United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

Research Paper

RMRS-RP-99

October 2012

Restoration of Plant Cover on 

Campsites in Subalpine Forests:

Sawtooth Wilderness, Idaho

David N. Cole

Liese Dean

Debarah Taylor

Troy E. Hall
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Cole, David N.; Dean, Liese; Taylor, Debarah; Hall, Troy E. 2012. Restoration of plant cover on campsites in 

subalpine forests: Sawtooth Wilderness, Idaho. Res. Pap. RMRS-RP-99. Fort Collins, CO: U.S. Department 

of Agriculture, Forest Service, Rocky Mountain Research Station. 32 p.

Abstract __________________________________________________

This study assessed the effectiveness of restoration treatments in enhancing the growth of Vaccinium 

scoparium transplants and plants established from seed on six closed campsites in subalpine forests in the 

Sawtooth Wilderness, Idaho. In the primary experiment, the soil on all plots was scarified and amended 

with organic matter; plots varied regarding the type and amount of organic matter in the amendments, 

whether or not they were fertilized, and whether or not they were covered with a mulch blanket. In the second experiment, plots varied regarding whether or not they were scarified, amended with organic matter, or 

received supplemental water. Compared to an earlier study in similar forests in the Eagle Cap Wilderness, 

Oregon, survival and growth of Vaccinium scoparium transplants was high, regardless of treatment, as long 

as campsites were closed and soils were scarified. In the primary experiment, 92 percent of transplants 

were still alive after five years and most transplants had increased in size. This greater success may reflect 

the larger size of transplants used in the Sawtooth study (mean of 315 cm2). The most pronounced main 

effect of treatments in the primary experiment was the beneficial effect of fertilization with Biosol® on the 

establishment and growth of seedlings, particularly graminoids. Certain combinations of mulch and type 

and amount of organic matter were more beneficial than other combinations, but none of these treatments 

had either consistent or substantial positive effects. Supplemental watering increased restoration success, 

suggesting that recovery is limited by water. Our results suggest that native vegetation can be restored on 

highly disturbed campsites in these forests. They also reinforce the importance of avoiding impact in the first 

place given the lengthy recovery periods required in these ecosystems and the intensive restoration efforts 

needed to speed recovery.

Keywords: organic fertilizer, recreation impact, soil amendments, transplanting, Vaccinium scoparium

Authors_____________________________

David N. Cole is Research Biologist, Aldo Leopold Wilderness 

Research Institute, Missoula, Montana. 

Liese Dean is Wilderness Program Manager, Sawtooth National Forest, Idaho.

Debarah Taylor is Botanist, Sawtooth National Forest, Idaho.

Troy E. Hall is Professor, Department of Conservation Social 

Sciences, University of Idaho, Moscow, Idaho.

Acknowledgments____________________

Many individuals and organizations contributed to this 

project. Wilderness Volunteers did much of the soil preparation work. The American Excelsior Company donated the 

mulch blanket, and Mystic Saddle Ranch workers packed 

materials in. Personnel from the Sawtooth National Recreation Area, Aldo Leopold Wilderness Research Institute, 

University of Idaho, and University of Montana assisted 

with implementing treatments and collecting data, as did a 

few unaffiliated volunteers. Dave Turner assisted with data 

analysis.
The use of trade or firm names in this publication is for reader information and does not 

imply endorsement by the U.S. Department of Agriculture of any product or service.

Contents

Introduction.............................................................................................................. 1

Study Sites............................................................................................................... 2

Methods.................................................................................................................... 3

Treatments.................................................................................................... 3

Measurements.............................................................................................. 7

Data Analysis and Presentation.................................................................... 8

Results...................................................................................................................... 9

Effects on Transplants ................................................................................ 10

Mean Transplant Area................................................................................ 10

Mean Transplant Height............................................................................. 13

Effect of Pruning ........................................................................................ 14

Effect of Transplant Size............................................................................ 15

Effects on Plants Establishing From Seed ................................................. 15

Seedling Density........................................................................................ 17

Seedling Cover .......................................................................................... 20

Effects of Supplemental Watering .............................................................. 24

Discussion and Management Implications......................................................... 26

Treatment Effects ....................................................................................... 28

Identifying the Best Treatment.................................................................... 29

Effects of Supplemental Watering .............................................................. 29

Management Prescription........................................................................... 30

Further Research................................................................................................... 31

Conclusions........................................................................................................... 31

References ............................................................................................................. 31

USDA Forest Service Res. Pap. RMRS-RP-99. 2012 1

Introduction ______________________________________________________

Subalpine landscapes, particularly those dotted with scenic lakes, attract a disproportionate amount of wilderness use. Consequently, the impacts of camping are particularly 

pronounced in subalpine forests. Wilderness managers frequently attempt to close and 

restore some of these campsites where camping impacts are severe, the number of 

campsites is considered excessive, or campsites are located in inappropriate places. Although little restoration research has been conducted on wilderness campsites (however, 

see Moritsch and Muir 1993), there is a substantial high-elevation restoration ecology 

literature that has demonstrated the effectiveness of restoration treatments, including 

transplanting (Conlin and Ebersole 2001), seeding (Smyth 1997), mulches (Petersen and 

others 2004), and organic amendments (Chambers 1997). All these studies stress that 

results likely vary with attributes of the situational context, particularly characteristics 

of the site and its disturbance history.

Throughout much of the Rocky and Cascade Mountains, extensive tracts of subalpine 

forest have an understory dominated by dwarf ericaceous shrubs, particularly Vaccinium 

scoparium (grouse whortleberry). Tree species in the overstory vary but the most common are Pinus contorta (lodgepole pine), Pinus albicaulis (whitebark pine), Abies 

lasiocarpa (subalpine fir), and Picea engelmannii (Engelmann spruce). The impacts of 

wilderness camping are probably more widespread in these vegetation types than in any 

others in the United States, making information about effective restoration treatments 

particularly useful in these forests.

Starting in 1995, experimentation with restoration treatments commenced on campsites at subalpine lakes in the Eagle Cap Wilderness, Wallowa Mountains, northeastern 

Oregon. Vegetation had an overstory of Pinus contorta, Pinus albicaulis, and Abies 

lasiocarpa; the discontinuous understory (about 50 percent cover) was highly dominated 

by Vaccinium scoparium (about 55 percent of understory cover). Specifically, experiments assessed the effectiveness of (1) soil scarification, (2) transplanting and seeding 

with local, native species, (3) ameliorating microclimatic conditions with a mulch mat, 

and (4) amending soils with organic matter, compost, and soil inoculum. Results of 

these experiments, followed for 15 years, indicated that most, but not all, treatments 

were effective in increasing vegetation recovery rates. Closure of the campsite to all use 

was necessary but not sufficient for recovery. Scarification, transplanting, seeding, and 

soil amendments individually and in combination facilitated more rapid revegetation, 

while the mulch mats had no effect (Cole 2007; Cole and Spildie 2006, 2007). The most 

pronounced failure was the response of the understory dominant Vaccinium scoparium. 

Only 45 percent of transplants survived, and the size of those plants that did survive

declined for seven years. After 15 years, V. scoparium cover was only 1.4 percent. 

Restoration of Plant Cover on 

Campsites in Subalpine Forests: 

Sawtooth Wilderness, Idaho

David N. Cole

Liese Dean

Debarah Taylor

Troy E. Hall
2 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

This is similar to the cover of the original V. scoparium transplants (1.3 percent) but 

much less than the 27 percent cover on undisturbed sites.

So the question arises, how can V. scoparium be more effectively restored? Would it 

be more effective if transplant density and/or size were increased? Aradottir (2012) has 

shown that transplants of several deciduous dwarf-shrub Vaccinium species, morphologically similar to V. scoparium, were much more successful if they were at least 400 

cm2 in size. The mean diameter of V. scoparium transplants in the Eagle Cap study was 

only about 150 cm2. Other questions are: (1) would the mulch mats have been more 

effective if summer conditions in the mid-1990s had not been so unusually moist; (2) if 

adding organic matter is beneficial, how much and what type is ideal; (3) would small 

amounts of bioorganic fertilizer provide some of the same benefits as large quantities 

of compost; and (4) since transplant mortality was particularly severe during droughty 

summers, would supplemental watering of plants increase success, both in addition 

to and instead of other restoration treatments? We implemented a series of restoration 

experiments on subalpine campsites in the Sawtooth Wilderness of central Idaho to 

address these questions.

Study Sites_______________________________________________________

The study was conducted on six campsites, three at Hell Roaring Lake (2260 m 

elevation) and three at Alpine Lake (2540 m elevation) (Fig. 1). The most abundant 

tree species around the campsites are Pinus contorta and Abies lasiocarpa; most tree 

regeneration is A. lasiocarpa. Understory vegetation is discontinuous (mean of 55 percent on undisturbed sites close to campsites). The most abundant species are Vaccinium 

scoparium (42 percent cover), Carex geyeri (elk sedge) (6 percent cover) and C. rossii 

(Ross’ sedge) (2 percent cover). Soils are derived from granitic substrates. Although 

snow typically covers the ground until late June/early July, snowmelt is typically followed by hot-dry summers. The frequency of summer thunderstorms varies from year 

to year. When thunderstorms are infrequent, soils can be highly droughty for most of 

the growing season.

Figure 1—One of the campsites at Hell Roaring Lake, illustrating the high degree of 

groundcover disturbance prior to restoration.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 3

Methods _________________________________________________________

Treatments

Campsite restoration began in 2006 with the closure of these sites to camping and 

day use, using closure signs and rope. The closures were highly effective. Over the five 

years of the study, nobody appeared to have camped on any of the sites. Two separate 

experiments were implemented on each campsite (Fig. 2). The primary experiment 

explored four factors and employed a split plot design. Sixteen treatment plots (1.25 m 

by 0.75 m) were established on each campsite. The soil was scarified on these plots using 

shovels, picks, pitchforks, hoes, and hand kneading to break up compaction and clods 

to a depth of about 20 centimeters. Substantial mixing of soil horizons was unavoidable 

in our resolve to develop a crumb texture. On several sites, large rocks were removed 

and numerous tree roots were cut and removed during scarification. This intensity of 

scarification exceeds that commonly undertaken on wilderness campsites.

Of the three factors in the primary split-plot experiment, the mulch treatment was 

the factor used to establish whole plot units because the most feasible technique was to 

apply mulch blankets over large areas. Eight contiguous plots on each site were covered 

with a mulch blanket made of curled aspen excelsior wood fibers stitched together with 

biodegradable thread (Curlex® NetFreeTM). The other eight contiguous plots were not 

mulched (Fig. 3). Within each of the two mulch whole plots, two levels of fertilization 

(fertilized or not), organic matter type (decomposed wood or decomposed wood mixed 

with needles and twigs), and organic matter amount (25 percent or 50 percent organic 

matter in the upper 15 cm of soil) were assigned to split-plot units in a completely randomized design. Each combination of these three factors occurred in each whole plot. 

Each campsite had a unique ordering of treatments within the mulch whole plots and 

provided one of six replicates.

A1 

O1 

F2 

A2 

O1 

F1 

A2 

O2 

F2 

A1 

O1 

F1 

A1 

O2 

F1 

A1 

O1 

F2 

A2 

O1 

F2 

A2 

O1 

F2 

A1 

O1 

F1 

A2 

O2 

F1 

A2 

O2 

F2 

A2 

O1 

F1 

A2 

O2 

F1 

A1 

O2 

F2 

A1 

O2 

F1 

A1 

O2 

F2 

S 

A2 

O2 

F2 

NS S 

SL S 

S 

SL S NS 

S 

A2 

O2 

F2 

Mulched 

Not Mulched 

Not Watered 

Watered 

A1 – added 25% organic matter by volume 

A2 – added 50% organic matter by volume 

O1 – organic matter: decomposed wood 

O2 – organic matter: decomposed wood, 

 plus twigs and needles 

F1 – not fertilized 

F2 – fertilized 

S – scarified, no other treatments 

NS – not scarified, no other treatments 

SL – covered with slash 

Figure 2—Distribution of treatments for the two experiments, illustrating random assignment 

of treatments within whole-plot mulch treatments (experiment 1) and water treatments (experiment 2).
4 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Plots were prepared by adding organic matter to the scarified soil. In half the plots, 

the organic matter consisted entirely of highly decomposed wood, typically fallen trees 

that had disintegrated into wood chunks no larger than I cm in diameter (Fig. 4). In the 

other half of plots, the organic matter was a 2:1 mix of decomposed wood and twigs 

and needles from the lower branches of trees. Branches were cut to a length of no more 

than 15 cm with at least 50 percent green needles (Fig. 5). The reason for adding this 

type of organic matter was to add woody material that might resist the recompaction of 

soils, providing longer-lasting passages for water to enter the soil. The plots that received 

a lesser amount of organic matter were amended with either 25 liters of decomposed 

wood or 12.5 liters of decomposed wood and 6.25 liters of twigs and needles. The plots 

that received more organic matter were amended with either 75 liters of decomposed 

wood or 37.5 liters of decomposed wood and 18.75 liters of twigs and needles. After 

the organic matter was mixed into the soil, half of the plots received a surface application of fertilizer; the other half was not fertilized. The fertilizer applied was Biosol®, 

a slow release fertilizer made of 96 percent fungal biomass (dry mycelium), 3 percent 

potassium-magnesia and 1 percent water. It was applied at a rate of 2.5 dl per plot, the 

equivalent of 200 g/m, the application rate suggested for reclaiming poor soils.

The second experiment was designed primarily to assess the effects of supplemental watering, scarification, and the general effects of the soil amendments tested 

in the first experiment. In addition, the effects of covering the ground surface in 

slash were assessed. This experiment also employed a split-plot design, this time 

with eight plots (1.25 m by 0.75 m). Watering was the factor used to establish 

whole plots. Four plots on each campsite received about 7.5 liters of water once 

a week throughout the summer (Fig. 6); the other four plots were not irrigated. 

Figure 3—Mulch treatment plots adjacent to plots that were not mulched.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 5

Figure 4—Campsite at Alpine Lake with a pile of decomposed wood to be used as an 

organic soil amendment.

Figure 5—Amending the soils with organic matter, in this plot a combination of decomposed wood, twigs, and branches.
6 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Figure 6—Half of the plots in experiment 2 were given 

supplemental water every week for five years.

Within each of the watering whole plots, each of four treatments was randomly 

assigned. One plot received no soil treatment—not even scarification. Another 

plot was just scarified. The third treatment was scarification and covering with 

slash, small tree branches with live needles. The fourth treatment was a replication 

of one of the treatments from the first experiment. It was fertilized and amended 

with the larger quantity of both decomposed wood and twigs and needles; there was 

no mulch. The slash on the plots with slash was often removed by campers and, 

therefore, was perceived to be ineffectual. Analysis indicated that these plots never 

differed significantly from those that were only scarified. Consequently, they are 

not included in the analysis.

Every plot in both experiments was planted in an identical manner. Each plot received three Vaccinium scoparium transplants dug up in the vicinity. Only a few of the 

transplants had established plants of other species, although many could have harbored 

viable seed. Transplants were variable in size but most were between 150 and 400 cm2

with a mean of 315 cm2. Transplanting involved digging a hole and placing transplants 

in the hole (Fig. 7) along with Vita-start (vitamin B-1) to reduce transplant shock and 

giving each transplant 0.6 liters of water. One transplant in each plot had about one-half 

of its foliage pruned to assess the effect of pruning. On mulched plots, holes were cut 

in the blanket so transplants emerged from underneath the blanket.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 7

Each plot was also seeded with an equivalent quantity of locally collected seed. At 

Hell Roaring campsites, each plot received seed in the following quantities: 5.75 g of 

Symphyotrichum spathulatum (western mountain aster), 8.3 g of Packera streptanthifolia (Rocky Mountain groundsel), and 3.2 g of Festuca idahoensis (Idaho fescue). At 

Alpine Lake campsites, each plot received seed in the following quantities: 3.5 g of 

Juncus parryi (Parry’s rush), 4.3 g of Antennaria microphylla (rosy pussy-toes), 8 g of

Packera streptanthifolia, 4 g of Arnica cordifolia (heart-leaf arnica), 5.5 g of Penstemon 

globosus (globe penstemon), and 3.5 g of Chionophila tweedyi (Tweedy’s snowlover). 

The quantity of seed we had was minimal. Seeds were broadcast prior to transplanting and many were undoubtedly buried during transplanting. Only 176 individuals of 

the species we seeded ever established. This is less than 15% of the individuals that 

established from seed and suggests that results would have been little different if we 

had not seeded plots.

Measurements

Vegetation response measurements were taken every year for five years in 1 m by 

0.5 m quadrats, centered within each plot. This left an unmeasured 0.25 m buffer between quadrats. We measured transplant survival and size, seedling density, and cover 

by species. For each live transplant, we mapped the areal extent of canopy cover using 

a 1 m by 0.5 m PVC frame with a 5 cm by 5 cm grid (Fig. 8), providing estimates of 

both the area of each transplant and the percent cover of transplants. We also recorded 

the maximum height of each transplant. Measurements were taken immediately after 

transplanting and pruning (September 2006) and in late August or early September of 

each year thereafter.

Figure 7—Planting a Vaccinium scoparium transplant.
8 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Plants that established from seed were counted, by species, within a 1 m by 0.5 m 

PVC frame. For each of these species, we also ocularly estimated cover to the closest 

percent if cover was 10 percent or less and in 10 percent increments thereafter. Density 

measures were most precise during the first years after treatment; as graminoids particularly coalesced, it became increasingly difficult to decide on the number of individuals in 

a clump. Conversely, cover estimates became increasingly precise over time as the size 

of individuals increased. A few mature plants that were harbored within the transplants 

are undoubtedly included.

Total vegetation cover and the cover of individual species were estimated in undisturbed plots near to each restored campsite. The means from these six plots are used as 

targets for successful restoration.

Data Analysis and Presentation

For the primary experiment, we performed repeated measures analyses of variance, 

appropriate for split-plot designs (using an autoregressive covariance structure, PROC 

GLIMMIX in SAS 9.3). The density data approximated a Poisson distribution; they 

were square-root transformed to better comply with assumptions about normality. The 

transplant and cover data did not require transformation. For the four factors included 

in the split-plot design (mulch, fertilization, organic type, and organic amount), main 

Figure 8—Transplant area was assessed by mapping each transplant using a gridded quadrat.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 9

effects of each factor and interactions among factors were assessed. In some cases, 

factor main effects interacted significantly with time since treatment. In these cases, we 

describe treatment effects for each of the five years of the experiment, but the significance of effects is only assessed at the end of the experiment in 2011. In cases where 

treatment interactions with time were not significant, we report results of the repeated 

measures analyses.

We used data from the second experiment to assess hypotheses that scarification, 

slash, and supplemental watering would each have positive effects. As noted before, 

the slash treatment was compromised, ineffectual, and will not be discussed further. As 

with the primary experiment, we performed repeated measures analyses of variance, 

appropriate for split-plot designs. The two factors in the split-plot design were watering 

and treatment. Within treatment, we compared plots that were not scarified with plots 

that were scarified but received no other soil amendments. We assessed our hypothesis 

that scarification would be beneficial using one-tailed Tukey-Kramer tests. We also 

assessed the effects of pruning on transplants using two-tailed t-tests.

Finally, to assess whether the types of soil amendments we included in the primary 

experiment were beneficial, we compared plots that were scarified but did not receive 

any soil amendments (from the second experiment) to the non-mulched plots in the primary experiment. We used a univariate analysis of variance, with campsite as a block, to 

evaluate the hypothesis that the soil amendments generally would have a positive effect.

Results __________________________________________________________

Over the first five years following treatment, total vegetation cover increased from 

0 to 31 percent on the plots with soil amendments (Fig. 9). The response of the transplants differed substantially from that of plants that established from seed. Transplant 

Figure 9—Variation in the cover of transplants, plants that established from seed and total 

cover, on plots that received soil amendments over the five years of the experiment.
10 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

cover declined the first year after treatment and increased slowly thereafter. After five 

years, Vaccinium scoparium transplant cover (19 percent) exceeded the cover that was 

planted on the plots (17 percent). Seedling cover increased more steadily and rapidly 

for the first four years after treatment, declining slightly in the fifth year.

Five years after treatment, total vegetation cover was significantly higher on plots 

that were scarified but without soil amendments (27 percent) than on plots that were not 

scarified (16 percent) (Tukey-Kramer, t = 3.0, p<0.01). Both plots that were and were 

not irrigated are included. Total vegetation was also significantly higher on plots with 

soil amendments (31 percent) than on plots that were scarified but neither amended nor 

irrigated (19 percent) (ANOVA, F = 3.9, p = 0.02). None of the treatments explored in 

the primary experiment had as pronounced a beneficial effect on total vegetation cover 

as scarification and organic soil amendments. Fertilization had a significant but small 

effect on total vegetation cover (Table 1). After five years, mean total vegetation cover 

was 33 percent on plots that were fertilized and 29 percent on plots that were not fertilized. Cover did not vary significantly with mulch, organic type, or organic amount. 

However, the effects of these treatments on the transplants differed from effects on 

plants that established from seed. Consequently, these effects will be explored separately.

Table 1—Effects of fertilizer, organic type, 

organic amount, and mulch on total 

vegetation cover, repeated measures analysis of variancea.

Effect df F p

Fertilizer 1 4.7 0.03

Organic Type 1 0.3 0.61

Organic Amount 1 2.2 0.14

Mulch 1 0.1 0.80

Year 4 80.4 <0.01 

a Interactions that are not significant (p ≤ 0.05) are 

not shown. Effects with bold numbers are significant.

Effects on Transplants

Changes in Vaccinium scoparium transplant cover were reflective of both transplant 

survival and change in the size of surviving transplants. Transplant survival was high; 

92 percent of the transplants in the primary experiment were still alive after five years. 

Transplant survival was significantly higher on plots that were scarified but without 

soil amendments (89 percent) than on plots that were not scarified (72 percent) (TukeyKramer, t = 1.9, p = 0.03). Survival was also higher on plots with soil amendments (92 

percent) than on plots that were scarified but neither amended nor irrigated (83 percent); 

however, this difference was not statistically significant (ANOVA, F = 2.0, p = 0.08). 

Moreover, none of the treatments in the primary experiment (mulch, fertilization, organic 

type, or organic amount) had a significant effect on transplant survival.

Mean Transplant Area—The mean size of transplants was affected by scarification, 

soil amendments, and, to a lesser degree, the nature of those amendments. Five years 

after treatment, the mean size of surviving transplants on plots that were scarified but 

without soil amendments was 331 cm2. This is significantly higher (Tukey-Kramer, 

t = 2.5, p = 0.01) than on plots that were not scarified (259 cm2) (Fig. 10). Mean surviving transplant area was also higher on plots with soil amendments (335 cm2) than 

on plots that were scarified but neither amended nor irrigated (211 cm2 ) (ANOVA, 

F = 5.0, p = 0.01) (Fig. 11).
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 11

Figure 10—Effect of scarification on the mean size of Vaccinium transplants. Both irrigated 

and non-irrigated plots are included. 

Figure 11—Effect of organic soil amendments on the mean size of Vaccinium transplants.
12 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

The effects of mulch, fertilization, and the organic amendments did not interact with 

year, so the results of the repeated measures analysis of variance can be used (Table 2). 

Results suggest that variation in the effectiveness of these treatments was small in 

comparison to the effectiveness of scarification and amending soils with organic matter. Of the main effects, only amount of organic matter significantly affected transplant 

size (Fig. 12); transplant size was greater when less organic matter was applied—25 

percent by volume rather than 50 percent. However, there were complex significant 

interactions among mulch, fertilizer, organic type, and organic amount (Table 2). This 

suggests that certain combinations of treatment might be substantially more effective 

than other combinations.

Figure 12—Effect of the amount of organic matter added to the soil on the mean size of 

Vaccinium transplants. 

Table 2—Effects of fertilizer, organic type, organic 

amount, and mulch on mean size of surviving transplants, repeated measures 

analysis of variancea.

Effect df F p

Fertilizer (F) 1 0.0 0.99

Organic Type (OT) 1 1.2 0.28

Organic Amount (OA) 1 8.4 <0.01

Mulch (M) 1 2.6 0.17

M*OT 1 6.4 0.01

F*OT 1 4.6 0.04

M*OT*OA 1 3.7 0.05

Year 4 55.4 <0.01

a Interactions that are not significant (p≤0.05) are not 

shown. Effects with bold numbers are significant.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 13

If plots were fertilized, mean transplant size in 2011 differed little between plots 

amended with decomposed wood (336 cm2) and those amended with decomposed 

wood and twigs/needles (341 cm2). However, on plots that were not fertilized, mean 

transplant size in 2011 was substantially less on plots amended with decomposed wood 

(302 cm2) compared to those amended with decomposed wood and twigs/needles (380 

cm2). The beneficial effect of using a lesser amount of organic matter is consistent but 

only substantial on plots that were not mulched and amended with decomposed wood 

and twigs/needles (Fig. 13). On mulched plots, organic type and amount did not have 

a substantial effect on transplant size. On plots that were not mulched, however, transplant size was substantially higher on plots that were amended with lower quantities of 

decomposed wood and twigs/needles than on plots amended with either decomposed 

wood only or larger quantities of decomposed wood and twigs/needles.

Figure 13—Interactive effect of mulch, organic type, and organic amount on the mean size 

of Vaccinium transplants, averaged across the five years following treatment. 

Mean Transplant Height—Five years after treatment, the mean maximum height of 

surviving transplants on plots that were scarified but without soil amendments was 12.1 

cm. This is significantly higher (Tukey-Kramer, t = 2.2, p = 0.02) than on plots that were 

not scarified (11.0 cm). Mean surviving transplant height was not significantly higher 

on plots with soil amendments (11.8 cm) than on plots that were scarified but neither 

amended nor irrigated (11.3 cm) (ANOVA, F = .30, p = 0.30). However, height did vary 

significantly, if not substantially, with treatment. As was the case with transplant area, 

the only significant main effect was organic amount (Table 3), but there were complex 

significant interactions among mulch, fertilization, organic type, and organic amount.

Five years after treatment, mean maximum height was 12.3 cm on plots that received 

lesser quantities of organic matter and 11.5 cm on plots that received more organic matter. However, this difference was only substantial on plots that were either fertilized 

but not mulched or mulched but not fertilized (Fig. 14). If plots were fertilized, organic 

matter type made little difference. However, on plots that were not fertilized, transplant 

height in 2011 was substantially less on plots amended with decomposed wood (10.2 cm) 

compared to those amended with decomposed wood and twigs/needles (12.1 cm).
14 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Effect of Pruning—Pruning the foliage of Vaccinium scoparium transplants after 

they were planted did not have a beneficial effect on transplant survival or growth. After 

five years, the survival rate of pruned transplants (90 percent) did not differ significantly 

from the survival rate of transplants that were not pruned (91 percent) (chi-square, 

X2 = 0.1, p = 0.81). The mean size of pruned transplants was smaller than the mean 

size of transplants that were not pruned. This difference was statistically significant for 

the first four years after treatment. By 2011, however, the difference between pruned 

transplants (316 cm2; SE = 18 cm2 ) and non-pruned transplants (344 cm2; SE = 15 cm2) 

was not significant (t-test, t = 1.2, p = 0.23).

Table 3—Effects of fertilizer, organic type, organic 

amount, and mulch on mean height of 

surviving transplants, repeated measures analysis of variancea.

Effect df F p

Fertilizer (F) 1 0.3 0.60

Organic Type (OT) 1 0.6 0.46

Organic Amount (OA) 1 6.1 0.02

Mulch (M) 1 0.1 0.83

F*OT 1 6.6 0.01

M*F*OA 1 3.8 0.05

Year 4 6.0 <0.01

a Interactions that are not significant (p≤0.05) are not 

shown. Effects with bold numbers are significant.

Figure 14—Interactive effect of mulch, fertilizer, and organic amount on the mean maximum height of Vaccinium transplants, averaged across the five years following treatment.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 15

Effect of Transplant Size—The original size of Vaccinium scoparium transplants 

ranged from 20 cm2 to 1173 cm2. Survival declined as original transplant size declined 

(Fig. 15). The mean size of transplants that died was 215 cm2 (SE = 25 cm2) compared 

to a mean size of 300 cm2 (SE = 11 cm2 ) for transplants that survived (t-test, t = 3.1, 

p < 0.01). However, if they survived, the smaller transplants grew more than the larger 

transplants. Change in transplant area between 2006 and 2011 was negatively correlated 

with original transplant area (r = -.43, p<0.01). The mean change in area of the 100 

smallest transplants (originally ≤200 cm2 in size) was an increase of 115 cm2 (SE = 17 

cm2); the mean change for the 100 largest transplants (originally ≥315 cm2 in size) was 

a decrease in area of 37 cm2 (SE = 17 cm2).

Figure 15—Variation in mortality with original size of Vaccinium scoparium transplants. 

Values are the number of transplants in that size class. 

Effects on Plants Establishing From Seed

For the plants that established from seed, we assessed both plant density and plant 

cover. The density of tree seedlings and forbs were relatively constant over time (Fig. 16). 

Most of the plants that established did so the first year after treatment. Graminoid density 

increased for the first three years after treatment and decreased thereafter. This decrease 

may be an artifact of the tendency for individuals to coalesce as they grow, making density appear to be less than it actually is. Seedling cover of each of these growth forms 

increased much more over time (Fig. 17).
16 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Figure 16—Variation in the density of trees, graminoids, and forbs that established from 

seed on plots that received soil amendments, over the five years of the experiment.

Figure 17—Variation in the percent cover of trees, graminoids, and forbs that established 

from seed on plots that received soil amendments, over the five years of the experiment.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 17

Table 4—Frequency, density, and cover of species that established from seed on plots in the 

primary experiment.

 Number Total Mean density Mean cover

Species of plots seedlings (#/m2) (%)

Abies lasiocarpa 21 36 0.8 0.1

Achillea millefolium 2 10 0.2 0.1

Anaphalis margaretacea 2 2 <0.1 <0.1

Arnica cordifolia (s)* 9 32 0.7 0.3

Arnica mollis* 14 44 0.9 0.4

Calamagrostis canadensis 5 17 0.4 0.1

Calamagrostis rubescens 7 9 0.2 0.2

Carex geyeri* 16 18 0.4 0.6

Carex microptera 3 3 <0.1 <0.1

Carex rossii* 86 424 8.8 6.8

Chamerion angustifolium* 13 26 0.5 0.2

Chionophila tweedyi (s) 4 9 0.2 <0.1

Danthonia intermedia 2 2 <0.1 <0.1

Dodecatheon jeffreyi 1 1 <0.1 0.1

Erigeron peregrinus* 14 43 0.9 0.4

Festuca idahoensis (s) 14 15 0.3 0.4

Hieracium gracile* 15 38 0.8 0.2

Juncus drummondii 1 1 <0.1 <0.1

Juncus parryi (s) 10 19 0.4 0.2

Ligusticum tenuifolium 1 1 <0.1 <0.1

Muhlenbergia filiformis 3 5 0.1 <0.1

Packera streptanthifolia (s) 9 33 0.7 0.3

Pedicularis racemosa 2 4 0.1 <0.1

Penstemon globosus (s) 10 18 0.4 0.1

Phlox longifolia 2 5 0.1 <0.1

Pinus contorta 64 138 2.9 0.8

Poa secunda 2 2 <0.1 <0.1

Ribes sp. 1 1 <0.1 <0.1

Solidago multiradiata 3 10 0.2 0.2

Stipa lettermanii 6 11 0.2 0.2

Trisetum spicatum 1 1 <0.1 <0.1

Valeriana edulis 2 7 0.1 0.1

Viola adunca* 7 30 0.6 0.1

(s) Seeded species.

* A few of these individuals were present in the Vaccinium scoparium transplants.

Five years after treatment, on plots in the primary experiment, 31 species had established from seed (Table 4). Most of these species were infrequently encountered and 

contributed little cover. Only 11 of these species occurred on at least 10 percent of the 

plots, including 3 of the 8 species that were seeded—Festuca idahoensis, Juncus parryi,

and Penstemon globosus. Only Carex rossii, C. geyeri, and Pinus contorta had a mean 

cover that exceeded 0.5 percent (Fig. 18); none of these were seeded. However, both 

Carex rossii and C. geyeri were present in some of the Vacciunium scoparium transplants. 

Five years after treatment, Carex rossi accounted for 56 percent of total seedling cover.

Seedling Density—As was the case with the transplants, the density of plants that 

established from seed was affected by scarification, soil amendments, and, to a lesser 

degree, the nature of those amendments. Five years after treatment, the mean density of 

plants established from seed on plots that were scarified but without soil amendments 

was 21 plants/m2, with a standard error of 5 plants/m2. This is significantly higher 

(Tukey-Kramer, t = 2.5, p = 0.01) than on plots that were not scarified (10 plants/m2; SE = 3 

plants/m2). Mean density was also higher on plots with soil amendments (21 plants/m2; 
18 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

SE = 2 plants/ m2) than on plots that were scarified but neither amended nor irrigated 

(16plants/m2; SE= 5 plants/ m2). Based on the repeated measures analysis, this difference 

is statistically significant (ANOVA, F = 3.8, p = 0.03) and amendment effects do not 

interact with year (ANOVA, F = 1.0, p = 0.38); however, in 2011, differences were not 

statistically significant at an alpha level of 0.05 (ANOVA, F = 2.6, p = 0.06) (Fig. 19).

Figure 18—A plot with substantial Carex rossii cover, as well as tree seedlings and a 

flowering Erigeron peregrinus.

Figure 19—Effect of organic soil amendments on the density of plants that established 

from seed.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 19

Table 5—Effects of fertilizer, organic type, organic 

amount, and mulch on density of plants 

that established from seed, in 2011a.

Effect df F p

Fertilizer 1 6.5 0.01

Organic Type 1 3.4 0.07

Organic Amount (OA) 1 0.0 0.85

Mulch (M) 1 0.5 0.51

OA*M 1 4.8 0.03

a Interactions that are not significant (p≤0.05) are not 

shown. Effects with bold numbers are significant.

In the repeated measures ANOVA, the effects of mulch and organic type interacted 

significantly with year, so only the 2011 results are presented. Significantly more plants 

established from seed on plots that were fertilized (Table 5). Mean seedling density in 

2011 was 24 plants/m2 on fertilized plots compared to 19 plants/m2 on plots that were 

not fertilized (Fig. 20). The significant interaction between mulch and organic amount 

suggests that (1) when less organic matter is applied (25 percent by volume), mulched 

plots have significantly higher densities; and (2) when there is no mulch, plots amended 

with higher quantities of organic matter (50 percent by volume) have higher densities.

The effects of these treatments varied between growth forms. Since most seedlings 

are graminoids (Fig. 16), the treatments that affect graminoid density (primarily fertilization) are the treatments that affect total seedling density. However, the density of tree 

seedlings was not significantly affected by fertilization; instead, it was influenced by 

organic amount. In 2011, plots amended with less organic matter had significantly more 

tree seedlings (5 plants/m2) than plots amended with more organic matter (3 plants/m2) 

(ANOVA, F = 21.5, p<0.01). Forb density was also influenced by organic amount but 

in an opposing manner. In 2011, plots amended with less organic matter had significantly fewer forb seedlings (7 plants/m2) than plots amended with more organic matter 

(5 plants/m2) (ANOVA, F = 4.3, p = 0.04).

Figure 20—Effect of fertilization on the density of plants that established from seed.
20 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Seedling Cover—Seedling cover was affected by scarification and particular types of 

soil organic amendments. Five years after treatment, the mean cover of plants established 

from seed on plots that were scarified but without soil amendments was 10 percent, 

with a standard error of 3 percent. Mean cover was substantially lower on plots that 

were not scarified (5 percent; SE = 2 percent), but the difference was not statistically 

significant (Tukey-Kramer, t = 1.7, p = 0.05). Mean cover was also higher on plots with 

soil amendments (12 percent; SE= 1 percent) than on plots that were scarified but neither 

amended nor irrigated (8 percent; SE = 4 percent). Although this difference was also 

not statistically significant (ANOVA, F = 1.1, p = 0.14), the effects of scarification and 

amendment appear to be additive. The difference between plots that were both scarified and amended (12 percent cover) and plots that were neither scarified nor amended 

(5 percent cover) was highly significant (Tukey-Kramer, t = 3.1, p<0.01).

In the repeated measures ANOVA, the effects of fertilization interacted significantly 

with year, so only the 2011 results are presented. The cover of plants established from 

seed was significantly higher on plots that were fertilized (Table 6). Mean seedling cover 

in 2011 was 14 percent on fertilized plots compared to 10 percent on plots that were not 

fertilized (Fig. 21). As was the case with seedling density, there is a significant interaction between mulch and organic amount. Mean seedling cover varied from 17 percent 

(SE = 3 percent) on mulched plots that received less organic matter to 8 percent (SE 

= 1 percent) on plots that were not mulched and received less organic matter; cover 

was 11 percent (SE = 2 percent) on plots that received more organic matter and were 

mulched and 12 percent (SE = 2 percent) on plots that received more organic matter 

and were not mulched. Differences associated with organic amount were not significant regardless of whether plots were mulched (t-test, t = 1.7, p = 0.10) or not mulched 

(t-test, t = 1.7, p = 0.10). When less organic matter was applied, seedling cover was 

significantly higher when plots were mulched (t-test, t = 2.6, p = 0.01); seedling cover 

did not vary significantly with mulch treatment when more organic matter was applied 

(t-test, t = 0.5, p = 0.62).

The effects of these treatments varied between growth forms. Graminoid cover was 

significantly higher when the soil on plots was amended with organic matter and when 

the amendments included fertilization, but scarification did not have a significant effect. Five years after treatment, mean graminoid cover was 5 percent on plots that were 

scarified but without soil amendments and 3 percent on plots that were not scarified 

(Tukey-Kramer, t = 0.8, p = 0.20). Graminoid cover was 9 percent (SE = 1 percent) on 

plots with soil amendments and 4 percent (SE = 2 percent) on plots that were scarified 

but neither amended nor irrigated (ANOVA, F = 2.7, p = 0.05) (Fig. 22). Fertilized plots 

had significantly more graminoid cover (mean = 11 percent; SE = 1 percent) than plots 

that were not fertilized (mean = 7 percent; SE = 1 percent) (Table 7).

Table 6—Effects of fertilizer, organic type, organic 

amount, and mulch on cover of plants 

that established from seed, in 2011a.

Effect df F p

Fertilizer 1 6.4 0.01

Organic Type 1 0.5 0.48

Organic Amount (OA) 1 0.5 0.47

Mulch (M) 1 1.4 0.29

OA*M 1 7.1 <0.01

a Interactions that are not significant (p≤0.05) are not 

shown. Effects with bold numbers are significant.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 21

Figure 21—Effect of fertilization on the cover of plants that established from seed.

Figure 22—Effect of organic soil amendments on the cover of graminoids that established from seed.
22 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Overall, mulching did not have a significant effect on graminoid cover (Fig. 23). 

There was also a significant interaction among fertilization, mulch, and organic amount. 

Mean graminoid cover varied from 14 percent (SE = 3 percent) on plots that were 

mulched, fertilized, and received less organic matter to 5 and 4 percent (SE = 1 percent) 

on plots that were not mulched and not fertilized, with less and more organic material, 

respectively. Teasing this apart, when not fertilized, graminoid cover was significantly 

higher on plots that were mulched (9 percent; SE = 2 percent) than on plots that were 

not mulched (4 percent; SE = 1 percent) (ANOVA, F = 5.3, p = 0.03). Graminoid cover 

was also significantly higher on mulched plots (12 percent; SE = 2 percent) than on 

non-mulched plots (6 percent; SE = 1 percent) when less organic matter (25 percent by 

volume) was applied (t-test, t = 2.3, p = 0.03). Mulching did not affect graminoid cover 

when more organic matter (50 percent by volume) was applied (t-test, t = 0.2, p = 0.82).

Table 7—Effects of fertilizer, organic type, organic 

amount, and mulch on cover of graminoids 

that established from seed, in 2011a.

Effect df F p

Fertilizer (F) 1 9.3 <0.01

Organic Type 1 0.0 0.96

Organic Amount (OA) 1 0.5 0.49

Mulch (M) 1 1.6 0.26

OA*M 1 4.9 0.03

F*OA*M 1 4.4 0.04 

a Interactions that are not significant (p≤0.05) are not shown. 

Effects with bold numbers are significant.

Figure 23—Effect of the mulch blanket on the cover of graminoids that established from 

seed. The mulch was beneficial on plots that were not fertilized or amended with less 

organic matter.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 23

The cover of tree seedlings did not differ significantly (at an alpha of 0.05) with either 

scarification (ANOVA, F = 1.4, p = 0.08) or with the soil amendments (ANOVA, F = 

0.2, p = 0.31). As was the case with tree seedling density, tree seedling cover differed 

significantly with organic amount (Table 8). Cover was significantly higher on plots that 

were amended with less organic matter (Fig. 24). Forb cover also did not differ significantly with either scarification (ANOVA, F = 1.0, p = 0.17) or with the soil amendments 

(ANOVA, F = 0.1, p = 0.44). The specific amendments applied also made little difference (Table 9). Exploration of the significant interaction between mulch and organic 

amount showed that when there was no mulch, forb cover was significantly higher on 

plots amended with more organic matter (3 percent; SE = 1 percent) than on plots with 

less organic matter (1 percent; SE<1 percent) (t-test, t = 2.2, p = 0.03).

Table 8—Effects of fertilizer, organic type, 

organic amount, and mulch on tree 

seedling cover, repeated measures 

analysis of variancea.

Effect df F p

Fertilizer 1 1.6 0.21

Organic Type 1 1.3 0.26

Organic Amount 1 4.2 0.04

Mulch 1 0.0 0.93

Year 4 19.8 <0.01

a Interactions that are not significant (p≤0.05) 

are not shown. Effects with bold numbers 

are significant.

Figure 24—Effect of the amount of organic matter added to soil on the cover of tree 

seedlings.
24 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Table 9—Effects of fertilizer, organic type, organic 

amount, and mulch on cover of forbs 

that established from seed, repeated 

measures analysis of variancea.

Effect df F p

Fertilizer 1 0.4 0.55

Organic Type 1 1.2 0.27

Organic Amount (OA) 1 1.2 0.27

Mulch (M) 1 0.2 0.69

OA*M 1 4.0 0.05

Year 4 19.8 <0.01

a Interactions that are not significant (p≤0.05) are not 

shown. Effects with bold numbers are significant.

Effects of Supplemental Watering

The purposes of experimenting with supplemental watering were to assess: (1) how 

the benefits of watering compared to the benefits of treatments designed to improve 

soil quality, and (2) whether the effects of watering and soil treatments were additive. 

Total vegetation cover responded positively to supplemental watering (Fig. 25). In 2011, 

vegetation cover was significantly higher on plots that were watered (35 percent) than 

on plots that were not watered (18 percent) (ANOVA, F = 8.0, p = 0.02). Similarly, the 

cover of Vaccinium scoparium transplants was significantly higher on plots that were 

watered (22 percent; SE = 2 percent) than on plots that were not watered (12 percent; 

SE = 1 percent) (ANOVA, F = 6.4, p = 0.03). Transplant survival was higher on watered 

plots (94 percent; SE = 3 percent) than on plots that were not watered (82 percent; SE = 

5 percent) (ANOVA, F = 3.6, p = 0.05), and the mean size of surviving transplants was 

higher on watered plots (394 cm2; SE = 30 cm2) than on plots that were not watered 

(239 cm2; SE = 20 cm2) (ANOVA, F = 6.4, p = 0.03). The cover of plants that established 

from seed was significantly higher on plots that were watered (12 percent; SE = 3 percent) than on plots that were not watered (6 percent; SE = 1 percent) (ANOVA, F = 8.1, 

p = 0.02), and the density of plants that established from seed was significantly higher 

on plots that were watered (11 plants/m2; SE = 2 plants/m2) than on plots that were not 

watered (7 plants/m2; SE = 1 plant/m2) (ANOVA, F = 5.5, p = 0.03).

The benefits of supplemental watering to restoration success were as substantial 

as those associated with scarifying and amending soils with organic matter and fertilizer (Fig. 26). There were no significant differences between plots that were watered 

and neither scarified nor amended and plots that were scarified and amended but not 

watered for total vegetation cover (Tukey-Kramer, t = 0.3, p = 0.82), transplant cover 

(Tukey-Kramer, t = 0.0, p = 1.00), or seedling cover (Tukey-Kramer, t = 0.4, p = 0.74). 

Moreover, the benefits of watering generally supplemented the benefits of the soil treatments (Fig. 26). For total vegetation cover, plots that were both watered and amended 

had significantly more cover than plots that were only amended (Tukey-Kramer, t = 

2.2, p = 0.03) and plots that were only watered (Tukey-Kramer, t = 2.3, p = 0.02). Plots 

that were both watered and amended had more seedling cover than plots that were only 

amended and plots that were only watered; the contrast with only watered plots was 

significant (Tukey-Kramer, t = 1.9, p = 0.04), but the contrast with only amended plots 

did not meet the 0.05 criterion for significance (Tukey-Kramer, t = 1.5, p = 0.08). Plots 

that were both watered and amended had more transplant cover than plots that were only 

amended and plots that were only watered, but neither of these contrasts was significant 

(Tukey-Kramer, t = 1.8, p = 0.09 for each).
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 25

Figure 25—Effect of supplemental watering on total vegetation cover.

Figure 26—Effect of supplemental watering compared to the effect of soil treatments for 

total vegetation cover, transplant cover, and the cover of plants that established from seed.
26 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Discussion and Management Implications_____________________________

The purposes of this research were to verify the effectiveness of restoration treatments 

applied in the Eagle Cap Wilderness and to extend that work (Cole 2007; Cole and 

Spildie 2006, 2007). Specifically, we wanted to explore ways to increase success with 

planting Vaccinium scoparium and to experiment with various quantities and types of 

organic soil amendments. As was the case with the Eagle Cap trials, we were successful 

at partially restoring native vegetation on these highly disturbed campsites. Starting with 

sites devoid of all vegetation cover, we planted enough Vaccinium scoparium shrubs to 

provide 17 percent cover. Five years later, total cover was 31 percent (Fig. 27). Although 

a substantial improvement, this is still less than the 55 percent cover typically found 

on undisturbed sites (Fig. 28; Table 10). The primary species with diminished cover 

was Vaccinium scoparium. Coverage of other species collectively was equivalent on 

campsites (12 percent) and references sites (13 percent). Among associated species, the 

primary distinction between campsites and reference sites was in the relative abundance 

of Carex geyeri and C. rossii. Carex geyeri was more abundant on reference sites and 

C. rossii was more abundant on the restored campsites. Carex rossii was also the species that volunteered most abundantly on closed campsites in the Eagle Cap Wilderness 

(Cole and Spildie 2007).

Despite the diminished cover of Vaccinium scoparium five years after treatment, this 

species was much more successful in the Sawtooth trials than in the Eagle Cap trials. 

In the Sawtooths, 92 percent of transplants in the primary experiment survived after 

five years, and the mean change in size of those that survived was an increase of 16 

percent (46 cm2). Consequently, Vaccinium scoparium cover increased from 17 percent 

immediately after planting to 19 percent five years later. On the Eagle Cap sites, only 

53 percent of transplants survived the first five years, and the mean change in size of 

those that survived was a decrease of 14 percent (18 cm2). Consequently, after five 

Figure 27—Substantial vegetation cover, five years after restoration, on the campsite shown 

in Figure 4.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 27

Table 10—Mean percent cover of species, growth forms, and 

all vegetation on treated campsites, five years 

after treatment, and undisturbed reference sites.

Campsites Undisturbed

Total vegetation cover 31 55

Vaccinium scoparium 19 42

Associated species 12 13

Carex rossii 7 2

Carex geyeri 1 6

Other graminoids 1 1

Forbs 3 4

Figure 28—The groundcover adjacent to the campsites suggests what complete recovery 

might look like. 

years, Vaccinium scoparium cover was less than one-half what it was after planting 

(Cole and Spildie 2006, 2007).

Higher survival and growth rates of Vaccinium scoparium transplants in the Sawtooth trials might reflect any of a number of uncontrolled variables—differences in soil, 

disturbance history, weather patterns, population genetics, and so on. However, greater 

success could also be the result of using larger transplants. As previously noted, 

working in Iceland, Aradottir (2012) found that transplants of several deciduous dwarfshrub Vaccinium species, morphologically similar to V. scoparium, were much more 

successful if they were at least 400 cm2 in size. The size of V. scoparium transplants in 

the Eagle Cap study was only about 150 cm2 compared to a mean size of 315 cm2 in the 

Sawtooth trials. In the Sawtooths, we found that smaller transplants were less likely to 

survive; however, when they did survive, they grew more than larger transplants. This 
28 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

suggests that using larger transplants increases success, but this does not completely 

explain the greater success in the Sawtooth study. We also scarified soils to a depth of 

20 cm compared to 15 cm in the Eagle Cap. Although this could have contributed to 

success, 56 percent of transplants survived on the plots that were not watered or scarified.

The lack of an effective seeding treatment in the Sawtooth trials resulted in reduced 

seedling densities compared to the Eagle Cap trials. Five years after treatment, mean 

seedling density on Sawtooth plots (21 plants/m2) was comparable to the density of 

volunteer seedlings on Eagle Cap plots (23 plants/m2) but much lower than the density 

of plants on seeded plots (177 plants/m2) (Cole 2007). Differences in seedling cover 

were less pronounced, however. Five years after treatment, mean seedling cover on 

Sawtooth plots (12 percent) was comparable to the mean seedling cover of seeded Eagle 

Cap plots (13 percent). This suggests that seeding sites may have little long-term effect 

on vegetation recovery on these sites. Indeed, 15 years after treatment seeding did not 

have a significant effect on seedling cover of the Eagle Cap plots (unpublished data).

Treatment Effects

The Sawtooth results confirmed a number of the findings from the Eagle Cap study 

regarding treatment effects. Soil scarification was beneficial to restoration success, as 

was amending soils with organic matter. The effect of the mulch blanket, however, was 

not substantial. The trials with mulch, fertilization, and different types and amounts of 

organic matter suggest that, although none of these treatments is vastly superior to any 

other, some treatment combinations may be somewhat more beneficial than others. 

However, treatment benefits vary between transplants and plants that grow from seed, 

as well as between growth forms and probably species. Watering is also beneficial but 

will seldom be feasible.

The most pronounced main effect of treatments other than watering was the beneficial effect of fertilization with Biosol® on the establishment and growth of seedlings, 

particularly graminoids. As was the case in the Eagle Cap study where the source of 

fertilizer was compost, fertilization was neither beneficial nor harmful to Vaccinium 

scoparium transplants or to tree seedlings (Cole and Spildie 2007). In Rocky Mountain 

National Park, Colorado, fertilization with Biosol® was also effective at increasing the 

cover of native graminoids (Paschke and others 2000).

The only other statistically significant main effect was from the amount of organic 

matter added to the soil. The growth of Vaccinium scoparium transplants was greater if 

less organic matter was added to the soil. The advantage of less organic matter might 

be due to the immobilization of available soil nitrogen by microbial populations that 

expand as they consume the increased carbon in the organic matter amendments (Tate 

1995). In the Eagle Cap study, the growth of Vaccinium scoparium transplants was not 

affected, for better or worse, by organic matter amendments. This suggests that any 

benefit from increased organic matter (for example, improving soil porosity and water 

holding capacity) may be small and easily offset by decreased available nitrogen. If so, 

larger quantities of organic matter could be detrimental. This explanation is consistent 

with our finding that on plots that were not fertilized, mean transplant size and height 

were substantially less on plots amended with decomposed wood compared to those 

amended with decomposed wood and twigs/needles; the amount of carbon in a given 

volume of decomposed wood is much greater than when that wood is mixed with 

needles and twigs. It is also consistent with our finding that when plots were fertilized, 

compensating for the immobilization of nitrogen, neither the type nor the amount of 

organic material mattered. The density of tree and forb seedlings also differed significantly with amount of organic matter, but in opposing ways. Tree density declined with 

increases in organic matter while forb density increased.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 29

The significant interaction between the effect of mulch and organic matter amount on 

seedling density and cover suggest that the effects are additive. More organic matter is 

beneficial in the absence of the mulch blanket, whereas the mulch blanket is beneficial 

if less organic matter is applied. If the benefits of organic matter are improved water 

relations, this might be explained by the mulch blanket keeping the soil from drying out 

as rapidly. However, if that were the case, we might have expected a generally positive 

effect of the mulch blanket. These complex interactions suggest that there are positive 

and negative consequences of these treatments that also vary with growth form and species. The Vaccinium scoparium transplants responded in an opposing manner, growing 

most when there was both no mulch and the least carbon amendment—a lesser amount 

of decomposed wood mixed with twigs and needles.

Identifying the Best Treatment

As noted earlier, all of the treatments used in the primary experiment were effective 

in promoting restoration of these campsites. However, identifying the “best” treatment 

is difficult, both because (1) differences among treatments are not that substantial in 

relation to the variability within treatments, and (2) treatment effectiveness varies among 

growth forms and species. What is best for the Vaccinium scoparium transplants may 

not be best for plants establishing from seed. Nevertheless, we can make a series of 

assumptions and use our data to separate some of the better options from some of the 

worst. For example, the treatment combination that was worst for both the Vaccinium 

scoparium transplants and seedlings was no mulch, no fertilization, and a lesser quantity 

of decomposed wood.

First, let us assume that regular watering is not an option and that we are primarily 

concerned about the survival and growth of Vaccinium scoparium transplants and the 

establishment and spread of graminoids. Trees can readily be established through transplanting, so tree seedling density should not be a concern. Moreover, the forbs responded 

equally well to all of these treatments. Second, because fertilization is important to 

graminoid seedlings, let us assume that fertilizer will be applied. When fertilizer was 

applied, none of the other treatments had a significant effect on either the Vaccinium 

scoparium transplants or graminoid seedlings. However, mulch effects interacted with 

organic amount effects. For both Vaccinium scoparium transplants and graminoid seedlings, less organic matter was better if there was a mulch blanket and more was better 

if there was not. This suggests that the best treatment for both Vaccinium scoparium 

transplants and graminoid seedlings is either fertilizer, mulch, and less organic matter; 

or fertilizer, no mulch, and more organic matter. The type of organic matter made little 

difference, although growth of both Vaccinium scoparium transplants and graminoid 

seedlings was somewhat (but not significantly) better if decomposed wood was used 

when there was a mulch blanket and when decomposed wood was combined with twigs 

and needles in the absence of a mulch blanket.

Effects of Supplemental Watering

The beneficial effect of supplemental watering indicates that vegetation recovery 

on these campsites is limited by water. We found that plant growth was comparable on 

plots with scarified and amended soils that were not watered and plots that were watered but not scarified or amended. This finding is consistent with our belief that much 

of the benefit of soil scarification and amendment results from improvements in water 

infiltration into the soil and the availability of soil water for plant uptake. Our finding 

that the effects of supplemental watering and soil amendment are additive suggest that 

any treatment that would further improve soil-plant water relations would be beneficial.
30 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Management Prescription

Cole and Spildie (2007) provided a prescription for campsite restoration based on the 

Eagle Cap study. On the basis of another five years of observation on those campsites 

and the results of the Sawtooth trials, that prescription can be revised as follows:

1. Effectively close the campsite to all use. Rope off the perimeter and post signs 

that instruct people to stay off the site and explain why.

2. Scarify soils to a depth of at least 15 cm, preferably 20 cm. Break up all clods 

to produce a crumb texture.

3. Decide whether or not to use a mulch covering such as the excelsior blanket 

used in this study. Our results suggest that lesser quantities of organic matter 

are needed if a mulch blanket is used.

4. If using a mulch blanket, amend soils with a 5 cm layer of locally collected, 

well-decomposed organic matter. This is about 50 liters or 13 gallons per m2. 

Without a mulch blanket, add more organic matter--up to the 15 cm layer of 

locally collected, well-decomposed organic matter we added in this study. 

Some of the decomposed wood can be replaced with twigs and needles. In our 

study, the addition of twigs and needles was somewhat beneficial when larger 

quantities of organic matter were added and there was no mulch blanket. Some 

of this organic matter could be replaced by compost, although that increases 

transportation costs.

5. Sprinkle a bioorganic fertilizer such as Biosol® over the surface at a rate of 

about 20 kg per 100 m2.

6. Transplant Vaccinium scoparium in large turfs (300 to 400 cm2). Plant enough 

to provide cover equal to between 50 and 100 percent of the cover of Vaccinium 

scoparium on undisturbed sites. Recovery times are largely dependent on the 

amount of Vaccinium scoparium planted on the site. Consider growing these 

shrubs in nurseries from seed collected close to the site. Using nursery-grown 

shrubs rather than local transplants becomes increasingly important as the area 

to be restored increases. However, we have not experimented with the success 

of nursery-grown plants and do not know what density of nursery plants to use. 

It also seems highly beneficial to transplant some small trees. If only a few sites 

are being restored, it may not be necessary to grow trees in nurseries.

7. If all the plants come from nurseries, the soil should be inoculated with native 

biota. This can be done by collecting soil from around the root zone of plants 

in the vicinity, particularly Vaccinium scoparium. Make a soil-water slurry by 

adding this soil to some water and sprinkling it over the amended soil prior to 

transplanting. In the Eagle Cap study, we used 1.2 liters of soil mixed with 20 

liters of water to inoculate 7 m2 of campsite. This might be most easily done 

by collecting a few plants for transplanting and obtaining soil for inoculation 

and using plants grown in nurseries for the rest.

8. Seeding is not critical but can be a way to rapidly add species diversity. To do 

so, collect seed from a wide variety of species growing in the vicinity, preferably a year before restoration. Match the species sown to site conditions.

9. If possible, water plants regularly during long, dry spells. This is probably most 

important in the first few growing seasons.

10. At a minimum, inspect the closures at the start of every year to verify that ropes 

and signs are still intact.
USDA Forest Service Res. Pap. RMRS-RP-99. 2012 31

Further Research__________________________________________________

One fruitful new research avenue would be to experiment with Vaccinium scoparium 

plants grown from seed in nurseries. This is the only sustainable way to restore Vaccinium scoparium communities over large areas, given the large numbers of transplants 

required. Therefore, we need to learn more about how to grow them in nurseries, when 

to transplant them and at what densities. We also need to understand the effects of restoration treatments on these younger, smaller plants.

Beyond this, it would be worthwhile to experiment further with the combination 

of treatments employed in this study. This might determine whether the combinations 

of treatments that worked well in this study do so elsewhere. There might be value in 

experimenting further with the magnitude of organic matter amendments, given that 

Vaccinium scoparium responded positively to organic amendments but particularly in 

lesser quantities. There also might be other treatments to explore, such as the judicial 

use of fire.

Conclusions______________________________________________________

Even with effective closure of campsites in these forests, recovery to conditions that 

approximate those that existed pre-disturbance will probably require many centuries 

(Cole and Spildie 2007). The results of this study and the earlier study in the Eagle Cap 

Wilderness show that recovery times can be reduced to several decades or even less. 

To do so, however, requires substantial investment of resources. To achieve the shortest 

recovery times requires intensive scarification and amendment of the soil followed by 

plantings at densities close to those found on undisturbed sites. Our experience suggests 

that soil preparation and planting of a moderate size campsite with 100 m2 devoid of 

vegetation might require 30 person/days of work. We spent at least a day working on 

each site with a crew that always exceeded six people and only restored about 20 m2

on each site. Although work crews would probably become much more efficient, this 

estimate suggests the magnitude of investment. Additional time and resources might 

be needed to gather seed, grow plants in nurseries, and transport materials to the site.

This estimate of the high cost of effective restoration emphasizes the importance 

of avoiding camping impacts in the first place in environments with low resilience. In 

places that receive regular use, concentration of use, perhaps on designated sites, can 

be beneficial (Marion and Farrell 2002). High costs also suggest that there is little value 

in expending resources on restoration unless available resources are sufficient to do it 

correctly. Managers must be highly strategic about which places to restore and develop 

realistic budgets and time frames for restoration work.

References _______________________________________________________

Aradottir, Asa L. 2012. Turf transplants for restoration of alpine vegetation: does size matter? Journal of 

Applied Ecology 49: 439-446.

Chambers, Jeanne C. 1997. Restoring alpine ecosystems in the western United States: environmental 

constraints, disturbance characteristics, and restoration success. In: Urbanska, Krystyna M.; Webb, 

Nigel R.; Edwards, Peter J., eds. Restoration ecology and sustainable development. Cambridge, UK: 

Cambridge University Press: 161-187.

Cole, David N. 2007. Seedling establishment and survival on restored campsites in subalpine forest. Restoration Ecology 15: 430-439.

Cole, David N.; Spildie David R. 2006. Restoration of plant cover in subalpine forests disturbed by camping: success of transplanting. Natural Areas Journal 26: 168-178.

Cole, David N.; Spildie, David R. 2007. Vegetation and soil restoration on highly impacted campsites in 

the Eagle Cap Wilderness, Oregon. General Technical Report RMRS-GTR-185. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station. 26 p.
32 USDA Forest Service Res. Pap. RMRS-RP-99. 2012

Conlin, David B.; Ebersole, James J. 2001. Restoration of an alpine disturbance: differential success of 

species in turf transplants, Colorado, U.S.A. Arctic, Antarctic, and Alpine Research 33: 340-347.

Marion, Jeffrey L.; Farrell, Tracy. 2002. Management practices that concentrate visitor activities: camping impact management at Isle Royale National Park, USA. Environmental Management 19: 763-771.

Moritsch, Barbara J.; Muir, Patricia S. 1993. Subalpine revegetation in Yosemite National Park, California: 

changes in vegetation after three years. Natural Areas Journal 13: 155-163.

Paschke, Mark W.; DeLeo, Claire; Redente, Edward F. 2000. Revegetation of roadcut slopes in Mesa Verde 

National Park, U.S.A. Restoration Ecology 8: 276-282.

Petersen, S. L.; Roundy, B. A.; Bryant, R. M. 2004. Revegetation methods for high-elevation roadsides at 

Bryce Canyon National Park, Utah. Restoration Ecology 12: 248-257.

Smyth, C. R. 1997. Early succession patterns with a native species seed mix on amended and unamended 

coal mine spoil in the Rocky Mountains of southeastern British Columbia, Canada. Arctic and Alpine 

Research 29: 184-195.

Tate, Robert L. III. 1995. Soil microbiology, 3rd ed. New York: John Wiley & Sons. 528 p.



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