United States 

Department of 

Agriculture 

Forest Service 

Hiker Trampling Impacts 

Northeastern Forest on Eastern Forests 

Experiment Station 

Research Paper R. E. Leonard 

N E-555 J. L. McMahon 

K. M. Kehoe 
The Authors 

R. E. Leonard is Project Leader, J. L. McMahon is a forestry technician, 

and K. M. Kehoe is a biological lab technician, Backcountry Recreation Facilities, Northeastern Forest Experiment Station, Durham, New Hampshire. 

Manuscript received for publication 15 June 1984 

Abstract 

Trampling impact studies were conducted in two eastern forest stands in 

the White Mountains, New Hampshire. Changes in plant mortality on simulated trails during a trampling period and a recovery period were monitored 

photographically. The extent of damage and rate of recovery varied among 

species. for most species, the greatest change in plant mortality occurred 

between 100 and 300 trampling passes. 
Introduction 

Before effective management 

strategies can be designed for backcountry areas, managers need information that either prescribes desired 

levels of use for a given set of ecological conditions or predicts ecological changes for known levels of use. 

Disturbances induced by recreational activities have been well 

documented. In a pioneer study, 

Bates (1935) observed that trampling 

had both direct and indirect effects 

on the vegetation of an area through 

mechanical damage to plant parts 

and changes in soil structure. Other 

studies (Frissel and Duncan 1965, 

Cole 1978) correlate trampling pressure to death of vegetation underfoot. 

Changes in species composition over 

time have been noted by LaPage 

(1967) and Bayfield (1971). Watson 

and coworkers (1970), Speight (1975), 

and others reported that the lack of 

vegetation on a site greatly increases 

the potential for soil erosion, which 

in turn may affect other areas of vegetation. Much of the work to date, 

however, is based on observations~ 

taken after high levels of use have 

already occurred on preexisting trails, 

or is descriptive rather than quantitative in nature. 

This trampling study was designed to relate given intensities of 

use to observed changes in the vegetation and soils of two previously 

undisturbed forest systems. The 

survival of certain plant species and 

the unvegetated ground were photographically mo~itored through a 

season of trampling and then for 

3 years of trail recovery. Soil compaction was also documehted. The greatest increase in plant mortality on 

simulated trails occurred at a low 

intensity of trampling, with gradual 

increases in mortality at higher intensities. This finding concurs with results reported by Frissel and Duncan 

(1965), LaPage (1 967), and Bell and 

Bliss (1973) who found that loss of 

cover occurs most rapidly at the 

onset of trampling, then subsides as 

trampling continues. When overall 

percentage of area coverage per 

species was compared between highand low-use trails (at the end of the 

trampling season), the high-use trails 

showed a noticeably greater reduction 

in area coverage than did the low-use 

trails. The width of the impacted zone 

(trail width) was established during 

the initial stages of trampling. Similar 

results were reported by More (1980). 

Background Information 

Doublehead Mountain is located 

within the White Mountain National 

Forest, 2.4 miles northeast of Jackson, New Hampshire. Its 4 miles of 

hiking and skiing trails were cleared 

in the 1930's by the Civilian Conservation Corps. Since then, the trails have 

been maintained by the USDA Forest 

Service. An estimated 1,500 to 2,000 

people use these trails each year. 

Glacial till deposited by the most 

recent episode of glaciation, the 

Wisconsin Ice Sheet, forms the major 

soil parent materials of Doublehead 

and most of the White Mountain 

region. Soils found on Doublehead 

belong to the Spodosol order, the 

Haplorthod subdivision, and the 

Marlow and Lyman-Berkshire series 

(Bailey and Pilgrim 1983, USDA, SCS 

1977). The bedrock of Doublehead 

Mountain is composed of Hastingsite 

granite, which is a greenish-gray, 

medium- to coarse-grained equigranular rock. Feldspar and quartz are the 

primary minerals in this rock type 

(Billings 1980). 

Simulated trails and study plots 

were established on two sites. Site 

No. 1 was in a mixed hardwoodsoftwood stand at approximately 

1,950 feet (590 m) elevation. Sugar 

maple (Acer saccharum Marsh.), red 

spruce (Picea rubens Sarg.), white 

ash (Fraxinus americana L.), and 

balsam fir (Abies balsamea L.) formed 

the canopy of this stand. The canopy 

had a 70 to 75 percent enclosure. 

Beneath this layer, the dominant 

understory plants included maple 

spp. (Acer saccharum Marsh., A. rubrum L., A. pensylvanicum L.), hobblebush ( Viburnum alnifolium Marsh.), 

red spruce and balsam fir. Ground 

cover species included starflower 

( Trientalis borealis Raf.), Indian cucumber root (Medeola virginiana L.), 

wood aster (Aster acuminatus Michx.), 

rose twisted-stalk (Streptopus roseus 

Michx.), and other forbs, ferns, and 

tree seedlings. The bouldery soil at 

this site consisted of a 7- to 9-inch 

(17.5 to 22.5 cm) organic layer of 

partly to fully decayed leaves, needles, 

and roots (the 01 and 02 soil horizons), over a 0.5- to 2-inch (1.3 to 5 cm) 

leached, grayish-brown layer (A2 horizon), over a 10-inch (25 cm) dark brown, 

sandy layer (the B horizon). Below this 

we intercepted a layer of gravel and 

rocks of unknown depth. Depth of 

bedrock was not measured. 

Site No. 2 was in a coniferous 

forest at approximately 3,000 feet 

(909 m) elevation. The canopy layer 

was composed primarily of balsam 

fir, with some red spruce and paper 

birch (Betula papyrifera Marsh.). Fir 

dominated the understory; fir seedlings, Canada mayflower (Maianthemum canadense Desf.), blue-bead lily 

(Clintonia borealis (Ait.) Raf .) and 

mosses covered the forest floor. 

Blowdowns were plentiful. A representative soil profile at this site consisted of a 1.5- to 2-inch (3 to 4 cm) 

thick surface organic layer, over a 

dark reddish-brown and yellowish-red 

fairly compact sandylpebbly layer of 

unknown depth. Slopes were less than 

5 percent at both sites. Plant identification was done in the field using 

Gray's Manual of Botany (Fernald 

1950). 

Methods 

Three 30-meter-long, I-meter-wide 

trails were set up at each site; two 

were trampled a given number of 

times, one remained a control. Trampling was done once a week over a 

10-week period from June to August, 

1978. High-use trails (trail A at the 

hardwood site, trail X at the conifer 

site) received 150 one-way passes 

per week for a season total of 1,500 

passes. Low-use trails (C at the hardwood site, Z at the conifer site) received 25 passes per week for a total 

of 250 passes. 

Four field assistants, weighing 

from 125 to 160 pounds, walked down 

the center of the simulated trails. 

They wore lug-soled boots because 
this type of sole seemed to be the 

most commonly encountered type of 

hiking boot in the 1970's. Backpacks 

were not worn by the tramplers. 

Percentage of Plant Survival 

To document ground cover 

changes over time, ten 1-meter by 

0.5-meter study plots were established randomly on each trail. Each 

plot was photographed a total of nine 

times. In 1978, photographs were 

taken before trampling began and 

at five 2-week intervals as trampling 

progressed throughout the summer. 

After trampling had ended and trails 

were recovering, each plot was photographed in June of 1979, 1980, and 

1981. 

The quadropod technique developed by McBride and Leonard (1982) 

was used for photographing the study 

plots. The photographs were analyzed 

in the lab in the following manner. 

The slide of the study plot was 

projected onto an audioviewer projector screen. An acetate overlay 

with a scaled-down outline of the 

quadrat frame was placed over the 

quadrat image, and boundaries of 

plant types and the unvegetated areas 

were marked. The area of each cover 

type was determined with a planimeter. Individual plants (such as fir 

seedlings) were counted by species 

if the area could not be accurately 

measured. These absolute numbers 

were converted to relative percentages 

by assigning the greatest number of 

plants or area coverage of a species 

on any given date in 1978 a value of 

100 percent. The dominant ground 

cover species at each site were selected for study. Site No. 1 species 

included rose twisted-stalk and sugar 

maple seedlings. Site No. 2 species 

included balsam fir seedlings and 

Canada mayflower. 

The major objectives of photoplot 

analysis were: 

1. to monitor the survival and eventual 

recovery of certain species; 

2. to determine what level of trampling caused plant mortality; and 

3. to determine trail width and soil 

compaction. 

Trail Width and Soil Compaction 

Trail width-the area of visible 

trampling damage-was measured in 

the same way as plant survival to 

determine whether an increase in 

trampling caused a corresponding 

increase in the disturbed area. 

A soil test penetrometer was 

used to measure soil compaction. 

Measurements were taken at the 

tread centers of each trail and at 

random intervals across the trails. A 

total of 50 samples were taken at the 

conclusion of the trampling period. 

Sixty samples were taken the following spring to measure changes after 

a recovery period. 

The relative compaction or penetration resistance of the forest 

soils was measured in an effort to 

determine: 

1. the levels of compaction in relation 

to the number of passes; 

2. the levels of compaction across 

the width of the trail; and 

3. the recovery of soils by the following spring (recovery period was 

9 months). 

Results and Discussion 

Percentage of Plant Survival 

Survival data (recorded in relative 

percentages) for selected species are 

presented in Table 1. Results are 

separated into high-use, low-use, and 

control categories for both the trampling and recovery phases of the 

study. High-use data (up to 1,500 

passes) during the trampling and 

recovery phases are shown in Figure 1. 

Percentage of survival of all four 

species dropped significantly between 

0 and 300 passes. This change is 

analyzed further in Figure 2, which 

depicts percentage of survival of 

plant species on trails subjected to 

lower levels of use (up to 250 passes). 

Two major trends are apparent 

from the results: 

1. All species seem to be significantly 

affected by initial trampling stress. 

The greatest reduction in percentage of survival for each species 

occurred at 300 passes on high-use 

trails. However, the highest plant 

mortality does not necessarily 

occur at the onset of trampling. 

In general, the largest change in 

percentage of survival occurred between 100 and 300 passes. Figure 1 

indicates that after 300 passes, 

reductions in percentage of survival 

become less pronounced. 

2. Revegetation of the trails was 

rapid and, for most species, percentage of survival during the 

recovery phase rose to near or 

above 100 percent. Recovery times 

varied with species. Other factors 

such as natural senescence, high 

seed years, and plant growth characteristics may have influenced 

percentage of survival and regeneration. Some of these factors are 

explained in the following discussion of individual species. 
Table 1.-Percentage of plant survival during trampling and 

recovery phases, by species and level of use. 

Trampling Phase Recovery Phase 

Trail OIOa 1001300 1501600 2001900 25011,500 614179 615180 613181 

6126178 711 9/78 7/24/78 811 0178 914178 

Control-B 97 100 89 93 79 83 131 113 

Low use-C 100 68 51 47 41 53 91 70 

High use-A 100 45 35 26 9 55 125 83 

A. saccharum 

Control-B 80 97 96 86 94 109 128 95 

Low use-C 93 84 63 66 64 230 202 178 

High use-A 100 48 47 40 41 75 72 138 

A. balsamea 

Control-Y 86 97 92 95 87 80 56 93 

Low use-Z 83 90 82 88 61 57 22 272 

High use-Z 100 40 30 28 22 35 14 126 

M. canadense 

Control-Y 100 66 61 58 20 91 126 171 

Low use-Z 100 64 53 43 5 55 66 132 

High use-X 100 25 15 19 4 51 69 86 

aNumber of passes for low uselhigh use. 

- S roseus 

- - -- A. saccharurn 

. . . . . . . . A. bo/samea 

100 -.-.- M. canadense 

. 

/ A*. G*' 

- TRAMPLING PHASE I-RECOVERY PHASE + 

(Number of passes 1 

Figure 1.-High-use data during trampling and recovery phases. 
Canada mayflower had the greatest decline in percentage of survival 

during the trampling period. This 

decline was paralleled in the control 

trail, indicating that the low survival 

by the end of the summer was partially 

due to the natural senescence. By 

the third year, recovery was complete 

(132 percent) on trails that had received 250 passes. On trails that had 

received 1,500 passes, recovery was 

only 86 percent by the third year. The 

decline in percentage of survival of 

rose twisted-stalk is very similar to 

that of Canada mayflower during the 

trampling phase. Both species are 

rhizomatous perennials with broad, 

delicate leaves. Regrowth probably 

occurred from underground rhizomes 

that were not damaged by trampling. 

Sugar maple and balsam fir seedlings showed more than 100 percent 

recovery after 3 years in both highand low-use trails. Sugar maple seems 

to be the most resilient of the species 

studied. Figure 2 suggests that low 

levels of trampling stress (up to 250 

passes) did not cause significant 

plant mortality and for sugar maple 

may actually have been beneficial. 

The percentage of survival of sugar 

maple rose to 230 percent in 1979. 

Low levels of trampling may have 

scarified the soil surface, creating a 

more favorable seedbed. Balsam fir 

showed a large percentage of survival 

increase between 1980 (22 percent) 

and 1981 (272 percent), which might 

be attributed to the occurrence of a 

high-seed year for fir. 

Trail Width and Soil Compaction 

After measuring the area of visible trampling stress and the change 

in percentage of unvegetated area in 

the plots, we observed the following: 

1. The initial 2 weeks of trampling 

established the width of the trail. 

Hiking pressure,.whether 250 or 

1,500 passes, resulted in nearly 

the same area of disturbance. 

Soils at the spruce-fir site were 

compacted nearly twice as much at 

1,500 tramples as at 250 tramples. 

By contrast, soil compaction 

changed only slightly between 

250 and 1,500 tramples at the 

hardwood-softwood site. 

Even though most visible disturbance occurred in the center portion 

of the study area, adjacent areas 

were indirectly affected by trampling stress. As was expected, 

peak compaction occurred at the 

center of the trails where the most 

footsteps landed. We were unable 

to obtain consistent results of 

changes in soil compaction after 

the recovery period. In general, 

high-use trails showed more compaction after a 9-month recovery 

period than during the trampling 

phase, and low-use trails showed 

less compaction. It is recommended 

that soil compaction be measured 

over a larger recovery period to 

obtain more conclusive results. 

TRAMPLING PHASE 

(Number of passes) 

Figure 2.-Low-use data during trampling phase. 
Conclusion 

In summary, the plant species 

studied reacted similarly to trampling 

pressure. All four showed the greatest 

reduction in percentage of survival 

at the first 300 passes. More specifically, 100 to 300 passes can be 

considered a threshold level at which 

most initial trampling damage occurs. 

Before 100 passes, damage is relatively low. After 300 passes, damage 

increases but at a more gradual rate. 

Plant species with steady rates 

of change during both trampling and 

recovery periods, such as Canada 

mayflower and sugar maple, should 

be used in further studies to ascertain 

their value as indicators of hiking 

pressure on ground cover. 

Recovery periods may be substantial at the use level of 1,500 passes 

per season. It is likely that if this use 

level recurred each year, recovery 

rates would decline. 

Literature Cited 

Bates, G. H. The vegetation of footpaths, sidewalks, cart-tracks, and 

gateways. Journal of Ecology. 23: 

470-487; 1935. 

Bailey, G. D.; Pilgrim, S. A. L. Soils of 

the White Mountains of New Hampshire and their suitability for recreational development. Mountain 

Research and Development. 3(1): 

53-60; 1983. 

Bayfield, N. G. Some effects of walking and skiing on vegetation at 

Cairngorm. Scientific Management 

of Animal and Plant Communities 

for Conservation. Norwich, England: 

University of East Anglia; 1971. 

Bell, K. L.; Bliss, L. C. Alpine disturbance studies: Olympic National 

Park. Biological Conservation. 5(1): 

25; 1973. 

Billings, M. P. The geology of New 

Hampshire. Part II: Bedrock geology. Concord, NH: New Hampshire 

State Planning and Development 

Commission; 1980. 203 p. 

Cole, D. N. Estimating the susceptibility of wildland vegetation to 

trailside alteration. Journal of Applied Ecology. 15:281-286; 1978. 

Fernald, Merritt Lyndon. Gray's manual of botany, 8th ed. Boston, MA: 

American Book Company; 1950. 

1,632 p. 

Frissel, S. S., Jr.; Duncan, D. P. Campsite preference and deterioration in 

the Quetico-Superior canoe country. Journal of Forestry. 63:256-260; 

1965. 

LaPage, W. F. Some observations on 

campground trampling and ground. 

cover response. Res. Pap. NE-68. 

Upper Darby, PA: U.S. Department 

of Agriculture, Forest Service, 

Northeastern Forest Experiment 

Station; 1967. 11 p. 

McBride, J. C.; Leonard, R. E. A system for measuring groundcover 

changes. Parks. 7(1):20; 1982. 

More, T. A. Trail deterioration as an 

indicator of trail use in an urban 

forest recreation area. Res. Note 

NE-292. Broomall, PA: U.S. Department of Agriculture, Forest Service, 

Northeastern Forest Experiment 

Station; 1980. 4 p. 

Speight, M. C. D. Discussion papers 

in conservation: Outdoor recreation 

and its ecological effects. A bibliography and review. London: University College; 1975. 

U.S. Department of Agriculture, Soil 

Conservation Service and Forest 

Service. Soil sutvey of Carroll County, 

New Hampshire. Washington, DC: 

U.S. Government Printing Office; 

1977-202-865150. 161 p. In cooperation with: New Hampshire Agricultural Experiment Station. 

Watson, A.; Bayfield, N.; Moyes, S. M. 

Research on human pressures on 

Scottish mountain tundra, soils 

and animals. In: Fuller, W. A.; 

Kevan, P. G., eds. Proceedings, 

conference on productivity and 

conservation in northern circumpolar lands; (dates unknown); Switzerland. New Series No. 16. (Place 

of publication unknown): IUCN 

Publications; 1970:256-266. 
Leonard, R. E.; McMahon, J. L.; Kehoe, K. M. Hiker trampling 

impacts on Eastern forests. Res. Pap. NE-555. Broomall, PA: 

U.S. Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station; 1985. 5 p. 

Trampling impact studies were conducted in two eastern forest 

stands in the White Mountains, New Hampshire. Changes in 

plant mortality on simulated trails during a trampling period and 

a recovery period were monitored photographically. The extent 

of damage and rate of recovery varied among species. For most 

species, the greatest change in plant mortality occurred between 

100 and 300 trampling passes. 

Keywords: Trampling, plant mortality, hiker impact 

a U.S. GOVERNMENT PRINTING OFFICE: 1985-505-0281538 
Headquarters of the Northeastern Forest Experiment Station are in 

Broomall. Pa. Field laboratories are maintained at: 

Amherst, Massachusetts, in cooperation with the University of 

Massachusetts. 

Berea, Kentucky, in cooperation with Berea College. 

Burlington, Vermont, in cooperation with the University of 

Vermont. 

Delaware, Ohio. 

Durham, New Hampshire, in cooperation with the University of 

New Hampshire. 

Hamden, Connecticut, in cooperation with Yale University. 

0 Morgantown, West Virginia, in cooperation with West Virginia 

University, Morgantown. 

Orono, Maine, in cooperation with the University of Maine, 

Orono. 

Parsons, West Virginia. 

Princeton, West Virginia. 

Syracuse, New York, in cooperation with the State University of 

New York College of Environmental Sciences and Forestry at 

Syracuse University, Syracuse. 

University Park, Pennsylvania, in cooperation with the 

Pennsylvania State University. 

Warren, Pennsylvania.