United States

Department of 

Agriculture

Forest Service

Northern 

Research Station

General Technical

Report NRS-11

Managing Timber to Promote 

Sustainable Forests: 

A Second-Level Course for 

the Sustainable Forestry 

Initiative of Pennsylvania

James C. Finley

Susan L. Stout

Timothy G. Pierson

Barbara J. McGuinness
Visit our homepage at: http://www.nrs.fs.fed.us/

Abstract

At least 80 percent of the raw material used for wood products by the forest industry is from 

privately owned woodlands. This publication provides material for a course designed to help 

landowners, foresters, and loggers work together to assess whether a planned timber harvest 

will retain the diversity of species on site. It includes methods for collecting overstory and 

understory data, inspecting these data, and assessing sustainability.

The Authors

JAMES C. FINLEY is a professor with Pennsylvania State University, School of Forest 

Resources, University Park, Pennsylvania. 

SUSAN L. STOUT is a research forester and Project Leader with the Northern Research 

Station’s Forestry Sciences Laboratory at Warren, Pennsylvania.

TIMOTHY G. PIERSON is a cooperative extension forester and educator with Pennsylvania 

State University, University Park, Pennsylvania.

BARBARA J MCGUINNESS is a forester with the Northern Research Station’s Forestry 

Sciences Laboratory at Warren, Pennsylvania.

Manuscript received for publication 7 August 2006

Published by: For additional copies:

USDA FOREST SERVICE USDA Forest Service

11 CAMPUS BLVD SUITE 200 Publications Distribution

NEWTOWN SQUARE PA 19073-3294 359 Main Road

 Delaware, OH 43015-8640

July 2007 Fax: (740)368-0152

Acknowledgment

The materials in this book were developed through a partnership among the USDA Forest 

Service Northern Research Station, the Pennsylvania State University, and the Pennsylvania 

Sustainable Forestry Initiative Program State Implementation committee (SFI SIC). The SFI 

SIC will use them in training programs for timber harvesters and landowners. Individuals 

interested in sustainable forestry also will find them valuable for self-study and application.
CONTENTS

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

Assessment Procedures...................................................................................................... 3

 Laying Out Your Survey ................................................................................................. 3

 Regeneration Assessment Procedure .......................................................................... 4

 Field Measurements .................................................................................................. 4

 Regeneration Assessment Variables ....................................................................... 5

Overstory Assessment Procedure ...................................................................................... 8

 Field Measurements .................................................................................................. 9

 Setting Up the Tally Sheet ......................................................................................... 9

 Collecting Overstory Data......................................................................................... 9

Field Data Summary ........................................................................................................... 13

 Summarizing Regeneration Data ................................................................................. 13

 Deer Impact .............................................................................................................. 13

 Advanced Regeneration.......................................................................................... 13

 Canopy Density ........................................................................................................ 13

 Interference .............................................................................................................. 13

 Summarizing Overstory Data ....................................................................................... 14

 Species Composition .............................................................................................. 14

 Seed Source ............................................................................................................. 15

 Residual Tree Quality .............................................................................................. 17

 Average Stand Diameter ......................................................................................... 18

 Interpreting the Overstory Assessment Tally Sheet .................................................. 22

 The Sustainability Key ............................................................................................ 22

 Alternative Treatment .............................................................................................. 24

What Have We Learned? .................................................................................................... 27

Additional Resources......................................................................................................... 27

Appendix A Estimating Average Stand Diameter ............................................................ 28

Appendix B Understory and Overstory Tally Sheets ...................................................... 30

Appendix C Timber Harvesting Assessment and Treatment Unit Sustainability

 Assessment Forms ...................................................................................................... 32

Forest Stewardship Bulletin No. 12 ................................................................................. 34
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1

INTRODUCTION

Sustainable forestry includes caring for wildlife, protecting water, providing recreation, 

and sustaining timber resources. The Sustainable Forestry Initiative (SFI) is built around 

core guiding principles that call upon participants to “meet market demands while using 

environmentally responsible practices that promote the protection of wildlife, plants, 

soil, and air and water quality.” Another guiding principle of SFI is to “meet the needs 

of the present without compromising the ability of future generations to meet their own 

needs by practicing a land stewardship ethic.”

Other continuing education courses through SFI of Pennsylvania cover introductions 

to forest ecology and silviculture, the importance of determining landowner objectives, 

effects of logging on wildlife habitat, road layout, and Best Management Practices 

(BMPs). This course focuses on timber resources, specifi cally, on assessing whether a 

planned timber harvest will retain timber species on the site. You will learn how to take 

regeneration and overstory data in the fi eld, interpret the data, and use a key to assess 

whether or not a harvest sustains desired species diversity.

Private forest-land owners contribute at least 80 percent or more of the raw material used 

by the forest industry to make a myriad of wood products. Certainly, landowners have 

a responsibility to make the right decisions to achieve sustainable outcomes, but they 

depend on all of us—timber harvesters, foresters, and the forest products industry—to 

guide them toward making responsible forestry decisions. We are all responsible for 

promoting good forestry and protecting forest resources for future generations (Fig. 1).

Figure 1.—Sustainability is everyone’s responsibility.

Retaining timber species 

onsite allows us to 

maintain the potential of 

the future forest.

Sustainable 

Forests Logger Forest Owners

Forester

Forest 

Industry
2

Traditionally, a forester would apply silviculture to develop a prescription designed to 

obtain a sustainable, healthy future forest, and a timber harvester would provide the 

expertise necessary for implementing a harvest, taking care to protect the soil resource 

and residual trees. However, many timber harvests in Pennsylvania are direct transactions 

between the timber harvester and the landowner. The assessment tool provided in this 

course will help timber harvesters and landowners apply basic principles of silviculture to 

promote sustainable forestry outcomes.

We will consider eight questions that focus our attention on existing and potential 

regeneration on the site, and the trees that will remain after the harvest (residual trees).

Regeneration:

 What is the impact of white-tailed deer?

 What is the condition of the existing advanced regeneration?

 How will light affect existing and potential regeneration?

 What is the role of interfering plants?

Residual trees:

 What will happen to species composition?

 Will adequate seed source be retained?

 What will happen to residual tree quality?

 What will happen to the average stand diameter?

Throughout this document, sidebars with shaded trees are used for defi nitions and 

discussion of the sample stand. Sidebars in boxes display threshold levels for sustainable 

forestry.

Silviculture is the art and 

science of controlling the 

establishment, growth, 

composition, health, and 

quality of forests and 

woodlands to meet the 

diverse needs and values of 

landowners and society on 

a sustainable basis.
3

ASSESSMENT PROCEDURES

Laying Out Your Survey

Before you collect data, walk through the area that you plan to harvest and consider the 

size of the area and the variability in both the overstory and understory vegetation. This 

exercise will help you determine how many plots to take and where to collect data within 

the area.

If the area is large and there is variation in the vegetation, consider dividing the entire 

harvest area into subunits of similar conditions (called stands), and making a separate 

assessment in each subunit. For example, if there are noticeable differences in the 

vegetation (one area has a high proportion of oak and a carpet of small oak seedlings, 

another has a high proportion of beech/hemlock and scarce regeneration), these areas can 

be treated as separate stands.

Within each harvest unit, or within each individual stand, you must determine how 

many plots to take. Table 1 shows the minimum number of plots to take in harvest 

units of different size; taking more plots increases the reliability of results. Foresters 

usually take more plots to develop an accurate assessment of overstory and understory 

conditions to develop silvicultural prescriptions. Often, the number of understory plots 

is twice the number of overstory observations since understory conditions frequently are 

more variable than overstory conditions. Your confi dence in the results of your survey 

and the accuracy of your information will increase as you increase the number of plots.

Where do you locate the plots? Again, consider the size and variability of the harvest 

unit. Choose a route through your harvest unit (you can double back in large areas) 

that allows you to establish the overstory and understory plots so that they are spaced 

fairly equally throughout the harvest unit. Make sure that the plot locations represent 

conditions throughout the area.

Try not to “choose” areas because they are easier to measure or because there are more 

trees there. If you do, the results will biased. Do not locate a plot so that it includes an 

existing road, forest edge, or any thing that makes the plot unique or does not represent 

the variation in the stand, for example, a plot on the same contour or on a bench.

Stands are forested 

subunits that are uniform 

in species composition, tree 

size, age, site conditions, 

and history.

Table 1.—Minimum number of plots for assessing stand and harvest area 

conditions (additional plots increase accuracy)

Harvest area (acres) Minimum number of plots per harvest

25 or less 5

26-100 10

101-200 15

More than 200 20
4

At each plot, use the same plot center for both the understory and overstory plots. 

Overstory measurements are taken on a 1/10-acre plot (a circular plot with a radius of 

37.2 feet) and understory data are collected on both a 1/1,000-acre (milacre) plot (a 

circular plot with a radius of 3.72 feet) and the 1/10-acre plot.

The fi rst few times you measure your plots, use a logger’s tape or marked rope to measure 

the plot’s limits. With practice, you will be able to assess this distance without measuring 

every time. However, it is useful to check yourself periodically, especially if you suspect 

that a tree is on the edge of the plot. Figure 2 shows how each combination overstory/

understory plot is laid out.

Regeneration Assessment Procedure

Every harvest, even a light one, must consider the effect on understory conditions. Begin 

with the regeneration assessment at each plot. This portion of the assessment is intended 

to answer the following regeneration questions:

 What is the impact of white-tailed deer?

 What is the condition of the existing advanced regeneration?

 How will light affect existing and potential regeneration?

 What is the role of interfering plants?

Field Measurements

Recognizing the existence and abundance of advanced regeneration and the barriers 

posed by white-tailed deer and interfering plants are keys to assessing the sustainability 

of a planned harvest, especially if a large portion of the overstory will be removed. The 

intent is not to obtain exact values but to estimate values relative to thresholds in a 

decision tree. Figure 2 shows the measurements taken to assess regeneration potential.

Figure 2.—Plot layout and data collected.

1/1,000-acre plot

(radius = 3.72 feet)

1/10-acre plot

(radius = 37.2 feet)

Plot center

1/1,000-acre plot (milacre plot)

Regeneration assessment 

(weighted number of seedlings)

1/10-acre plot

Canopy density

(percent light available)

Coverage of fern, grasses and sedges 

(percent of area), and interfering 

woody plants (checkmark)

Tree species and quality by diameter 

class

Landscape

Deer impact (high/low)
5

Other items or variables can enter the decision but are more diffi cult to assess or are 

encountered less often. Among these are rocks, water, and poor soil drainage, as well as 

sprouting and potential seed production. The focus of the assessment in this course is to 

raise awareness about the condition of the stand before harvesting and its relationship to 

the condition of the stand following harvesting. Figure 3 is a sample tally sheet used to 

collect and summarize regeneration data. 

Regeneration Assessment Variables

White-tailed deer. Across Pennsylvania, regeneration failures are common and deer 

along with other factors often are the cause. The effect of white-tailed deer on forest 

regeneration is extremely variable across the State and depends on current and historic 

population levels, alternative food sources, and cover. On the basis of the description of 

the impacts of white-tailed deer that follows, record an estimate of whether the effect of 

deer on regeneration success will be high (H) or low (L) in the harvest area as a whole. 

Look beyond your plot for this assessment; consider the impact of deer across the harvest 

area and even at the landscape level (one square mile or more).

Evidence of high deer impact is demonstrated by heavy browse damage on seedlings, 

understories that are dominated by species that deer avoid or that are resilient to deer 

browsing (see list at left), or high crop damage on local farmland. Harvest areas with a 

low deer impact will have diverse understory species that are variable in height and no 

visible browse line. Assessment of this variable should include discussions with adjacent 

landowners and observations of conditions on their properties.

Record deer impact for the entire harvest area. Checking with the local wildlife 

conservation offi cers or foresters for their assessment of the local situation is another 

useful way to estimate the deer density and probable impact. If the landowner is 

planning to fence the harvest area immediately following the timber harvest, mark the 

stand as low deer impact.

Species that dominate 

where deer density is high:

Herbaceous plants: 

ferns, grasses

Shrubs: 

blueberry, mountain 

laurel, sweet fern, 

spicebush

Woody species: 

beech, striped maple

Figure 3.—Example regeneration tally sheet for harvest area or stand of 25 acres or less.

Plot 1

Deer 

Impact 

(H/L)

2

Regen.

Adequate

3

Canopy 

Density 

(percent)

4

Fern 

(percent)

5

Grasses/

sedges 

(percent)

6

Woody 

plants 

(percent)

7

Any 

Interference 

(check)

1 20 50 40 20 10 √

2 0 40 70 10 15 √

3 50+ 40 40 0 5 √

4 50+ 30 20 0 20

5 10 40 30 20 10 √

percent 

stocked

average 

percent

percent

≥ 30

percent

≥ 30

percent

≥ 30

percent with 

√

Stand H
6

Forest regeneration. Forest regeneration is assessed on the 1/1,000-acre plot. The focus 

of this evaluation is on commercially desirable tree species. In Pennsylvania, most of 

the tree species in this category depend on seedlings established before harvest as the 

most reliable source of regeneration. Hence, the focus for this variable is on established 

(advanced) regeneration.

The condition of regeneration, especially its age and size, is an important consideration. 

Seedlings that are at least one growing season old are better than new germinants. 

Gently tug on several small seedlings. Those that pull from the soil or have roots 

only in the litter layer are less likely to survive or develop. Do not count them in the 

assessment. Give extra weight to larger and older seedlings (see Table 2) as they are 

more likely to survive. Record a weighted count of the seedlings of desirable species on 

your milacre regeneration plot. Estimate by multiples of 5 up to 50 seedlings; if you 

have more than 50 seedlings, record 50+.

Stump sprouts and seeds stored in the forest litter also are sources of regeneration. 

If you or the landowner wish to count on these sources, use a more sophisticated 

assessment tool. Where deer impact is high, more or larger seedlings are required. 

The values in Table 3 set minimum seedling densities per plot for adequate advanced 

regeneration.

As an example, 50 small seedlings (less than 1 foot tall) of desirable species on a plot are 

suffi cient regeneration at low or high deer impact. Another plot with 25 small seedlings 

and 1 seedling 3 to 5 feet tall (counted as 20 in Table 2) has a total weighted count 

of 45 seedlings. This is insuffi cient regeneration for a plot in a high-deer-impact area, 

though the plot would meet the threshold as an area with low deer impact.

Canopy density. Light is a critical factor in evaluating the likelihood of regeneration. 

The amount of light striking the forest fl oor helps us evaluate the relative importance of 

Forest regeneration 

threshold:

Deer impact affects 

forest regeneration 

thresholds. With high 

deer densities, it is 

necessary to have a 

weighted count of 50 

seedlings per plot. Under 

low deer impact, the 

required weighted count 

is 15 seedlings per plot.

Canopy density 

threshold:

Canopy closure of 

less than 50 percent 

suggests a regeneration 

harvest.

Deer impact Weighted number of seedlings 

per milacre plot

Low 15

High 50

Weight Seedling height

1 2 inches to 1 foot

2 1 foot to 3 feet

20 3 feet to 5 feet

50 5 feet and taller

Table 2.—Regeneration weights by seedling height

Table 3.—Regeneration thresholds by deer impact (1/1,000-acre plot)
7

residual trees or regeneration after the harvest, and whether to designate the harvest as a 

partial cut or a regeneration cut.

To measure canopy density you must look ahead to conditions that will exist after the 

harvest. Therefore, you have to decide which trees will remain and which will be cut. 

Looking straight up at several points in the 1/10-acre plot, record your average estimate 

of the percentage of sky (in increments of 10 percent) that will be fi lled by the forest 

canopy following the harvest (see Figure 4 for an example). This is an acquired skill and 

will take some time during your fi rst several assessments. Record this estimate for every 

plot in the harvest area.

Ferns. Ferns interfere with seedling regeneration in several ways. Most importantly, they 

capture light that seeds require to sprout and seedlings need to grow. Record an estimate 

of the percentage of the ground (in increments of 10 percent) on the 1/10-acre plot that 

is completely shaded by single-frond ferns (see below). As with crown density, mentally 

“squeeze” dispersed fern cover into a patch with 100 percent cover, and estimate the 

percentage of the plot covered.

For this assessment, ferns fall into two categories: those that grow in clumps and those 

with single fronds or leaves. Among the clump ferns are Christmas, interrupted, sword, 

and woods ferns. These dot the landscape, forming obvious clumps. They spread slowly 

and rarely form dense, continuous shade across large expanses of forest area.

The single-frond ferns can spread rapidly. Among those this group of special concern 

are New York, hayscented, and bracken ferns. The fi rst two have single, heavily divided 

leaves that originate from aggressive underground rhizomes. Bracken fern has a single 

stem that rises 2 feet or more above the forest fl oor before dividing into three fronds or 

leaves.

For all practical purposes, deer do not eat ferns. Hence, because of historically 

high white-tailed deer populations, fern occurrence and density is on the increase. 

Disturbance from logging leads to increased light levels and encourages ferns to spread. 

Figure 4.—Estimating crown density on the 1/10-acre plot helps us consider the effect of light on the future 

stand. Consider the preharvest crown closure (A). By mentally placing the crown coverage on a pie grid (B), we can 

estimate preharvest crown closure at 85 percent. A partial cut (C) may leave 60 percent, while a regeneration harvest 

(D) leaves less than 50-percent canopy closure.

Fern threshold: 

When 30 percent or 

more of an area is 

covered by fern, it is 

likely to interfere with 

the establishment 

and development of 

regeneration after a 

partial cut.

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8

Grasses and sedges. Grasses and sedges interfere with tree establishment in much the same 

way as ferns. Dense grasses and sedges cause shade, inhibiting the development of tree 

seedlings. When considering these plants, focus on the amount of shade they produce. 

As with ferns, visually “squeeze” all the grass and sedge into a clump and estimate the 

percentage of the plot it covers. Record the percentage of the plot area in increments 

of 10 percent. If there are even trace amounts of grass or sedge, record 1 percent or 5 

percent. These traces indicate a seedbank and should infl uence the choice of herbicide if 

such a treatment is planned.

Sedges are grassy plants with wedge-shaped leaves. Most sedges have triangular stems 

when viewed in cross section and their leaves grow on all three sides of the stems. Sedge 

stems also are solid. Grass stems often are round and always are hollow. Grass leaves 

grow on two sides of the stalk. Sedges can indicate seasonally wet soils. Removing 

too much of the overstory may increase soil moisture, encouraging aggressive sedge 

expansion and creating diffi cult conditions for seedling establishment and growth. If 

you observe that many of the plants recorded on your plot are sedges and the planned 

cut is heavy, draw the landowner’s attention to the risk of exacerbating a soil-moisture 

problem.

Woody plants. Some woody plants can develop as dense canopies (up to 30 feet tall) 

under the overstory, interfering with establishing adequate regeneration through the 

shade they cast,. Some of the recognized species of concern are primarily shade-tolerant 

species like mountain laurel, ironwood (hophornbeam), musclewood (hornbeam), 

striped maple, black birch, sweet fern, blueberries, and beech. Some of these plants 

provide food or cover for wildlife and enhance species diversity. They can prevent 

regeneration however, when they dominate the forest understory. Record your estimate 

of the percentage of the 1/10-acre plot that is covered by the shade cast by these plants. 

Focus your estimate from ground level up to 30 feet.

Any interference. This variable captures the presence or absence of interference on a plot. 

We assess each interfering plant separately and then record a checkmark in this column 

if any species meets or exceeds the 30-percent threshold. If any cover for ferns, grasses 

and sedges, or woody plants is equal to or greater than 30 percent, record a checkmark 

in this column.

Overstory Assessment Procedure

This portion of the assessment is designed to answer the following residual tree 

questions:

 What will happen to species composition? 

 Will the seed source be retained?

 What will happen to residual tree quality?

 What will happen to the average stand diameter? 

Grasses and sedges 

threshold: 

At least 30-percent 

coverage of the 1/10-

acre plot indicates 

interference.

Woody plant threshold: 

At least 30 percent of the 

1/10-acre plot. The stem 

diameter of these plants 

is not important; what 

matters is the amount of 

shade they cast on the 

forest fl oor.
9

Field Measurements

Controlling timber species composition, seed source, residual stem quality, and diameter 

distribution is the key to attaining a sustainable harvest. By using the procedures that 

follow, you will develop a picture of the stand before harvesting that will suggest whether 

the intended harvest will be sustainable.

Setting Up the Tally Sheet

The larger top part of the overstory assessment tally sheet in Figure 5 works from the 

bottom up. The size class line defi nes four diameter classes: 3 to 5.5 inches, 5.6 to 11.5 

inches, 11.6 to 17.5 inches, and 17.6 inches and larger. List the species that occur for 

each diameter class and enter the species code. Start in the left-hand column of a given 

diameter class and list the shade-tolerant species followed by intermediates and fi nally the 

intolerants.

In northern hardwood forests, typical shade-tolerant species include sugar maple (HM), 

hemlock (HE), and American beech (BE). Intermediates include red maple (RM), red 

oak (RO), white oak (WO), black oak (BO), chestnut oak (CO), other oaks (OO), 

hickory (HI), white ash (WA), yellow birch (YB), black birch (BB), and black gum (BG). 

Intolerant species include white pine (WP), black cherry (BC), yellow-poplar, (YP), 

cucumbertree (CU), Virginia pine (VP), and aspen (AS).

In our example stand (Figure 6), species would be listed in the following order from left 

to right: HE, SM, RO, WO, YP, and BC. This provides a view of size classes by species 

and tolerance. This requires practice but by doing it you will develop insights into how 

harvesting affects species composition and stand structure.

Collecting Overstory Data

On the overstory tally sheet, record all trees larger than 3 inches on your fi rst 1/10-acre 

plot. You need not mark individual trees but remember which tree was fi rst and go 

around the plot in a clockwise or counterclockwise direction. Be consistent so that you 

do not miss a tree or count a tree twice.

For each tree encountered, measure its diameter at breast height (d.b.h.), which is 

measured at 4.5 feet above the ground. Because we are using diameter classes, eventually 

you will be able to estimate the size class for most trees. When in doubt, always measure 

the tree. Using the d.b.h., record the tree in one of the four diameter classes in the 

correct species column.

Record the tree using a symbol for its tree-condition code. Acceptable growing stock 

(AGS) contains or potentially contains at least one sawlog and will survive until the 

next harvest (record with a “+”). Unacceptable growing stock (UGS) never will produce 

a sawlog or is likely to die before the next harvest (record with a “-”). If you plan to 

harvest the tree, circle the quality code. The completed tally sheet for one plot will look 

something like Figure 7.
10

Figure 5.—Overstory assessment tally sheet.

QUALITY (Q)

302928272625242322212019181716151413121110

987654321

 Species

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species CompositionSeed Source TotalResidual Quality

 Species Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition

Seed Source Total Priority Sp. Average Stand AverageSeed Source Average Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality

12

345678

Owner: Date: Location: Stand:
11

Figure 6.—Overstory assessment tally sheet with species codes.

QUALITY (Q)

302928272625242322212019181716151413121110

987654321

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species CompositionSeed Source TotalResidual Quality

 Species Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition

Seed Source Total Priority Sp. Average Stand AverageSeed Source Average Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality

123456

78

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 
12

Figure 7.—Completed overstory assessment tally sheet.

QUALITY (Q)

3029282726252423 +22 +21 +20 +19 +18 - +17 - +16 - +15 - - +-14 - - ++13 - +- + +12 - +- + +11 - +- + +10 - - +- + +

9 - - +- + +8 - - +- + +7 - - +- +- +6 - - + - ++ +5 - - + - - ++ +4 - - + - + + ++ +3 - - + - + + ++ +2 - - - - + + ++ +1 - - - - - + - - ++ ++ + +

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species CompositionSeed Source TotalResidual Quality

 Species Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition

Seed Source Total Priority Sp. Average Stand AverageSeed Source Average Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality

123456

78

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 

O

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OO

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OO

O

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O

OO

OO

O

OO

OO

OO

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O

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13

Culls and unacceptable growing-stock trees usually are removed fi rst in a harvest. 

However, some may remain because they provide important habitat for wildlife or 

otherwise contribute to species diversity in the stand. For example, a butternut, even a 

cull one, is worth retaining.

Again, after determining the acceptability of a tallied tree, circle the coded symbol if 

the tree is marked for harvest, or, if the stand is unmarked, you plan to harvest the tree. 

Doing this will enable you to develop a picture of the residual forest stand following the 

harvest.

FIELD DATA SUMMARY

Once you have collected the data, you must summarize the information to understand 

the implications of the harvest relative to the stand. We will begin this process by fi rst 

summarizing the regeneration data.

Summarizing Regeneration Data

Figure 8 is a sample regeneration tally sheet that you will develop as you work through 

this section. 

Deer Impact

First, review the estimated deer impact for the stand. Use the deer impact to determine 

the regeneration threshold as shown in Table 3.

Advanced Regeneration

Using Table 3, determine which weighted number of seedlings is the appropriate 

threshold for this harvest area based on the deer impact. Determine the percentage of 

your plots that met or exceeded that threshold-weighted number of desirable seedlings.

Canopy Density

Add your plot-level estimates and record the total in the cell provided. Divide this 

number by the number of plots you evaluated to determine the average (see Figure 8).

Interference

Determine the percentage of the stand’s plots that exceed the threshold for any 

interference. This is the percentage of the cells in Column 7 with a checkmark. For 

example, if you took fi ve plots and four of them have checkmarks in Column 7, 80 

percent of your plots have an interference problem.

If this percentage is at least 30 percent, you might want to summarize Columns 4, 

5, and 6 in the same way to document which interfering plants are the source of the 

problem in the harvest area. Remember that even if grasses and sedges are present at 

levels below the threshold, their mere presence may indicate problems related to soil 

moisture and seed source.

In our example stand, 

Deer impact is estimated 

to be high (H, recorded 

in the “total” cell in the 

deer impact column). The 

regeneration threshold 

is 50 since it is a high 

deer-impact area. Two 

plots had a weighted 

seedling count of 50 

or more (plots 3 and 

4). Therefore, only 40 

percent of the plots have 

adequate regeneration. 

In other words, advanced 

regeneration in this 

harvest area is inadequate.

The average canopy 

density is 40 percent. 

Therefore, this is a 

regeneration harvest, not a 

partial cut.

Fern cover is at least 30 

percent on 80 percent 

of the understory plots. 

Grasses and sedges are 

less common than ferns 

and are less than the 

30-percent threshold on 

any plot. Likewise, woody 

plants are not an issue; 

they are less than the 

30-percent threshold on 

all fi ve plots. Nonetheless, 

interference occurs on 80 

percent of the plots.
14

Summarizing Overstory Data

The rows at the bottom of the overstory tally form (Fig. 9) provide a place for 

summarizing the overstory data collected earlier. They will help you understand how 

decisions about harvesting affect the four critical variables mentioned previously: species 

composition, seed source, residual tree quality, and stand diameter.

Species Composition

Sustainable forestry implies retaining species composition. Diverse species composition 

ensures future management options and refl ects consideration of wildlife, aesthetic, and 

other values. Some harvests reduce the number of tree species in a stand or remove too 

many trees of a particular species.

For example, across the Allegheny Plateau, black cherry is relatively easy to regenerate 

and may be the only valuable species that regenerates with high deer populations. Black 

cherry is a desirable species but we should exercise care that we do not develop stands 

dominated by single species (monocultures). Monocultures lack the resiliency of mixedspecies stands because they may be at a higher risk for disease and insect injury.

In some cases it is desirable to reduce the abundance of individual tree species in a stand. 

There are occasions when species under threat of disease or insect outbreaks might be the 

focus of the harvest, for example, American beech when under attack by the beech bark 

Figure 8.—Sample regeneration tally sheet showing all sample data.

Figure 9.—Overstory tally form summary data.

Species composition 

threshold:

If the harvest will 

eliminate a species or 

reduce its presence in 

the residual stand by 

more than 50 percent, 

species composition may 

be a concern.

Plot 1

Deer 

Impact (H/

L)

2

Regen.

Adequate

3

Canopy 

Density 

(percent)

4

Fern 

(percent)

5

Grasses/

sedges 

(percent)

6

Woody 

plants 

(percent)

7

Any 

Interference 

(check)

1 20 50 40 20 10 √

2 0 40 70 10 15 √

3 50+ 40 40 0 5 √

4 50+ 30 20 0 20

5 10 40 30 20 10 √

percent 

stocked

average 

percent

percent

≥ 30

percent

≥ 30

percent

≥ 30

percent with √

Stand H 40 40 80 0 0 80

Species Composition

Seed Source Total

Residual Quality

 Species Stand Summary

Species Composition

Seed Source Total Priority Sp. Average Stand Average

Seed Source Average

Residual Quality

# AGS # UGS Stand Diameter (+ or -)

Before After cut Before After cut

Overall Stand Quality
15

In our example stand, 

there are reductions for BC 

in the small sawlog size 

class. Likewise, there were 

reductions for HE, RM, 

and BC in the large sawlog 

size class. For HE and 

RM, species that occur in 

only two size classes, there 

was a reduction in half of 

the size classes in which 

those species occurred, so 

each receives a “-” in the 

stand summary block.

BC occurred in three 

size classes and shows a 

reduction in two, so it, too, 

receives a “-” in the stand 

summary block. The 50-

percent rule was violated 

for HE, RM, and BC.

BE occurs in three classes 

and had a reduction only 

in the largest one, so it 

receives a “0” in the stand 

summary block.

Seed source threshold:

Fifteen large sawtimber 

trees or 30 small 

sawtimber trees per acre 

usually are suffi cient to 

preserve the option of 

natural regeneration for 

a species.

scale complex. Some operations may include salvaging dead and dying trees. If there are 

concerns about a species that might create an interfering understory, e.g., black birch or 

black gum, you might also reduce it in a harvest.

If you maintain 50 percent or more of the individuals in that species in that size class, 

enter “0” in the species composition summary row of the tally sheet. Enter “–” if you 

reduced the number of individuals in the species by more than 50 percent in that size 

class. If there are no individuals of a species, leave the size classes blank for that species.

The lower portion of the tally sheet and the smaller summary table at the bottom aid in 

summarizing the information you have collected. Figure 10 displays the summary data 

for the example stand, demonstrating how the planned harvest will alter the stand. If a 

“–” is in half or more of the size classes in which that species occurred, record “–” for the 

stand.

Seed Source

Research has shown that 15 large to 30 small sawtimber-size black cherry trees per acre 

are necessary to successfully regenerate that species, and that a similar amount of red oak 

is adequate to ensure successful regeneration of that species. Similar data are not available 

for other species in Pennsylvania’s forests. However, leaving 15 small to 30 large healthy 

sawtimber trees of each desired species per acre after harvest is a reasonably safe way to 

preserve the option of natural regeneration for those species. We want to ensure that 

the current harvest will leave suffi cient seed source to regenerate desired species into the 

future. The only situation in which seed source does not matter is a regeneration harvest 

with well-established adequate regeneration and little or no interfering plants.

Identify the priority species, ideally through conversations with the landowner and 

forester, and ensure a seed source for that individual species. This should be the 

minimum residual stocking for stands in which regeneration is not already ensured. 

Retain additional healthy sawtimber trees for regeneration of other species. We will 

evaluate seed source using a weighted count of 30 per acre as the threshold. Large 

sawtimber trees, which generally produce more seed, are counted double. Since each of 

your plots is 1/10 acre, this threshold translates to an average of three trees per plot.

In the summary section at the bottom of the tally sheet, work with this variable only in 

the sawtimber size classes. For each species, record the weighted number of trees to be 

retained after harvest in the seed source total row. For small sawtimber trees, record the 

actual number of trees retained. For large sawtimber trees, record twice the number of 

trees retained as this class is weighted more heavily because these larger trees generally 

produce more seed.

In the row for seed source total in the stand summary block, record a weighted total 

equal to the number of small sawtimber trees plus the weighted number of large 

sawtimber trees. Divide these numbers by the number of plots taken and record this as 

the average seed source for each species in the row for seed source average.
16

Figure 10.—Overstory assessment tally sheet with stand summary data.

QUALITY (Q)

3029282726252423 +22 +21 +20 +19 +18 - +17 - +16 - +15 - - +-14 - - ++13 - +- + +12 - +- + +11 - +- + +10 - - +- + +

9 - - +- + +8 - - +- + +7 - - +- +- +6 - - + - ++ +5 - - + - - ++ +4 - - + - + + ++ +3 - - + - + + ++ +2 - - - - + + ++ +1 - - - - - + - - ++ ++ + +

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species Composition 00 000 0 -000 - - - -Seed Source Total 314 30 0 0

Residual Quality 0 0 00 0 0 +0 0 0

 Species HE BE SM YB RM BC Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition - 0 0 0 0 - species reduced

Seed Source Total 314 3 Priority Sp. Average Stand AverageSeed Source Average .6 .2 .8 .6 1.2 2.2 Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality 0 0 + 0 0 0 sugar maple improved

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality 64 23 51 46 proportion of UGS increased

123456

78

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 

O

O

OOOO

O

O

OOO

OO

O O

O

OO

O

O

O

O

OO

OO

O

OO

OO

OO

O

O

O

O

OOO

O

O

OO O

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17

In the sample stand, the overstory tally is based on fi ve plots, so we divide by fi ve. 

Finally, in the stand summary cell, record the average for the priority species and for the 

stand. In the sample stand, black cherry and sugar maple are the priority species. The 

planned harvest leaves three black cherry, four red maple, one yellow birch, and three 

sugar maple, all in the small sawtimber class. Thus, our total residual is 6 priority trees 

and 11 total residual sawtimber trees, or an average of about 1 priority tree per plot (6/5 

= 1.2) and about 2 (11/5 = 2.2) sawtimber trees per plot. Both of these totals are below 

the threshold for seed source.

Residual Tree Quality

In a timber harvest, it is easy to focus only on the trees to be removed. Sustainable 

forestry also focuses on residual trees—those retained after the harvest. Following 

a harvest, the residual stand should contain a higher proportion of quality trees of 

desirable species relative to the original stand conditions. But the residual stand also 

should include two to fi ve trees with obvious internal or external defects or other health 

problems. These trees are left to preserve species composition (as a seed source), and/or 

as cavities or snags (standing dead trees) for wildlife. However, it is possible to leave too 

many trees of undesirable quality. Such trees may occupy too much of the next forest and 

interfere with the growth of desirable residual trees or regeneration.

What will the harvest do to residual tree quality? Record your interpretations by species 

and size class in the residual tree quality row of the tally sheet (Fig. 10, Row 3). Enter “0” 

if you did not change the relative proportion of AGS to UGS, “–” if you increased the 

proportion of UGS to AGS, or “+” if you improved the proportion of AGS to UGS.

Then, for each species assess the change across all size classes in the stand (Fig.10, Row 

7). Enter “0” if you did not change the relative proportion of AGS to UGS, “–” if the 

proposed cut increased the proportion of UGS to AGS, or “+” if you improved the 

proportion of AGS to UGS.

Continuing with the example in Figure 10 (refer to the SM column in the small sawlog 

size class), we see that the relative proportion of AGS to UGS has improved. Record “+” 

in the small sawtimber sugar maple cell in the summary block at the bottom of the tally 

sheet. For sugar maple, there was no change in relative quality in the sapling and pole 

classes, so record “0” in each of those cells and leave the large sawtimber sugar maple cell 

blank since there are no sugar maple trees in that size class. In the stand summary block, 

record “+” for sugar maple since the overall impact of the harvest will be to increase the 

proportion of sugar maple AGS in the stand. Leave cells blank if a species was removed 

in that size class, e.g., beech in small sawtimber and red maple in large sawtimber.

In the sample stand, black cherry receives a blank in saplings (there were none) and in 

large sawtimber (the species was eliminated). In poles and small sawtimber, black cherry 

receives a “0” because all of the black cherry were AGS before the harvest, and only black 

cherry AGS remain after the harvest in these categories. For the stand as a whole, then, 

black cherry receives a “0.”

Relative residual tree 

quality threshold:

The intent is to increase 

the relative proportion 

of good quality trees 

(i.e., AGS to UGS) after 

the timber harvest.
18

On the bottom line, record the number of AGS and UGS in the stand as a whole both 

before and after harvest. Consider any changes in the proportion of AGS to UGS in the 

stand. By species, apparently there was little change in residual tree quality for the stand. 

Sugar maple actually improved while the other species showed no change. However, the 

overall occurrence of UGS increased relative to AGS. Before our sample harvest there 

were 64 AGS and 51 UGS (more AGS than UGS, both nearly half the stand). After 

harvest, there were twice as many UGS as AGS, and all of the AGS were removed from 

the larger diameter class.

Average Stand Diameter

The stand’s average d.b.h. helps us understand and interpret shifts in the distribution 

of tree size following harvesting. How will the harvest affect stand structure? Will the 

harvest take trees from both large- and small-diameter classes? How will this cut affect 

the next harvest and the stand’s regeneration? It is important for growth potential, 

fi nancial value, wildlife habitat, and aesthetic character of forests.

Will the harvest take trees from both large and small diameter classes? In many 

Pennsylvania stands, there is a wide range of tree diameters and heights. Sometimes 

this is due to difference ages within the stand, but more often, it is due to differences 

is species growth rates and the stand is actually even-aged. Within the stand, the fastest 

growing species tend to have diameters that are greater than those of trees of the same 

age from slower growing species. Within a species, the fastest growing individuals have 

the largest diameters.

For example, in cherry-maple forests of the Allegheny Plateau, it is common to fi nd an 

18-inch, 90-year-old black cherry growing next to a 12-inch, 90-year-old sugar maple. If 

we harvest primarily the smaller trees in the stand, we increase the average stand diameter 

and leave the fastest growing individuals to continue growth. If we harvest primarily the 

larger trees, we reduce average stand diameter and leave slower growing individuals. We 

also change the distribution of foliage in the stand and the amount and quality of light 

reaching the regeneration on the forest fl oor as well as the character of wildlife habitat in 

the stand.

In even-aged forests, an improvement harvest (crown partial cut) in which competing 

trees are removed to create growing space for residual trees should maintain or 

increase the average stand diameter. In uneven-aged forests, selection harvest should 

cut throughout the diameter distribution, leaving the average diameter essentially 

unchanged. The harvest operation should emphasize leaving high-quality, vigorous trees. 

Whether the harvest is a selection or a partial cut, the goal is to improve the stand for 

future harvests.

How will this cut affect the next harvest? Harvests that increase stand diameter or leave 

it unchanged result in a residual stand that is growing as fast or faster than before the 

harvest. If the increase in stand diameter was accompanied by creation of conditions 

Stand structure is the 

distribution of tree sizes 

across the harvest area—

tree diameter, height, and 

foliage distribution.

Average stand 

diameter threshold:

Concerns should be 

raised if the average 

stand diameter 

decreases by more than 

10 percent, e.g., the 

average stand diameter 

before the cut is 16 

inches and 14 inches 

after the cut.
19

good for regeneration, a fi nal harvest of desirable composition and value is likely in the 

near future.

In uneven-aged stands with diameters unchanged by harvest, volume growth should 

continue steadily as before the harvest. However, diameter-limit harvests that remove 

primarily large trees leave a forest that looks younger than it is because the heights and 

diameters of the residual trees are smaller than before the harvest. The growth rates of 

trees that are left behind will be slower than those of trees that were cut. The severity of 

this decrease in growth rate depends on the severity of the cut, and on residual species 

composition and quality. In cases of high-grading, the practice of removing the largest 

and most valuable trees, stand growth can be set back and recovery of harvestable 

products from the tract in the future delayed for many decades.

How will this harvest affect the stand’s regeneration potential? Cuts not intended as 

regeneration harvests—those with residual canopy closure of at least 50 percent—still 

have important consequences for regeneration potential in the harvested stand. If 

average diameter is increased through the cutting, more light will reach the forest fl oor 

to stimulate the germination and growth of advanced seedlings. If the average diameter 

is reduced because only the largest trees are harvested, low-shade conditions may be 

created that delay or prevent regeneration establishment and growth.

Appendix A includes a detailed procedure for estimating change in average stand 

diameter. We suggest a graphical method for determining the impact of the planned 

harvest on average diameter. Use a pencil and the overstory assessment tally sheet (Fig. 

11) to make this determination. Mentally total up the tolerant and midtolerant species 

in each size class, including both the trees you plan to leave and cut ( the “+” and “-” 

with or without circles), and draw a solid free-form curve that represents the distribution 

of these species through the size classes.

For example, in the sample stand the free-form curve would start with 25 saplings, go 

off the chart completely in the poletimber class, with 18 sugar maple, 1 hemlock, and 

13 beech, and fall to 11 and 8 in the small and large sawtimber, respectively. Draw a 

similar curve for the intolerant species, starting from the other end. In the sample stand, 

this curve would start with 15 black cherry in the large sawtimber class, 23 black cherry 

in the small sawtimber class, and 1 black cherry in the pole class. Visually estimate the 

average diameter based on these two curves—for the sample stand, somewhere near the 

low end of the small sawtimber class, around 11 inches.

Now make two more curves (Fig. 12), counting only those trees scheduled as residuals 

after the planned harvest (the symbols that are not circled). Lightly shade in the 

differences between the two curves to indicate the harvest planned, and again visually 

estimate the average diameter in the sample stand. In the example, where the entire 

harvest is scheduled to occur is in the sawtimber classes, it would fall to the lower end 

of the poletimber class, around 8 inches. This is much more than a 10-percent drop in 

High-grading is removing 

only the largest and most 

valuable trees in a stand.
20

Figure 11.—Overstory assessment tally sheet with preharvest curve and stand summary data.

QUALITY (Q)

3029282726252423 +22 +21 +20 +19 +18 - +17 - +16 - +15 - - +-14 - - ++13 - +- + +12 - +- + +11 - +- + +10 - - +- + +

9 - - +- + +8 - - +- + +7 - - +- +- +6 - - + - ++ +5 - - + - - ++ +4 - - + - + + ++ +3 - - + - + + ++ +2 - - - - + + ++ +1 - - - - - + - - ++ ++ + +

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species Composition 00 000 0 -000 - - - -Seed Source Total 314 30 0 0

Residual Quality 0 0 00 0 0 +0 0 0

 Species HE BE SM YB RM BC Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition - 0 0 0 0 - 2 species reduced

Seed Source Total 314 3 Priority Sp. Average Stand Average

Seed Source Average .6 .2 .8 .6 1.2 2.2 Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality 0 0 + 0 0 0 sugar maple improved

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality 64 23 51 46 proportion of UGS increased

123456

78

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 

O

O

OOOO

O

O

OOO

OO

O O

O

OO

O

O

O

O

OO

OO

O

OO

OO

OO

O

O

O

O

OOO

O

O

OO O

O
21

Figure 12.—Overstory assessment tally sheet with residual tree d.b.h. curves and trees scheduled for removal shaded.

QUALITY (Q)

3029282726252423 +22 +21 +20 +19 +18 - +17 - +16 - +15 - - +-14 - - ++13 - +- + +12 - +- + +11 - +- + +10 - - +- + +

9 - - +- + +8 - - +- + +7 - - +- +- +6 - - + - ++ +5 - - + - - ++ +4 - - + - + + ++ +3 - - + - + + ++ +2 - - - - + + ++ +1 - - - - - + - - ++ ++ + +

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species Composition 00 000 0 -000 - - - -Seed Source Total 314 30 0 0

Residual Quality 0 0 00 0 0 +0 0 0

 Species HE BE SM YB RM BC Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition - 0 0 0 0 - 2 species reduced

Seed Source Total 314 3 Priority Sp. Average Stand Average

Seed Source Average .6 .2 .8 .6 1.2 2.2 Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality 0 0 + 0 0 0 sugar maple improved

# AGS # UGS Stand Diameter (+ or -) -

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality 64 23 51 46 proportion of UGS increased

12345678

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 

O

O

OOOO

O

O

OOO

OO

O O

O

OO

O

O

O

O

OO

OO

O

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22

average diameter, so record “–” in the stand diameter row of the summary block (note in 

Appendix A that the more precise calculation of change in average diameter from these 

data suggest a reduction of 27 percent).

Interpreting the Overstory Assessment Tally Sheet

The Overstory Assessment Tally Sheet (Fig. 12) provides important information for 

determining whether the planned harvest will yield a sustainable outcome. Specifi cally, 

we are interested in understanding what the harvest will do to species composition, seed 

source, residual tree quality, and average stand diameter. We want to retain or improve 

species composition and tree quality, retain seed source, and increase or maintain average 

stand diameter.

The stand in Figure 12 is signifi cantly different from the one we inventoried. It is clear 

that the harvest is taking all of the large sawlog trees and nearly all of the small sawlog 

trees. Some of the SM and RM are retained in the residuals but nearly all of the BC, an 

important tree species in this stand, has been removed resulting in a stand of low quality 

BE and SM. All of the HE in the large sawlog size class have been removed. Quality of 

the residual stand is evident from the number of “-” symbols relative to “+” symbols.

We have changed this stand by reducing species diversity (reducing the amount of BC 

and HE), and the overall quality (the residual forests has many more low quality trees 

because we took all those AGS in the larger size classes). Also, the average stand diameter 

has dropped considerably, an estimated 3 inches or 27 percent (see Appendix A).

The Sustainability Key

Using the sustainability key in Figure 13 along with the regeneration data from Figure 

8 and summarized overstory data in Figure 12, we can determine whether the proposed 

harvest will achieve a sustainable outcome. As shown, the sustainability key asks a series 

of paired questions or couplets that relate to the harvesting decisions you made for the 

stand.

The fi rst item relates to the estimated residual overstory density. If it is less than 50 

percent, which it is, the planned harvest is a regeneration cut and we move to item 2. 

Less than 70 percent of the plots have adequate advanced regeneration so we move to 

item 6. Looking at the summary stand data in Figure 12, we see that the seed source is 

inadequate; two species were lost or reduced (HE and BC), and our stand average is 2.2 

trees/acre in small and large sawtimber to provide seed source in a stand that already 

lacks adequate advanced regeneration. The key tells us to delay the harvest and seek 

assistance.
23

Figure 13.—Sustainability key.

Item Description Go To:

1 Residual overstory canopy > 50% (partial 

cut)

Go to

Residual overstory canopy ≤ 50% 

(regeneration cut)

Go to 2

2 Advance regeneration < 70% Go to 6

Advance regeneration ≥ 70% Go to 3

Regeneration 

harvest

Advanced 

regeneration 

present, abundant

3 Percent plots stocked with interfering 

vegetation overtopping desirable regeneration 

≥ 70%

Go to 4

Percent plots stocked with interfering 

vegetation overtopping desirable regeneration 

< 70%

Go to 5

4 Interference treatment planned in 

conjunction with harvest

Go to 5

Interference treatment not planned Delay harvest. Seek assistance

5 Deer impact low or deer impact reduction 

planned (fencing or very aggressive hunting)

Treat and harvest. Follow up 

stand development. Probably 

sustainable.

Deer impact high and no deer impact 

treatment planned

Seek assistance. Will seedlings 

overwhelm deer?

Regeneration 

harvest

Advanced 

regeneration scarce 

or absent

6 One or more desirable seed source species lost 

or reduced in overstory to < 15 large or 30 

small sawlog trees per acre with strong crowns

Delay harvest. Seek assistance.

Desirable seed source species ≥ 15 large or 

30 small sawlog trees with strong crowns 

retained

Go to 7

7 Fern ≥ 30% of 30% plots Go to 10

Fern < 30% on 30% of plots Go to 8

8 Grass/sedge ≥ 30% on 30% of plots Go to 10

Grass/sedge < 30% on 30% of plots Go to 9

9 Woody interference ≥ 30% of 30% plots Go to 10

Woody interference < 30% on 30% of plots Go to 10
24

Figure 13.—continued.

Item Description Go To:

10 All interfering plants ≥ 30% on 30% of plots Go to 11

All interfering plants < 30% on 30% of plots Go to 12

11 Interference treatment planned with harvest Go to 12

Interference treatment not planned Delay harvest. Desirable seedlings 

not likely to be competitive after 

harvest. Seek assistance.

12 Deer impact low or deer impact reduction 

planned (fencing or aggressive hunting)

Treat and harvest. Follow up 

stand development. Probably 

sustainable.

Deer impact high and no deer impact 

treatment planned

Delay harvest. Scarce seedlings 

likely to disappear after harvest. 

Seek assistance.

Partial cut

Check seed source

13 One or more desirable seed source species lost 

or reduced in overstory to < 15 large or 30 

small sawlog trees per acre with strong crowns

Delay harvest. Seek assistance.

Desirable seed source species ≥ 15 large or 

30 small sawlog trees with strong crowns 

retained

Go to 14

Partial cut

Seed source 

adequate

Check residual 

stand

14 Average DBH retained or increased (≤ 10% 

reduction)

Rate of growth likely sustained or 

improved. Go to 15.

Average DBH reduced (> 10% reduction) Rate of growth likely slowed. Go 

to 15

15 Timber quality sustained or improved by 

harvest, average DBH retained or increased

Future valuable harvest probable. 

Probably sustainable.

Timber quality sustained or improved by 

harvest, average DBH reduced 

Future valuable harvest probable, 

though later than with diameter 

improvement. Probably 

sustainable.

Timber quality reduced by best trees removed 

and/or damage to residual, ≥ 15 large or 

30 small sawlog trees with strong crowns 

retained as seed source

Future valuable harvest at risk. 

May not be sustainable.Consider 

regenerating

Alternative Treatment

Figure 14 suggests an alternative treatment for this stand. The proposed harvest still 

will take some of the small and large BC sawlogs, but not all. This way, we retain the 

seed source and we have a potential for cherry in the future stand if we control for the 

interfering plants identifi ed in the regeneration assessment. We have retained some of the 

larger HE and RM, improved the SM by cutting UGS, and put more of the operation 

into the smaller diameter classes, improving overall stand quality, retaining species 

composition, and maintaining or increasing stand diameter.
25

Figure 14.— Alternative cut.

QUALITY (Q)

3029282726252423 +22 +21 +20 +19 +18 - +17 - +16 - +15 - - +-14 - - ++13 - +- + +12 - +- + +11 - +- + +10 - - +- + +

9 - - +- + +8 - - +- + +7 - - +- +- +6 - - + - ++ +5 - - + - - ++ +4 - - + - + + ++ +3 - - + - + + ++ +2 - - - - + + ++ +1 - - - - - + - - ++ ++ + +

 Species HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC HE BE SM YB RM BC

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species Composition - - 00- 0 -000 00 -Seed Source Total 4 1 2 12 8 2 12

Residual Quality 0 0 0 0 0 0 ++ 0 0 0 + 0 +

 Species HE BE SM YB RM BC Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition 0 - - 0 0 0 2 species reduced

Seed Source Total 8 4 1 4 24 Priority Sp. Average Stand Average

Seed Source Average 1.6 .8 .2 .8 4.8 5.6 8.2 Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality + + + 0 0 + improved

# AGS # UGS Stand Diameter (+ or -) +

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality 64 36 51 20 proportion of AGS increased

12345678

Owner: Jane Doe Date: 6/10/03 Location: Logtown Stand: 2 

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

OO

O

O

O

O

O

O

O

O

O

OO

OO

O

O

O

O

O

O

O O O

O

+++++ +O

+++O++O+O

+O+O+O+O+O -O

O

+O

O

O

OOO

O

O

OOO

O

OOOOO
26

This harvest does not produce as much immediate income but the next harvest will have 

additional value, and we have protected our options for regenerating the stand. Now 

work it through the sustainability key, starting with item 6.

Since we are retaining adequate seed source, we would move to item 7. From Figure 

8, we know that fern cover exceeds the 30-percent threshold on 80 percent of the 

plots, so we would be instructed to go to item 10 where the question relates to any 

interference. The summary data in Figure 8 column 7, any interference, again indicate 

that interference occurs on 80 percent of the plots. The key sends us to item 11, where 

we encounter a major concern—we have an interference problem that will result in an 

unsustainable harvest outcome.

If no treatment to control interfering plants is planned, we should seek assistance. If a 

treatment to control interfering plants is planned, we are instructed to go to item 12, 

where we need to consider deer—another barrier to successful regeneration. If the deer 

impact is low or fencing or aggressive hunting are planned, we can treat the stand for 

interfering vegetation and deer impact and harvest. With follow up, the stand probably is 

sustainable, but if deer impact is high or no control is planned, we are instructed to delay 

the harvest and seek assistance.

When treating interfering plants, it is important to understand that the herbicide 

or mechanical treatment may destroy existing advanced regeneration, and that the 

treatment must be given time to be effective. After treating interfering plants and waiting 

for the treatment to take effect, it is essential to collect new understory data and to start 

with item 2. It is essential for a sustainable harvest to have regeneration conditions that 

ensure that the next forest is in place.

Finally, obtaining a sustainable outcome from a timber harvest depends on protecting 

the residual stand and having adequate advanced regeneration. When harvesting a stand, 

especially during a partial or improvement cut, you are attempting to ensure that future 

generations have high-quality trees to harvest.

Do everything you can to make sure that you protect the trees you are leaving. Practice 

directional felling; avoid hitting the stems and crowns of residual trees to the extent 

possible.

Use bumper trees along skid trails, skid roads, and haul roads to protect the trunks 

of trees you intend to keep. Depending on the harvest, consider bucking stems in the 

woods into shorter lengths. When feasible, limit barking by harvesting during the 

dormant season, rather than when trees are actively growing. Information on BMPs is 

available from your cooperative extension offi ce, Bureau of Forestry, or Pennsylvania SFI 

offi ce.
27

It is easy to focus on the condition of the residual stems but also be aware of what is 

occurring below ground to the roots of these trees. Skidding damage occurs to roots 

primarily through soil compaction. Harvesting when soils are wet can signifi cantly 

increase root damage to residual trees. Skidding without a plan increases the overall 

disturbance in the stand and can lead to excessive root damage and soil disturbance. Plan 

the harvest operation before starting.

WHAT HAVE WE LEARNED?

Coming away from this program, you now can differentiate between a partial cut and 

regeneration cut. With respect to regeneration cuts, you can evaluate sites that will pose 

problems and those that will produce sustainable forests. You now are aware of barriers 

that interfere with regeneration and know when to seek assistance when problems arise.

Remember to seek assistance when there is a species loss, a major drop in average stand 

d.b.h., or when you suspect regeneration problems (such as an overabundance of ferns or 

too many undesirable woody plants).

You also can evaluate the quality of the residual trees. With simple data-collection tools, 

you can describe species composition, estimate diameter distribution by species, evaluate 

crown closure, and understand the effect of light on tree growth and regeneration.

It is the hope of all of us working with Pennsylvania’s forests that by using these skills you 

will earn a more professional image and improve relationships with the public, forestland owners, foresters, and other loggers. Our mutual goal is to sustain our valuable 

timber resources and forest products industry. To obtain this goal, we need to work 

together.

ADDITIONAL RESOURCES

Appendices B and C provide additional information that you might fi nd helpful. 

Appendix B includes blank overstory and understory inventory sheets. Appendix C 

includes SFI’s timber harvesting assessment and treatment unit sustainability assessment 

forms. Both forms are designed to summarize postharvest conditions on a property. 

Information on BMPs for Pennsylvania forests is featured in the Forest Stewardship 

Bulletin that is reprinted at the end of this report.
28

APPENDIX A

ESTIMATING AVERAGE STAND DIAMETER

Figures 15 and 16 provide a way to rapidly estimate average stand diameter from the data entered 

in Figure 7. Since we have not recorded the actual diameters for each tree (we are working with 

diameter classes), we only can estimate the change in average diameter. It is obvious from Figure 

10 that the cut focused on large trees, so we expect the those trees left in the stand will be smaller 

on average. We can roughly estimate the change in average diameter by using the average diameter 

for each of the size classes we used to record the trees tallied (i.e., saplings, poles, and small 

sawlogs, and the small end of the large sawlog class). Because the calculation of average stand 

diameter is based on averages for size classes, it is not as sensitive as it would be in a normal cruise. 

Nonetheless, it can provide a rough estimate of the amount and direction of the diameter shift.

Figure 15.—Diameter distribution summary worksheet.

Size Class

Pre-Harvest

Tree Total

 by size classes

Multiplier (Sum this column)

Sapling (3-5.5 in) X 4.0 =

Poles (5.6-11.5 in) X 8.5 =

Small sawlogs (11.6-17.5 in) X 14.5 =

Large sawlogs (>17.5 in) X 17.5 =

Total (B) = (A)

Average DBH = A ÷ B

(A) = (B)Pre-Harvest

Average DBH (PRE)

Size Class

Post-Harvest

Tree Total

 by size classes

Multiplier (Sum this column)

Sapling (3-5.5 in) X 4.0 =

Poles (5.6-11.5 in) X 8.5 =

Small sawlogs (11.6-17.5 in) X 14.5 =

Large sawlogs (>17.5 in) X 17.5 =

Total (B) = (A)

Average DBH = A ÷ B

(A) = (B)Post-Harvest

Average DBH (POST)

Post-Harvest Diameter– Pre-Harvest Diameter

Pre-Harvest Diameter X 100 = Percent Change in Diameter

POST ( ) – PRE ( )

PRE ( ) X 100 = Percent Change in Diameter
29

Figure 16. —Sample diameter distribution summary.

Figure 15 is a worksheet for computing the direction and for estimating the percentage change in 

average diameter in a marked stand using data in Figure 7. Figure 16 shows the completed example 

using data from Figure 8. It often is possible to estimate the preharvest and postharvest diameter 

distributions by examining the overstory data sheet. However, it takes little time to complete the 

diameter distribution summary sheet and this exercise is useful for understanding how cutting 

changes stand characteristics. In Figure 16, we see that the preharvest average diameter is 11.1 

inches. If we follow the marking instructions indicated by the plusses and minuses in Figure 7, the 

postharvest average diameter drops to 8.1 inches, a 27-percent decrease in average stand diameter. 

This large drop is clearly attributed to the removal of all of the trees in the large sawlog class and 

nearly all in the small sawlog group. Note that there was no intentional thinning in the smaller 

diameter classes.

Size Class

Pre-Harvest

Tree Total

by size classes

Multiplier (Sum this column)

Sapling (3-5.5 in) 25 X 4.0 = 100

Poles (5.6-11.5 in) 33 X 8.5 = 280.5

Small sawlogs (11.6-17.5 in) 34 X 14.5 = 493

Large sawlogs (>17.5 in) 23 X 17.5 = 402.5

Total 115 (B) = 1276 (A)

Average DBH = A ÷ B

(A) 115 = 11.1

(B) 1276

Pre-Harvest

Average DBH (PRE)

Size Class

Post-Harvest

Tree Total

by size classes

Multiplier (Sum this column)

Sapling (3-5.5 in) 25 X 4.0 = 100

Poles (5.6-11.5 in) 33 X 8.5 = 280.5

Small sawlogs (11.6-17.5 in) 10 X 14.5 = 145

Large sawlogs (>17.5 in) 0 X 17.5 = 0

Total 65 (B) = 525.5 (A)

Average DBH = A ÷ B

(A) 65 = 8.1

(B) 525.5

Post-Harvest

Average DBH (POST)

Post-Harvest Diameter– Pre-Harvest Diameter

Pre-Harvest Diameter X 100 = Percent Change in Diameter

POST ( 8.1 ) – PRE ( 11.1 )

PRE ( 11.1 )

X 100 = -27
30

APPENDIX B

UNDERSTORY AND OVERSTORY TALLY SHEETS

Plot

1

Deer

Impact

(H/L)

7

Regen.

Adequate

2

Canopy

Density

(%)

3

Fern

(%)

4

Grasses/

Sedges

(%)

5

Woody 

Plants

(%)

6

Any

Interference

(Check)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

percent 

stocked

average 

percent

percent

≥ 30

percent

≥ 30

percent

≥ 30

percent 

with √

Stand
31

QUALITY (Q)

302928272625242322212019181716151413121110

987654321

 Species

Size Class 3 to 5.5 inches (saplings) 5.6 to 11.5 inches (poles) 11.6 to 17.5 inches (small saw) 17.6 inches or larger (large saw)Species CompositionSeed Source TotalResidual Quality

 Species Stand Summary Enter species into the size class columns by order of tolerance, most tolerant to the left 

and most intolerant to the right. Species Composition

Seed Source Total Priority Sp. Average Stand AverageSeed Source Average Acceptable Growing Stock (AGS) code as “+” and Unacceptable Growing Stock (UGS) 

code as “-”. Residual Quality

# AGS # UGS Stand Diameter (+ or -)

Before cut After cut Before cut After cut Remember to circle the code if the tree is marked or if the stand is unmarked and you 

plan to harvest the tree. Overall Stand Quality

12

345678

Owner: Date: Location: Stand:
32

APPENDIX C

TIMBER HARVESTING ASSESSMENT AND TREATMENT 

UNIT SUSTAINABILITY ASSESSMENT FORMS

Return to: Sustainable Forestry Initiative of Pennsylvania 

315 South Allen Street, #418, State College, PA 16801 

SUSTAINABLE FORESTRY INITIATIVE® OF PENNSYLVANIA 

TREATMENT UNIT SUSTAINABILITY ASSESSMENT FORM

Harvests may include multiple treatment units. For example, the harvest might include a 10-acre unit to 

release regeneration and a 40-acre stand improvement unit. A separate Treatment Unit Sustainability 

Assessment Forms (TUSAF) should be completed for each treatment unit. Attach all TUSAF forms to 

the single Timber Harvesting Assessment form for the area. (All detailed landowner, location and 

contractor information provided on the (TUSAF) form will be kept confidential by the SFI of PA office. Forms 

tallied for analytical purposes will be identified numerically and will not contain specific names or locations.) 

This form is for Unit # Harvesting Company ________________________

Township of Harvest 

_______ of _______ 

 TUSAF Assessor(s) ________________________ 

County of Harvest 

Total Harvest Acres 

Treatment Unit Acres 

% of Unit Harvested 

Dates of Harvest 

Assessment Date 

Product Destination ____________________ 

Landowner _______________________________ 

Person to contact for follow-up information or to 

schedule a site visit: 

Name: ___________________________________ 

Address: _________________________________ 

City, State, Zip: ____________________________ 

Phone: ___________________________________ 

E-mail: ___________________________________ 

 Signature: ____________________Date_______ 

1. Who developed the harvest recommendation and prescription? 

__ Landowner or Landowners family __Landowner’s Forester __ Buyer’s Forester 

__ Timber Harvester / Logger __ Timber Buyer __ Other __________________ 

2. What ownership category best describes the current owner? 

__ Private forest landowner owning ______ acres in PA. 

__ Industrial forest landowner 

__ Forest investment owner 

__ Municipal 

__ State 

__ Federal 

3. Is this harvest associated with conversion to non-forest use? 

__ Yes __ No If yes, what?______________________________________

Please refer to the diagram below when answering questions 4 and 5 for trees 6 inches DBH and larger. 

4. Estimate the percent summer canopy 

closure that best describes the unit 

prior to harvest? 

__ Greater than 75% __ 51 to 75% 

__ 26 to 50% __ Less than 25%

5. Estimate the percent summer canopy 

closure that best describes the unit 

after harvest? 

__ Greater than 75% __ 51 to 75% 

__ 26 to 50% __ Less than 25%
33

Return to: Sustainable Forestry Initiative of Pennsylvania 

315 South Allen Street, #418, State College, PA 16801 

6. How did the harvest affect the average tree diameter? 

__ The average diameter increased (many to most of the trees cut were smaller than the average tree 

size before harvest) 

__ The average diameter remained the same 

__ The average diameter decreased (many to most of the trees cut were larger than the average tree 

size before harvest) 

__ N/A overstory removed 

7. Did the harvest result in a change of timber quality in the residual stand? 

__ Timber quality improved (most of the trees cut were of below-average quality) 

__ Timber quality remained the same 

__ Timber quality decreased (a majority of the high-quality stems were removed or damaged during 

the harvest and lesser quality stems predominate in the remaining stand) 

__ N/A (overstory removal) 

8. How has the harvest affected the species composition of the overstory? 

__ The percent of medium to low value species decreased 

__The percent of medium to high value species decreased 

__ The percent species composition remained relatively unchanged. 

__ N/A (overstory removal) 

Answer questions 9 – 14 if the residual overstory canopy closure after harvest will be less than 50% 

(see question 5). 

9. Estimate the percent of the area stocked with advanced desirable seedlings (rooted in mineral soil) 

and vigorous saplings. 

__ Less than 10% _ 10 to 30% __ 31 to 50% __ 51 to 70% __ Greater than 70% 

10. Estimate the percent of the area covered with interfering plants including ferns, grasses/sedges, 

and/or woody non-commercial species (such as beech, black locust, fire cherry, striped maple, 

rhododenron, mountain laurel). 

__ Less than 10% __ 10 to 30% __ 31 to 50% __ 51 to 70% __ Greater than 70% 

11. Are the seedlings/saplings in question 9 overtopped by the interfering vegetation? 

__ On less than 10% of the area __ On 10 to 30% __ On 31 to 50% __ 51 to 70% __ On greater 

than 70% 

12. Is an interfering plant treatment that conserves seedlings planned in association with this harvest? 

__ Yes – Describe treatment and schedule _________________________________________ __ No 

13. What is the expected deer impact on regeneration in this treatment unit? 

__ High __Medium __ Low 

14. Is there a plan to mitigate deer impact? __ Yes __ No If yes, mark all that apply: 

__ Fence __ Fertilization __ DMAP (Additional Hunting) __ Other _______________________
34

FOREST STEWARDSHIP BULLETIN NO. 12 

Text reprinted with permission from Penn State College of Agricultural Sciences. 

Artwork reprinted with permission from Patrick Britten.

Forest Stewardship

Best Management Practices for Pennsylvania Forests

Best Management Practices (BMPs) for silvicultural activities in forested wetlands and 

for controlling erosion and sedimentation from timber harvesting operations have been 

established for Pennsylvania forests. (See references, pages 7 and 9.) The BMPs outlined 

in this bulletin supplement existing BMPs to benefi t a wider array of forest resources and 

values. They refl ect what we know today about ensuring forest sustainability.

A 48-page booklet, Best Management Practices for Pennsylvania Forests, includes additional 

information about Pennsylvania forests, ecological principles and processes, the role of 

timber harvesting, silvicultural practices, forest protection and health, and rules and 

regulations affecting timber harvesting activities. The booklet is available through the 

Pennsylvania Department of Conservation and Natural Resources (DCNR) Bureau of 

Forestry and Penn State Cooperative Extension.

This publication is written under the assumption that voluntary compliance with BMPs, 

reinforced with education, will serve all of us better in the long run, both economically 

and socially. In practical terms, voluntary compliance in implementing BMPs can 

help avoid the establishment of additional regulatory statutes, many of which can be 

burdensome, time consuming, costly, and not necessarily conducive to long-term forest 

health and productivity.

BMPs are universally accepted activities that have positive effects or minimize negative 

effects on the forest ecosystem. Their impacts can be limited to individual stands or 

spread over multiple ownerships.

Some BMPs are multipurpose. For example, buffer strips along streams designed to 

control sedimentation can also serve as wildlife travel corridors, result in habitat diversity, 

and maintain stream water temperature and nutrient levels.

BMPs must remain fl exible over time, to accommodate changes in the social, economic, 

and environmental contexts of forest resource use. Our education in this area must be 

ongoing.

The BMPs provide the basics—minimal acceptable standards—of good forest 

management, although some landowners may choose to do more. You will probably 
35

want to review the information in this publication with the natural resource professionals 

who help you manage your land.

The Best Management Practices that follow are divided into three areas of forest 

management: planning, forest operations, and forest values. Each forest resource 

management component includes an objective, the primary issue upon which the BMPs 

are based, considerations and concerns regarding the management component, and 

a checklist of BMPs that address those considerations and concerns. The checklist is 

provided in general terms. You can get detailed information from the publications listed 

at the end of each management component, under “For Additional Information.”

Definitions for italicized 

terms not explained 

within the text are 

provided in Forest 

Stewardship Bulletins 

No. 4 (Terminology)

and No. 7 (Timber 

Harvesting: An Essential 

Management Tool).

HIGH-GRADING

There is concern among all sectors of the forestry community that high-grading—the 

harvesting of only those trees that will give the highest immediate economic return—

may lead to a widespread decline in forest resource quality. Two practices, diameterlimit cutting and selective cutting, generally fall into this category. In diameter-limit 

cutting, all saleable trees above a certain diameter are harvested. Selective cutting 

usually removes the largest, most valuable trees and may leave large-diameter, poorquality, low-value trees. In each case, most of the trees that remain after the harvest 

are genetically inferior or physically defective. Neither method gives any thought to the 

composition of the future forest.

In even-aged forests such as those in Pennsylvania, smaller-diameter trees are not 

necessarily younger trees. It is more probable that these smaller trees are:

1. slow-growing species of the same age as different, fast-growing species;

 2. the same species of the same age but growing on an inferior microsite; or

 3. the same species of the same age but genetically inferior to their larger

 -diameter counterparts.

Because slower-growing and poor-quality trees are retained, high-grading 

diminishes the diversity and economic value of the future forest. Landowners may 

agree to high-grading because of a lack of knowledge about the practice and its 

undesirable consequences. High-grading also can be driven by short-term economic 

considerations. Immediate cash fl ow may be higher with high-grading, but potential 

environmental degradation and decreased future timber values will more than cancel 

the immediate cash advantage.

Stewardship requires that landowners consider the future consequences of highgrading when making a decision whether or not to accept the use of the practice on 

their land. Resource professionals and harvesters also have an obligation to look 

beyond the present when recommending forest management practices to landowners.
36

PLANNING

Objective:

To optimize short-term and 

long-term benefi ts of forest 

management activities through 

adequate planning.

Issue:

Management activities 

undertaken without planning 

can produce undesirable 

environmental, economic, and 

aesthetic consequences.

Considerations and concerns:

1. Many private landowners 

are not aware of the values available from their forestland.

2. Many private landowners do not defi ne what they want from their forestland.

3. Many private landowners do not involve resource professionals in forest 

management planning.

4. Forest management activities, particularly harvesting, are often undertaken for 

short-term gain, without thought for the forest’s future. 

BMPs:

1. Inventory resources on the property, including general plant-tree communities, 

water resources (streams, spring seeps—a class of wetland created by groundwater 

emerging in small pools surrounded by vegetation, wetlands, vernal ponds), 

soils, and unique areas (endangered, threatened, or rare species habitat, rock 

outcroppings, notable views).

a. Initially inventory at a level of detail necessary to address preliminary goals 

and objectives.

b. Later conduct a more detailed analysis to meet specifi c landowner 

operational needs, such as harvesting.

c. Be aware of how the resources on the property fi t in with the surrounding 

landscape.

2. Work with a natural resource professional to identify preliminary goals and 

objectives.

3. Mark and maintain property boundary lines.

4. Develop realistic goals and objectives based on the resource inventory and 

available landowner time and fi nances. Be as specifi c as possible when 

enumerating objectives (e.g., does “managing for wildlife” mean creating habitat 

for a wide variety of wildlife or concentrating on habitat requirements for one or 

two species).

5. Consider the effects of planned activities on surrounding properties.
37

6. Create a written management plan based on the resource inventory and 

landowner objectives. Include a map showing stands or management units and a 

timetable for completion of recommended activities.

For additional information:

Fajvan, Mary Ann. Pennsylvania Woodlands No. 9: Developing a Woodland Management 

Plan. College of Agricultural Sciences, Penn State Cooperative Extension, University 

Park, Pa.

Finley, James C. Pennsylvania Woodlands No. 3: Resource Evaluation. College of 

Agricultural Sciences, Penn State Cooperative Extension, University Park, Pa.

Harvey, Helene, and James C. Finley. Forest Stewardship Bulletin No. 6: Planning Your 

Forest’s Future. DCNR Bureau of Forestry, Harrisburg, Pa.

Jones, Stephen B., and Roe S. Cochran. Pennsylvania Woodlands No. 11: Managing Your 

Woodlot with the Help of a Consulting Forester. College of Agricultural Sciences, Penn 

State Cooperative Extension, University Park, Pa. 

FOREST OPERATIONS

Regeneration and Renewal

Objective:

To ensure that the forest of the future is a 

productive forest.

Issue:

Timber is being harvested without regard for 

forest regeneration and renewal (growth of a new 

forest plant community).

Considerations and concerns:

1. Pennsylvania’s forests are maturing; 

harvesting should lead to renewal.

2. Preharvest assessment of advanced 

regeneration and potential problems will 

minimize the possibility of regeneration failure.

3. Deer are having a major impact on forest regeneration.

4. Pennsylvania forests lack advanced regeneration of desirable species.

5. Once seed sources of desirable species are gone, it is diffi cult to reproduce a 

productive forest for the future.

BMPs:

1. Assess advanced regeneration, seed sources for postharvest regeneration, and 

potential stump and root sprouting.

2. Assess and, if necessary, control competing vegetation such as ferns, grasses, and 

other undesirable understory tree and shrub species.

3. Assess and, if necessary, control the potential loss of seed, seedlings, and sprouts 

to deer and other wildlife.
38

4. Provide for regeneration each time harvests are made under the uneven-aged 

system.

5. Consider the biological requirements of the species you want to regenerate, 

whether by natural reproduction or planting.

For additional information: 

Bihun, Yuri, James C. Finley, Stephen B. Jones, and Ellen Roane. Forest Stewardship 

Bulletin No. 7: Timber Harvesting: An Essential Tool of Forest Stewardship. DCNR 

Bureau of Forestry, Harrisburg, Pa.

Grace, James R. Pennsylvania Woodlands No. 8: Principles of Silviculture. College of 

Agricultural Sciences, Penn State Cooperative Extension, University Park, Pa.

Grace, James R. Pennsylvania Woodlands No. 10: Hardwood Management for Economic 

Return. College of Agricultural Sciences, Penn State Cooperative Extension, 

University Park, Pa.

FOREST OPERATIONS

Tending 

Stand—residual stand protection

Objective:

To minimize the negative impacts of management activities on vegetation remaining on 

the site.

Issue:

The stand that will remain after intermediate treatments is subject to damage or 

degradation during forest management operations.
39

Considerations and concerns:

1. Intermediate treatments should leave the forest in better condition than it was in 

before the activity was undertaken.

2. Careless operation of equipment results in damaged trees.

3. Proper planning can minimize the chances of damaging or degrading the 

residual stand.

BMPs:

1. Focus on protection of the residual stand rather than on the trees being 

removed.

2. During intermediate operations, retain seed source of species needed to achieve 

long-term management objectives.

3. Avoid intermediate cuttings that may increase interfering plant communities, 

such as grasses and ferns, or be prepared to treat interfering vegetation before the 

regeneration cut.

4. Design and lay out skid trails (trails, used to drag logs, that require less 

construction than skid roads because of less frequent use) and skid roads

(designed for frequent use by skidding equipment and usually incorporating 

water control structures) to minimize damage by avoiding residual trees and 

using bumper trees (trees left standing along skid trails and roads until the end of 

the harvesting operation) to protect them from skidding damage.

5. Exercise special care when harvesting trees during the growing season (usually 

between April and August), when residual trees are most susceptible to felling 

and skidding damage.

6. Identify and mark unique vegetation to be protected.

7. Ensure that a stand compatible with long-term management objectives remains 

after intermediate treatments. Instead of selecting for cutting, select for 

retention:

a. species adapted to the site

b. trees not likely to develop epicormic branching (branching that occurs after 

other branches have developed higher on the tree trunk) from exposure to 

increased sunlight

c. properly spaced trees

8. Avoid high-grading (see page 2).

For additional information:

Grace, James R. Pennsylvania Woodlands No. 10: Hardwood Management for Economic 

Return. College of Agricultural Sciences, Penn State Cooperative Extension, 

University Park, Pa.
40

FOREST OPERATIONS

Tending

Stand—insects, diseases, 

and fi re

Objective: 

To minimize the adverse 

effects of insects, diseases, 

and fi re on forest resources.

Issue:

Insects, diseases, and 

fi re can make it diffi cult 

to accomplish forest 

management goals and objectives.

Considerations and concerns:

1. Most landowners and some resource professionals fail to recognize the effects of 

insects and diseases on forests.

2. Proper management can minimize the impacts of insects and diseases.

3. Landowner objectives may have to be modifi ed to deal with insects and diseases.

BMPs:

1. Monitor insect and disease populations.

2. Take appropriate control measures when insects or diseases are likely to prevent 

the accomplishment of landowner goals and objectives.

3. Consider increasing species diversity, changing species composition, or changing 

stand structure to minimize susceptibility to insect and disease attack.

4. Maintain access roads to facilitate fi re control.

5. Consider a timber harvest to salvage dead and dying trees.

For additional information:

National Acid Precipitation Assessment Program. Diagnosing Injury to Eastern Forest 

Trees. USDA Forest Service, Forest Pest Management, Atlanta, Ga., and Penn State 

Department of Plant Pathology, University Park, Pa.
41

FOREST OPERATIONS

Tending

Site quality protection—productivity

Objective:

To protect the soil’s ability to sustain 

desired plant and animal communities.

Issue:

Operations at the wrong location and 

during inappropriate weather can damage 

soil structure and lower site quality.

Considerations and concerns:

1. Current equipment makes it 

possible to move large volumes of 

timber in all kinds of weather and soil conditions.

2. Careful removal of forest products can be the key to having a productive forest 

in the future.

3. Soil compaction inhibits regeneration.

4. Deep ruts can damage roots, which can lead to decay, stain, reduced growth, 

and mortality.

BMPs:

1. Minimize soil compaction and rutting by matching operating techniques, season 

of operation, and equipment to soil types and moisture levels.

2. Use soil surveys, topographic maps, and on-site evaluations as guides when 

planning log landing (area at end of a skid road where harvested timber is stored 

or prepared for transport), skid road, and haul road (road used by trucks to 

move harvested timber from the log landing to its destination) locations.

3. Modify landing and road locations to refl ect actual soil, parent material (rock 

from which soil is derived), and topographic conditions.

4. Keep the landing and road network at minimum size necessary to remove 

harvested timber effi ciently.

5. Do not contaminate soils with fuels, lubricants, and other chemicals.

For additional information:

Brown, Darlene B., ed. 1993. Best Management Practices for Silvicultural Activities in 

Pennsylvania’s Forest Wetlands. College of Agricultural Sciences, Penn State Cooperative 

Extension, University Park, Pa.

Department of Environmental Protection (DEP) Bureau of Land and Water 

Conservation, Cambria County Conservation District, and College of Agricultural 

Sciences, Penn State Cooperative Extension. Controlling Erosion and Sedimentation 

from Timber Harvesting Operations. 1992. College of Agricultural Sciences, Penn State 

Cooperative Extension, University Park, Pa.
42

FOREST OPERATIONS

Tending

Site quality protection—water resources

Objective: 

To minimize the movement of soil into water resources during forest management 

operations.

Issue: 

Erosion and sedimentation from forest management activities can affect water quality.

Considerations and concerns:

1. Operations that affect soil and water are regulated by law.

2. Small changes in the operation can eliminate many of the negative impacts.

3. Forested wetlands are often diffi cult to identify, especially during dry seasons.

BMPs:

1. Comply with all provisions of Chapter 102 and Chapter 105 of the Clean 

Streams Law and the Dam Safety and Encroachments Act, respectively.

2. Design roads to shed surface water quickly.

3. Design roads and landings to prevent or divert surface water fl ow.

4. Avoid locating roads and landings on seasonly wet soils (refers to wetlands that 

have water at or near the surface only during periods of abundant rainfall or 

snow melt).

5. Consider slope when laying out roads and landings.

6. Provide adequate riparian buffers between disturbed areas, such as roads or 

landings, and streams or wetlands.

7. Bridges and culverts are the preferred methods of crossing intermittent (not 

fl owing continuously throughout the year) and perennial (continuous fl ow) 

streams. When fords (shallow stream sections) are used for truck crossings, 

stabilize the bottom with clean rock.

8. Cross wetlands only when absolutely necessary.
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9. If forest operations necessitate taking heavy equipment into wetlands, conduct 

those operations, whenever possible, during the driest periods or when the wet 

area is solidly frozen.

10. Do not skid through water courses or spring seeps.

11. Do not contaminate water bodies and soil with forest management chemicals 

and petroleum products.

12. Retire the road network properly at the completion of operations.

For additional information:

Brown, Darlene B., ed. 1993. Best Management Practices for Silvicultural Activities in 

Pennsylvania’s Forest Wetlands. College of Agricultural Sciences, Penn State Cooperative 

Extension, University Park, Pa.

DEP Bureau of Land and Water Conservation, Cambria County Conservation District, 

and College of Agricultural Sciences, Penn State Cooperative Extension. Controlling 

Erosion and Sedimentation from Timber Harvesting Operations. 1992. College of 

Agricultural Sciences, Penn State Cooperative Extension, University Park, Pa.

FOREST VALUES

Aesthetic Considerations

Objective:

To minimize the adverse visual effects of harvesting 

and other forest management activities.

Issue:

Much of the opposition to forest management 

activities, particularly harvesting, is due to the 

changed physical appearance of the area.

Considerations and concerns:

1. Most landowners are concerned about the 

appearance of their property.

2. Acceptance of forest management activities by 

the general public is increased by having the 

job look good.

BMPs:

1. Cut all broken trees, leaners (trees tipped or 

dislodged during a harvesting operation), and badly scarred trees except where 

they are being retained for a specifi c purpose.

2. Locate landings away from public view.

3. Protect and release from competition trees with unusual shapes and colors.

4. Design cutting areas to take advantage of natural contours; avoid straight lines 

when possible.
44

5. Lop (cut up) tops of harvested trees near public roads, frequently used trails, 

recreational areas, and residential sites. (Note: This might increase the adverse 

impacts of deer on regeneration, because intact tree tops left behind help protect 

young growth.)

6. Use as much of the harvested wood as possible to minimize debris. (Note: This 

might reduce habitat for small mammals, reptiles, amphibians, and benefi cial 

insects.)

7. Clean up all refuse (man-made debris) daily.

8. Regrade and seed landings, using native grasses wherever possible.

9. Keep mud off public roads and out of streams.

10. Consider leaving a visual buffer along traveled roads.

For additional information:

Kendra, Angelina, and Ellen M. O’Donnell. Forest Stewardship Bulletin No. 8: Planning 

for Beauty and Enjoyment. DCNR Bureau of Forestry, Harrisburg, Pa.

FOREST VALUES

Understanding Wildlife Habitats

Objective:

To consider the impacts of forest 

management activities on wildlife 

resources and understand the 

trade-offs necessary to accomplish 

landowner goals and objectives.

Issue:

Forest management activities 

have positive and negative effects 

on wildlife resources.

Considerations and concerns:

1. Wildlife is important to 

landowners and the general 

public.

2. The effects of forest management activities on wildlife are often overlooked.

BMPs:

1. Inventory habitat features on the property, and be aware of their relationship to 

surrounding lands.

2. Protect sensitive habitats, such as spring seeps, vernal ponds, riparian zones, 

cliffs, caves, and rubble land (area with high content of large rock fragments).

3. Develop missing special habitats, such as evergreen cover, grape arbors, and 

herbaceous (nonwoody plants) openings, through planting, cutting, or other 

manipulations.
45

4. Protect cavity trees, snags, and food-producing shrubs and vines.

5. Maintain overhead shade along cold-water streams.

6. Use forest management activities to develop habitats required by species desired 

by the landowner.

For additional information:

Brooks, Robert P., Daniel A. Devlin, and Jerry Hassinger. 1994. Wetlands and Wildlife.

College of Agricultural Sciences, Penn State Cooperative Extension, University Park, 

Pa.

Devlin, Daniel, and Jack Payne. Pennsylvania Woodlands No. 6: Woodland Wildlife 

Management. College of Agricultural Sciences, Penn State Cooperative Extension, 

University Park, Pa.

Hassinger, Jerry, Lou Hoffman, Michael J. Puglisi, Terry D. Rader, and Robert G. 

Wingard. 1979. Woodlands and Wildlife. College of Agricultural Sciences, Penn State 

Cooperative Extension, University Park, Pa.

Hassinger, Jerry, and Jack Payne. Pennsylvania Woodlands No. 7: Dead Wood for Wildlife.

College of Agricultural Sciences, Penn State Cooperative Extension, University Park, 

Pa.

Sullivan, Kristi L., and Margaret C. Brittingham. Forest Stewardship Bulletin No. 5: 

Wildlife. DCNR Bureau of Forestry, Harrisburg, Pa.

FOREST VALUES

Species of Special Concern and Unique Habitats

Objective:

To recognize the importance and 

contribution of unique or special 

resources to the ecological integrity of 

the property and the Commonwealth.

Issue:

Unique areas and plant and animal 

species of special concern need to 

receive specifi c attention in forest 

management activities.

Considerations and concerns:

1. Landowners often are unaware of the existence of species of special concern or 

unique areas on their properties.

2. Many landowners would be willing to protect special resources on their 

properties if they had information and advice on what actions to take to protect 

them.

3. The loss of additional endangered, threatened, or rare species will diminish the 

biological wealth of our state.
46

BMPs:

1. Become aware of the presence of and protect endangered, threatened, and rare 

species’ habitats and unique habitat features.

2. Know the habitat requirements of endangered, threatened, and rare species on 

the property so that activities can be planned either to avoid disturbing or to 

enhance these habitats.

3. Keep in mind that plant habitats can be very small and specifi c. Learn to 

recognize these special microsites (small areas in which soil nutrients, water 

availability, sunlight, and other resources affect only one or a few trees and other 

plants).

4. Develop specifi c management plans for unique areas and habitats with the help 

of a resource professional.

For additional information:

McGuinness, Barbara J., ed. 1995. A Heritage for the 21st Century: Conserving 

Pennsylvania’s Native Biological Diversity. Pennsylvania Fish and Boat Commission, 

Harrisburg, Pa.

Pennsylvania Fish and Boat Commission and Pennsylvania Game Commission. 1985. 

Endangered and Threatened Species of Pennsylvania. Wild Resource Conservation 

Fund, Harrisburg, Pa.

REGULATIONS AFFECTING FOREST MANAGEMENT

Timber harvesting activities are subject to a number of federal, state, and local 

regulations. These include Section 404 of the Federal Water Pollution Control Act, 

Chapter 102 of Pennsylvania’s Clean Streams Law, Chapter 105 of Pennsylvania’s Dam 

Safety and Encroachments Act, Municipal Notifi cation of DEP Permit Application 

Submittal, and Pennsylvania’s Fish and Boat Code. The Pennsylvania Department 

of Environmental Protection can provide information about these regulations. 

Pennsylvania Department of Transportation (PennDOT) regulations that apply include 

Chapter 441, Access to and Occupancy of Highways by Driveways and Local Roads; 

and Chapter 189, Road Bonding Regulations.

In Pennsylvania, the Right to Practice Forestry Act and the Timber Trespass Law also 

apply. The DCNR Bureau of Forestry can familiarize you with these regulations, which 

were enacted to protect landowners and others involved with timber harvesting.

Most municipalities have regulations concerning zoning and land use. A growing 

number of municipalities also have regulations concerning earth moving, timber 

harvesting, and other activities associated with forest management. These regulations 

vary considerably from one municipality to another, so be sure to familiarize yourself 

with the laws in your area.
47

Visit Penn State’s College of Agricultural Sciences on the Web: http://www.cas.psu.edu

Penn State College of Agricultural Sciences research, extension, and resident education programs are funded in part 

by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.

This publication is available from the Publications Distribution Center, The Pennsylvania State University, 

112 Agricultural Administration Building, University Park, PA 16802. For information telephone (814) 

865-6713.

Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, 

in cooperation with the U.S. Department of Agriculture and the Pennsylvania Legislature. T. R. Alter, 

Director of Cooperative Extension, The Pennsylvania State University.

This publication is available in alternative media on request.

The Pennsylvania State University is committed to the policy that all persons shall have equal access to 

programs, facilities, admission, and employment without regard to personal characteristics not related to 

ability, performance, or qualifi cations as determined by University policy or by state or federal authorities. 

It is the policy of the University to maintain an academic and work environment free of discrimination, 

including harassment. The Pennsylvania State University prohibits discrimination and harassment 

against any person because of age, ancestry, color, disability or handicap, national origin, race, religious 

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© The Pennsylvania State University 1997

The Forest Stewardship Program is administered nationally by the USDA Forest Service 

and is directed in Pennsylvania by the DCNR Bureau of Forestry with assistance from a 

statewide steering committee. The Forest Stewardship Program assists forest landowners 

in better managing their forestlands by providing information, education, and technical 

assistance. For more information about program services and publications contact: The 

Pennsylvania Forest Stewardship Program, DCNR Bureau of Forestry, P.O. Box 8552, 

Harrisburg, PA 17105-8552. Phone: (800) 235-WISE, or (717) 787-2106. 

Prepared by Shelby E. Chunko, former stewardship project associate, School of Forest 

Resources, Penn State; and Wilbur Wolfe.

Cover Illustration by Doug Pifer. Illustrations on pages 3 thru 11 by Patrick Britten.

CAT UH102 R7.5M7/01ps4191
Printed on Recycled Paper

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on 

the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial 

status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because 

all or part of an individual’s income is derived from any public assistance program (Not all prohibited 

bases apply to all programs.) Persons with disabilities who require alternate means for communication 

of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 

(202) 720-2600 (voice and TDD). To fi le a complaint of discrimination, write to USDA, Director, Offi ce 

of Civil Rights, 1400 Independence Avenue, S.W., Washington, DC 20250-9410, or call (800)795-3272 

(voice) or (202)720-6382 (TDD). USDA is an equal opportunity provider and employer. 

Finley, James C.; Stout, Susan L.; Pierson, Timothy G.; McGuinness, Barbara J. 

2007. Managing timber to promote sustainable forests: a second-level 

course for the Sustainable Forestry Initiative of Pennsylvania. Gen. Tech. 

Rep. NRS-11. Newtown Square, PA: U.S. Department of Agriculture, Forest 

Service, Northern Research Station. 47 p.

At least 80 percent of the raw material used for wood products by the forest 

industry is from privately owned woodlands. This publication provides material for 

a course designed to help landowners, foresters, and loggers work together to 

assess whether a planned timber harvest will retain the diversity of species on site. 

It includes methods for collecting overstory and understory data, inspecting these 

data, and assessing sustainability.
www.nrs.fs.fed.us

Capitalizing on the strengths of existing science 

capacity in the Northeast and Midwest to attain a more 

integrated, cohesive, landscape-scale research program