United States

Department of 

Agriculture

Forest Service

Northeastern 

Research Station

Research Paper NE-728

Residual Overstory Density 

Affects Survival and Growth 

of Sheltered Oak Seedlings 

on the Allegheny Plateau

Thomas M. Schuler

Patrick Brose

Robert L. White
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Abstract

As many as two decades may be required to achieve natural regeneration of northern 

red oak (Quercus rubra L.) on mesic sites. However, when unplanned major disturbances 

affect desirable mixed-oak forests, both the amount of time and viable options available for 

influencing the composition of post-disturbance regeneration are reduced greatly. Salvage 

logging of dead or dying oaks and other valuable species followed by artificial regeneration of 

oak has been attempted following gypsy moth-induced mortality on the Allegheny Plateau in 

western Pennsylvania. We evaluated the use of tree shelters to protect planted northern red 

oak seedlings following salvage logging that resulted in a range of residual stand densities. 

This practice was common on the Allegheny National Forest in the early 1990’s following 

widespread gypsy moth defoliation and subsequent mortality. A better understanding of this 

practice will enhance efforts to implement artificial regeneration of oak after unplanned major 

disturbance due to insects, disease, or factors such as storm damage. Artificial regeneration 

of oak using tree shelters can be effective when regeneration harvests are planned but 

natural oak regeneration is inadequate or lacking. This situation is common in mixed-oak 

forests of the Eastern United States.

The Authors

THOMAS M. SCHULER, research forester, received an M.S. degree in silviculture from 

Colorado State University and a Ph.D. degree in forest biology from Purdue University. He 

is currently engaged in research on the ecology and silviculture of Appalachian hardwood 

forests and the restoration of central Appalachian spruce forests at the Northeastern 

Research Station’s Timber and Watershed Laboratory at Parsons, West Virginia.

PATRICK BROSE, research silviculturist, received a B.S. degree in botany and range 

science from Brigham Young University and M.S. and Ph.D. degrees in forest resources 

from The Pennsylvania State University and Clemson University, respectively. He is currently 

researching the role of fire in the mixed oak forests of Pennsylvania at the Northeastern 

Research Station’s Forestry Sciences Laboratory at Irvine, Pennsylvania.

ROBERT L. WHITE, forester, received a B.S.F. degree in forest science from The 

Pennsylvania State University and is a certified silviculturist in the Eastern Region. He 

currently serves as the Forest Silviculturist and Pesticide Coordinator on the Allegheny 

National Forest, Warren, Pennsylvania.

Manuscript received for publication 6 April 2005

Cover photo: Tree shelter and emergent northern red oak located within the Allegheny 

National Forest following salvage logging.
1

Introduction

Natural regeneration of northern red oak (Quercus rubra

L.) requires adequate numbers of advanced seedlings 

of suffi cient size before overstory removal (Sander and 

others 1984; Loftis 1990a). In eastern mixed-oak forests, 

shelterwood regeneration methods are recommended so 

that understory oak can grow large enough to compete 

with faster growing species following fi nal overstory 

removal (Loftis 1990b; Brose and others 1999). If 

herbivory by white-tailed deer is moderate to high, oak 

seedlings developing in the understory of a shelterwood 

must be protected from deer with fencing (Miller and 

others 2004). To reduce understory competition to oak 

seedling development, herbicides and/or prescribed fi re 

often are needed as an additional step (Loftis 1990b; 

Brose and Van Lear 1998; Miller and others 2004). 

Oak shelterwood regeneration methods may require 10 

years or longer for oak seedlings to reach suffi cient size 

and density before fi nal overstory removal. However, 

unplanned events such as storm damage or gypsy moth 

defoliation that cause signifi cant stand-level mortality 

necessitate the establishment of competitive reproduction 

in a shorter period. Such disturbances, possibly in 

conjunction with salvage logging, often remove all or part 

of the overstory before the understory oak component—if 

present—can respond vigorously to the sudden increase in 

available growing space. To establish competitive seedlings 

and saplings in a shorter time than that provided by 

shelterwood methods, plastic tree shelters are being used 

to protect planted seedlings.

Tree shelters are translucent plastic tubes that protect 

seedlings from animal damage and possibly create a 

greenhouse effect. Over the past 15 years, research has 

shown that planting and sheltering oaks in new clearcuts 

can establish competitive oak seedlings that can persist 

and respond to some types of crop-tree release in young, 

even-aged stands (Lantagne and others 1990; Smith 1993; 

Lantagne 1995; Schuler and Miller 1999). Tree shelters 

are particularly effective where new seedlings or seedlingsprouts of desirable species such as northern red oak are 

browsed heavily by deer (Gillespie and others 1996). 

The recommended use of tree shelters in the Central 

Appalachians includes clearcutting during the dormant 

season followed by spring planting and sheltering of highquality, root-pruned northern red oak seedlings at least 

0.5 inch in diameter at the root collar (Schuler and Miller 

1996).

The effects of residual overstory trees on oak seedling 

development in tree shelters are not fully understood. 

In several cases following shelterwood harvests, residual 

trees reduced the height growth and survival of planted 

northern red oak seedlings protected with tree shelters 

(Teclaw and Isebrands 1991; Walters 1993; Lantagne 

and Miller 1997; Bardon and others 1999), though 

residual overstory stocking improved the development 

of oak seedlings protected with tree shelters in northern 

Wisconsin (Teclaw and Zasada 1996). In the latter 

case, the authors speculated that residual trees provided 

additional protection from growing-season frosts. While 

it seems clear that in most studies, residual overstory 

stocking typical of most shelterwood regeneration 

methods (e.g., 50 to 75 percent residual stocking) reduced 

the growth and survival of seedlings protected with tree 

shelters, the effect of lower levels of stocking on northern 

red oak seedlings in tree shelters has not been evaluated in 

other studies.

In this study, we discuss the use of tree shelters to 

protect northern red oak seedlings when planted under 

different levels of residual overstory stocking. Study sites 

incorporate existing operational efforts by the Allegheny 

National Forest (ANF) and include a range of residual 

overstory stocking levels. Levels of overstory stocking 

available for examination resulted from repeated gypsy 

moth defoliation, drought, and secondary pathogens that 

resulted in overstory densities reduced by mortality and 

subsequent salvage logging in the late 1980’s (Walters 

1993). Study sites were selected to limit variability 

associated with factors other than residual stocking, e.g., 

shelter design, regeneration source (seed vs. seedling), 

time since planting, and use of fencing. The primary 

objective was to prevent a signifi cant reduction of oak 

from the affected sites by replacing overstory oak with 

understory oak rather than red maple (Acer rubrum L.), 

black cherry (Prunus serotina Ehrh.), black birch (Betula 

lenta L.), or American beech (Fagus grandifolia Ehrh.) 

(Walters 1993). We also wanted to identify an upper 

range of overstory density that is compatible with the use 

of tree shelters and planted oak seedlings in the heavily 

deer-impacted Allegheny Plateau of western Pennsylvania.
2

Methods

In May 1995, study sites were established 

at four locations several miles south of 

Warren, Pennsylvania, adjacent to State 

Road 337 on the ANF (Fig. 1). Each 

location was the site of an ongoing 

regeneration effort using planted 2-0 

northern red oak seedlings protected by 

5-foot-tall, white Tubex® tree shelters 

but not by fencing (Table 1). Study sites 

are hereafter referred to as 411-1, 411-2, 

424-3, and 424-4. The history of each 

site was obtained from ANF records. A 

sample of 100 sheltered trees at each site 

were selected by randomly choosing the 

fi rst tree and then using the next 99 trees 

in sequence, both live and dead trees were 

included in the original sample. Trees were 

identifi ed with brass tags for a total of 

400 identifi ed trees in shelters. Data from 

each tree included status (live or dead), 

tree height, crown class, general remarks, 

species of competing vegetation, and 

height of competing vegetation. Annual 

measurements were conducted from 1995 

through 1999 and in 2001 and 2003. In 

April 1997, site 424-4 was dropped from 

annual measurements due to the theft 

of brass tags identifying the seedlings. 

However, following the 2003 growing 

season, a random sample of 100 sheltered 

seedlings (live and dead) was obtained 

in the same location as the originally tagged shelters to assess both 

understory and overstory conditions. Overstory measurements were taken 

in May 1995 and October 2003 (Table 1). Overstory characteristics 

Figure 1.—Study sites on the Allegheny National Forest. 

Table 1.—Overstory residual mean basal area (SE in parentheses) of tree shelter study sites on 

the Allegheny National Forest as determined from 10 0.1-acre sample plots at each location

Basal area

Study site Date of origina May 1995 October 2003

 - - - - - - - - - ft2

/acre - - - - - -- - - -

411-2 1992 14.5 (4.8) 17.3 (4.6)

424-3 1991 31.8 (7.8) 50.3 (11.1)

424-4 1993 59.4 (5.2) 87.3 (9.7)

411-1 1991 62.8 (11.7) 85.7 (9.0)

a

Planted before the onset of the growing season in the year specifi ed.
3

were sampled by randomly selecting 10 sheltered tree 

locations from each study site as center points of 0.1-

acre circular plots (n = 40). Overstory sample locations 

differed in 1995 and 2003. In 1995, we recorded species 

and diameter at breast height (d.b.h.) for all trees ≥ 5 

inches. In 2003, we added 0.01-acre overstory plots and 

included all trees with a d.b.h. ≥ 1 inch. Our intent was 

to determine whether smaller plot sizes can be used to 

predict the survival of sheltered seedlings.

In 1996, we began releasing overtopped seedlings when 

the competing vegetation was from the same stratum. 

This entailed removing stems that overtopped the 

desired crop tree, resulting in a codominant crown of 

the desired tree after release. This procedure has helped 

maintain height growth and crown class of northern 

red oak in West Virginia (Schuler and Miller 1999). All 

years in which individual trees received a crown release 

were documented. It was not our intention to evaluate 

the utility of crown release so no trees were selected as 

controls. However, our records provide some insight into 

the percentage, frequency, and need for crown release.

We used binary logistic regression to determine the 

probability of survival of sheltered northern red 

oak seedlings as a function of the basal area of the 

surrounding overstory. To provide a relative measure of 

model fi t, we generated Hosmer-Lemeshow statistics 

and examined the percent concordant and discordant 

between predicted and observed responses (Allison 1999) 

for both 0.1-(BA1) and 0.01-(BA01) acre overstory plots. 

In 2003, BA1 ranged from zero to 132.8 ft2/acre (mean: 

80.1 ft2

/acre; SE: 17.4 ft2/acre), while BA01 ranged from 

zero to 582.8 ft2

/acre (mean: 60.1 ft2/acre; SE: 6.3 ft2/

acre). Of course, high basal areas of smaller plot sizes do 

not mean such levels of stocking exist over larger areas.

Results

On the basis of the 2003 sample data, both BA1 and 

BA01were signifi cant predictors of the survival of 

sheltered northern red oak when evaluated independently 

(Table 2), but BA01 provided the best goodness of fi t 

(rescaled R2

 = 0.43, Hosmer and Lemeshow Goodnessof-Fit chi-square = 6.98, df = 8, P = 0.5387). In binary 

stepwise regression, only BA01 (P = 0.01) and an 

intercept term were included in the fi nal model. The 

overall correct model classifi cation was 82.5 and 77.5 

percent for BA01 and BA1, respectively. BA01 correctly 

classifi ed 86.9 percent of the dead and 76.5 percent of 

the live seedlings; BA1 correctly classifi ed 82.6 percent of 

the dead and 70.5 percent of the live seedlings. Survival 

probability of 10 to 12 years after outplanting was about 

70 percent when BA01 was below 10 ft2

/acre and nearly 

50 percent when BA01 was about 35 ft2

/acre (Fig. 2).

Survival of individual trees related to residual basal area 

were consistent with our stand-level assessments (Fig. 

3). In 2003, site 411-2, which had a stand-level residual 

basal area of less than 20 ft2

/acre (Table 1), had the 

highest survival of sheltered trees (78 percent). Survival 

in units 411-1 and 424-4, both of which were about 90 

ft2/acre of basal area at the most recent census, was 23 

and 16 percent survival, respectively. These sites were 

characterized mostly by closed canopy conditions, though 

411-1 had infrequent canopy gaps. These gaps were 

correlated with the survival of sheltered seedlings as more 

than 60 percent of the surviving seedlings in 411-1 were 

beneath breaks in the canopy. In these instances, survival 

of sheltered seedlings was predicted correctly more often 

using BA01 as the explanatory variable in the logistic 

regression equation (Table 2). For example, at 411-1, two 

surviving seedlings in gaps had BA1 values of 70 and 76 

ft2

/acre, and BA01 values of 10 and 0 ft2/acre, respectively. 

Table 2.—Parameter estimates and measures of signifi cance for predicting survival of 

sheltered northern red oak seedlings for a range of overstory densities as determined 

by binary logistic regression (BA1 and BA01 calculated from fi eld inventories in 2003)

Variable df Parameter estimate Wald chi-square P > chi-square

BA01 1 -0.0318 6.7060 0.0096

Intercept 1 1.1268 3.7906 0.0515

BA1 1 -0.0308 8.1500 0.0043

Intercept 1 1.2989 3.8567 0.0495
4

Only BA01 values and parameter estimates predict 

correctly that these seedlings survive.

As expected, higher levels of survival were correlated with 

greater growth. Height growth of surviving trees was 

inversely proportional to stand-level basal area (Tables 1 

and 3). In 411-2, maximum height growth occurred from 

1994 to 2003 (22.4 feet). Current height growth of 

surviving sheltered seedlings is similar among the three 

intact study sites (Fig. 4). Mean annual height growth for 

the last 2 years was 1.7, 1.9, and 2.1 feet for sites 411-1, 

411-2, and 424-3, respectively. These rates are similar to 

that expected of free-to-grow northern red oak saplings 

(northern red oak site index50 = 70) during early stand 

development (Schnur 1937). Although sapling height 

growth refl ected historical norms, crown release often was 

necessary due to the greater height growth of competing 

vegetation.

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200

Basal Area (ft2/acre)

Probability of Survival (%)

Figure 2.—Predicted probability of survival 

of northern red oak sheltered seedlings 

planted in northwest Pennsylvania under 

different levels of residual overstory 

density. Basal area was determined from 

all trees growing within 0.01-acre around 

the sheltered seedling (four observations 

with high levels of residual overstory basal 

area are not shown).

Figure 3.—Survival of planted and sheltered northern red 

oak seedlings (n = 100) at four study sites south of Warren, 

Pennsylvania. Observations at site 424-4 were suspended 

after 1997 due to the loss of sample-tree identifi cation tags; 

data from 2003 are based on a random sample at the same 

location. Survival increased in some years because trees 

classifi ed as dead, subsequently sprouted from the root collar 

the following year and were added to the live-tree category.

Figure 4.—Mean height of surviving northern red oak 

seedlings planted and sheltered at four locations south of 

Warren, Pennsylvania. Observations at site 424-4 were 

suspended after 1997 due to the loss of sample-tree 

identifi cation tags; data from 2003 are based on a random 

sample at the same location.

1990 1995 2000 2005

Year

20

30

40

50

60

70

80

90

100

Survival (%)

424-4

424-3

411-2

411-1

Study Site

1990 1995 2000 2005

Year

5

10

15

20

Mean Height (ft)

424-4

424-3

411-2

411-1

Study Site
5

Crown release was most common at 411-2, which had 

the lowest level of residual overstory basal area and the 

most aggressive encroachment by competing stems. 

At this location, we released 38 trees at least once; of 

these, 34 were alive in 2003. About half (n = 40) of 

the surviving trees at 411-2 have not required release 

thinnings as of the most recent remeasurment. This 

unit also had the best average crown class of any of 

the study sites (Table 3). Only three trees received a 

crown release at the more heavily stocked 411-1 and 

none survived. At 424-3, 12 trees were released at least 

once. All survived and fi ve were thinned in 2003. The 

most common competing vegetation of the planted and 

sheltered northern red oak was red maple and black 

cherry (Table 4). In the absence of the planting and 

sheltering effort, the new cohort established following the 

gypsy moth/salvage logging disturbance would contain 

virtually no oak species. Even with management efforts 

to maintain oak in these stands, the new cohort will 

remain predominantly red maple and/or black cherry. 

Regeneration failures where fern or grass dominated the 

competing vegetation varied considerably among study 

sites (Table 4), but were in all cases less common than 

developing young stands of woody regeneration.

Discussion

The results of this study show that enrichment planting 

using tree shelters under a residual overstory, such as in 

salvage logging operations, should be used only at low 

levels of residual overstory stocking. Our predictions 

of survival of sheltered northern red oak using binary 

logistic regression (Table 2) indicate that overstory basal 

area should be no more than about 22 ft2

/acre if survival 

probabilities of about 60 percent are expected 10 years 

after planting and sheltering (Fig. 2). It should be noted 

that this level of residual overstory equates to only about 

10 trees per acre with a d.b.h. of 20 inches. If the residual 

stand meets or exceeds criteria for full stocking following 

Table 3.—Stand level height and height-growth characteristics of sheltered northern red 

oak (NRO) and competing woody vegetation in western Pennsylvania, 1995-2003 

Study site

Basal area 

(1995)

Mean height 

growth

Mean height of 

NRO saplings 

(2003)

Mean height of 

competing woody 

vegetation (2003)a

Mean crown 

class of NROb

 - -ft2/acre - - - - - - - - - - - - - - - - - - - ft - - - - - - - - - - - - - - - - - 

411-2 14.5 12.8 17.3 18.7 2.5 

424-3 31.8 9.9 14.3 18.7 3.1 

411-1 62.8 5.4 9.3 6.7 3.8 

a

Competing vegetation of the same cohort as the sheltered oak seedlings; does not 

include residual overstory competition, if present.

b

Dominant = 1, codominant = 2, intermediate = 3, overtopped = 4.

Table 4.—Competing vegetation of planted and sheltered northern red oak by study 

site, in percent

Competing vegetation 411-2 424-3 424-4 411-1

Black birch 0 0 6.3 4.4

Black cherry 20.7 40.9 0 21.7

Red maple 74.1 27.3 68.8 13.0

Mountain-laurel 0 0 0 17.4

Fern 0 27.3 6.3 39.1

Grass 1.7 0 0 0

Other 3.5 4.5 18.6 4.4
6

salvage logging or other disturbances 

(Gingrich 1967; Stout and Nyland 

1986), the stand need not be treated 

as a regeneration unit, and enrichment 

planting and sheltering is unnecessary 

and unlikely to succeed.

If salvage logging of dead trees will 

result in a residual stand well below 

fully stocked, we recommend marking 

to further reduce basal area to no more 

than about 20 ft2

/acre during the salvage 

logging operation if underplanting of 

oaks with tree shelters is desired. If 

possible, the spatial arrangement of 

residual trees should be in patches and 

enrichment planting and sheltering 

should be done between the patches of 

residual trees to minimize the effect of 

residual stocking. All pole-size trees of 

undesirable species (e.g., red maple) between the patches 

should be felled so that they do not compete with planted 

seedlings. Grouping residual overstory trees also may 

reduce windthrow and the development of epicormic 

branches. We suspect that even with an herbicide 

treatment of small undesirable regeneration at the time 

of salvage logging (e.g., basal spraying of undesirable 

stems less than 1 inch d.b.h. within 5 feet of planted 

stock), crown release of developing planted stock still 

will be required. Herbicide applied to individual stems at 

the time of logging does not prevent new seedlings from 

developing that eventually will compete with and overtop 

desirable oak regeneration (Schuler and Miller 1995).

On the Allegheny Plateau, mixed-oak forests are less 

common than the Allegheny hardwood forest type. To 

maintain regional forest-type diversity, it is important 

to manage mixed-oak forests in a sustainable manner, 

regenerating oak when natural or planned disturbances 

create new waves of recruitment. The species composition 

of all the stands examined in this study was classifi ed 

as mixed-oak by ANF personnel, but the regeneration 

following salvage logging was dominated by black cherry 

and/or red maple, major constituents of the Allegheny 

hardwood type, a subset of the northern hardwood type 

(Braun 1950; Stout and Nyland 1986). Thus it is likely 

that in the absence of enrichment planting, sheltering, 

and subsequent crown release, these mixed-oak stands 

affected by gypsy moth induced mortality would become 

more like the Allegheny hardwood type that dominates 

the region, reducing regional forest-type diversity.

Guidelines for successful use of tree shelters summarized 

by Schuler and Miller (1996) include issues related 

to shelter design, seedling age, planting location, and 

maintenance requirements. When doing enrichment 

planting, crown release of planted northern red oak also is 

necessary as seen in this study and in Schuler and Miller 

(1999). Crown release was necessary even though the 

planted oaks were growing according to expected rates of 

free-to-grow oaks in young even-aged stands.

In addition, we stress the importance of the following: 

1) Removing netting from the top of the shelter before 

the seedling comes in contact with the netting. On the 

ANF, netting used to prevent birds from entering the 

shelters (Crothers 1991) often caused signifi cant stem 

deformities when the shoot did not pass easily through 

it (Fig. 5). Nets should be removed in the spring before 

stem elongation. Since stems often grow more than 2 feet 

Figure 5.—Deformed northern red oak stem that resulted from the emergent 

seedling contacting netting placed over the top of the shelter to exclude birds.
7

annually inside the shelters, most nets 

should be removed during the second 

year of growth when beginning with 2-

0 planting stock; 2) Checking that the 

tree shelters themselves do not restrict 

growth. In our study and elsewhere 

where tree shelters have been used for 

a decade or more, many trees were 

constricted by the shelter, especially 

near the groundline (Fig. 6). Shelters 

were stretched tightly by the growing 

stems and trapped rainwater. None of 

the shelters we observed had begun 

to disintegrate or become brittle and 

it is not clear whether a shelter could 

damage or kill a tree when this occurs. 

Newer designs by some manufacturers 

may prevent this but checks of older 

tree shelter installations should be 

conducted. We recommend cutting the 

shelters with a knife and leaving them in place once the 

trees become rigid and self supporting. Retaining the 

cut shelter protects the stem from deer rubs and makes 

the tree easier to fi nd for secondary treatments; 

3) Ensuring that tree shelters are not adjacent to or 

within patches of tall logging debris. At sites 411-2 and 

424-3, we observed fast-growing natural regeneration in 

small clumps that were protected from deer browsing by 

the residual tops of harvested trees from salvage logging 

operations. These clumps often were dominated by pin 

cherry (Prunus pensylvanica L. f.), a preferred browse 

species on the Allegheny Plateau, and greatly exceeded 

the growth rates of the sheltered oak seedlings. As such, 

browsing probably had a positive effect on the survival 

of sheltered seedlings by slowing the development of 

competing vegetation when sheltered seedlings were not 

located near thick logging debris that deterred browsing. 

We also do not recommend using tree shelters inside 

deer exclosure regeneration fences for the same reason. 

Fencing is becoming a standard regeneration technique 

when the impact of deer is moderate or higher (Miller 

and others 2004), but sheltered oak seedlings inside 

an exclosure will have much greater competition from 

competing stems and probably will require much greater 

competition control than unfenced sheltered seedlings.

On the basis of the results of this study and the 

performance of sheltered seedlings, we do not 

recommend using tree shelters in small gaps (e.g., 0.1 

acre) in otherwise unbroken canopies. It is not clear 

whether sheltered seedlings can be used in conjunction 

with group selection or patch clearcutting if gaps 

are 0.5 acre or larger. The location within the gap, 

site characteristics, and height of the surrounding 

competition are potentially critical factors related to the 

survival and growth of sheltered seedlings within gap 

environments. Additional research on the effect of these 

factors is needed.

Our results need not be applied solely to unplanned 

disturbances and salvage logging operations. Private 

landowners who are adverse to delaying a harvest until 

natural oak regeneration is established suffi ciently, can 

use these results to plan artifi cial regeneration efforts. 

The alternative to preparing for natural regeneration of 

oak over a 10-year period is to conduct the harvest now 

and use artifi cial regeneration methods. Harvest revenues 

could pay for planting and sheltering operations, and 

artifi cial regeneration gives landowners much greater 

fl exibility in timing the harvest.

Figure 6.—Example of a tree becoming too large for the shelter before 

the shelter began to disintegrate. 
8

Finally, we add a cautionary note about using the results 

of this study. Our research developed following a series 

of unplanned events and as such does not conform to 

standards for designing ecological fi eld experiments with 

respect to randomization and replication. As a result, 

we cannot estimate our precision or ensure an absence 

of bias in our stand-level comparisons. However, given 

that the patterns we documented are consistent with 

past research and robust patterns of stand dynamics, 

it is reasonable to assume that our conclusions can be 

used to further refi ne the use of tree shelters in forestmanagement activities. Managers who adopt our 

recommendations should plan on periodic assessments 

to monitor performance and make adjustments in the 

fi eld if necessary.

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Printed on Recycled Paper

Schuler, Thomas M.; Brose, Patrick; White, Robert L. 2005. Residual overstory 

density affects survival and growth of sheltered oak seedlings on the 

Allegheny Plateau. Res. Pap. NE-728. Newtown Square, PA: U.S. Department 

of Agriculture, Forest Service, Northeastern Research Station. 9 p.

When unplanned major disturbances affect desirable mixed-oak forests, both the 

amount of time and viable options available for influencing the composition of postdisturbance regeneration are reduced greatly. We evaluated the use of tree shelters 

to protect planted northern red oak seedlings following salvage logging that resulted 

in a range of residual stand densities. This practice was common on the Allegheny 

National Forest in the early 1990’s following widespread gypsy moth defoliation and 

subsequent mortality. A better understanding of this practice will enhance efforts to 

implement artificial regeneration of oak after unplanned major disturbance due to 

insects and diseases or factors such as storm damage. 

Keywords: tree shelters, northern red oak, artificial regeneration, Allegheny 

National Forest
Headquarters of the Northeastern Research Station is in Newtown Square, 

Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

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

Morgantown, West Virginia, in cooperation with West Virginia University

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

Warren, Pennsylvania

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