United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

Research Paper

RMRS-RP-53

March 2005

Reforestation Trials and

Secondary Succession with Three

Levels of Overstory Shade in the

Grand Fir Mosaic Ecosystem

Dennis E. Ferguson

John C. Byrne

Dale O. Coffen

Partial

Cut

Clearcut

Uncut
Abstract ______________________________________

Ferguson, Dennis E.; Byrne, John C.; Coffen, Dale O. 2005. Reforestation trials and

secondary succession with three levels of overstory shade in the Grand Fir Mosaic

ecosystem. Res. Pap. RMRS-RP-53. Fort Collins, CO: U.S. Department of Agriculture,

Forest Service, Rocky Mountain Research Station. 16 p.

Grand Fir Mosaic habitats are difficult to regenerate because of pocket gophers (Thomomys

talpoides) and successional plant communities dominated by bracken fern (Pteridium

aquilinum) and western coneflower (Rudbeckia occidentalis). This study tested reforestation

practices recommended by previous research, tested hypotheses about the effects of

overstory shade on regeneration success, and documented secondary succession. Natural

regeneration is not a reliable reforestation method on Grand Fir Mosaic sites. Clearcut and

planting was the best regeneration method if pocket gophers are controlled. Partial cutting and

planting was the best regeneration method if pocket gophers were not controlled. Most

gopher-caused seedling mortality occurred the first summer, first winter, and second winter

after planting. The clearcut treatment resulted in the loss of shrub species and the dominance

of bracken fern and/or western coneflower. In the partial cut treatment, shrubs were retained

and there was less bracken fern and/or western coneflower than in the clearcut treatment.

Keywords: planting, Pteridium aquilinum, bracken fern, Rudbeckia occidentalis, western

coneflower, Thomomys talpoides, pocket gophers

Acknowledgments ____________________________

We thank Dave Powell for initiating our interest in the Grand Fir Mosaic ecosystem

on the Umatilla NF, Kathy Roche for assisting with the study design at Little Big Hole,

Larry Frank and Nancy Berlier for providing seeds of genetically adapted species at

Little Big Hole, Phil Poulsen and Clare Brick for helping with study installation at

French Mountain, and Victor Murphy for installing study sites and collecting data.

Also, thanks to Dave Adams, Dave Powell, and Andy Youngblood for helpful

technical reviews of the manuscript.

The Authors ___________________________________

Dennis E. Ferguson is a Research Silviculturist, John C. Byrne is a Forester, and

Dale O. (Duke) Coffen is a Forestry Technician (now retired) with the Rocky

Mountain Research Station in Moscow, ID.
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 1

Introduction ____________________

In the Grand Fir Mosaic (GFM) ecosystem in northern Idaho

and northeastern Oregon (Ferguson and Johnson 1996), the

establishment of conifer regeneration is difficult because of

pocket gophers (Thomomys talpoides) and successional plant

communities dominated by bracken fern (Pteridium aquilinum)

and western coneflower (Rudbeckia occidentalis). This study

was designed as a demonstration of reforestation practices

recommended by previous research in the GFM, and also

tested hypotheses about the effects of overstory shade on

regeneration success and secondary succession.

The GFM occurs at elevations between 4,000 and 6,000 feet

on and near the Clearwater, Nez Perce, and southern Idaho

Panhandle National Forests (NF) in northern Idaho, and northern Umatilla NF in northeastern Oregon and southeastern

Washington. The extent of the GFM is estimated at 500,000

acres, and the name for the GFM comes from the dominant

conifer—grand fir (Abies grandis)—and the variety of sizes

and shapes of natural openings in the forest canopy.

Wildfire is the major historical disturbance agent in the

GFM, with long intervals between major fires. Grand Fir

Mosaic sites stay relatively cool and moist, which reduces the

potential for large or severe fires (Smith and Fischer 1997).

Tree sizes in old growth stands indicate an uneven age distribution, with regeneration of shade-tolerant species occurring

on rotten logs. Bracken fern glades, ranging up to about 15

acres, apparently persist for centuries. Timber harvesting has

replaced wildfire as the most common disturbance. Green and

Jensen (1991) have documented successional pathways in the

GFM where some harvest and site preparation treatments

result in protracted stages of secondary succession.

Bracken fern and western coneflower are usually present in

small amounts under forest canopies, and both rapidly expand

following disturbances that open up the overstory canopy.

During secondary succession, bracken fern gains dominance

via rhizome expansion, with fronds reaching heights of 6 feet

and densities of 116,000 fronds per acre (Znerold 1979), and

western coneflower expands via seeds and growth of the

Reforestation Trials and

Secondary Succession with

Three Levels of Overstory Shade

in the Grand Fir Mosaic

Ecosystem

Dennis E. Ferguson

John C. Byrne

Dale O. Coffen

caudex, reaching heights of 5 feet. Bracken fern and western

coneflower interfere with the establishment and growth of

other species through competition for resources and allelopathy (Ferguson 1991, Gliessman and Muller 1978, Stewart

1975).

Pocket gopher populations are high in the GFM; for example, gopher mounds averaged 429 per acre in the stands

listed by Green and Jensen (1991). Gophers directly affect

succession by feeding on forbs, grasses, shrubs, and conifer

seedlings. They can kill entire plantations of seedlings. Small

seedlings are usually pulled from below ground into tunnels

(Crouch 1971, Marsh and Steele 1992, Teipner and others

1983). With larger seedlings and saplings, gophers may eat all

or most of the root system. Gopher feeding on root systems can

go unnoticed until the tree dies or begins to tip over because

there are not enough roots for support.

Previous research studies on the GFM have provided new

information and additional hypotheses to test. Natural regeneration of conifers is not a reliable reforestation method in

clearcuts because of high populations of gophers, bracken fern,

and western coneflower (Ferguson and Boyd 1988). Planted

trees survive interference from bracken fern and western

coneflower, but growth is reduced (Ferguson 1999). For example, heights of lodgepole pine (Pinus contorta) 7 years after

planting were 1.5 feet shorter in plots with bracken fern and

western coneflower than in plots where bracken fern and

western coneflower were removed.

Pocket gophers can cause a substantial amount of mortality

to planted seedlings in GFM clearcuts. For example, gophercaused mortality was 35.9 percent 2 years after planting for six

species tested by Ferguson (1999). Most gopher-caused mortality to planted seedlings took place in the first summer after

planting and during the first and second winters. Ferguson

(1999) reported 76.8 percent of the seedlings killed by gophers

were killed during the first summer, first winter, or second

winter. Engelmann spruce (Picea engelmannii) and western

white pine (Pinus monticola) had the lowest gopher-caused

mortality, while subalpine fir (Abies lasiocarpa) and grand fir

had the highest gopher-caused mortality. Western larch (Larix
2 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

occidentalis) had high mortality rates from nongopher causes,

and both western larch and lodgepole pine had high incidence

of top damage.

Comparison of a GFM site to adjacent non-GFM sites

showed some additional reasons for slow secondary succession to woody species in the GFM (Ferguson and Byrne 2000).

The GFM site had a shorter growing season than adjacent

forest habitat types, even though one of the sites was a

subalpine fir habitat type 140 feet higher in elevation. Also,

summer soil moisture at the GFM site did not dry to the

permanent wilting point as often as non-GFM sites, so moisture at the GFM site was usually above the wilting point during

the growing season.

The biggest difference between the GFM site and non-GFM

sites was soil pH (Ferguson and Byrne 2000). Soil pH at the

GFM site fluctuated between 6 and 7 during the winter, and

then dropped to 4 to 5 during the summer. Adjacent sites did not

have this seasonally cyclic pattern. The combination of acidic

soils, high water availability in most years, high organic matter

inputs from forb communities dominated by bracken fern and

western coneflower, and a source of aluminum from weathered

volcanic ash in the soil likely results in active aluminum that is

complexed with soil organic matter. Aluminum toxicity is

common to many agriculture crops below about pH 5.0 (Shoji

and others 1993), so it is likely that aluminum toxicity is

influencing succession at GFM sites (Johnson-Maynard and

others 1997).

Consideration of the four factors that cause the slow rate of

secondary succession to woody vegetation at GFM clearcut

sites—competition for resources, allelopathy, pocket gophers,

and low soil pH—led to the hypothesis that partial overstory

retention may improve regeneration success. The study reported here was designed to quantify the tradeoffs among three

levels of overstory density versus survival and growth of

planted conifers. Partial shade should result in lower densities

of pocket gophers, bracken fern, and western coneflower, but

partial shade would also be expected to result in slower growth

of conifers. In addition to studying planted trees, we quantified

natural regeneration, secondary succession, and pocket gopher

activity under various levels of overstory density, and tested

recommendations for reforesting GFM sites.

Methods _______________________

Study Sites

Two study sites within the GFM were selected—one in

Idaho (French Mountain) and one in Oregon (Little Big Hole).

The French Mountain demonstration area was selected to

represent typical GFM conditions in northern Idaho and initially was the only site planned for study. However, personnel

from the Umatilla National Forest in northeastern Oregon had

sites that were apparently similar to GFM sites in Idaho, and

they wanted to know if recommendations for GFM sites in

Idaho applied to GFM sites in Oregon. Therefore, a second

demonstration area was chosen in Oregon.

The French Mountain site is on the Clearwater NF, Pierce

Ranger District, T36N, R6E, S2. Mean elevation is 5,000 feet

with a 190 degree aspect and 15 percent slope. At French

Mountain, the habitat type is Thuja plicata/Asarum caudatum,

Taxus brevifolia phase, as described by Cooper and others

(1991). The Little Big Hole site is on the Umatilla NF, Walla

Walla Ranger District, T4N, R39E, S11. Mean elevation is

4,200 feet with a 150 degree aspect and 15 percent slope. The

habitat type at Little Big Hole is Abies grandis/Taxus brevifolia,

Clintonia uniflora phase, as described by Johnson and

Clausnitzer (1991).

Prior to treatment, the overstory species composition at

French Mountain was 67.1 percent grand fir, 18.9 percent

Engelmann spruce, 9.8 percent Douglas-fir (Pseudotsuga

menziesii), 2.1 percent western redcedar (Thuja plicata), 1.4

percent western white pine, and 0.7 percent subalpine fir. The

pretreatment overstory species composition at Little Big Hole

was 75.0 percent grand fir, 11.5 percent western larch, 7.1

percent Engelmann spruce, and 6.4 percent Douglas-fir.

Each site had three overstory density treatments—uncut,

partial cut, and clearcut. At French Mountain, overstory basal

area densities were 264 square feet per acre in the uncut

treatment, 128 square feet per acre in the partial cut, and zero

in the clearcut treatment. At the Little Big Hole site, overstory

densities were 268 square feet per acre in the uncut treatment,

132 square feet per acre in the partial cut, and zero in the

clearcut treatment.

The French Mountain site was harvested during winter 1994

to 1995, the clearcut was broadcast burned in fall 1995, and

seedlings were planted in spring 1996. Harvesting was done at

the Little Big Hole site during winter 1996 to 1997; slash piles

in the clearcut were burned in the fall 1997, and seedlings were

planted in spring 1998. Environmental variables were recorded in each treatment at both sites with six remote data

loggers. Environmental characteristics will be reported elsewhere (Ferguson and Byrne, in prep.).

Planted Seedlings

Eight 16.5 by 33 foot rectangular plots were spaced within

a 2-acre area in each treatment away from stand boundaries to

reduce edge effects. Five conifer species were tested in each

rectangular plot by planting 10 trees of each species in rows

3.3 feet apart, with 3.3 feet spacing between trees. Within each

rectangular plot, species were assigned randomly to rows. No

trees were planted around the perimeter of the plots because

our previous experience in GFM areas showed that mortality

and differential growth rates among species nullified attempts

to grow uniform plots of trees that were affected on all sides by

competition. Instead, we planted trees far enough apart that

there would be little adjacent competition from other trees for

at least 5 years.

Planted species were Douglas-fir, Engelmann spruce, lodgepole pine, western larch, and western white pine. Seedlings for

the French Mountain site were obtained from local Ranger

District planting stock. Seedlings were 2-0 bareroot stock
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 3

except western white pine, which was 3-0 bareroot stock.

Seedlings for the Little Big Hole site were grown from seed

obtained from the Walla Walla Ranger District except white

pine seed, which came from the Moscow, ID, seed orchard.

Seedlings for Little Big Hole were grown as containerized

stock for 1 year, but loose planting soil was gently shaken from

the roots prior to planting so that roots came in contact with

native soil. Seedlings were genetically adapted to the planting

sites at French Mountain and Little Big Hole (see Rehfeldt

1994), but this means that the same seed sources were not used

at the two sites.

Seedlings were planted at the French Mountain site in spring

1996. Pocket gophers in all three treatments at French Mountain were controlled with strychnine oats (0.5 percent poison)

in 1996 and 1997. The July 21, 1996, application used 4 pounds

of bait in and adjacent to the treatments, and the July 25, 1997,

application used 8.5 pounds of bait. Seedlings were planted at

the Little Big Hole site in spring 1998, and pocket gophers were

not controlled.

A total of 2,400 seedlings were planted. Seedling heights

were recorded each fall for 5 years after shoot elongation had

ceased. Seedling survival and condition were recorded each

spring and fall. The cause of mortality was recorded when it

could be determined; for example, seedlings eaten by pocket

gophers. Seedlings that died were pulled from the ground to

inspect roots for gopher feeding or other causes of death.

Seedling condition included top damage, snow damage,

gopher-caused damage, and damages caused by insects and

diseases.

Additional Plantings

We had the opportunity to test other hypotheses about

seedling survival and growth, but at a smaller scale. At French

Mountain, we tested planting western white pine at different

times of the year. At Little Big Hole, we tested planting older/

larger western white pine (3 years old versus 1 year old) and

Douglas-fir (2 years old versus 1 year old).

The Pierce Ranger District provided additional 3-0 bareroot

western white pine to plant at French Mountain. The spring

planted white pine were planted in 1996 along with the four

other test species described in the previous section. An additional 240 trees from the same nursery stock were transplanted

into containers and grown in a greenhouse in Moscow, ID, until

planted later in the year. In the summer (July 30-31), 120 trees

were planted by adding another 10-tree row to the oddnumbered rectangular plots. In the fall (September 24-26), the

other 120 trees were planted by adding another 10-tree row to

the odd-numbered rectangular plots.

We tested planting larger western white pine and Douglasfir at Little Big Hole. The white pine and Douglas-fir planted

in the test described in the previous section were 1-year-old

containerized stock. An additional 80 3-1 containerized white

pine seedlings were planted alongside the even-numbered

rectangular plots in the clearcut (40 seedlings) and partial cut

(40 seedlings) treatments. The Walla Walla Ranger District

furnished and planted 50 2-0 bareroot Douglas-fir seedlings.

Ten-tree rows of 2-0 Douglas-fir were added to rectangular

plots 1, 5, and 7 in the clearcut, and plots 5 and 7 in the partial

cut treatments.

Data analysis compared seedling heights and survival of

3-0 bareroot white pine planted in the spring, summer, and fall

at French Mountain; 1-0 and 3-1 containerized white pine

planted at Little Big Hole; and 1-0 and 2-0 Douglas-fir planted

at Little Big Hole. The additional seedlings described in this

section were compared only to the same species planted on the

same rectangular plots; thus, the analyses compared side-byside planting success.

Pocket Gopher Activity

A line intercept transect was used to quantify winter pocket

gopher activity. The line transect was installed in each rectangular plot centered between rows 3 and 4 each spring. A

15-foot line segment, beginning 5 feet inside the rectangular

plot, was searched for gopher activity. The gopher activity

index was the number of times the line intersected a winter

gopher mound, cast, or soil plug. Indices were recorded for 5

years after planting.

The purpose of the gopher index was to monitor variation in

gopher populations by plot, treatment, and year. Without some

information on gopher activity, it would be difficult to relate

seedling survival to treatments. For example, seedling survival

in the presence of gopher activity is important information for

interpreting results. Because the indices quantify winter pocket

gopher activity, they can be analyzed for correlation with

percent gopher-caused mortality during the same winter periods. The correlation between the pocket gopher activity index

and percent gopher-caused mortality should be high when

gophers are actively killing seedlings. The correlation would

decline if (1) gophers did not kill or stopped killing seedlings,

(2) there were no more seedlings (or only a few) for the gophers

to kill, or (3) gopher populations declined.

Correlations between the gopher activity index and percent

gopher-caused mortality were done by site and winter time

period, with line transects being the experimental unit. Pearson

correlation coefficients were generated by PROC CORR in

SAS (SAS 1999). The Pearson correlation is a parametric

measure of association for two continuous random variables.

Natural Regeneration and Vegetation

Vegetation response to treatments was sampled on 10

1/300-acre circular plots that were systematically spaced within

a 2-acre area in each treatment away from stand boundaries to

reduce edge effects. The 2-acre area was the same as used for

planted seedlings, but circular vegetation plots did not overlap

the rectangular plots used for planted seedlings. The purpose of

recording vegetation was to document changes in vegetation

and to record any conifer regeneration that became established

after treatment installation.

Vegetation was sampled at French Mountain in 1994

(preharvest), 1996 (second summer following the harvest in

the partial cut and first summer following site preparation in
4 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

the clearcut treatment), and 2003. Vegetation was sampled at

Little Big Hole in 1995 (preharvest), 1997 (first summer

following the harvest, except the uncut treatment was not

sampled), and 2003. Percent canopy coverage was recorded

for shrubs (by species), bracken fern, western coneflower, all

remaining forbs combined, and all grasses combined. The

canopy coverage method described by Daubenmire (1959)

was used to record vegetation, except we used circular plots

instead of rectangular.

Analysis of vegetation data included calculation of average

percent canopy coverage and constancy. Percent canopy coverage is an ocular estimate of the vertical projection of the

foliage on the horizontal plane of the plot, providing data on

species dominance. Some ecologists calculate average coverage based only on the plots where the species occurs (for

example, Cooper and others 1991). We calculated average

percent canopy coverage based on all sample plots; therefore,

our averages can be used to compare average coverage among

species. Constancy is the percentage of plots on which a species

occurs, providing data on dispersion throughout an area.

Results ________________________

The two sites were installed to demonstrate previous research findings, as well as to test different levels of overstory

shade on survival and growth of planted conifers. The sites

differ in several ways—location, habitat type, years of harvest

and site preparation, site preparation method, seed source for

planted seedlings, overstory species, and pocket gopher control. Because there is no replication of treatments within sites

(for example, gopher controlled versus not controlled at each

site), sites cannot be considered as blocks in a randomized

block design (Kirk 1982). Therefore, sites were analyzed

separately.

However, it is important to make comparisons between the

two sites where it is appropriate, such as answering questions

about the effects of overstory shade on regeneration success,

the effects of overstory shade on vegetation development, as

well as similarities and differences between the two sites.

Results from the two sites are discussed together so that readers

can more easily see trends that may be useful in developing

prescriptions for GFM sites.

Planted Seedlings

Mortality—The causes of seedling mortality differed by

gopher control, treatment, and species. The biggest difference

in mortality was whether or not gophers were controlled.

Where gophers were controlled at French Mountain, average

gopher-caused mortality for all five species after 5 years was

only 1.5 percent in the clearcut treatment (table 1). The

corresponding percentage is 51.5 percent at Little Big Hole

where gophers were not controlled. In the partial cut treatment,

gopher-caused mortality averaged 12.7 percent for all species

at French Mountain (gophers controlled) versus 28.0 percent at

Little Big Hole (gophers not controlled).

Table 1—Average gopher-caused seedling mortality (percent)

5 years after planting.

Treatment DF* ES* LP* WL* WP* All

French Mountain

Clearcut 2.5 2.5 0.0 2.5 0.0 1.5

Partial 31.2 6.2 3.8 16.2 6.2 12.7

Uncut 15.0 10.0 17.5 2.5 11.2 11.2

Little Big Hole

Clearcut 56.2 50.0 47.5 50.0 53.8 51.5

Partial 32.5 18.8 14.8 41.2 32.9 28.0

Uncut 15.0 12.5 11.2 12.5 25.0 15.2

*DF =Douglas-fir, ES = Engelmann spruce, LP = lodgepole pine,

WL =western larch, WP = western white pine

Overstory shade was associated with reduced gopher-caused

mortality at Little Big Hole, where gophers were not controlled. All species had substantial declines in gopher-caused

mortality as overstory density increased (table 1). At Little Big

Hole, average gopher-caused mortality for all species was 51.5

percent in the clearcut, 28.0 percent in the partial cut, and 15.2

percent in the uncut treatment.

At the Little Big Hole clearcut treatment, gophers did not

appear to have strong preferences for any species. The average

gopher-caused mortality after 5 years varied from 47.5 percent

for lodgepole pine to 56.2 percent for Douglas-fir (table 1). In

the partial cut treatment at both sites, Engelmann spruce and

lodgepole pine had the lowest gopher-caused mortality relative to the other species.

Gopher-caused mortality by time periods is shown in tables

2 and 3. At French Mountain, gophers were controlled in July

of the first and second summers, and there was virtually no

gopher-caused mortality during those two summers. Gophercaused mortality was extremely low in the clearcut treatment,

even after gophers were no longer controlled. Most additional

gopher-caused mortality at French Mountain occurred in the

partial and uncut treatments during the winter time periods.

At Little Big Hole (no gopher control), most gopher-caused

mortality occurred the first summer, the first winter, and the

second winter (table 3). In the clearcut treatment, gophercaused mortality for all species averaged 14.5 percent the first

summer, 25.2 percent the first winter, and 6.2 percent the

second winter. This means that 89.1 percent of all gophercaused mortality in the clearcut treatment took place during

those three time periods. Corresponding averages for the

partial cut treatment are 1.5 percent the first summer, 12.2

percent the first winter, and 5.5 percent the second winter;

therefore, 68.6 percent of the gopher-caused mortality in the

partial cut treatment took place during those three time periods.

In the uncut treatment, 57.9 percent of all the seedlings that

were killed by gophers died the first summer, first winter, and

second winter.

Another feature about gopher-caused mortality is that it was

higher in some areas of the treatments than in other areas. For
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 5

Table 2—Gopher-caused mortality (percent) by time periods at French Mountain.

Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Cum. %

Species 1122334455 mort.

Clearcut

DF 0.0 1.2 0.0 0.0 0.0 1.2 0.0 0.0 0.0 0.0 2.5

ES 0.0 0.0 1.2 0.0 0.0 0.0 0.0 0.0 1.2 0.0 2.5

LP 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

WL 0.0 0.0 0.0 0.0 0.0 0.0 1.2 1.2 0.0 0.0 2.5

WP 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

All 0.0 0.2 0.2 0.0 0.0 0.2 0.2 0.2 0.2 0.0 1.5

Partial cut

DF 1.2 3.8 0.0 2.5 0.0 16.2 1.2 5.0 1.2 0.0 31.2

ES 0.0 1.2 0.0 1.2 0.0 1.2 0.0 0.0 0.0 2.5 6.2

LP 0.0 0.0 1.2 1.2 0.0 1.2 0.0 0.0 0.0 0.0 3.8

WL 0.0 7.5 0.0 2.5 0.0 1.2 0.0 3.8 1.2 0.0 16.2

WP 0.0 0.0 0.0 1.2 0.0 2.5 1.2 0.0 0.0 1.2 6.2

All 0.2 2.5 0.2 1.7 0.0 4.5 0.5 1.8 0.5 0.7 12.7

Uncut

DF 0.0 0.0 0.0 5.0 0.0 5.0 2.5 0.0 0.0 2.5 15.0

ES 0.0 0.0 0.0 8.8 0.0 1.2 0.0 0.0 0.0 0.0 10.0

LP 0.0 0.0 0.0 3.8 0.0 5.0 3.8 2.5 0.0 2.5 17.5

WL 0.0 0.0 0.0 2.5 0.0 0.0 0.0 0.0 0.0 0.0 2.5

WP 0.0 0.0 0.0 1.2 0.0 7.5 1.2 0.0 0.0 1.2 11.2

All 0.0 0.0 0.0 4.3 0.0 3.7 1.5 0.5 0.0 1.2 11.2

Table 3—Gopher-caused mortality (percent) by time periods at Little Big Hole.

Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Cum. %

Species 1122334455 mort.

Clearcut

DF 8.8 41.2 0.0 3.8 0.0 0.0 0.0 2.5 0.0 0.0 56.2

ES 10.0 18.8 0.0 13.8 0.0 3.8 0.0 2.5 0.0 1.2 50.0

LP 8.8 30.0 2.5 3.8 0.0 1.2 0.0 1.2 0.0 0.0 47.5

WL 13.8 21.2 3.8 5.0 2.5 1.2 0.0 1.2 0.0 1.2 50.0

WP 31.2 15.0 1.2 5.0 0.0 1.2 0.0 0.0 0.0 0.0 53.8

All 14.5 25.2 1.5 6.2 0.5 1.5 0.0 1.5 0.0 0.5 51.5

Partial cut

DF 2.5 15.0 0.0 6.2 0.0 3.8 0.0 3.8 0.0 1.2 32.5

ES 1.2 10.0 0.0 1.2 0.0 2.5 0.0 2.5 0.0 1.2 18.8

LP 0.0 7.4 1.2 5.0 0.0 0.0 0.0 1.2 0.0 0.0 14.8

WL 2.5 12.5 1.2 10.0 0.0 5.0 1.2 3.8 0.0 5.0 41.2

WP 1.2 16.4 3.8 5.0 0.0 3.8 0.0 1.2 0.0 1.3 32.9

All 1.5 12.2 1.2 5.5 0.0 3.0 0.2 2.5 0.0 1.8 28.0

Uncut

DF 2.5 1.2 0.0 0.0 0.0 0.0 3.8 2.5 0.0 5.0 15.0

ES 3.8 2.5 0.0 1.2 0.0 0.0 0.0 0.0 0.0 5.0 12.5

LP 2.5 2.5 1.2 0.0 1.2 1.2 0.0 0.0 0.0 2.5 11.2

WL 3.8 5.0 1.2 0.0 0.0 0.0 2.5 0.0 0.0 0.0 12.5

WP 6.2 12.5 0.0 0.0 0.0 0.0 1.2 1.2 0.0 3.8 25.0

All 3.8 4.8 0.5 0.2 0.2 0.2 1.5 0.8 0.0 3.2 15.2
6 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

example, the eight rectangular plots in the clearcut treatment at

Little Big Hole had a low of 24.0 percent gopher-caused

mortality after 5 years and a high of 84.0 percent. Mortality in

three of the plots was relatively low (24.0, 28.0, 32.0 percent),

two intermediate (42.0, 44.0 percent), and three high (76.0,

82.0, 84.0 percent).

Seedling mortality not caused by gophers was substantial,

and it varied by treatment and species 5 years after planting

(table 4). The uncut treatment had the highest nongophercaused mortality, averaging 67.5 percent at French Mountain

and 47.6 percent at Little Big Hole; both of these averages are

over twice as high as in the clearcut or partial cut treatments.

Most of the mortality not caused by gophers in uncut treatments was attributed to unknown causes. Seedlings probably

died from lack of adequate sunlight in these dense treatments,

especially western larch, which is very intolerant of shade

(Minore 1979).

At both French Mountain and Little Big Hole, 5-year

nongopher mortality rates were similar in the clearcut and

partial cut treatments (table 4). Therefore, partial retention of

the overstory did not increase levels of mortality from nongopher

causes.

Figures 1 and 2 summarize the status of all seedlings,

whether alive after 5 years or dead from various causes. These

figures reinforce two results. First, gopher control resulted in

higher seedling survival in the clearcut treatment (fig. 1).

Second, where gophers were not controlled, the partial cut

treatment resulted in the highest percentage of live trees at

5 years (fig. 2).

The overall survival of planted trees in figures 1 and 2 is

also shown in table 5. At French Mountain (where gophers

were controlled the first two summers), survival is highest in

the clearcut (71.2 percent), intermediate in the partial cut

(54.5 percent), and lowest in the uncut treatment (21.3 percent). The results at French Mountain show that the clearcut

treatment is best for overall survival if gophers are controlled.

At Little Big Hole (where gophers were not controlled),

survival was highest in the partial cut (54.7 percent), intermediate in the uncut stand (37.2 percent), and lowest in the

clearcut treatment (28.2 percent). The results at Little Big

Table 4—Average nongopher seedling mortality (percent) 5

years after planting.

Treatment DF ES LP WL WP All

French Mountain

Clearcut 3.8 25.0 35.1 43.8 28.8 27.3

Partial 17.6 32.5 37.6 47.6 28.8 32.8

Uncut 60.1 70.0 60.0 91.3 56.3 67.5

Little Big Hole

Clearcut 21.3 21.3 12.5 23.8 22.6 20.3

Partial 16.3 16.3 12.4 16.4 25.3 17.3

Uncut 53.8 28.9 46.3 76.3 32.6 47.6

Figure 1—Seedling status 5 years after planting

at French Mountain by species and treatment.

DF=Douglas-fir, ES=Engelmann spruce, LP =

Lodgepole pine, WL=Western larch, WP=White

pine, C=Clearcut, P=Partial cut, U=Uncut. Filled

portions on bars are live trees. Open patterns on

bars are dead trees killed by various causes.

French Mountain

CAUSE Alive Gophers Missing Other Unknown Percent

0

20

40

60

80

100

Species and treatment

D

F

-

C

D

F

-

P

D

F

-

U

E

S

-

C

E

S

-

P

E

S

-

U

L

P

-

C

L

P

-

P

L

P

-

U

W

L

-

C

W

L

-

P

W

L

-

U

W

P

-

C

W

P

-

P

W

P

-

U

Hole show that the partial cut treatment is best for overall

survival if gophers are not controlled.

Western larch had the poorest overall survival of all species

tested (table 5)—a result caused by both gopher and nongopher

causes. Survival of Douglas-fir in the clearcut treatment was

highest at French Mountain (93.7 percent) and lowest at Little

Big Hole (22.5 percent). Lodgepole pine survival ranked

highest among the five species at Little Big Hole in the clearcut

and partial cut treatments. At Little Big Hole in the uncut and

partial cut treatments, Engelmann spruce survival ranked first

and second, respectively, among the five species.

Seedling survival in the uncut treatment was surprisingly

high (table 5). At French Mountain, 21.3 percent of seedlings

were alive after 5 years in the uncut treatment, and 37.2 percent

were alive at Little Big Hole. Western larch, the most shade-
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 7

Figure 2—Seedling status 5 years after planting at

Little Big Hole by species and treatment.

DF=Douglas-fir, ES=Engelmann spruce, LP =

Lodgepole pine, WL=Western larch, WP=White

pine, C=Clearcut, P=Partial cut, U=Uncut. Filled

portions on bars are live trees. Open patterns on

bars are dead trees killed by various causes.

Table 5—Percent seedling survival 5 years after planting.

Treatment DF ES LP WL WP All

French Mountain

Clearcut 93.7 72.5 64.9 53.7 71.2 71.2

Partial 51.1 61.3 58.6 36.2 65.0 54.5

Uncut 24.9 20.0 22.5 6.2 32.5 21.3

Little Big Hole

Clearcut 22.5 28.7 40.0 26.2 23.6 28.2

Partial 51.2 64.9 72.8 42.4 41.8 54.7

Uncut 31.2 58.6 42.5 11.2 42.4 37.2

intolerant species in the study, had the lowest survival in the

uncut treatment.

Growth—Seedling heights 5 years after planting, by species at both sites, were always largest in the clearcut, intermediate in the partial cut, and smallest in the uncut treatment

(table 6). Average seedling heights for the five test species at

French Mountain were 2.6 feet in the clearcut, 1.6 feet in the

partial cut, and 1.0 foot in the uncut treatment. At Little Big

Hole, average seedling heights at 5 years were 2.7 feet in the

clearcut, 1.6 feet in the partial cut, and 0.7 foot in the uncut

treatment. Lodgepole pine and western larch were the tallest of

the five species treated.

Average 5-year heights of seedlings in the uncut treatment

were low. Seedlings in the uncut treatment grew slowly because of the dense overstory shade, and they often had negative

Table 6—Average seedling heights (feet) 5 years after planting.

Treatment DF ES LP WL WP All

French Mountain

Clearcut 2.9 2.4 3.6 3.4 2.4 2.6

Partial 1.8 1.4 1.9 2.2 1.7 1.6

Uncut 1.3 1.1 1.0 1.9* 1.1 1.0

Little Big Hole

Clearcut 1.6 1.7 3.1 4.0 1.5 2.7

Partial 1.2 1.3 1.8 2.0 1.1 1.6

Uncut 0.7 0.8 0.8 1.0* 0.6 0.7

*fewer than 10 trees used to calculate average

Little Big Hole

CAUSE Alive Gophers Missing Other Unknown Percent

0

20

40

60

80

100

Species and treatment

D

F

-

C

D

F

-

P

D

F

-

U

E

S

-

C

E

S

-

P

E

S

-

U

L

P

-

C

L

P

-

P

L

P

-

U

W

L

-

C

W

L

-

P

W

L

-

U

W

P

-

C

W

P

-

P

W

P

-

U

height growth because of terminal damage caused by pocket

gophers, snow, or various other environmental causes.

Damages—The damages that occurred to the five test species were grouped into four categories by site, treatment, and

species. Categories were:

1. Damage to the top of seedlings (terminal broken, terminal

chewed by unknown animal, terminal chewed by gopher,

and terminal dead).

2. Forked (two or more leaders).

3. Severe lean (which we defined as greater than or equal to

40 percent lean from vertical).

4. Gopher damage (branches chewed by gopher, main stem

buried by gopher mound, terminal chewed by gopher

{also included in the top damage category}, lateral branch

chewed by gopher, seedling loose in the soil because of

gopher feeding on the roots, and main stem chewed by

gopher).

Top damage varied from a low of 5.5 percent for Engelmann

spruce in the French Mountain clearcut treatment to 75.8

percent for western larch in the French Mountain uncut treatment (table 7). In nearly every instance, top damage was least

in the clearcut, intermediate in the partial cut, and highest in the

uncut treatment. Western larch was clearly the species with the

most top damage.
8 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

The percentage of seedlings with forked tops varied from 4.1

percent for western larch in the Little Big Hole uncut treatment

to 23.8 percent for Douglas-fir in the Little Big Hole clearcut

treatment (table 7). Even though the percentage of seedlings

with top damage increased with increasing overstory density,

the percentage of seedlings with forked tops did not follow the

same trend. For example, western larch had 75.8 percent top

damage in the French Mountain uncut treatment, but only 7.6

percent forking. Across all treatments and sites, Engelmann

spruce had the least forking (11.7 percent) and Douglas-fir had

the most forking (17.1 percent).

Snow damage to seedlings was common. The number of

leaning trees was always highest in the spring inventories and

lowest in the fall inventories. Seedlings frequently recovered

from snowlean during the summer. The average percentages of

seedlings with severe lean are shown in table 7. Averages

varied from 0.4 percent for lodgepole pine in the French

Mountain clearcut treatment to 39.1 percent for western larch

in the Little Big Hole uncut treatment. Severe lean increased

with increasing overstory density, except for Engelmann spruce

at Little Big Hole. Across all treatments and sites, there were

low averages for Engelmann spruce (2.5 percent), intermediate averages for white pine (7.0 percent), Douglas-fir (8.0

percent), and lodgepole pine (8.3 percent), and high averages

for western larch (18.8 percent).

Seedlings eventually grew large enough to withstand the

heavy snow loads, and since seedling growth was negatively

related to overstory density, seedlings in the clearcut treatment

were the first to become large enough to withstand snow loads

(table 8). Engelmann spruce had the lowest number of winter

time periods where severe lean occurred on greater than or

equal to10 percent of the seedlings versus highest averages for

Table 7—Percent of damaged seedlings by site, treatment, species, and cause of damage 5 years since

planting.

Damage French Mountain Little Big Hole

category Species Clearcut Partial Uncut Clearcut Partial Uncut

Top DF 13.5 23.8 32.0 8.9 12.0 33.4

ES 6.4 14.9 36.4 5.4 5.5 18.9

LP 7.2 18.1 43.9 17.0 10.0 32.3

WL 21.3 49.9 75.8 23.0 23.6 40.0

WP 5.0 10.3 40.1 16.2 16.2 30.0

Forked DF 17.7 13.3 7.9 23.8 18.6 21.4

ES 8.9 12.8 9.5 9.6 12.1 17.5

LP 11.1 11.9 9.3 22.8 13.6 17.0

WL 16.6 19.8 7.6 16.6 13.3 4.1

WP 10.2 11.4 12.3 18.6 18.5 20.4

≥40% lean DF 1.4 10.9 18.7 2.1 3.8 11.3

ES 0.6 3.5 3.5 1.6 0.9 5.0

LP 0.4 5.2 19.1 3.2 3.5 18.4

WL 3.7 21.3 28.4 8.1 12.3 39.1

WP 1.9 8.0 17.1 3.3 4.6 7.4

Gopher DF 1.0 5.1 6.4 8.2 6.2 9.0

ES 0.8 3.1 7.4 4.5 3.2 10.0

LP 1.1 3.0 7.1 9.1 5.7 11.7

WL 0.6 6.2 9.5 7.1 8.2 6.6

WP 0.4 3.6 9.4 9.5 6.7 11.1

Table 8—Number of winters (out of five) when severe lean (≥40 percent from vertical)

occurred on ≥10 percent of the seedlings.

French Mountain Little Big Hole

Species Clearcut Partial Uncut Clearcut Partial Uncut

DF 0 2 4 12 4

ES 0 1 2 00 2

LP 0 3 5 11 4

WL 1 5 5 34 5

WP 1 3 5 12 2
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 9

lodgepole pine and western larch. Across all treatments and

sites, severe lean occurred approximately the first winter in the

clearcut, winters 1 and 2 in the partial cut, and winters 1

through 3 in the uncut treatment (data not shown).

Nonlethal pocket gopher damages to seedlings varied

from 0.4 percent for white pine in the French Mountain

clearcut treatment to 11.7 percent for lodgepole pine in the

Little Big Hole uncut treatment (table 7). In general, gophercaused damages were less at French Mountain, where gophers

were controlled for 2 years, compared to Little Big Hole,

where gophers were not controlled. At French Mountain,

gopher-caused damages increased with increasing shade. At

Little Big Hole, gopher-caused damages were lowest in the

partial cut treatment, except for western larch. Within treatment and site, there were no strong differences between the

five test species relative to gopher damages.

Additional Plantings

Table 9 shows summary statistics for the summer and fall

planted western white pine at French Mountain compared to

the spring planted white pine. Each planting time has 120 trees

(3 treatments x 4 rectangular plots x 10 tree rows).

Few trees were killed by pocket gophers in the clearcut

treatment, while more trees were killed by gophers in the

partial and uncut treatments (table 9). Within the partial and

uncut treatments, more summer and fall planted white pine

were killed by gophers than spring planted seedlings. A total of

12.5 percent of spring planted white pine were killed by

gophers in the partial cut treatment, while 30.0 percent of the

summer and 20.0 percent of the fall planted white pine were

killed by gophers. Similarly, 7.5 percent of the spring planted

white pine were killed by gophers, while 20.0 percent of the

summer planted and 17.5 percent of the fall planted white pine

were killed by gophers. In the partial cut and uncut treatments,

gopher-caused mortality remained relatively high during the

third winter for summer planted and fall planted white pine

(data not shown).

Generally, death from nongopher causes increased as the

amount of overstory shade increased, regardless of planting

time (table 9). A large difference in mortality occurred in the

clearcut treatment where only 17.5 percent of summer-planted

white pine died from nongopher causes, while 35.0 percent of

the spring-planted and 32.5 percent of the fall-planted white

pine died from nongopher causes.

Overall survival of the three planting times for white pine

was always highest in the clearcut, intermediate in the

partial cut, and lowest in the uncut treatments (table 9).

Summer-planted white pine had the highest overall survival

(80.0 percent) in the clearcut, but had the lowest survival

(27.5 percent) in the uncut treatment. In the partial cut

treatment, spring-planted white pine had the best overall

survival (62.5 percent).

There is a definite trend of declining 5-year heights of white

pine with later plantings (table 9). For example, seedling

heights in the clearcut treatment after 5 years were 2.4 feet for

spring planting, 1.3 feet for summer planting, and 1.0 foot for

fall planting. The partial and uncut treatments follow the same

trend. Also, there is a clear decline in heights as the amount of

overstory shade increases.

Table 10 shows summary statistics for 3-1 versus 1-0 western white pine and 2-0 versus 1-0 Douglas-fir at Little Big

Hole. Each age class for white pine has 80 trees (2 treatments x 4 rectangular plots x 10 tree rows). Douglas-fir age

classes have 30 trees each in the clearcut treatment and 20 trees

each in the partial cut treatment.

There was higher gopher-caused mortality for 3-1 white pine

(75.0 percent) versus 1-0 (60.0 percent) in the clearcut, with the

same trend in the partial cut treatment (table 10). However,

death from nongopher causes was much lower for 3-1 versus

1-0 white pine. The 3-1 white pine in the clearcut treatment had

zero percent nongopher-caused mortality after 5 years, while

there was 17.5 percent for 1-0 white pine. The partial cut

treatment was similar, with 5.0 percent nongopher-caused

mortality for 3-1 white pine versus 25.0 percent for 1-0 white

pine.

Overall survival was slightly higher in the clearcut treatment

for 3-1 white pine (25.0 percent) versus 1-0 (22.5 percent), and

survival in the partial cut treatment was higher for 3-1 white

pine (62.5 percent) versus 1-0 (47.5 percent). Also, survival

was much higher for white pine in the partial cut than the

clearcut treatment.

Seedlings were taller for 3-1 white pine than 1-0 (table 10).

After 5 years, 3-1 white pine seedlings were approximately

twice the height of 1-0 seedlings in both the clearcut and partial

Table 9—Fifth year summary statistics for spring-, summer-,

and fall-planted western white pine at French

Mountain.

Spring Summer Fall

Treatment planted planted planted

Death caused by gophers (%)

Clearcut 0.0 2.5 0.0

Partial 12.5 30.0 20.0

Uncut 7.5 20.0 17.5

Dead from nongopher causes (%)

Clearcut 35.0 17.5 32.5

Partial 25.0 22.5 35.0

Uncut 55.0 52.5 45.0

Alive (%)

Clearcut 65.0 80.0 67.5

Partial 62.5 47.5 45.0

Uncut 37.5 27.5 37.5

Average seedling heights (feet)

Clearcut 2.4 1.3 1.0

Partial 1.6 1.0 0.8

Uncut 1.1 0.5 0.5
10 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

cut treatments. Both 3-1 and 1-0 white pine were taller in the

clearcut than the partial cut treatment.

Planting success for the 2-0 Douglas-fir was much better

than for 1-0 Douglas-fir (table 10). Pocket gophers killed

63.3 percent of 1-0 Douglas-fir in the clearcut treatment, but

only 6.7 percent of 2-0 Douglas-fir. Similarly, gophers killed

40.0 percent of the 1-0 Douglas-fir in the partial cut treatment,

but only 5.0 percent of the 2-0 Douglas-fir. Death from nongopher causes in the clearcut treatment was 20.0 percent for

1-0 Douglas-fir and 3.3 percent for 2-0. No Douglas-fir seedlings died from nongopher causes in the partial cut treatment.

Overall survival of Douglas-fir in the clearcut treatment was

lowest for 1-0 seedlings (16.7 percent) and highest for 2-0

seedlings (90.0 percent). Survival of Douglas-fir in the partial

cut treatment was lowest for 1-0 seedlings (60.0 percent)

versus 2-0 seedlings (95.0 percent). As was the case with white

pine, overall survival of Douglas-fir was higher in the partial

cut than the clearcut treatment, especially for the 1-0 seedlings.

Seedling heights were taller for 2-0 versus 1-0 Douglas-fir in

both the clearcut and partial cut treatments (table 10). For

example, 2-0 Douglas-fir were 3.2 feet tall after 5 years in the

clearcut treatment, while 1-0 Douglas-fir were 1.5 feet tall.

Both 2-0 and 1-0 Douglas-fir were taller in the clearcut than the

partial cut treatment.

Pocket Gopher Activity

An average winter pocket gopher activity index was calculated from the line transects installed in the rectangular plots.

For each 15 foot line transect, we counted the number of times

the line intersected a pocket gopher mound, cast, or soil plug.

At French Mountain for the 3 years when gophers were not

controlled (1998 to 2000), the average gopher activity index

was 2.1 in the clearcut, 4.5 in the partial cut, and 1.2 in the uncut

treatments. At Little Big Hole, the 5-year (1998 to 2002)

gopher activity index was 4.9 in the clearcut, 4.1 in the partial

cut, and 1.9 in the uncut treatments.

Pearson correlation coefficients between the gopher activity

index and gopher-caused mortality to planted seedlings during

winter time periods are shown in table 11, and scatter plots are

shown in figure 3. At French Mountain where gophers were

controlled in the summers of 1996 and 1997, the gopher

Table 10—Summary statistics for 3-1 versus 1-0 western white pine and 2-0

versus 1-0 Douglas-fir at Little Big Hole 5 years after planting.

WP WP DF DF

Treatment 1 year old 3 years old 1 year old 2 years old

Death caused by gophers (%)

Clearcut 60.0 75.0 63.3 6.7

Partial 27.5 32.5 40.0 5.0

Dead from nongopher causes (%)

Clearcut 17.5 0.0 20.0 3.3

Partial 25.0 5.0 0.0 0.0

Alive (%)

Clearcut 22.5 25.0 16.7 90.0

Partial 47.5 62.5 60.0 95.0

Average seedling heights (feet)

Clearcut 1.7 3.3 1.5 3.2

Partial 1.1 1.8 1.0 1.7

Table 11—Pearson’s correlation coefficients showing correlation between pocket gopher activity index and gophercaused mortality to planted seedlings, by site.

French Mountain Little Big Hole

Winter Gopher % gopher-caused Gopher % gopher-caused

number activity index mortality Correlation activity index mortality Correlation

1 0.58 0.92 0.02 4.25 14.08 0.72*

2 2.12 2.00 0.82* 3.63 4.00 0.60*

3 2.00 2.83 0.48* 3.08 1.58 0.02

4 2.58 0.83 0.35 3.33 1.58 0.03

5 3.21 0.67 0.25 3.79 1.83 0.38

* significant at the 0.05 confidence level
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 11

Figure 3—Scatter plots of gopher-caused seedling mortality

(natural log scale) versus the gopher activity index.

French Mountain

ln(%mortality)

-3

-2

-1

0

1

2

3

4

Gopher activity index

01234567

Little Big Hole

ln(%mortality)

-3

-2

-1

0

1

2

3

4

Gopher activity index

01234567

activity indices account for virtually no correlation with

gopher-caused mortality the first winter (0.02), a significant

correlation the second winter (0.82), a smaller but still significant correlation in winter 3 (0.48), and nonsignificant correlations in winters 4 (0.35) and 5 (0.25). The pocket gopher index

was low in all three treatments the first winter after planting,

which likely resulted from pocket gopher control. Significant

correlations during the second and third winters agree with

high gopher-caused seedling mortality during winters 2 and 3

(table 2).

At the Little Big Hole site where gophers were not controlled, the correlation between pocket gopher activity and

gopher-caused mortality is significant the first and second

winters (0.72 and 0.60, respectively), then is nonsignificant in

winters 3, 4, and 5. Significant correlations during the first and

second winters agree with high gopher-caused seedling mortality during winters 1 and 2 (table 3). Gopher activity continued after the second winter, but gophers killed few additional

seedlings.

Natural Regeneration and Vegetation

The 1/300-acre circular plots were used to record natural

regeneration and vegetation development. There were 10 circular plots in each site/treatment combination.

Establishment of natural regeneration by 2003 was sparse.

The best stocking was found in the clearcut treatment at

French Mountain, where 13 seedlings were found on eight of

the 10 1/300-acre circular plots, totaling 390 trees per acre.

Species composition was Douglas-fir, Engelmann spruce, and

grand fir. Only three seedlings were found on two plots in the

partial cut treatment at French Mountain, and no seedlings

were found in the uncut treatment.

In 2003, seven seedlings were found on five plots in the

clearcut treatment at Little Big Hole, totaling 210 trees per

acre. Species in the clearcut were Engelmann spruce (three

trees), grand fir (three), and western larch (one). Four plots

were stocked with seven seedlings in the partial cut treatment

(210 trees per acre), consisting of Douglas-fir (one tree),

Engelmann spruce (two), and grand fir (four). The uncut

treatment at Little Big Hole had only one tree on 10 plots—a

lodgepole pine.

Nonconifer vegetation responded differently to the treatments, yet responses by species were similar at both sites. We

chose five species for analysis that had the highest constancy

during the study to characterize vegetation dynamics initiated

by the treatments.

Rocky Mountain maple (Acer glabrum) coverage decreased

over time in the clearcut treatment from pretreatment averages

of 3.0 percent at French Mountain and 2.3 percent at Little Big

Hole to nearly absent in 2003 (table 12). Coverage declined

only slightly in the partial cut treatment. Constancy (the

percentage of plots with maple) declined an average of 22.5

percent over time in both the clearcut and partial cut treatments

at both sites (table 13). Most of the decline in maple coverage

took place between the pre- and postharvest inventories, but

most of the decline in constancy took place after the postharvest

inventory.

Pacific yew (Taxus brevifolia) had moderate coverage and

constancy before the clearcut treatment, but was entirely gone

in 2003 at both clearcut sites (tables 12 and 13). The largest

decline was between the pre- and postharvest inventories. Yew
12 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

Table 12—Percent coverage of representative plant species, by site, treatment, and year.

French Mountain Little Big Hole

Preharvest Postharvest Postharvest Preharvest Postharvest Postharvest

Species* Treatment (1994) (1996) (2003) (1995) (1997) (2003)

ACGL Clearcut 3.0 0.3 0.1 2.3 0.1 0.0

Partial 5.7 4.2 4.2 0.7 0.3 0.6

Uncut 2.1 3.1 2.3 0.2 – 0.1

TABR Clearcut 10.5 0.0 0.0 0.4 0.1 0.0

Partial 15.5 8.3 10.0 0.4 0.2 0.1

Uncut 9.0 9.6 7.7 18.3 – 15.2

VAME Clearcut 6.1 0.5 0.8 0.3 0.2 0.1

Partial 8.3 7.4 11.3 0.4 0.2 0.5

Uncut 17.2 19.1 19.2 0.7 – 1.2

PTAQ Clearcut 1.6 5.2 18.2 2.8 2.5 8.8

Partial 0.1 1.7 1.1 3.0 1.0 5.5

Uncut 0.6 0.6 1.1 12.3 – 3.4

RUOC Clearcut 0.0 0.0 0.2 3.4 4.2 40.5

Partial 0.1 2.1 4.6 0.7 1.2 14.7

Uncut 1.7 4.1 3.1 1.6 – 2.9

*ACGL = Acer glabrum (Rocky Mountain maple); TABR = Taxus brevifolia (Pacific yew); VAGL = Vaccinium membranaceum (big huckleberry);

PTAQ = Pteridium aquilinum (bracken fern); RUOC = Rudbeckia occidentalis (western coneflower); – = no data

Table 13—Constancy (percent) of representative plant species, by site, treatment, and year.

French Mountain Little Big Hole

Preharvest Postharvest Postharvest Preharvest Postharvest Postharvest

Species Treatment (1994) (1996) (2003) (1995) (1997) (2003)

ACGL Clearcut 30 30 10 40 10 0

Partial 80 60 60 30 30 20

Uncut 30 40 50 20 – 10

TABR Clearcut 20 0 0 40 10 0

Partial 40 70 70 40 20 10

Uncut 20 30 40 90 – 70

VAME Clearcut 40 10 40 30 20 10

Partial 80 60 70 40 20 50

Uncut 60 50 60 70 – 80

PTAQ Clearcut 70 70 100 70 80 80

Partial 10 30 20 90 60 90

Uncut 20 20 20 70 – 70

RUOC Clearcut 0 0 20 70 70 100

Partial 10 20 30 70 80 100

Uncut 30 30 30 20 – 60

coverage declined slightly after the partial cut treatment at

French Mountain, but constancy increased. Yew coverage and

constancy both decreased over time at the Little Big Hole

partial cut treatment, which was also the trend in the uncut

treatment.

Big huckleberry (Vaccinium membranaceum) coverage

declined in the clearcut treatment at both sites and is barely

represented in the 2003 inventory (table 12). In the partial cut

treatment, huckleberry coverage showed slight declines

after treatment and is increasing slightly over pretreatment

coverages (table 12), and constancy follows this same pattern

(table 13).

Bracken fern increased in coverage and constancy after the

clearcut and partial cut treatments at both sites. Increases in

bracken were largest at French Mountain compared to Little

Big Hole. In the French Mountain clearcut treatment, average

bracken coverage increased from 1.6 percent pretreatment to

18.2 percent in 2003 (table 12). At the Little Big Hole clearcut
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 13

treatment, average bracken coverage increased from 2.8 percent pretreatment to 8.8 percent in 2003. Constancy of bracken

in 2003 is 100 percent at French Mountain and 80 percent at

Little Big Hole in the clearcut treatment (table 13). Bracken

coverage increased slightly in the partial cut treatment at both

sites.

Western coneflower increased in coverage and constancy

after the clearcut and partial cut treatments at both sites.

Increases in coneflower were largest at Little Big Hole compared to French Mountain. Average coverage for western

coneflower increased from 3.4 percent preharvest to 40.5

percent in 2003 at Little Big Hole in the clearcut treatment

(table 12). Average coverage of coneflower in the French

Mountain clearcut treatment was only 0.2 percent in 2003, but

constancy had increased from zero to 20 percent. Constancy of

coneflower at Little Big Hole in 2003 is 100 percent in both the

clearcut and partial cut treatments (table 13). Western coneflower coverage increased somewhat in the partial cut treatment at both sites—from 0.1 percent pretreatment to 4.6

percent in 2003 at French Mountain, and from 0.7 percent

pretreatment to 14.7 percent in 2003 at Little Big Hole.

In table 14 we summarize the relationship between the

combined coverage of shrubs and the combined coverage of

bracken/coneflower. The average sum of coverages for individual shrubs was compared to the average sum of coverages

for bracken and coneflower by site and treatment. In the

clearcut treatment, there is a decline in the sum of coverages for

shrubs, especially at French Mountain where average preharvest

coverage of 20.9 percent dropped to 3.5 percent in 2003. There

is a corresponding increase in bracken/coneflower in the

clearcut treatment; increasing from 1.6 percent preharvest to

18.4 percent in 2003 at French Mountain, and increasing from

6.2 percent preharvest to 49.3 percent in 2003 at Little Big

Hole. In the partial cut treatment, shrub cover decreases over

time, with a corresponding increase in bracken/coneflower

coverage; however, the changes are not large compared to the

changes occurring in the clearcut treatment.

In addition to increases in bracken fern and western coneflower constancy, other forb species increased or decreased

substantially as a result of the treatments. Forb species that

decreased following treatment were pathfinder (Adenocaulon

bicolor), queen cup beadlily (Clintonia uniflora), and starry

Solomon-seal (Maianthemum stellatum = Smilacina stellata).

Pathfinder constancy decreased in the clearcut treatment

from 100 percent preharvest to 70 percent in 2003 at French

Mountain, and from 90 percent preharvest to 30 percent in

2003 at Little Big Hole. Constancy at both sites in the partial

cut treatment remained about the same.

Constancy of queen cup beadlily decreased in the clearcut

treatment from 90 percent preharvest to 30 percent in 2003 at

French Mountain, and from 40 percent pretreatment to 0 percent

in 2003 at Little Big Hole. Constancy at both sites in the partial

cut treatment remained about the same.

Starry Solomon-seal constancy decreased in the clearcut

treatment at both sites but stayed about the same in the partial

cut treatment. At French Mountain, constancy decreased in the

clearcut treatment from 80 percent preharvest to 10 percent in

2003. At Little Big Hole, the decrease was from 100 percent

preharvest to 60 percent in 2003.

Forb species that increased substantially following treatment were fireweed (Chamerion spp. = Epilobium spp.),

strawberry (Fragaria vesca), globemallow (Iliamna rivularis),

varileaf phacelia (Phacelia heterophylla), and thistle species

(Cirsium spp.).

Fireweed constancy increased in both the partial cut and

clearcut treatments. Preharvest constancy was zero in both

treatments at both sites. By 2003, fireweed constancy increased to 10 percent in the French Mountain partial cut, 70

percent in the French Mountain clearcut, and 80 percent each

in the Little Big Hole partial cut and clearcut treatments.

Strawberry increased in both the partial cut and clearcut

treatments at both sites. At French Mountain, constancy increased from 30 percent preharvest in the partial cut treatment

to 80 percent in 2003, and from 20 percent preharvest in the

clearcut treatment to 100 percent in 2003. At Little Big Hole,

constancy increased from 70 percent preharvest in the partial

cut treatment to 80 percent in 2003, and from 60 percent

preharvest in the clearcut treatment to 100 percent in 2003.

Globemallow was quite interesting because of high

postharvest constancy in the French Mountain clearcut, the

only place where this species was recorded. Globemallow

stores seed in the soil, which then germinates following fires

(see Smith and Fischer 1997). Probably as a result of the

broadcast burn site preparation in the French Mountain clearcut

treatment, globemallow constancy increased from zero perTable 14—Average sum of coverages (percent) for shrubs versus average sum of coverages for bracken/coneflower.

French Mountain Little Big Hole

Preharvest Postharvest Postharvest Preharvest Postharvest Postharvest

Treatment Lifeform (1994) (1996) (2003) (1995) (1997) (2003)

Clearcut Shrubs 20.9 2.6 3.5 4.4 1.1 3.4

PTAQ/RUOC 1.6 5.2 18.4 6.2 6.7 49.3

Partial Shrubs 33.7 25.3 29.8 3.8 1.8 2.7

PTAQ/RUOC 2.0 3.8 5.7 3.7 2.2 20.2

Uncut Shrubs 31.2 36.3 31.1 21.1 – 20.3

PTAQ/RUOC 2.3 4.7 4.2 13.9 – 6.3
14 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

cent preharvest to 90 percent postharvest. New seeds from

these globemallow plants are probably now stored in the soil,

awaiting the next fire.

Varileaf phacelia increased following treatment at both sites

in both the partial cut and clearcut treatments. No phacelia

were recorded preharvest at French Mountain, but constancy in

2003 was 20 percent in the partial cut and 90 percent in the

clearcut treatment. At Little Big Hole, phacelia constancy

increased from 10 percent preharvest in the partial cut to 70

percent in 2003, and from 30 percent preharvest to 90 percent

in 2003 in the clearcut treatment.

Thistles were not recorded in the preharvest inventory at

French Mountain, but in 2003, constancies were 10 percent in

the partial cut and 100 percent in the clearcut treatment. At

Little Big Hole, thistle constancy increased from zero preharvest

to 50 percent in 2003 in the partial cut, and from 20 percent

preharvest to 70 percent in 2003 in the clearcut treatment.

Discussion _____________________

This study quantifies the tradeoffs among three levels of

overstory density for plantation success, pocket gopher activity, and vegetation development.

If pocket gophers were controlled, the clearcut treatment

was best for meeting reforestation objectives because of higher

seedling survival and better growth rates. Gopher-caused

mortality was only 1.5 percent at French Mountain where

gophers were controlled versus 51.5 percent at Little Big Hole

where gophers were not controlled. Nongopher causes of

mortality were lower in the clearcut treatment, so overall

seedling survival was highest in the clearcut treatment where

gophers were controlled. For example, overall survival after

5 years in the French Mountain clearcut treatment averaged

71.2 percent for the five test species, while overall survival in

the French Mountain partial cut treatment averaged 54.5 percent. Also, seedling heights were tallest in the clearcut treatment at both sites, regardless of gopher control. Average 5-year

seedling heights in the clearcut treatment were 2.4 times taller

than in the partial cut treatment at French Mountain, and 1.9

times taller than in the partial cut treatment at Little Big Hole.

Seedlings in the uncut treatment grew very little.

If pocket gophers were not controlled, the partial cut treatment was best for meeting reforestation objectives because

fewer seedlings were killed by gophers and seedling growth

was adequate, compared to the clearcut treatment. At Little Big

Hole (no gopher control), gophers killed 51.5 percent of the

five test species within 5 years of planting in the clearcut

treatment, while only 28.0 percent of seedlings were killed by

gophers in the partial cut, and 15.2 percent were killed in the

uncut treatment. Compared to the clearcut treatment, the

partial cut treatment had lower gopher-caused mortality (28.0

versus 51.5 percent) and lower nongopher-caused mortality

(17.3 versus 20.3 percent). Therefore, overall seedling survival was highest in the partial cut (54.7 percent), intermediate

in the uncut (37.2 percent), and lowest in the clearcut treatment

(28.2 percent). The partial cut treatment did not increase

nongopher-caused mortality to seedlings relative to the clearcut

treatment. Seedling heights were not as tall in the partial cut

versus clearcut treatment; however, the nearly double survival

in the partial cut versus clearcut treatment compensates for

slower growth.

Of the seedling mortality caused by pocket gophers, most of

it occurred during the first summer, the first winter, and the

second winter after planting. At Little Big Hole, 89.1 percent

of all the gopher-caused mortality in the clearcut treatment

took place the first summer, first winter, and second winter.

Corresponding averages were 68.6 percent for the partial cut

and 57.9 percent for the uncut treatment. The finding of highest

gopher-caused mortality during the first summer, first winter,

and second winter is consistent with other research (Crouch

1971, Ferguson 1999).

Knowledge of the time periods when pocket gophers kill

seedlings in GFM plantations allows managers to plan control

strategies and design silvicultural prescriptions. If the objective is to reduce gopher predation on planted seedlings, our

data suggest that gophers would need to be controlled prior to

or at the time of spring planting, and throughout the summer if

necessary. Before the end of the first summer (prior to the first

winter time period), gophers may need to be controlled again

because juvenile pocket gophers disperse in late spring, summer, or early fall (Marsh and Steele 1992). Gophers should

again be controlled before the second winter. The objective of

fall gopher control is to control gophers as late as possible (so

the tunnels are not reinvaded prior to winter) but early enough

that a thorough job can be done finding the gopher tunnels.

There appears to be no reason to control gophers in the

spring/early summer beyond the first summer. Gophers preferentially feed on forbs that are plentiful during the growing

season (Marsh and Steele 1992), and they killed few seedlings

during the summers (other than the first summer after planting)

in this and other studies (Crouch 1971, Ferguson 1999).

Increasing overstory density at Little Big Hole was associated with decreased pocket gopher activity. The 5-year average gopher activity index at Little Big Hole was 4.9 in the

clearcut, 4.1 in the partial cut, and 1.9 in the uncut treatment.

It is also interesting to note that gophers are present in uncut

forests, which means that gophers do not need to invade a

newly disturbed area because they are already present in

undisturbed areas.

There was not a strong preference by pocket gophers for

any of the five conifer species planted in the clearcut

treatment. At Little Big Hole in the clearcut treatment,

average 5-year gopher-caused mortality varied from a low

of 47.5 percent for lodgepole pine to a high of 56.2 percent

for Douglas-fir, a range of only 8.7 percent. Gopher-caused

mortality to Engelmann spruce and lodgepole pine were

relatively low in the partial cut treatment at both sites,

which translated to high overall survival of spruce and

lodgepole in the partial cut treatment. White pine also had

lower gopher-caused mortality and high overall survival in

the partial cut treatment at French Mountain.
USDA Forest Service Res. Pap. RMRS-RP-53. 2005 15

The additional plantings provided information about options for managing GFM sites. The summer- and fall-planted

white pine had higher gopher-caused mortality versus springplanted in the partial and uncut treatments, so no advantage

was gained by a delayed planting time. Delayed planting had

a large negative effect on 5-year heights. Average seedling

heights of spring-planted white pine in the clearcut treatment

at French Mountain were 2.4 feet versus 1.3 feet for summerplanted and 1.0 foot for fall-planted white pine. Similar trends

occurred in the partial and uncut treatments. Therefore, delayed planting was not beneficial for survival or growth.

The summer and fall plantings tested the idea of delayed

planting to avoid anticipated gopher-caused mortality the first

summer. An alternative test would be to plant seedlings in the

fall before the usual spring planting; this schedule may have

merit and should be tested because the seedlings would have

time to acclimate to the planting site, expand their root systems,

and begin growth early the next spring. However, fall-planted

seedlings may be vulnerable to gopher predation during the

winter when preferred food sources are not available.

Planting older/larger seedlings was helpful—both for increased survival and growth. The 2-0 Douglas-fir planted at

Little Big Hole had less gopher-caused mortality than the

1-0 Douglas-fir (6.7 versus 63.3 percent in the clearcut, and

5.0 versus 40.0 percent in the partial cut treatment). Death from

nongopher causes was also higher for 1-0 Douglas-fir, compared to 2-0 planting stock. Douglas-fir heights after 5 years

were about double for 3-0 Douglas-fir (3.2 feet for 2-0 and

1.5 feet for 1-0) in the clearcut, and 1.7 times larger in the

partial cut treatment.

Compared to the 1-0 white pine, the 3-1 white pine had

higher gopher-caused mortality (75.0 versus 60.0 percent in

the clearcut, and 32.5 versus 27.5 percent in the partial cut

treatment), but 1-0 white pine had much higher mortality

from nongopher causes. The 3-1 white pine were about twice

as tall as 1-0 white pine (3.3 feet versus 1.7 feet) in the clearcut,

and 1.6 times taller in the partial cut treatment (1.8 feet versus

1.1 feet).

The close spacing for planted seedlings (3.3 by 3.3 feet) was

necessary for accurately relocating the exact planting spot to

determine if the seedling was still alive and, if not, the cause of

death. It is certainly possible that close spacing resulted in

higher gopher-caused mortality, but this conclusion cannot be

made based on available data, and we know of no studies that

have tested this hypothesis. The effect of planting density will

depend on pocket gopher density, size and shape of gopher

home ranges, and availability of alternative forage. Even if

gopher-caused mortality were higher because of close spacing,

relative comparisons among treatments and by time periods

are still valid.

Overstory density had a dramatic effect on vegetation development. The clearcut treatment at French Mountain became

dominated by bracken fern, and the Little Big Hole clearcut

treatment by western coneflower. Meanwhile, shrubs present

before treatment became nearly nonexistent after treatment.

Coverage and constancy of Rocky Mountain maple decreased

in the clearcut treatment at both sites (from 2.6 percent preharvest

to 0.05 percent at 8 and 9 years, and constancy decreased from

35 to 5 percent). Pacific yew, which has a shrubby growth form

in the GFM, had an average of 5.5 percent coverage and 30

percent constancy in the clearcut treatment, but decreased to

zero coverage and constancy at 8 and 9 years. Big huckleberry

also decreased in coverage (from 3.2 to 0.4 percent) and

constancy (from 35 to 25 percent).

Conversely, bracken fern and western coneflower increased

rapidly in the clearcut treatment. At French Mountain in the

clearcut treatment, bracken coverage increased from 1.6 to

18.2 percent in 9 years, and constancy increased from 70 to 100

percent. At Little Big Hole in the clearcut treatment, coneflower coverage increased from 3.4 to 40.5 percent, and

constancy increased from 70 to 100 percent. There is a clear

transition in the clearcut treatment from a shrub-dominated

understory preharvest to bracken/coneflower dominance

postharvest.

The partial cut treatment retained good shrub representation

while limiting development of bracken and coneflower. Coverage and constancy of Rocky Mountain maple decreased only

slightly (coverage decreased 0.8 percent), Pacific yew coverage decreased only 2.9 percent, and big huckleberry coverage

increased slightly in the partial cut treatment (1.6 percent).

Bracken coverage in the partial cut treatment at French Mountain increased only 1.0 percent, and coneflower coverage in the

partial cut treatment at Little Big Hole increased 14.0 percent.

As was the case with pocket gophers, bracken fern and

western coneflower are present under dense overstory canopies. Bracken is poised to respond to disturbances by rapid

growth of rhizomes. Coneflower increases following disturbances with larger plants and increased number of plants via

seeds.

None of the treatments resulted in adequate natural regeneration within a 5-year timeframe. This finding agrees with our

observations at other GFM sites: the process of natural

regeneration following disturbance of GFM sites is slow and

unreliable.

Planted Engelmann spruce did well in these tests. Gophercaused mortality was low, overall survival was high, growth

was adequate, percent top damage was low, percent forking

was low, and percent severe lean was low. Spruce was also a

recommended species in another GFM study (Ferguson 1999).

Lodgepole pine also had low mortality caused by gophers

and good overall survival. Heights were almost always the

tallest among the five test species. Snow damage is a big

concern for lodgepole pine (Ferguson 1999). We have seen

several lodgepole pine plantations in the GFM where trees

have severe lean, twisting, and broken stems. In these plantations, it appears that lodgepole may not be well adapted to snow

loads in the GFM, so managers should evaluate the potential

for snow damage to lodgepole pine. Interesting, it is unusual to

find naturally occurring lodgepole pine in the GFM (Ferguson

and Johnson 1996).

Western larch grew well in the clearcut treatment, but this

species performed poorly in the partial cut and uncut treatments.
16 USDA Forest Service Res. Pap. RMRS-RP-53. 2005

Larch had the highest mortality from nongopher causes, had a

high percentage of top damage, had a high percentage of severe

lean, and took a relatively long time to withstand snow loads.

Ferguson (1999) reported that western larch had the highest

incidence of top damage at other GFM sites. Also, Haig and

others (1941) reported that western larch had the highest percentage of trees killed by snow damage, compared to Douglasfir, lodgepole pine, and western white pine (they did not have

data for Engelmann spruce).

Douglas-fir had good overall performance. Nongopher causes

of mortality were relatively low, so overall survival was good.

Douglas-fir had a tendency to fork more than the other species.

Planting larger Douglas-fir boosted survival and growth of this

species.

Western white pine ranked in the middle for many attributes

among the five test species. Gopher-caused mortality was not

as high as some other species. Overall survival ranked among

the best at French Mountain, but ranked in the middle at Little

Big Hole. White pine is ranked intermediate in shade tolerance,

so it grew relatively well in the partial cut treatment. Planting

larger white pine seedlings improved survival and growth

compared to smaller seedlings.

This study shows that GFM sites are similar in Idaho and

Oregon, and there are a number of alternatives for regenerating

GFM sites. If reforestation within a reasonable amount of time

is an objective, trees should be planted for all regeneration

methods. A clearcut is a viable regeneration method if pocket

gophers are controlled during the first summer, first winter,

and second winter after planting. Clearcuts will most likely

lose most of their preharvest component of shrubs, and they

will rapidly develop high coverages of bracken and/or coneflower. Our observations are that bracken fern will dominate

GFM sites on and near the Clearwater National Forest, and

coneflower will dominate GFM sites on and near the Nez Perce

and Umatilla National Forests. Pocket gopher populations will

be abundant in GFM clearcuts.

A partial cut should result in lower pocket gopher populations, less coverage by bracken and coneflower, and better

retention of the preharvest shrub component. If gophers are not

controlled, planted trees will have better overall survival in

partial cuts than in clearcuts. A drawback of partial cuts is

slower growth of seedlings than in clearcuts. Height growth

can be increased by removing part or all of the overstory a few

years after planting.

References _____________________

Cooper, S. V., Neiman, K. E., and Roberts, D. W. 1991 (revised). Forest habitat

types of northern Idaho: a second approximation. Gen. Tech. Rep. INT-236.

Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain

Research Station. 143 p.

Crouch, G. L. 1971. Susceptibility of ponderosa, Jeffrey, and lodgepole pine

to pocket gophers. Northwest Science. 45:252-256.

Daubenmire, R. 1959. A canopy-coverage method of vegetational analysis.

Northwest Science. 33:43-64.

Ferguson, D. E. 1991. Allelopathic potential of western coneflower (Rudbeckia occidentalis). Canadian J. Botany. 69:2806-2808.

Ferguson, D. E. 1999. Effects of pocket gophers, bracken fern, and western

coneflower on planted conifers in northern Idaho—an update and two more

species. New Forests. 18:199-217.

Ferguson, D. E., and Boyd, R. J. 1988. Bracken fern inhibition of conifer

regeneration in northern Idaho. Res. Pap. INT-388. Ogden, UT: U.S.

Department of Agriculture, Forest Service, Intermountain Research Station. 11 p.

Ferguson, D. E., and Byrne, J. C. (in prep). Effects of overstory density on

environmental characteristics of two Grand Fir Mosaic sites. Res. Pap.

RMRS-RP-000. Fort Collins, CO: U.S. Department of Agriculture, Forest

Service, Rocky Mountain Research Station.

Ferguson, D. E., and Byrne, J. C. 2000. Environmental characteristics of the

Grand Fir Mosaic and adjacent habitat types. Res. Pap. RMRS-RP-24.

Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky

Mountain Research Station. 20 p.

Ferguson, D. E., and Johnson, F. D. 1996. Classification of Grand Fir Mosaic

habitats. Gen. Tech. Rep. INT-GTR-337. Ogden, UT: U.S. Department of

Agriculture, Forest Service, Intermountain Research Station. 16 p.

Gliessman, S. R., and Muller, C. H. 1978. The allelopathic mechanisms of

dominance in bracken (Pteridium aquilinum) in southern California. J.

Chemical Ecology. 4:337-362.

Green, P., and Jensen, M. 1991. Plant succession within managed grand fir

forests of northern Idaho, p. 232-236 In: Harvey, A. E., and

Neuenschwander, L. F. (comp.), Proceedings – management and productivity of western-montane forest soils. Gen. Tech. Rep. INT-280. Ogden,

UT: U.S. Department of Agriculture, Forest Service, Intermountain

Research Station.

Haig, I. T., Davis, K. P., and Weidman, R. H. 1941. Natural regeneration in the

western white pine type. U.S. Department of Agriculture, Forest Service.

Tech. Bull. 767. 99 p.

Johnson, C. G., Jr., and Clausnitzer, R. R. 1991. Plant associations of the Blue

and Ochoco Mountains. R6-ERW-TP-036-92. Baker City, OR: U.S. Department of Agriculture, Forest Service. 207 p.

Johnson-Maynard, J. L., McDaniel, P. A., Ferguson, D. E., and Falen, A. L.

1997. Chemical and mineralogical conversion of andisols following invasion by bracken fern. Soil Science Society of America Journal. 61:549-555.

Kirk, R. E. 1982. Experimental design: procedures for the behavioral sciences.

2nd ed. Belmont, CA: Brooks/Cole Pub. 911 p.

Marsh, R. E., and Steele, R. W. 1992. Chapter 10 - Pocket gophers, p. 205-230.

In: Black, H. C. (Tech. Ed.), Silvicultural approaches to animal damage

management in Pacific Northwest forests. Gen. Tech. Rep. PNW-287.

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station.

Minore, D. 1979. Comparative autecological characteristics of Northwestern

tree species—a literature review. Gen. Tech. Rep. PNW-87. Portland, OR:

U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest

and Range Experiment Station. 72 p.

Rehfeldt, G. E. 1994. Evolutionary genetics, the biological species, and the

ecology of the interior cedar-hemlock forests, p. 91-100. In: Proceedings

Interior cedar-hemlock-white pine forests: ecology and management. March

2-4, 1993. Pullman, WA: Washington State University, Department of

Natural Resource Sciences.

SAS Institute Inc. 1999. SAS Procedures Guide, Version 8. Cary, NC. 1729 p.

Shoji, S., Nanzyo, M., and Dahlgren, R. A. 1993. Volcanic ash soils: genesis,

properties, and utilization. Amsterdam, The Netherlands: Elsevier Science

Publishers. 288 p.

Smith, J. K., and Fischer, W. C. 1997. Fire ecology of the forest habitat types

of northern Idaho. Gen. Tech. Rep. INT-363. Ogden, UT: U.S. Department

of Agriculture, Forest Service, Intermountain Research Station. 142 p.

Stewart, R. E. 1975. Allelopathic potential of western bracken. J. Chemical

Ecology. 1:161-169.

Teipner, C. L., Garton, E. O., and Nelson, L. Jr. 1983. Pocket gophers in forest

ecosystems. Gen. Tech. Rep. INT-154. Ogden, UT: U.S. Department of

Agriculture, Forest Service, Intermountain Forest and Range Experiment

Station. 53 p.

Znerold, R. M. 1979. Western bracken control with asulam. Pullman, WA:

Washington State University. M. S. thesis. 36 p.
You may order additional copies of this publication by sending your

mailing information in label form through one of the following media.

Please specify the publication title and number.

Telephone (970) 498-1392

FAX (970) 498-1396

E-mail rschneider@fs.fed.us

Web site http://www.fs.fed.us/rm

Mailing Address Publications Distribution

Rocky Mountain Research Station

240 West Prospect Road

Fort Collins, CO 80526
Federal Recycling Program Printed on Recycled Paper

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its

programs and activities on the basis of race, color, national origin, sex, religion,

age, disability, political beliefs, sexual orientation, or marital or family status. (Not

all prohibited bases apply to all programs.) Persons with disabilities who require

alternative means for communication of program information (Braille, large print,

audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice

and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights,

Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington,

DC 20250-9410 or call (202) 720-5964 (voice or TDD). USDA is an equal

opportunity provider and employer.

ROCKY MOUNTAIN RESEARCH STATION

RMRS

The Rocky Mountain Research Station develops scientific information and technology to improve management, protection, and use of

the forests and rangelands. Research is designed to meet the needs

of National Forest managers, Federal and State agencies, public and

private organizations, academic institutions, industry, and individuals.

Studies accelerate solutions to problems involving ecosystems,

range, forests, water, recreation, fire, resource inventory, land reclamation, community sustainability, forest engineering technology,

multiple use economics, wildlife and fish habitat, and forest insects

and diseases. Studies are conducted cooperatively, and applications

may be found worldwide.

Research Locations

Flagstaff, Arizona Reno, Nevada

Fort Collins, Colorado* Albuquerque, New Mexico

Boise, Idaho Rapid City, South Dakota

Moscow, Idaho Logan, Utah

Bozeman, Montana Ogden, Utah

Missoula, Montana Provo, Utah

Lincoln, Nebraska Laramie, Wyoming

*Station Headquarters, Natural Resources Research Center,

2150 Centre Avenue, Building A, Fort Collins, CO 80526