United States 

Depart men t of 

Agriculture 

Forest Service 

Southeastern Forest 

Experiment Station 

General Te~hnical 

Report SE-32 

A Loblolly Pine 

Management Guide 

Managing Site Damage 

F ging 

W.H. McKee, Jr. 

G.E. Hatchell 

A.E. f iarks 
October 1985 

Southeastern Forest Experiment Station 

200 Weaver Blvd. 

Asheville, North Carolina 28804 
Managing Site Damage 

From Logging 

W. H. McKee, Jr. 

Research Soil Scientist 

Southeastern Forest Experiment Station 

Charleston, South Carolina 

G. E. Hatchell 

Research Forester 

Southeastern Forest Experiment Station 

Athens, Georgia 

and 

A. E. Tiarks 

Research Soil Scientist 

Southern Forest Experiment Station 

Pineville, Louisiana 

A Loblolly Pine Management Guide 

ABSTRACT 

Serious damage to forest sites duri ~g fogqi ng ran 

he avoided through careful plaqning of logging, preparation of the site for logging, and close sclpervision 

of the work. Losses in productivity caused by compaction can be largely restored by cultivation and 

fertilization. 

Keywords: Pinus taeda, site producti vi ty, ferti 1 - i zation, drainagexffi cabi 1 i ty, soi 1 co~npdction. 

Loggi ng operat ions can seriously damage forest sites by destroying soi 1 structure, blocking 

drainage, damaging seed1 i ngs, and transporting 

nutrients. As much as two-thirds of a logged area 

can be damaged, and costs in lost productivity can 

be $60 to $90 per acre on Coastal Plain sites. 

Growth of seedlings, for example, may he halved by 

soi 1 compaction (table 1 ). Historical ly, the 

blame for this damage has been placed on logging 

contractors and their employees, hut much of the 

damage can be prevented by a land manager through 

careful planning of the sale and full preparation 

of the site for the logging operation. Careful 

control is then needed during the logging operation. Damaged sites can be largely restored to 

productivity by cultivation and fertilization, but 

the less damage done to a site the less special 

site preparation is needed. 

Preparing for the Timber Harvest 

Methods for minimizing site damage prior to 

logging include preparing the timber stand for 

cutting, determining when to log, laying out skid 

trails, and choosing the proper equipment. Planning before the sale allows the manager to understand the hazards of logging a site and to devise 

practices suited to the site. 
Table 1 .--Dry weights of 1 -year-old lob101 ly pine 

seedlings grown on soils of various textures with 

and without compact i on 

Tree component wei ght 

Soil treatment -- - 

Shoot Root Total 

---- - -- Ounces - - - - - 

Not compacted 12.13 3.70 15.83 

Compacted 6.49 2.33 8.82 

Site Pre~aration 

Foresters are accustomed to thinking of site 

preparation as a silvicultural practice designed 

to improve growth of seeded or planted trees. 

Site preparation for logging may, therefore, seem 

foreign. The primary objective here is to reduce 

damage to the site during logging, and this objective can he met in two ways. Fi rst, visi bi li ty 

can be improved. This step permits the skidder 

operator to see well and avoid obvious wet spots. 

Second, drainage of wet areas can be improved. In 

addition to faci litating logging and reducing site 

damage, these practices often provide si 1 vi - 

cultural benefits. 

Prescribed burning is the most economical way 

to improve visibility on a logging site. This 

technique is especi a1 ly suited to even-aged pine 

stands, in which hardwood invasion is a constant 

problem. Control of hardwoods throughout the pine 

rotation ensures an open site and reduces site 

preparation costs. Timber buyers are willing to 

pay more for stands that are free from brush and 

understory growth. This factor alone may offset 

the cost of prescribed burning. 
In wet conditions, logging equipment can leave deep 

ruts. The compacted soil is difficult to prepare for 

planting, but without intensive site preparation tree 

growth will be poor. 

In open park1 i ke stands, machine operators 

can see the ground and avoid many low, wet places 

t-hat would otherwise be masked by thick underbrush. It is also easier to locate skid trails to 

the advantage of both the logger and stand manager 

in such stands. Thus, open stands often bring 

better prices than brushy ones. Brush may be 

beneficial on some very wet sites, where small 

stems serve as a mat for support of logging equipment, but such sites seldom carry a fire. A forest floor that has built up over a number of years 

may contain a major portion of the site's mineral 

nutrients (nitrogen, phosphorus and cal ci um). 

During logging, skidders di splace the forest floor 

and some topsoil, leaving skid trails poor in 

nutrients and surface mi neral soi 1. This process 

often can be prevented by prescribed burning, 

which reduces 80 or 90 percent of the forest floor 

to ash and renders the nutrient layer less suscepti ble to movement by logging equipment. 
Herbicides may he a satisfactory suhsti tute 

for prescribed burning where fire is 1i kely to 

lower the quality of the harvested stand, where 

the forest floor wi 11 not carry a fire, or where 

fire may increase soi 1 erosion. The herbicide to 

be used and the method of application wi 11 depend 

on target species, available facilities, and cost 

savings expected from opening up the stand for 

harvest. Federal and State regulations must be 

followed in selecting and applying a herbicide. 

Possible effects of herbicides or fire on other 

resources such as wildlife should also be considered. Suppression of unmerchantable hardwoods 

and understory vegetation with fi re or herbicide 

frequently r e q u i r e s repeated treatment over a 

period of 1 to 3 years. These treatments should 

be planned we1 1 in advance of the actual cutting. 

Drai naqe 

On wet, flat areas, artificial drainage may 

be needed to facilitate logging as well as regeneration. A ditch system should lower the water 

table to 12 to 18 inches below the surface on 

mineral soi 1s and to about 24 inches on organic 

soils. Draining of large areas is costly and requi res heavy equipment; small areas can frequent ly 

be drained with farm equipment. Drainage of wetlands is also subject to regulation by government 

agencies, and permits may be requi red. 

Season of Loggi nq 

In much of the Southern Coastal Plain, the 

water table is at or near the soil surface during 

some portion of the year. In other seasons, the 

water table may be quite deep and the soil is hard 

enough to support the heaviest of equipment. It 

is common sense to avoid logging of such sites 

when the water table is high. Sometimes, however, 

stumpage prices are somewhat higher during the wet 

season because relatively little timber is accessible. In such cases, the manager of a tract must 
A Unaerstory vegetation can cornpl icate logging 

hy obstructing vision of operators. It also 

hinders regeneration. 

B Prescribed burning opens stands for logging, 

increasing the value of timber, reducing 

site damage, and aiding in regeneration. 

C Where burning is impractical, injection with 

herbicides may be desirable for opening a 

stand. 
decide whether the higher stumpage price will offset the additional costs of repairing the site or 

the lost growth caused by logging damage. 

In steep terrain, soi 1 compaction and shallow 

water tables are seldom problems. Here, erosion 

during heavy rains is the primary concern. Thus, 

in hi1 ly areas it is best to plan logging operations for periods when heavy rains are unlikely. 

Site Lavout 

Some site damage during logging often is inevitable, but careful location of skid trails can 

concent rate soi 1 damage on 1 imi ted areas, thereby 

minimizing repair costs. The-greatest concern is 

disruption of drainage. Logging trails can dam 

water, change a drainage course, or leave a ditch 

on a slope where gully erosion can begin. Correcting these problems can add to site repair 

costs. The best solution is a careful layout 'of 

logging trai 1s prior to harvest. From the driver's seat of a skidder, small changes in land 

elevation are impossible to see, but on the ground 

after heavy rains, drainage patterns are easily 

recognized. Skid trails can be laid out to improve drainage on poorqy drained flat areas. On 

excessively drained sites, it is often desi rable 

to skid along contours to create drainage barriers 

and slow runoff. 

Soi 1 Maps 

County soi 1 surveys, which include descriptions of drainage, trafficabi 1 ity, and other soi 1 

characteristics, give insight into how and when 

equipment can be used with the least impact. 

Frequently, soil maps can be used to locate roads, 

log decks, and skid trails on the least productive 

soils, leaving the most productive sites free of 

logging damage. Area ~onservationists with the 

Soi 1 Conservation Service can he1 p with soi 1 

mapping. Armed with soi 1 maps and a tentative 
operating plan, the manager and the logging contractor should carefully inspect the site. Dopressi ons, gull ies, ditches, and other features 

that are not noted on the soil map should he 

flagged so that appropriate changes cao be made in 

the layout of log decks and skid trails. 

The potential for damage of a site by logging 

equipment is variable, and appropriate actions 

depend upon local conditions. In general, however, 

it is best to place log decks at the tops of 

ridges in steep terrain. When logs are skidded 

uphi 11, skid trai 1s fork as they go downhi 11. 

Thus, drainage water on them is dispersed rather 

than concent rated. 

Soi 1 Propert i es 

Soi 1 texture provi des an index for sel ect i ng 

the seasons when logging damage wi 11 be minimized. 

We1 1 -drained sandy soi 1s are damaged less in wet 

than in dry seasons because sands are very resistant to compaction but become unstable and are 

likely to rut when dry. In contrast, silty, loamy, 

and clayey soils are more subject to rutting when 

wet-. 

A less tangible factor to consider is site 

fertility. In general, the higher the site fertility the less the effect of soil compaction and 

puddling in the next rotation. Nevertheless, it 

seems wise to minimize damage on the best sites. 

Roads, Log Decks, and Skid Trails 

The layout of roads and skid trails must do 

the least harm to the site while meeting the 

requirements of the logging operation. Normally, 

rubber-tired skidders can operate from 500 to 1,000 

yards from a log deck, but track-type vehicles can 

be used only up to 600 yards from the deck. 

Yarding distance for cable rigs is about 300 yards. 
Ditching may be required before 

logging some areas. The ditch size 

and equipment needed depend on the 

1 oca 1 conditions . 

Skidding across a drainage is bound 

to cause damage. 
In addition to the capacity of the specific equipment, size of logs skidded and tree density are 

part of the formula. Some basic guides in locating 

skid trails are: 

In steep terrain, do not run trai 1s downhill 

where they will concentrate water and cause 

erosion. 

Concentrate trai ls, where possible, to minimize, 

the area affected. 

Do not cross stream channels or excessively v~et 

areas. 

If a choice is available, locate skid trails on 

sandy rather than clayey soils, which are more 

susceptible to compaction. 

In this publication, we make no attempt to 

discuss road construction or log-deck design, which 

are adequately descri bed in many references. Here, 

however, are some useful guidelines on deck 

location. 

Locate decks to avoid skidding across wet, unstable soils and to limit length of skid trails. 

Avoid steep slopes; use natural breaks in the 

terrain such as benches or moderate slopes. 

Avoid creeks or obvious wet areas. 

Place decks and trai 1 s no closer than 130 feet 

from any st ream channel to prevent sedi rnentati on 

of the st ream channel . Choosing Equipment 

The type of logging equipment that is used is 

a primary determinant of the amount of logging 

damage that will be sustained. A typical rubbertired skidder puts a pressure of 20 pounds per 
square inch on the soil. A crawler tractor exerts 

about half that pressure, and wide flotation machines may exert only 5 pounds per square inch on 

the soil. Finally, a cable-logging setup lifts the 

logs from the ground and exerts no pressure. The 

amount of compaction damage sustained is roughly 

proportional to the pressure exerted on the soil. 

Damage also depends upon the type of soil and 

its wetness. In this brief treatise, it is impractical to describe a1 1 the combinations of equipment, 5oi1, and moisture conditions that may he 

encountered. Instead, we have developed a hazard 

index by which a site can be classified according 

to the soil texture (sand, silt, or clay) and the 

depth to the water table in the wet season (fig. 

1). The rating is designed to give an indication 

of the probability of damage during the wet season. 

During dry periods, most soils dry sufficiently to 

support logging equi pment . Frequently, however, cruising and timber-sale 

planning are done during the dry season. Since our 

hazard rating scheme requires an estimate of the 

depth to the water table.in the wet season, we 

offer a simple method for estimating that value 

from measurements taken in the dry season. Using a 

soil auger or a spade, dig a hole to the depth 

where mottling occurs. "Mottling" is a soil scientist's term for a distinctive change in color. 

Whereas the soil above the mottling is likely to 

have reds in its brown, mottled soil contains 

blotches of gray, lighter brown, and yellow. This 

color change is caused by the presence of water for 

extended peri ods . Figure 1 guides the selection of appropriate 

logging equipment. The objective is to choose 

equipment that will keep the plotted pressure 

exerted. by the vehicle and the depth to wet-season 

water table below the diagonal line for your particular soil type. The widths of tires and tracks 

strongly influence the pressure placed on the soi 1 
so it is best to get a specific value for the 

equipment that is available in your area. 

On steep slopes with erosive soils, the land 

manager may choose to permit only cab1 e-1 oggi ng 

equipment. On flat areas in wet seasons, cable 

logging is also an option, hut so is light flotation track equipment, which exerts very little 

pressure on the soil. 

DEPTH TO WET- SEASON WATER TABLE (inches) 

Figure 1.--Hazard of rutting during wet-season loggi~g. 
Cont 1-01 Over Loggi ng 

Site preparation and planning are futile without close control over the harvest i ng operati on. 

Logging should be monitored to see that the contractor is using the equipment agreed to in the 

sale. Tires and tracks on equipment should be inspected. Worn, underinflated or improperly installed tires do not have the required traction and 

cause rutting and other soil disturbance. Moreover, they add to the cost of logging, require more 

fuel, and cause harder wear on tractors. 

The final responsibility for preventing or at 

least reducing site damage rests with the tractor 

operator. Responsi bl e machi ne operators are an 

absol ute necessity. Reckless operation of tractors 

not only damages the site but also is hard on equipment and represents a work safety problem. Close 

supervision by the logging contractor and land manager is indispensable. 

With most kinds of equi pment , poorly drai ned 

sites are sometimes too wet to log without damage. 

The point at which logging should stop must be specified in the subcontract. The limitations of soil 

wetness depend on the internal drainage of the soil 

and the equipment used. Well-drained to excessively drained soils may require few limitations 

except on some steep slopes and unstable soils. As 

drainage deteriorates, the sensitivity of the site 

to compaction and puddling increases. Puddling is 

a loss of soil structure caused by working in wet 

conditions. Compacted or puddled soil loses its 

abi 1 i ty to provide ai r to plant roots. In general, 

sensitivity of soil to compaction and puddling 

increases as texture varies from sandy to clayey 

soi 1 and *as soi 1 organic matter decreases. In a1 1 

cases, soil becomes more sensitive to physical 

forces as the moisture content increases. 

When is it too wet? That depends on the 

equipment used, the experience of the logger, and 
the requirements imposed by the land manager. It 

is probably too wet when skidders produce ruts over 

10 inches deep in one or two passes or when the 

soi 1 has reached its "1 iquid 1 imit .I1 When a handful of soil is squeezed and water drips out, the 

soi 1 has passed its liquid limit and wi 11 not support traffic. The suscepti bi 1 ity of a soi 1 to compaction again is variable, and a knowledge of local 

soi 1 conditions is needed. 

Most compaction of a soi 1 occurs during the 

first pass of equipment, and two or three addi - 

tional trips wi 11 compact it about as much as the 

vehicle is capable of compacting it (fig. 2). For 

thi s reason, most land managers favor concentrat i ng 

skid trails to limit the area affected by logging. 

0 123456789 

NUMBER OF TRIPS 

Figure 2.--Relationship of bulk density of surface soil 

to number of vehicular trips with 10 pounds per square 

i nch of ground pressure. 

Note: Most compaction occurs during the first three 

passes. 

Logging equipment ranges widely in its effects on the 

soi 1 : A, Wide tires on rubber-tired skidder reduce 

soil pressure; B, track-type hauler exerts less 

pressure; C, wide track; even less; and 11, cable 

equipment exerts none at a1 1. 
The following guides are suggested for management of a logging operation: 

Re sure that proper equipment is used, that 

equipment is in proper repair, and that it is 

bei ng used correctly. 

Do not log clayey and loamy soils when water can 

be squeezed from them by hand. 

Do not log if two or three passes leave ruts 10 

inches deep. 

When water seeps into ruts on one-third to onehalf of a skid trail, logging should be halted. 

Repai ri ng Damaged Areas 

Before any repair can be prescribed, the type 

and amount of damage must be known and understood. 

The most serious types of soi 1 damage from logging 

are compaction, erosion, and drainage impedance. 

Repair must be designed to a1 leviate the damage and 

it should be concentrated where the damage is most 

severe, such as on logging decks. 

The equipment used to repair a site is often 

as heavy as the logging equipment that caused the 

original damage. Thus, the ti 1 lage operation can 

increase compaction under adverse conditions. 

Repair should be attempted only when the soil is 

dry enough to support the equipment and when the 

tillage will thoroughly break up the soil. During 

logging it may be necessary to operate the equipment under less-than-ideal conditions, but there is 

never a reason to attempt repair of the site unless 

the soil conditions are acceptable. 

Soi 1 Compact i on 

Even when soil moisture content is below the 

liquid limit, some compaction will occur on skid 
trai 1 s and log decks. These areas should be 

treated to avoid serious loss in productivity. The 

most effective treatment is tillage coupled with 

fertilization (table 2), The ti 1 lage equipment 

should run only deep enough to break up the compaction. Deep compaction, caused by heavy equipment 

on wet soi 1 s, may requi re special ly modi fied equipment. Bedding machines commonly used in site preparation can be fitted with a ripping shank at the 

center to loosen soil to a depth of 18 inches, 

which is adequate for penetration of pine taproots. 

For this treatment to be effective, however, the 

soil must be fairly dry down to the depth of the 

shank. Other practices must be considered on soils 

that are normally wet much of the year. 

Table 2.--Heights of loblolly pines 4 years 

after planting on a compacted skid trail that 

was bedded and ferti 1 izedl 

Treatment Tree hei ght on-- 

Compacted Uncompacted 

Bedding Fertilization skid trail area 

Pounds per acre - - - - - Feet - - - - 

None None 5.5 6,7 

200-50-1 00 8.1 8.6 

Bedded None 9.6 11.3 

200-50-1 00 12.5 11.6 

l~oi 1 is a poorly drained Bethera Series in the 

Coastal Plain of South Carolina. 
Left rear ti re is i n s t a l l e d backwards, reducing traction 

and increasing site damage. 

Logging when it is too wet strai ns equipment in addition 

to damaging the site. 
Nutrient Loss --- 

The application of fertilizer is a practical 

way to offset the effects of physical damage to the 

soi 1, especial ly on logging decks and skid trai 1 s. 

Particularly on wet or compacted soils, the application of phosphorus appears to allow the plant to 

overcome restricted aerat i on. The fert i 1 i zer does 

not completely rep1 ace good aeration but represents 

a relatively inexpensive a1 tornative to intensive 

mechanical treatments on wet sites. On sites that 

remain too wet to repai r mechanical ly, fert i 1 i - 

zation may be the only alternative. The method of 

application is unimportant. Between 200 and 500 

pounds per acre of triple super-phosphate (0-46-0) 

or di ammoni um phosphate (1 8-46-0) are adequate. In 

a1 1 but poorly drained clay soils, nitrogen as we1 1 

as phosphorus should be added. 

Soi 1 Erosion 

Erosion can be a problem on relatively gentle 

slopes if the soil is compacted, laid bare, or left 

with ruts running uphi 11 and downhi 11. Sheet erosion should be prevented by tilling the site to 

-reduce compaction and then revegetating the area as 

quickly as possible. Ditches and ruts should be 

fiiled to prevent the formation of gullies. On 

sites with bare soil subject to erosion, nitrogen 

is needed as we1 1 as phosphorus because the original nitrogen was concentrated primarily in the 

forest floor and surface mineral soi 1. In general, 

300 pounds per acre of mixed fertilizer such as 

10-1 0-1 0 wi 11 speed revegetati on. 

In addition to fertilizer, a cover crop is 

often needed to prevent erosion of bare soi 1. 

Quick cover can be obtained by seeding a fastgrowing species, such as ryegrass, in early fall or 

spring along with a perennial species that will 

vegetate the site until woody plants become established. Because of its aggressiveness, the ryegrass should not be seeded at a rate of over 5 
pounds per acre. The perennial grass should be 

seeded at a heavier rate, 50 to 60 pounds per acre 

of tall fescue or 40 to 50 pounds per acre of Bermuda grass. qepending on site and climate requirements, other grass species rnay he desirable. 

Drainage --- 

The drainage of a site can be considerably 

disrupted during logging, and displaced soi 1 may 

create dams. Such conditions can he a1 leviated by 

di sking or bedding during site preparation. Even 

on sites that had good internal drainage before 

logging, deep rutting may restrict lateral flow of 

water in the soil, raising the water table to the 

poi nt where pl anted trees cannot survi ve. Beddi ng 

may be required on these sits to raise the seedlings above the new water table. 

Rough Areas and Tree Regeneration 

Leveling the ground surface with a dozer blade 

may be a practical alternative on heavily disturbed 

sites, such as skid trails and log decks, if compaction is not a problem. If the site is to be 

regenerated naturally, special consideration should 

be given to these areas. The skidding and repair 

operations in these areas wi 11 have destroyed the 

seed1 i ngs a1 ready there. These areas should either 

be planted or direct-seeded to ensure a uniform 

stand. Local guidelines for establishment of the 

species used should be followed. 

The following guides are suggested for repairing damage to soils in log decks and skid 

trails.$ 

Rip (subsoi 1 ) and bed areas that are compacted 

or puddled. 

Apply phosphorus or nitrogen and phosphorus 

ferti 1 izer. 
Where slopes exceed G percent, ferti 1 i ze and seed 

with grass hefore planting trees. 

Clear blocked drai nages. 

If a natural regeneration system is used on tho 

area as a whole, trails and log decks may have to 

be planted with seedl ings. 

Acknowledgment 

Photographs for this guide were furnished by E.R. 

Priegel , USDA Forest Service Region 8 (reti red). 

*U.S. GOVERNMENT PRINTING OFFICE: 1985-551-910 Region 4. 

21 

McKee, W.H., Jr. ; Hatchel 1, G.E. ; Tiarks, A.E. 

Managing site damage from logging. A Ioblolly pine 

management guide, Gen. Tech. Rep. SE-32. Ashevi 1 le, NC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station ; 1985. 21 pp . 

Serious damage to forest sites during logging can be avoided 

through careful planning of logging, preparation of the site 

for 1 ogging, and close supervision of the work. Lasses in 

productivity caused by compaction can be largely restored by 

cultivation and fertilization. 

Keywords: Pi nus taeda, site producti vify, ferti 1 i zation, 

drainage, trafficability, soil compaction. 

McKce, W.H., Jr. ; Hatchel I, G.E. ; Tiarks, A.E. 

Managing site damage from logging. A loblol ly pine 

management guide, Gen. Tech. Rep. SE-32. Asheviite, NC: 

;J.S, Department of Agriculture, Forest Service, 

S~utheastern Forest Experiment Station ; 1985. 21 pp. 

Ser3ious damage to forest sites during logging can be avoided 

through careful planning of logging, preparation of the site 

for logging, and close supervision of the work. Losses in 

productivity caused by compaction can be largely restored by 

cultivation and fertilization. 

Keywords: Pinus taeda, site productivity, ferti 1 izati on, 

drainage, trafficabi 1 ity, soi 1 compaction. 
The Forest Service, U.S. Department of Agriculture, is dedicated to the principle of multiple 

use management of the Nation's 

forest resources for sustained 

yields of wood, water, forage, 

wildlife, and recreation. nrough 

forestry research, coopetation 

with the States and private forest 

owners, and management of the 

National Forests and National 

Grasslands, it strives-as directed by Congress---to provide 

increasingly greater service to a 

growing Nation. 

USDA policy dms not permit discrimination because of 

race, color, national origin, sex or religion Any vrson 

who believes k or she has been disc~minated against in 

any USDA-related activity shoufd write immediately to 

the Secretary ofA@c=ulture, Washington, D.C. 20250.