
mantle gives way to the natural
stresses acting upon it. The binding
action of tree and plant roots pro¬
vides some resistance to the sliding
forces that cause shallow-seated
slides.”

8

This shallow-seated mantle slide occurred in
a hemlock-Sitka spruce stand on the Tongass
National Forest, southeastern Alaska.

“Where there are deep zones of
slope weakness, root strength can't
keep a slope from sliding. Land¬
slides on such sites may originate
hundreds of feet beneath the rooting
zone, and may be several miles
across. In these situations, the
sliding forces overwhelm the
resisting forces provided by the
vegetation.”

Shallow-seated mantle slides are
comon in all of the coastal forests
Ziemer has studied. On the Siuslaw
National Forest in Oregon, for exam¬
ple, more than 200 of these slides
occurred in one winter!

Findings used

The research has attracted con¬
siderable interest. Paul Brouha,
senior fisheries biologist for the
Shasta-Trinity National Forest in
northern California, says, “Ziemer
has given us substantial insight into
the strength of the roots of different
brush and timber species." George
Bush, soil scientist for the Siuslaw

National Forest, says that the
research is a key element in assess¬
ing landslide risk on the Forest.

“Root strength is the primary
variable that we use to show that
we are getting an acceleration of
landsliding — over and above the
natural landslide rates — after clear-
cutting. On the Siuslaw, many sites
that are highly productive have a
high landslide risk. Ziemer’swork
gives us the kind of backup we
need — proof of the potential for
landslide occurrence following clear-
cutting.” Bill Hicks, engineering
geologist on the Rogue River Na¬
tional Forest, Oregon, describes root
strength research as “a needed
piece of the stability data package
required for correct land manage¬
ment prescriptions.” He says that
Ziemer’s work has “added to the
accumulating body of knowledge
regarding the stability reponse of the
soil mantle to logging,” and has
“helped convince forest managers
of the fragility of mountainous
slopes.”

For further reading

Burroughs, E.R., Jr., and B.R.
Thomas. 1977. Declining Root
Strength in Douglas-fir After Felling
as a Factor in Slope Stability. U S.
Dep. Agric. Forest Serv. Res. Pap.
INT-190, 27 p., illus. Intermt. Forest
and Range Exp. Stn., Ogden, Utah.

Wu, T.H., W.P. McKinnell III, and
D.N. Swanston. 1979. Strength of
Tree Roots and Landslides on Prince
of Wales Island, Alaska. Can. Geo¬
tech. J. 1 6(1 ):1 9-33.

Ziemer, Robert R. 1 978. An Ap¬
paratus to Measure the Crosscut
Shearing Strength of Roots. Can. J.
For. Res. 8(1): 142-1 44.

Ziemer, Robert R. [in press] Root
Strength. In 1981 McGraw-Hill Year¬
book of Science and Technology.

Ziemer, R.R. [in press] Roots and
the Stability of Forested Slopes. In
Proceedings of the International
Symposium on Erosion and Sedi¬
ment Transport in Pacific Rim
Steeplands [Jan. 25-31 , 1 981 ,
Christchurch, New Zealand], Int.
Assn. Hydrol. Sci. Pub. No. 132.

Ziemer, R.R., and D. N. Swanston.

1 977. Root Strength Changes After
Logging in Southeast Alaska. USDA
Forest Serv. Res. Note PNW-306,

10 p., illus. Pacific Northwest Forest
and Range Exp. Stn., Portland, Oreg.

9

Giving the land
back to nature

by Louise Kingsbury,
Intermountain Station

Southeastern Idaho’s sagebrush
deserts and forested mountains
house prime fishing, hunting, and
grazing. But this area is also a big
phosphate producer, and several
large mines dot the landscape.
Mining and its associated activities
have taken a heavy toll on this part
of the country. Huge waste dumps,
seemingly incapable of supporting
any plants or animals, mar the view.
Massive soil runoff creates water
pollution for miles around.

Five years ago little was being done
to clean up the waste dumps. To¬
day, application of extensive
hydrological and revegetation
research is transforming these
dumps into foliaged wildlife habitat
and eliminating water pollution.

Knowing the amount of moisture at a waste
dump helps researchers in revegetation
efforts. Precipitation from snow and rain is
measured. The degree of ground water
saturation is determined with a nuclear
measuring device. Such measurements help
indicate ground stability or erosion problems
of spoils just mined or already revegetated.

“I would like to look at a hill and not
know whether it was mined or not,”
said Paul Packer, project leader
of the Mine Spoil Reclamation
Research Work Unit, before his re¬
cent retirement. The work unit is at
the Forestry Sciences Laboratory in
Logan, Utah. Also involved in the
research is the Shrub Improvement
and Revegetation Research Work
Unit at the Shrub Sciences Labora¬
tory in Provo, Utah. Both units are
part of the Intermountain Forest and
Range Experiment Station.

10

Two problems

Packer says the reclamation
research concentrates on solving
two pressing and related problems
in phosphate rehabilitation. One is
erosion and mass instability caused
by steepness of waste dump slopes
and accumulation of pockets of
saturation, or ground water, within
the dumps. Forest hydrologist
Eugene E. Farmer uses nuclear
measuring devices and computer
and plastic models to determine
ground instability problems and to
illustrate to miners how to best con¬
struct waste dumps.

The other problem is revegetation of
the barren and nutrient-poor
materials to reduce erosion and
restore wildlife habitat. Research
forester Bland Z. Richardson
stresses the practical application of
revegetation research by actively
helping industry restore the spent
earth. Several major phosphate
mining companies, with the help of
Forest Service personnel, are now
restoring the waste dumps located
on public lands.

Included in these reclamation proj¬
ects is the Ballard Mine (Monsanto
Chemical Co.), where this Forest
Service research began. Results
were later applied to other Idaho
mines, including the Wooley Valley
Mine (Stauffer Mining Co.), Maybe
Canyon Mine (Beker Industries), and
Conda and Gay Mines (both J. R.
Simplot Co.).

A billion tons of ore

These mines and other phosphate
areas in southeast Idaho hold one of
the world’s richest known phosphate
reserves. More than 1 billion tons of
potentially recoverable ores have
been identified here. The area,
centered around Soda Springs,
Idaho, comprises 90 percent of the
identified phosphate reserves in the
1 30,000 square miles of the western
phosphate field (Idaho, Wyoming,
Utah, and Montana), and about 35 to
50 percent of all the phosphate
reserves in the United States. The
annual phosphate production from
southeast Idaho is about 5.5 million
tons, mostly from surface mines
high on steep mountainsides.

Phosphate is valuable for its many
industrial and commercial uses. It is
used primarily for fertilizer and
detergents and secondarily for such
things as toothpastes and plastics. A
phosphate byproduct, vanadium, is
added to steel to make some of the
world’s finest cutlery.

There is no known substitute for
phosphate, according to Packer.
“But southeastern Idaho has 125
years of phosphate mining left. That
means a great challenge for making
these lands habitable after industry
has mined them.’’

Packer points out that this part of
the United States is known for its
excellent wildlife habitat, especially
for sagehen, sandhill crane, moose,
elk, and cutthroat trout. Mining,
in some cases, adversely affects
wildlife habitat, and erosion from
dumps frequently contaminates
streams and lakes, harming aquatic
habitat and drinking water.

The Intermountain Station began
phosphate rehabilitation research in
1 972 when it joined existing efforts
on the Caribou National Forest. The
cooperative work broadened in 1974
under the Surface Environment and
Mining (SEAM) program. Intermoun¬
tain Station researchers were par¬
ticularly concerned with waste
dumps.

Steps in rehabilitation

Constructing a stable, vegetated
mine dump requires solving several
major problems. Eugene Farmer at¬
tacks the first problem of dump
stability using detailed measure¬
ments of ground water at various
depths on one dump site. The re¬
sultant computer models recently
served as the pattern for a multi¬
layered plastic model. This three-
dimensional model graphically
demonstrates subsurface soil prob¬
lems. The model is used in training
and in meetings with industry.

North- and east-facing slopes retain heavy
winter snowpack late into the spring, resulting
in potentially high erosion hazards- At a mine
dump, such slopes require immediate ground
cover to hold the barren earth in place. "1 1

“We can take our research results
to industry and show how problems
can be solved long before a waste
dump is constructed," says Farmer.
“How to build the dump is the key."

On an existing dump, reshaping a
slope is the first step in successful
rehabilitation. Leveling the dump to
something less than a 33 percent
grade makes revegetating and land
stabilizing easier.

Revegetation is next. Richardson
points out that for maximum sta¬
bility, ground cover must be planted
on the entire dump in the first year.
The degree of revegetation success
depends on adequate site prepara¬
tion, which includes ripping, harrow¬
ing, fertilizing, and planting.

According to Richardson, sterile
spoils and the surface temperature
of dark spoils on south-facing slopes
are the biggest obstacles to revege¬
tating phosphate dumps. Tempera¬
tures as high as 1 74° F have been
recorded on these slopes. Re¬
searchers studied some 500 plant
species in the quest for those that
would best overcome these
obstacles. Temperature problems
have been solved by choosing the
correct time for planting, method of
planting, manipulation of spoil, and
proper selection of plant species.

“One of our goals is to restore
the land to productivity,” says
Richardson. “This especially means
selecting plants that add organic
matter and nutrients to the spoils.
Legumes, for instance, add
nitrogen.’’

At Idaho 's Ballard Mine, vegetation in
experimental plots is assessed for species
composition and density

Research results

The result of the research is that
even on hot, steep, south-facing
slopes, lush vegetation now grows
and the ground is stabilizing. Erosion
that once removed as much as 500
tons of earth a year off a mine dump
is now curbed through vegetation
that includes grasses, sagebrush,
and legumes, and on north-facing
slopes, mixed conifers and shrubs.

On one study site, for example, the
erosion rate averaged 85 tons per
acre during the first year following
construction. Workers immediately
revegetated the dump, and erosion
rates during the second year
dropped dramatically to an average
of 4.4 tons per acre — about a 95
percent reduction. As the plants
take a firmer grip on the earth in
succeeding years, erosion should
not exceed a ton or so per acre,
much closer to the land’s condition
before mining.

Research results have been
distributed to industry and other
government agencies through per¬
sonal contact, as well as meetings,
symposia, and publications. The
researchers are also working on a
videotape “how to" program center¬
ing on rehabilitating phosphate
dumps but also touching on other
mining types. The 30-minute, color
tape, produced by the Colorado
School of Mines, will be released by
early summer 1 981 . It is aimed at
reclamation specialists in industry
and at land managers in charge of
evaluating reclamation techniques.

The research in southeastern Idaho
also provides recommendations on
revegetation techniques in other
mining operations, including coal,
heavy metals, oil shale, and barite.
Over 60 mines, including phosphate,
operate in the Western United
States, with nearly 500 people in¬
volved in reclaiming the waste
dumps.

Research results and recommenda¬
tions, and the instructional material,
give to industry and government the
techniques needed to fulfill Federal
and State laws requiring rehabilita¬
tion of mined lands.

Roger R. Bay, director of the Inter¬
mountain Station, says industry has
taken readily to the Station’s
rehabilitation techniques. “An in¬
creasing awareness of the value of
public and private lands has placed
a stronger emphasis on their
restoration to true multiple use,"
says Bay. “The result speaks well
for government and industry con¬
cern for the future.”

12

Leafy spurge
—Scourge of
the West

by Matthew McKinney,
Rocky Mountain Station

Leafy spurge has taken over this once excellent
pasture in Wyoming.

Leafy spurge (Euphorbia esula L.) is
a tenacious perennial weed infesting
nearly 2.5 million acres of range and
croplands in the U.S. Despite
millions of dollars spent annually on
control efforts, the weed has spread
steadily since its introduction around
the turn of the century.

Leafy spurge originated and is
widespread in continental Europe. It
extends through central Russia and
into Siberia. Seed is believed to
have been first brought to the U.S.
in shipping ballast. The first her¬
barium specimen was collected
here in 1827. Since then, it has
spread like a plague throughout
several states, with a concentration
center in the northern Great Plains
and southern Canada.

Scientists at the Rocky Mountain
Station’s Forest Research
Laboratory at Rapid City, South
Dakota, are part of a multi-agency
effort to find efficient and effective
ways to control the weed.

Dan Noble, research forester at the
lab, says, “Leafy spurge is a prob¬
lem on tree belts, parks, waterways
and roadsides. The real economic
impact, however, is on crop and
rangelands.” The weed displaces
useful forage and, if unchecked, will
take over as the dominant species

on pastures and ranges. It also in¬
vades croplands, especially un¬
cultivated fields, and can cut crop
yields dramatically.

Leafy spurge is a poisonous plant
and, externally, causes dermatitis to
man and animals. Taken internally,
it causes scours and weakness in
cattle and may cause death. Sheep
become sick by eating mature
plants, but are less affected by
small plants. They have also been
used on a limited scale for control.
Livestock will eat dried plants in
hay, but usually avoid eating grow¬
ing plants except under poor range
conditions.

Why is leafy spurge such a problem,
and why haven’t control efforts been
successful? One factor is the root
system. Each plant has an extensive
root-rhizome network that occupies
a large volume of soil. Roots have
been measured down to 15 feet in
depth. The plant is able to withstand
drought conditions, and can store a
three-year supply of nutrients in its
roots. The roots and rhizomes are
woody and tough, and if cut, have
great ability to produce new shoots
from various depths. In addition, the
plant spreads rapidly. One seedling
of the weed can spread to occupy
an area of soil 24 feet in diameter in
4 years.

13

The weed has yellowish-green
flower-like clusters that are
pollinated primarily by insects. Seed
stalks are prolific, producing up to
150 seeds each. Under favorable
conditions up to 99 percent of the
seeds will germinate.

Control efforts

Farmers, ranchers, government
agencies, and others spend several
million dollars annually, primarily on
herbicides, fighting leafy spurge.
Chemicals currently being used
include 2,4-D, picloram and
glyphosphate. However, all have had
only limited success. Not only can
these herbicides be damaging to
existing grasses, forbs and other
beneficial plants, but they are
expensive and may not be cost ef¬
fective on a large scale.

Biological control is another method
gaining interest, but is still in the
early stages of development. There
are several species of insects and a
rust (Urormyces striatus) that attack
leafy spurge. While most of these
organisms are found in Europe, they
are from a climate similar to the
Canadian and U.S. prairies, and hold
promise for future use. Plans are
now underway to test several of
these insects and disease agents on
leafy spurge.

Noble says controlled burning has
been used successfully to battle
the weed. He says that a good,
hot fire will kill most of the seed
in a stand, but top growth should be
killed first with a herbicide for max¬
imum effectiveness.

Noble believes that an integrated
regional control program, backed by
state and federal governments is
needed to effectively control leafy
spurge. “To initiate a good regional
control program,’’ he explains, “we
first need a complete inventory of
the weed, which should include land
ownership, type of habitat and ter¬
rain infested, and intensity of the
infestation. Techniques to evaluate
results of control treatments are
also necessary.”

Root nodes of leafy spurge are prolific and
1 4 very resistant to chemicals.

A flowering leafy spurge plant.

Field equipment, such as this herbage meter
helps measure the production and spread of
the weed

Aerial surveys

This is where Rocky Mountain Sta¬
tion scientists with the Resources
Evaluation Techniques Program at
Fort Collins, Colorado offer help.
They are studying the feasibility of
using aerial photography for inven¬
torying spurge and evaluating treat¬
ment methods. Several flights have
already taken place using both color
and infrared at different photo
scales. These scales and film types
are currently being tested to deter¬
mine which combination is best
suited for large area surveys, quan¬
titative site measurements, inventory
and monitoring.

Several states are carrying on their
own research and treatment pro¬
grams. In 1978, the Wyoming
legislature passed a Leafy Spurge
Control Act, launching a multi-million
dollar program that has seen over
18,000 acres treated and 2,500
acres retreated. Other states are
considering similar action.

Noble says, “We still could be
several years away from an inte¬
grated large-scale treatment pro¬
gram that offers full success in
controlling leafy spurge. However,
through continued research, proper
land management, public education,
and the development of a regional
control plan, leafy spurge may even¬
tually become a problem of the
past.’’

As leafy spurge continues to spread,
more and more state and federal
agencies are joining forces against
the weed. A steering committee was
recently named to help develop a
program package for needed attack
on leafy spurge. The program in¬
volves research, extension, edu¬
cation and improved coordination
between the agencies.

15

New

publications

Single copies of publications referred
to in this magazine are available
without charge from the issuing
station unless another source is in¬
dicated. When requesting a pub¬
lication, give author, title and
number.

Organic debris in
Maybeso Creek,
Alaska

Events following logging in the
Maybeso Creek drainage in south¬
east Alaska emphasize that natural
accumulations of large organic
debris play an active role in the
form and structure of stream chan¬
nels. A comparison of conditions
found during a ground survey in
1 978 after the watershed was
logged, and conditions shown on
earlier maps, indicates that timber
harvests from 1 953 to 1 960 caused
extensive changes in the stream
channel. Although some of the
changes were caused by equipment
operating in the stream, most were
related to the reduction of ac¬
cumulations of large woody debris.

Before logging, sparse accumula¬
tions of large debris were scattered
throughout the stream. During
logging, all major concentrations of
natural debris were affected. Large
amounts of floating logging debris
were sieved by the stable natural
debris until massive, unstable jams
were created. These were washed
out by annual autumn floods. Ten
years after logging, there were
fewer accumulations than in 1 949
before logging. The removal of old-
growth forest along the streambank
has effectively eliminated the source
of new large organic debris. Except
in the few remaining uncut areas, no
new large material has entered the
stream. Present channel morphom¬
etry (form and structure) appears to
be determined by stream bank and
bedrock formations. Small, young
hemlock and alder do not have the
same effect on the channel as did
old-growth spruce and hemlock.

Details, including maps of the debris
in the creek, are provided in Evolu¬
tion of Large, Organic Debris After
Timber Harvest: Maybeso Creek,
1949 to 1978 by Mason D. Bryant,
General Technical Report PNW-101 .
Copies are available from the
Pacific Northwest Station.

Air pollution and
forests reviewed

Results of recent research on the ef¬
fects of air pollution on forests are
summarized in a new publication
from the Pacific Southwest Station.
Proceedings of Symposium on
Effects of Air Pollutants on Mediter¬
ranean and Temperate Forest
Ecosystems, General Technical
Report PSW-43, is a collection of 28
papers and 29 poster presentations
from this June 1 980, conference.

The reports cover the major pollu¬
tion problems of two climatic
regions — the world’s temperate
forests, including those of the U.S.,
Canada, Japan, northern Europe,
and other areas; and the Mediter¬
ranean-type regions, including the
Mediterranean Basin, southern
California, southwestern Australia,
central Chile, and southern Africa.

Studies of short- and long-term ef¬
fects of such pollutants as ozone,
sulfur dioxide, nitrogen oxide, and
hydrogen fluoride are described by
researchers from throughout the
U.S. and several foreign countries.
Summaries of the effects that acid
rain has on forests and lakes are
presented by scientists from the
East Coast of the U.S. and from
northern Europe, two areas where
this problem is severe. Other
researchers detail the effects of
pollutants on insects, birds, lichens,
and other forest life.

One of the main purposes of the
conference was to evaluate the use
of computer models for simulating
the impact of pollution and for
predicting future pollutant damage.
These predictions are needed in
order for regulatory agencies to set
standards of air quality. Problems
with current models, and sugges¬
tions for their improvement, are
presented in several of the papers.

Copies of the Proceedings may be
requested from the Publications
Section, Pacific Southwest Station.

16

Nongame bird
proceedings

Proceedings entitled Management of
Western Forests and Grasslands for
Nongame Birds is now available
from the Intermountain Station. The
36 papers came from the fourth and
last workshop in a series whose
goal was to solve the problems of
meeting avian habitat needs while
managing other forest resources.

Forest Service Chief Max Peterson,
in his keynote address in these
proceedings, emphasizes the need
for a “completely integrated wildlife
program.” He notes that the pro¬
ceedings help National Forests in
their land management plans and in
meeting Resources Planning Act
requirements.

“Everything we do as resource
managers will benefit some species,
be detrimental for some, and,
perhaps, not even affect others,”
says Peterson. “The key is to plan
for diversity of both plants and
wildlife.”

The workshop in Salt Lake City,

Utah, in February 1980 focused
on the state-of-the-art of nongame
bird research and management in
western States. Previous workshops
looked at the special circumstances
of other ecoregions. The workshop
series was the outcome of a 1 975
symposium where avian ecologists
and forest resource managers met
to discuss their common concerns.
Participants in the series included
representatives of the U.S.
Department of Agriculture, U.S.
Department of the Interior, and
several wildlife associations.

You may obtain your copy of the
535-page proceedings from the
Intermountain Station. Ask for
General Technical Report INT-86
FR-25.

Classifying vegeta¬
tion in Alaska

One thing Alaska has needed is a
unified, statewide system for classi¬
fying vegetation to coordinate the
many divergent systems used over
the years by groups and agencies to
map and inventory vegetation. A
hierarchical system based on the
characteristics of vegetation has
now been proposed.

The classification system has five
levels of increasing complexity. The
first, or broadest, level has five
categories: forest, tundra, shrub-
land, herbaceous vegetation, and
aquatic vegetation. For each of
these broad categories there are
four additional descriptive levels.
The breakdown for forests, for
example, is conifer, deciduous, and
mixed. The third level classifies
these three types of forest as open,
closed, or woodland, depending on
the amount of canopy cover. The
finest level of resolution lists
over 400 plant communities by the
dominant species in the tree, shrub,
and herb layers.

The classification was first drafted
in 1 976 and has been reviewed ex¬
tensively by scientists from public
agencies and universities. The
system is designed to be revised
and refined as new information
becomes available.

A new publication explains details of
the classification system: A
Preliminary Classification System
For Vegetation of Alaska, by Leslie
A. Viereck and C. T. Dyrness,
General Technical Report PNW-106.
Copies are available from the
Pacific Northwest Station.

Increasing and
optimizing aspen
harvests in the
Rocky Mountains

Grading methods are being
evaluated to assess the potential of
standing aspen timber and saw logs
for conversion into wood products.
These grading systems allow for
separation of trees and logs into
different levels of volume and
dollars value recovery.

Recent surveys show the Rocky
Mountain states have more aspen
sawtimber (more than seven billion
fbm of sawtimber) than any other
area in the United States. While only
10 million board feet are now
annually harvested, as much as 60
million board feet could be cut
for optimum management of the
species.

Since aspen is a softwood, tree and
log grades developed for hardwoods
are not appropriate for estimating
lumber yields. In addition, lack of
information on the lumber recovery
potential of aspen in the Rocky
Mountains and unfamiliarity of the
possible uses for aspen contribute
to underutilization.

Scientists at the Rocky Mountain
station are working to relate lumber
recovery to characteristics of aspen
stands. Their research has indicated
the importance of lumber volume
and grade recovery in relation to
visual attributes of downed logs and
standing trees.

If you would like to know more
about these management tech¬
niques, contact the Rocky Mountain
Station and request Lumber Yield
Potential of Aspen in the Rocky
Mountain, Research Paper RM-227,
by Eugene M. Wengert and Dennis
M. Donnelly.

Fire ecology of
Montana habitats

An Intermountain Station paper sum¬
marizes the available fire ecology
and management information that
applies to habitat types of the Lolo
National Forest, but is applicable to
many of these habitats throughout
western Montana.

Fire Ecology of Lolo National Forest
Habitat Types is written by Kathleen
M. Davis, Bruce D. Clayton, and
William C. Fischer.

The authors arranged the habitat
types into 10 "Fire Groups” based
on the response of the tree species
to fire and the roles of these species
during successional stages. They
review the literature on fire and
succession and present a diagram
of the role of fire on all the habitat
types in each Fire Group. Based on
such information, the authors then
suggest how to develop fire
management plans that support land
and resource management
objectives.

Contact the Intermountain Station
for copies of General Technical
Report INT-79 FR-25.

18

Guide lists sources
of economic data

More than 300 different sources of
economic data that are useful in
wildland planning and management
are listed in a new directory from
the Pacific Southwest Station. The
publication is Economic Data for
Wildland Planning and Management
in the Western United States: A
Source Guide, General Technical
Report PSW-42.

The Guide is an introduction to
published reports, computerized
data bases, and other compilations
of data that are provided by Federal
and State agencies, colleges and
universities, private organizations,
and other groups. Sources of data
about costs, returns, supply and de¬
mand, and other economic factors,
are presented for six wildland
management activities — outdoor
recreation and wilderness, wildlife
and fish, range, timber, land and
water, and minerals and energy. The
brief description of each data
source includes the title, the
address of the author or issuing
agency, and comments about the
types of information the source
provides.

Federal sources, for example,
include Western Economic In¬
dicators, issued by the Federal
Reserve Bank of San Francisco;
the Bureau of Land Management’s
Public Land Statistics; and the U.S.
Department of Labor’s Chartbook on
Prices, Wages, and Productivity.

Typical of the State sources is
Alaska Economic Trends, issued by
the State’s Department of Labor; or
Montana Agricultural Statistics, an
annual compilation of crop and
livestock production data from the
Montana Department of Agriculture.

University sources include Colorado
Ski and Winter Recreation Statistics,
issued annually by the University of
Colorado’s Business Research Divi¬
sion; or the Survey of Hunters in
Oregon, prepared every 2 years by
Oregon State University’s Survey
Research Center.

Data sources maintained by private
organizations include The Sporting
Goods Market, an annual guide
issued by the National Sporting
Goods Association; or Western
Lumber Facts, issued monthly by
the Western Wood Products
Association.

The 1 25-page Guide was prepared
by two Pacific Southwest Station
cooperators, Eric Eisenman and Lee
C. Wensel; and two former Station
researchers, Thomas W. Stuart and
Edward C. Thor. Copies of the
publication are available from the
Pacific Southwest Station.

19

Make your own
residue photos

Researchers at the Pacific North¬
west Station have prepared
guidelines to help managers make
their own photo series to illustrate
the amount and character of dead
and down residues. The guidelines
provide complete instructions for
selecting, photographing, and inven¬
torying examples of different levels
of residue, to supplement photo
series already published.

Authors Wayne G. Maxwell and
Franklin R. Ward have written three
previous publications which combine
photographs of residue with detailed
descriptions to illustrate a range of
residue levels. With these tools,
managers find it easier to estimate
the amount and characteristics of
residue, predict the amount of
residue from a planned harvest, and
communicate with other managers
and specialists about residue.

Photo Series for Quantifying Forest
Residues in the Coastal Douglas-fir-
hemlock Type and Coastal Douglas-
fir-hardwood Type, General
Technical Report PNW-51 , is out of
print but may be available through
library services. Photo Series for
Quantifying Forest Residues in the
Ponderosa Pine and Associated
Species Type, Lodge pole Pine Type,
General Technical Report PNW-52 is
available from the U.S. Government
Bookstore, 91 5 2nd Ave., Rm. 1 94,
Seattle, Washington 98174. Photo
Series for Quantifying Forest
Residues in the Sierra Mixed Conifer
Type and Sierra True Fir Type,
General Technical Report PNW-95,
and the newest one, Guidelines for
Developing or Supplementing
Natural Photo Series, Research
Note PNW-358, are available from
the Pacific Northwest Station.

Recreation and
wildlife: A
bibliography

Hikers, cross-country skiers, photog¬
raphers, and other recreationists
visit backcountry areas in numbers
that have caused wildlife to cease
using otherwise desirable habitat.
And while studies on recreational
impacts on campsites, trails, and
vegetation frequently provide infor¬
mation for management plans, the
effect of backcountry recreationists
on wildlife has been given less
attention. This is probably because
most wildlife species are not fixed to
the spot (as are plants), and
therefore recreational effects are
not immediately evident.

The Intermountain Station has
published a bibliography that is, in
part, a response to the concerns of
land managers and recreationists
who appreciate the value of wildlife
and wish to reduce the uninten¬
tionally harassing effects of
increased people-wildlife en¬
counters. The bibliography contains
232 references concerning these
encounters.

The criteria for selecting papers
were that they describe the inter¬
action of recreationists with some
species of wildlife in a natural
setting, or present research findings
and techniques that could be used
to reduce people’s impact on
wildlife.

Recreation (skiing, backpacking,
hiking, photographing, and
birdwatching) was considered
“backcountry” where it affected
wildlife in natural, undeveloped
areas, whether the areas were
wilderness as defined in the 1 964
Wilderness Act, or lightly roaded.
The emphasis, however, was on
lands that were not heavily used by
motorized vehicles.

Impact of Backcountry Recrea¬
tionists on Wildlife: An Annotated
Bibliography, compiled by Catherine
H. Ream, is available from the Inter¬
mountain Station. Ask for General
Technical Report INT-84 FR-25.

20

Managing
ponderosa pine
in the Southwest

Ponderosa pine occupies the largest
area of commercial forest land in
Arizona and New Mexico. How
these forests are managed affects
lumber production, wildlife habitat,
livestock forage, watersheds,
recreation and scenic splendor.

With intensified resource manage¬
ment, managers are concerned with
quickly regenerating cutover areas,
increasing the growth rate of a new
stand by control of stand density,
and improving quantity and quality
of yields by periodic thinning to
maintain stocking control and
growth rates while reducing
mortality.

Potential production of ponderosa
pine stands is the theme of a
recently published Research Paper.
Scientists at the Rocky Mountain
Station have utilized an existing
computer program, RMYLD, to
simulate stand density, site index,
age and thinning schedule for
southwestern ponderosa pine
forests in order to optimize multiple
use tradeoffs.

These estimates will help land
managers maintain the productivity
of a ponderosa pine forest under an
even-aged management system
while producing acceptable multiple
use tradeoffs.

If you would like a copy of the paper
contact the Rocky Mountain Station
and request Management of Ponder¬
osa Pine in Even-Age Stands in the
Southwest, Research Paper RM-225,
by Robert R. Alexander and Carleton
B. Edminster.

Plant a tree! Mark the 75th birthday
of the Forest Service by giving a
living gift to future generations.

Watch for the next issue of Forestry
Research West. You’ll read about a
new biological system for water
quality testing of lakes and streams;
see a pictorial history of the effects
of fire and other influencing factors
on wildlife habitat; review several
new research publications; plus
more.

If you know of someone who would
be interested in this publication, he
or she can be added to the mailing
list by filling out the coupon below
and mailing it to us.

Please add my name to the
mailing list for Forestry
Research West.

Mail to: Forestry

Research West

U.S. Department of Agriculture
Forest Service
240 West Prospect Street
Fort Collins, Colorado 80526

21

U-S. GOVERNMENT PRINTING OFFICE: 1981-778-594/218

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