United StatesDepartment ofAgriculture

Forest Service

NortheasternResearch Station

Resource Bulletin NE-163

Forests of the Garden State

Richard H. Widmann

Published by: For additional copies:

USDA FOREST SERVICE USDA Forest Service11 CAMPUS BLVD SUITE 200 Publications DistributionNEWTOWN SQUARE PA 19073-3294 359 Main Road

Delaware, OH 43015-8640May 2005 Fax: (740)368-0152

Visit our homepage at: http://www.fs.fed.us/ne

AcknowledgmentI thank the New Jersey Department of Environmental Protection, Division of Parks andForestry, for its cooperation and assistance, Jon Klischies for helpful comments andsuggestions in reviewing an earlier draft of this report, and NE-FIA staff members Douglas M.Griffith, Tonya W. Lister, Andrew J. Lister, and Eric H. Wharton, whose contributions wereinvaluable.

AuthorRICHARD H. WIDMANN is a forester with the Northeastern Research Station’s ForestInventory and Analysis unit at Newtown Square, Pennsylvania (www.fs.fed.us/ne/fia).

Manuscript received for publication 8 October 2004

1

Preface

New Jersey’s forests, a critical component of the State’s natural resources,have been rich in history from colonial settlement to the present. In theNation’s most densely populated state, forests cover 45 percent of New Jersey’sland mass and differ greatly in character from the coastal plain to the highlandsregion. These highly diverse forests provide globally significant biologicalcommunities, habitat for wildlife, forestry products, water quality, andopportunities for recreational. Although population growth and expansioninto the rural environment have placed increased pressure on the State’s forests,management professionals with the New Jersey Department of EnvironmentalProtection’s Forest Service continue to protect this valuable natural resourceand provide sound stewardship to ensure that the broad range of benefitsderived from these forests will be available to future generations.

2

Forests of the Garden StateLong known as the Garden State, New Jersey also isnoted for lots of people, congested roads, suburbansprawl, and industrial development, all which havechanged the character of the State over the last halfcentury. Despite this change, much of the Garden Stateis forested —more than one might think. Like a garden,a forest produces valuable products and related benefitsthat must be tended and protected. Looking after thisimportant resource requires a knowledge of current forestconditions and trends. To obtain this information, theUSDA Forest Service periodically inventories theNation’s forests. In 1998, in cooperation with the NewJersey Department of Environmental Protection,Division of Parks and Forestry, researchers with theNortheastern Research Station’s Forest Inventory andAnalysis (FIA) unit completed the fourth survey of NewJersey’s forests. This report summarizes the findings ofthe most current and previous inventories (1956, 1972,and 1987), as well as major changes that have occurredin the State’s forests.

Historical PerspectiveSettlers arriving in what is now New Jersey more than300 years ago followed the waters inland and wereconfronted with dense forests. Along the coastal plain tothe south, there were extensive forests of pines and thickstands of Atlantic white-cedar. The settlers alsoencountered huge hardwood forests along the DelawareRiver, and vast forested hills and mountains in thenorthern region. The Native Americans who lived herehad barely disturbed these forests; but the settlers--Dutch, Swedes, and English--needed land for farms andtowns as well as wood to build houses and for itemsranging from implements and fuel to pine tar, pitch, andtimber for ships. And a growing population demandedthat increasing amounts of land be cleared for growingcrops and for pasture. So forests fell in New Jersey. By1860, many stands had been cut over many times—yetthe cutting continued. Of course, some timber remainedand new growth responded in cutover areas, but by theCivil War, lumber production peaked in the State as treefelling declined because of an ever dwindling supply. Innorthern New Jersey, residents began to use coal fromPennsylvania to heat their homes as firewood became

more difficult to obtain. And in Philadelphia, buildersobtained shingles from Maine to offset the scarcity ofcedar. Fire that often followed timber cutting also slowedthe natural recovery of New Jersey’s forests.

Today, forests now cover much of the State due to thesharp decrease in wood harvests beginning around 1860along with a corresponding decrease in the amount ofacreage farmed. This recovery was aided by the rise of aconservation ethic that began in the late 1800’s. Given achance to grow under sound management, trees becamereestablished naturally and relatively quickly in mostregions of New Jersey. Efforts to control wildfires andlow populations of white-tailed deer greatly facilitatedthis regeneration process.

Jersey’s residents have changed in how they look at andvalue forests. Originally, forests were seen as barriers toprogress and needed to be cleared for settlement to occur.Timber products, fuelwood, and wild game were themajor benefits received from the forest. Although theseremain important, today’s forest is valued andappreciated for amenities that enhance the quality of life:watershed protection, opportunities for recreation,conservation of wildlife habitat, diverse landscapes, andscenic beauty.

About Forest InventoriesWidespread abuse of land in the Eastern United Statesled to the passage by Congress of conservation legislation

Forest Inventory and Analysis field crews receive permission fromprivate landowners before taking tree measurements on their land.

3

in the early part of the 20th century. Under this andsubsequent Acts, the Forest Service’s FIA units initiatedongoing forest surveys of all states to provide currentdata about the Nation’s forest resources. FIA providesobjective and scientifically credible information on keyforest ecosystem processes, for example, the amount offorest land and whether it is increasing or decreasing inarea, changes in species composition, and the rate atwhich trees are growing, dying, or being harvested. Suchdata are invaluable to numerous users because they:

• Help policymakers at both the federal and statelevel revise existing forest-management policies andformulate new ones, and enable land managers tobetter assess the effects of current and pastmanagement practices.

• Serve as a starting point for a variety of scientificinvestigations of processes by which forestecosystems change over time.

• Keep the public informed as to the current healthand sustainability of the Nation’s forests.

• Address important resource issues such asurbanization, forest fragmentation, invasive pestspecies, wildfire risk, global climate change, andwater quality.

FIA did not count every tree in inventorying NewJersey’s forests. Instead, it used a scientifically designedsampling method. First, photointerpreters studied aerialphotographs of the entire State. Then a grid of 17,000points was overlaid on the photos. Each of the pointswas classified as to land use and, if forested, the size ofthe trees. For New Jersey, a sample of 433 plots was

selected for measurement. Included were plotsestablished during previous inventories. By remeasuringthese plots, data were obtained on how individual treesgrow. Some plots that had been established nearly 50years ago were measured for the fourth time. Field crewscollected information on a host of forest attributes,including the number, size, and species of trees. Thesedata enabled FIA researchers to make reliable estimatesof the current condition and overall health of NewJersey’s forests, as well as the degree to which this vitalresource is changing over time.

Land Use and Forest CoverExtent of and Trends in Forest-Land Area

Forests cover 45 percent of New Jersey, or 2.1 millionacres. This amount of forest cover is remarkable for astate that has seen tremendous population growth andeconomic development during the last decade. TheState’s forest land has remained relatively stable because

most of the population growth historically hasbeen concentrated in areas adjacent to New YorkCity, and because there has been a decrease in farmland. Land in farms is now less than half of what itwas in 1956— a loss of more than a million acres.Although much of what formerly was farm landhas been developed, a substantial portion has beenleft untended and has reverted to forest throughnatural regeneration. These new forests havenegated losses in forest to development.

Land Use in New Jersey

Forest land45%

Farm land14%

Other nonforest land

41%

Trend in New Jersey's Farm Acreage

0

0.5

1

1.5

2

2.5

1899 1950 1960 1970 1980 1990 2000

Year

Mill

ions

of A

cres

Source: USDA National Agriculture Statistices Service

4

In addition, New Jersey is a national leaderin protecting land by regulatory legislation.State planning has attempted to balance theneed to conserve natural resources with thedemands of a growing economy bypromoting sustainable development.Conservation efforts to keep land in forests,farms, and other green space include bothpurchases of land and easements by theState and nongovernmental organizations.Conservation easements restrict futuredevelopment while leaving the responsibility formanagement and ownership in private hands. Bymanaging growth wisely, the adverse impacts of urbansprawl can be minimized in New Jersey. Still, despitethese conservation efforts, a steady decline in forest-landarea is likely throughout the State due to continuedpressure placed on forests and farm land fromdevelopment.

The 1999 FIA forest inventory revealed that forest landin New Jersey increased by 143,900 acres since the 1987survey. This increase is attributed to the use of a moreinclusive definition of forest land. Small forested areas inrights-of-way and in certain urban areas that previouslywere classified as nonforest were reclassified as forest.These areas are at least an acre in size, more than 120 feetwide, and stocked with trees. This change in inventoryprocedure was required because the value of all forestland is increasingly being recognized. Otherwise, therehas been little change in the total forest land area in theState since the 1987 inventory. A separate survey by theNational Resources Conservation Service showed adecrease in nonfederal rural forest land in New Jerseyfrom 1987 to 1997.

Forest land is categorized by the Forest Service astimberland or “other” forest land. These categories aid inunderstanding the availability of forest resources andforest management planning. Although New Jersey is notconsidered a timber-producing state, 88 percent of itsforest land (nearly 1.9 million acres) is classified astimberland that is potentially available for harvesting.

The amount of timberland has not changed appreciablyduring the last three decades even though New Jersey’spopulation increased by 15 percent (1.2 million) between1970 and 2000.

The other category of forest land includes reserved landsand unproductive forests. Harvesting for timber productson these lands is administratively restricted oreconomically impractical. Examples include parks,wildlife management areas, and wetlands where growingconditions are poor. Most of these forests are owned bypublic agencies. This category increased in area by nearly150,000 acres (to 256,100) from 1956 to 1999. Nearlyall of this increase is attributed to the reclassification oftimberland to reserve status where timber harvesting isrestricted.

Distribution of Forest LandForested areas are not distributed evenly across the State.Sussex County is the most heavily forested (68 percent);Essex, Hudson, and Union Counties are the leastforested. Generally, forests are concentrated in thenorthernmost portion of the State and in the PineBarrens in Atlantic, Burlington, and Ocean, Counties inthe south. Portions of the Pine Barrens also extend intothe less forested counties of Camden, Cumberland, CapeMay, and Gloucester.

Forest-land Area Trends

0

0.5

1

1.5

2

2.5

1860 1899 1956 1972 1987 1999

Year

Mil

lio

n A

cre

s

Timberland Other Forest Land

2.2

1.9 2.02.1

5

People and ForestsUrban ForestsAs the population of the Garden State continues togrow, the State’s forests are becoming moreurbanized. Urban forests are valued because theycreate more livable cities and towns, but frequentlytheir value as habitat for wildlife and for ensuringbiodiversity is impaired. The extent of urbanizationcan be depicted as a range of population densities.The urbanization map shows forest land by thepopulation per square mile of the census block inwhich it occurs. The highest population densitiesare in those areas designated as urban by the U.S.Census Bureau. In addition to these designatedurban areas, all forests in New Jersey are influencedby urbanization to some extent. In many instances,forests in areas with dense populations are on landthat was initially rejected for development becausethe terrain was too wet, steep, or rocky. However, due to high prices forbuilding lots and advanced building techniques, nearly all land ispotentially suitable for development. Conservation efforts are focusing onidentifying and preserving the most ecologically important of these urbanforests. Areas with low population densities correspond to those with largepublic ownerships; Wharton State Forest in the south and Stokes andWorthington State Forests in the northwest portion of the State.

Trend in New Jersey's Population

0

2

4

6

8

10

1900 1920 1940 1960 1980 2000

Census Year

Mil

lio

ns

of

Peo

ple

Source: U.S. Census Bureau

Major changes currently affecting New Jersey’s forests are the result of people:it is people who decide where to clear land for houses and people whointentionally or unintentionally allow land to revert to forest. Absent people,nearly all of the State would be forested—but New Jersey’s population is nearly8.5 million and growing. How these people live on the land is a significant forcein shaping the forest. New Jersey is the Nation’s most densely populated state,yet it ranks ninth in the percentage of land area covered by forest.

6

Fragmentation is DegradingForest Habitats

When a large portion of a forest is lost to newresidential and urban development, the remainingforest land often is broken up into smaller tractsor noncontiguous patches. Known as forestfragmentation, this phenomenon is of growingconcern to land managers and plannersthroughout the Northeastern United States. Thefragmentation of forests, particularly by urbanuses, degrades watersheds, reduces wildlifehabitat, increases site disturbances, and favorsinvasion by exotic plant species. Many wildlifebiologists believe that fragmentation is acontributing factor in the decline of some bird andwildlife species, though fragmentation favors speciessuch as raccoons, squirrels, and white-tailed deer.These species are habitat generalists that havebecome acclimated to living near humans.Fragmentation also changes the character of ruralareas because unlike owners of large tracts, ownersof small parcels are less likely to manage theirforests and/or allow access to their land for activitiessuch as fishing and hunting.

Forest Service scientists are attempting tocharacterize the distribution and fragmentation offorest land in New Jersey. One way to accomplishthis is to determine the size of these forest patchsand their frequency. The State contains numerouspatches that are 1 to 5 hectares (2.5 to 12.4 acres),but they represent only 5 percent of the total forestland. Three-quarters of New Jersey’s forest land is inpatches that exceed 100 hectares (247 acres). Thelargest patch, 5,726 hectares (14,149 acres), is inWarren County.

Forest Fragmentation

0

10

20

30

40

1-5 5-10 10-50 50-100100-500

500-1000 1000-50000

Patch Size Classes (hectares)

Par

cels

(th

ou

san

ds)

0

100

200

300

400

Are

a (t

ho

usa

nd

s o

f h

ecta

res)

Number of patches Total area in class

(1 hectare=2.47 acres)

Forest land depicted as a range of population densities with Census-designated urban overlain.

Urbanization of forest Land in New Jersey

Nonforest01-2525-5050-100100-250250-500500-1000>1000Urban area

Forested People/sq mi

Forest land depicted as a range of population densities with Census-designated urban overlain.

Urbanization of forest Land in New Jersey

Nonforest01-2525-5050-100100-250250-500500-1000>1000Urban area

Forested People/sq mi

Nonforest01-2525-5050-100100-250250-500500-1000>1000Urban area

Forested People/sq mi

High deer populations change the amount and composition offorest regeneration. They eat suburban landscaping and causehigh numbers of traffic accidents in many areas of New Jersey.

7

Average Forest Patch Size

Monmouth30 ac.

Morris61 ac.

Warren

50 ac.

PassaicBergenEssexHudsonUnion

33 ac.

SomersetMiddlesexMercer

25 ac.33 ac.

Hunterdon

Ocean64 ac.

Burlington

55 ac.

CamdenGloucester

31 ac.

Salem27 ac.

Cumberland38 ac. Atlantic

Cape May 53 ac.

Sussex81 ac.

Who Owns the Forest?New Jersey has the highest percentage of forestland in public ownership of any state east of theMississippi River. But unlike many western states, the Garden State has no NationalForests and little forest land in federal ownerships. The State owns more than500,000 acres of forest land—the largest ownership in New Jersey. However, thiswas not always the case. Because of public demand for recreation and clean waterand a desire to keep parts of New Jersey undeveloped, State and local municipalitieshave been purchasing forest land and other open space. As a result, during the lasthalf century, public ownership of forest land has more thandoubled to 810,000 acres, increasing from 29 to 38 percent offorest land from 1987 to 1999. New Jersey is a leader inkeeping land undeveloped for future generations to enjoy.Despite these increases in public ownership, the responsibilityfor managing the majority (62 percent) of New Jersey’s forestland is in the hands of a large number of private owners.Recent estimates show that there are 89,000 forest-land ownersin the State and their numbers are growing rapidly. They arerepresented by individuals, farmers, and corporations,including private land trusts. The reason for the rise in thenumbers of forest-land owners is that large ownerships arebeing subdivided into smaller parcels to accommodatedevelopment. Owners have a wide range of reasons for owningland and diverse objectives in land management. Land trusts,whose holdings are increasing, work to keep land in forest by buying it outright oracquiring conservation easements that place restrictions on future use.

Development not only takes land out of forest but fragmentsthe remaining forest habitat into small patches.

Distribution of Forest Land Area by Ownership

County and Municipal

8%

Farmer2%Corporate

23%

State25%

Federal5%

Individual37%

8

Forest Structure and Composition Change Over TimeAs forests mature, the species composition at a particular site undergoes what ecologists callforest succession. During this process, long-lived plants that can tolerate shaded conditionsreplace short-lived plants that need full sunlight to thrive. This continuous process isinfluenced by disturbances from natural as well as human sources. Examples of disturbanceoccurring in New Jersey’s forests include drought, fires, outbreaks insect pests such as thegypsy moth caterpillars, land clearing followed by abandonment, and logging. Theinteraction of these and other factors working over time have shaped the State’s diverse forestresource. An understanding of the changes taking place in New Jersey’s forest is helpful infully appreciating this valuable resource and in making wise decisions regarding its future.

New Jersey’s Forests Are MaturingMany of the changes occurring in New Jersey’s forests areassociated with their age and maturation. Across theNortheastern States, forests are maturing as they recover frompast land clearing and abuse. In the Garden State, many acresof forest land are abandoned farm lands that have naturallyreverted to forest since the 1940’s. Two-thirds of New Jersey’sforests are younger than 60 years old. Because fewer acres ofland are being allowed to revert, acreage in young stands willdecrease. And once they mature, these stands will not bereplaced. Maintaining forests that are well distributed acrossage classes enhances the biodiversity of the landscape andreduces the susceptibility to catastrophic damage.

Trees Have Increased in Size and Number

How well forests are populated with trees is determined by measures of tree size and number.Foresters measure a tree at its diameters at 4½ feet above the ground and refer to this as

Age Distribution of New Jersey Forests, 1999

0

10

20

30

40

0-20 21-40 41-60 61-80 81-100 100+

Age Class of Overstory Trees (years)

Per

cent

age

of F

ores

t Lan

d

Public ownership of forest land providesrecreational opportunities, protects watersupplies, and preserves ecological values.

9

diameter at breast height (d.b.h.). Of trees 5 inchesand larger in diameter, the average d.b.h. hasincreased from 8.2 to 8.9 inches since 1972.During this period, the average number of trees atleast 5 inches in diameter has increased from 119to 161 per acre of timberland. Combined, thesemeasures indicate that tree density has increased inNew Jersey.

Forest CompositionChanges in the numbers of trees have not beendistributed evenly across diameter classes. Since1972, the numbers of saplings has decreased whilethe numbers of trees in all diameter classes above 5inches has increased. Combined, trees in the 2- and 4-inch diameter classes account for 70 percent of the treesat least 1 inch in d.b.h. Trees in the 6-, 8-, and 10-inchclasses account for 24 percent; all trees 12 inches orlarger account for 6 percent. The number of small treesdeclines as forests mature because the subsequent lack ofsunlight reaching the forest floor inhibits thereproduction and growth of seedlings.

When describing a forest, people speak of the species oftrees growing there, e.g., a pine, oak, or beech forest.Foresters use the term forest type to describe groups ofspecies that are frequently found growing in associationwith one another. The 1999 inventory identified 36forest types growing in the State.

Located primarily in the State’s pinelands region and freshwaterwetlands, Atlantic white-cedar swamps are essential storage areasfor rainwater and water runoff. They help maintain productivity ofwetland communities, provide essential habitat for wildlife andplant life, including threatened and endangered species, and addto the diversity and beauty of New Jersey’s forest resource.

Pitch pine is the dominate tree in the pinelands of southern NewJersey.

The New Jersey Forest Fire Service puts out most wildfires beforethey can threaten communities and structures. Forests in the PineBarrens are adapted to disturbance from fires and recover with time.

Courtesy of New Jersey Division of Parks and Forestry - New Jersey Forest Service

Average Number of Trees Per Acre and Average Diameter

(Trees 5 Inches and Greater d.b.h.)

119

143

161

8.28.6

8.9

0

40

80

120

160

1972 1987 1999

Year

Tre

es P

er

Acre

(nu

mb

ers

)

0

2

4

6

8

10

Dia

mete

r at

Bre

ast

Heig

ht

(in

ch

es)

Average trees/acre Average dbh

10

Similar forest types are combined into forest-type groups.Oak/hickory, the most common such group in the State,consists of well-known species such as white oak, northernred oak, hickory species, white ash, walnut, yellow-poplar,and red maple. The oak/hickory group covers two-thirds ofNew Jersey’s forests. The pitch pine type, which is in theloblolly/shortleaf pine group, and the oak/pine group growin the Pine Barrens in the southern part of the State. Thisarea has a long history of wildfires, which promotes thegrowth of pine. Included in the oak/gum/cypress group are32,000 acres of Atlantic white-cedar stands. Althoughcovering too small an area to be captured by this inventory,some native red spruce grows in the extreme northwestportion of the State. These broad species groups, which havechanged little in area since 1989, are another reflection of thediversity of New Jersey’s forests.

The 1999 inventory also identified 77 species of trees,including many that are uncommon. Red maple, the mostnumerous species among trees less than 5 inches in diameter,is found to some extent in every forest-type group. Pitchpine is the most numerous species in the 6- to 10-inchdiameter classes, while all oak species combinedoutnumber pitch pine and red maple trees in diameterclasses above 12 inches.

The 10 most common species listed in theaccompanying chart account for 79 percent of the totalcubic-foot volume of trees in the State. Cubic-footvolume is a measure of the amount of wood in the boleof a tree between a 1-foot stump and a 4-inch topdiameter. Pitch pine remained the leading species byvolume, followed by red maple. However, red mapleshowed the largest increase in volume and likely willovertake pitch pine in terms of volume in the near future.Together, oak species represent 29 percent of the totalvolume of live trees at least 5 inches in d.b.h. Individualspecies are distributed by how well they are suited toparticular site conditions. In addition to the factorsmentioned, the numbers and types of animals present alsoaffect species distribution. Deer, mice, and squirrelsinfluence forest composition by browsing seedlings,consuming available seeds of preferred species, and storingseeds that later geminate. For example, deer prefer tobrowse oak rather than red maple and yellow-poplarseedlings.

0

10

20

30

40

50

60

70

80

6 8 10 12 14 16 18 20

Oaks

Pitch pine

Red maple

Number of Trees for Selected Species, 1999

Diameter Class (inches at breast height)

0

20

40

60

80

100

120

140

160

180

200

2 4

Mill

ions

of T

rees

Volume of Live Trees Greater Than 5 Inches d.b.h.

0 100 200 300 400 500

Atlantic white-cedar

Sweetgum

Other white oaks*

Ash

White oak

Northern red oak

Yellow-poplar

Other red oaks

Red maple

Pitch pine

Spe

cies

Million cubic feet

1987

1999

+47%

+33%

+1%

+66%

+47%

-1%

+13%

+13%

+8%

+15%

* Includes chestnut and post oak.

Area of Timberland by Forest-type Group

0

200

400

600

800

1000

Oak/H

icko

ry

Loblo

lly/S

hortle

af

Oak/P

ine

North

ern H

ardw

oods

Elm/A

sh/R

ed M

aple

Oak/G

um/Cyp

ress

Aspen

/birc

h

Th

ou

san

ds

of

Acr

es

1987

1999

0

20

40

60

80

100

120

140

6 8 10 12 14 16 18 20

1972

1987

1999

Number of Trees by Diameter Class

Diameter class (inches at breast height)

0

100

200

300

400

500

600

700

2 4

Mill

ions

of T

rees

11

Relative Importance of Five Common Tree Species Across New Jersey

Pitch Pine Red Maple White Oak

Northern Red Oak Other oaks

Relative Importance

Low

Moderate

High

Very high

Nonforest

How were these maps created?The inventory plots were used as known data. Then the values at unknown locations were predicted frominformation from those plots. For example, an unknown area near a group of plots with large amounts ofpitch pine probably has high amounts of pitch pine as well. Using this principle, we made predictions atevery location on the map. The values of relative importance are the percentage of a stand’s stockingthat is composed of that species. The categories used are low (less than 5 percent of a stand’s basalarea), moderate ( 5-19 percent), high (20-49 percent), and very high (50 percent or greater). Stand basalarea is the total cross-sectional area of trees at breast height--usually calculated as square feet per acre.

12

Red maple grows abundantly throughout New Jerseyexcept in the Pine Barrens, where wildfires have keptpopulations of this fire-susceptible species low andrestricted its distribution to wet areas. In the dry, sandysoils of the Pine Barrens, pitch pine flourishes and isfrequently found growing with blackjack and scarlet oakand a dense shrub layer of huckleberry and blueberry. Aswith many of the plants that grow here, pine and oakspecies are able to survive and reproduce after firesbecause of their thick bark and ability to sprout fromstumps when the tree bole is killed. In addition, fire isthe mechanism that causes the cones of pitch pine toopen and release their seeds.

Shrubs

Understory vegetation is an important component offorested habitats because it provides both food and coverfor wildlife. Huckleberry and blueberry are the mostcommon shrub species in New Jersey. Barberry, a

Huckleberry and blueberry are the most abundant shrub in New Jersey’sforests, turning a bright red in the fall.

nonnative plant that invades natural plant communities,is the eleventh most common shrub growing in theState’s forests. High deer populations contribute to thespread of barberry because it is browsed infrequently.

Huckleberry 24,323

Blueberry 12,802

Sweet pepperbush 4,550

Sheep laurel 2,055

Rose 1,087

Briers/Brambles 930

Common spicebush 894

Mountain laurel 736

Maple-leaf viburnum 573

Maleberry/Staggerbush 506

Barberry 443

Fetterbush 277

Top 12 shrub species in New Jersey (Millions of stems)

13

The Changing Face ofNew Jersey’s Forest HabitatThe types and number of wildlife species thatinhabit a forest change as it matures. In theseedling-sapling stage that follows majordisturbances such as clearcutting, fire, and landabandonment, many wildlife species use low-growing herbaceous and shrub vegetation.Species that prefer this type of habitat includethe American goldfinch, cedar waxwing, songsparrow, and eastern cottontail. As larger treesbecome established and shade out much of thelow-growing vegetation, species that depend onthis early pioneer vegetation decline in numberas others that use the boles of trees move intothe area. This intermediate stage corresponds tothe poletimber-size class. Many poletimberstands lack the low-growing vegetation of theregeneration stage and the tree boles lack thebark flaps, cavities, and other bolecharacteristics that develop as a stand matures.As a result, the number of species present is lowbetween the dense thicket vegetation of theregeneration stage and the mature orsawtimber-size class, which is dominated bylarge trees. The number of species reaches amaximum in mature, overmature and all-agestands. Species that are more likely to inhabitmature stands include the black bear,porcupine, and pileated woodpecker.

In New Jersey, the area in the regenerating or seedling-sapling stage has decreased because less farm land isbeing allowed to revert to forest. Conversely, the area inthe mature or sawtimber-size trees has increased becauselow rates of harvesting have contributed to thecontinued growth and maturation of the forest. Thesechanges have been accompanied by a remarkablerecovery and return of many woodland species duringthe last century. Population increases have been noted forbeaver, black bear, white-tailed deer, and wild turkeys.

Wildlife populations are dependent on the quality of theforest habitat. Habitat characteristics that increase asstands mature include the size of mast-producing treesand the number of standing dead and cull trees. Beech,

Change in Stand-size Class on Timberlandand Percentage of Total

0

200

400

600

800

1000

1200

Sapling-Seedling-

Poletimber Sawtimber

Thou

sand

s of

Acr

es

1972 1987 1999

54%

24%

13%21%

39% 37%

25%

37%

50%

New Jersey’s forests are maturing. On half of the forest land, sawtimber-size treesare the dominate vegetation.

14

hickory, and the oaks are important mast-producing species. Hard mast such asnuts and hard seeds produced by overstory trees is an important forage resourcefor wildlife. Species that depend on acorns and other hard mast include theblack bear, blue jay, chipmunk, gray fox, red-headed woodpecker, ruffedgrouse, squirrel, striped skunk, white-tailed deer, and wild turkey. The amountof mast produced increases as trees become larger, so it can be assumed thatmast production has increased in New Jersey with the increase in the numberof large diameter beech, hickory, and oak. Since 1987, the number of oak andbeech trees 11 inches and larger in diameter has increased by 26 and 23percent, respectively.

Standing-dead and cull trees are important feeding and nesting sites forwildlife. These trees have a higher probability of being used by primary cavitynesters such as woodpeckers as their wood is more easilyexcavated. These and natural cavities caused by disease or injuryare used as resting or nesting sites by various species of birds andsmall mammals. In New Jersey, 8 percent of all standing treesmore than 5 inches in d.b.h. are dead. On average, there are 15dead trees 5.0 inches or larger in diameter per acre of timberland.A third of the dead trees are species of oak.

Cull trees, which also are important to wildlife, exceedmaximum allowances for defects for use as timber products. Yetsome of the same characteristics that make these trees undesirablefor timber products are beneficial to wildlife. Examples includecavities, broken tops, pockets of rot, and boles with numerousforks and limbs. On average, there are 16 cull trees per acre of timberland.

Number of Dead and Cull Trees Per Acre

0

5

10

15

5.0-10.9 11.0-14.9 15+

Diameter (inches at breast height)

Nu

mb

er o

f tr

ees

per

acr

e

Dead

Cull

Land reverting to forest from abandon farmland offsets forest land lost to development.Only a small portion of New Jersey’s forestland is covered with early successionalseedling/sapling stands.

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Biomass

Trees play an important role in the world’s carbon cycle.They act as a sink for carbon, removing it from theatmosphere in the form of carbon dioxide (a greenhousegas) and storing it as cellulose. In this role, forests helpmitigate the effect of burning fossil fuels and theresulting global climate change associated with increasedlevels of carbon dioxide in the atmosphere. In NewJersey, because of increases in tree volume, the State’sforests contribute greatly to the sequestration of carbon.

Woody biomass, a measure of how much carbon is beingstored on forest land, is the total weight of both live anddead trees, including branches, roots, and stumps, plusthe weight of shrubs. The total dry weight of all biomasson New Jersey’s timberland equals 135 million tons or 83tons per acre. The largest portion of this amount (55percent) is contained in the merchantable boles ofcommercially important trees. It is this component thatcan be converted to high-value wood products. Otherportions of biomass are underutilized and can beconsidered as a potential source of fuel for commercialpower generation. Because it is a renewable source ofenergy, biomass could help reduce the Nation’sdependence on fossil fuels. In some regions of thecountry, the use of biomass to fuel commercial powergenerating plants has provided markets for low-gradetrees and other waste wood.

Sustainability and Use of New Jersey’sForestsWell-tended forests supply a continuous flow of productswithout impairing long-term productivity. Unlike coaland oil, forests are alive and renewable. One way to judgethe sustainability of a forest is to look at the componentsof inventory change—growth, removals, and mortality.

During the last 50 years, the growth of New Jersey’sforest resource has greatly outpaced losses due to theremoval of trees by cutting and mortality. Removalsinclude trees harvested on land that remains in forest,trees lost because the forest was developed for a nonforestuse, and trees removed from the timber resource basebecause they grow on land where harvesting now isrestricted. The most recent inventory revealed that since

1987, on an annual basis, the net growth of trees in NewJersey averaged 58 million cubic feet versus 36 millioncubic feet in removals. This surplus translates to anannual net increase of 0.8 percent in the volume of woodon the State’s timberland.

Nearly 70 percent of removals are attributed to theconversion of forests to nonforest uses; 27 percent isattributed to timberland reclassified to reserve status, and5 percent to harvesting. Trees regenerate and thrive afterharvesting so long as the land remains in forest. Forestsclassified as reserved continue to provide benefits otherthan timber products. Converting large amounts offorest to nonforest use threatens sustainability becausesuch changes usually are permanent. As a result, futuretimber growth from these lands is lost, as are relatedbenefits, for example, the recharge of groundwateraquifers. Loss of forest land to development is a growingconcern in New Jersey as the adverse effects of clearingforests for development are cumulative over time. Bycontrast, forests recover from sustainable timber harvests.Because harvesting represents only 3 percent of theannual net growth, it has few impacts on the State’stimber resource. New Jersey currently has few sawmills,so a large portion of the harvested trees is shipped tomills in Pennsylvania and New York. The lack of marketsfor raw wood products makes it more difficult for forestowners to generate profits from their land and increasesthe likelihood that these tracts will be converted to othernonforest uses.

In addition to insects and diseases, disturbances such asfire, wind, and competition among trees contribute totree mortality. The volume of trees that die from causes

Components of Woody Biomass

Dead trees1%

Saplings/ seedlings

9%

Live trees > 5 inches dbh

87%Shrubs

3%

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other than cutting is reported as mortality. In1999 in New Jersey, average annual mortalitywas 16.8 million cubic feet or 0.6 percent ofthe inventory volume. This rate, similar tothose in neighboring states, is considerednormal. Generally, mortality rates were higherfor trees less than 11 inches d.b.h. than forlarger diameter trees; mortality rates werehigher for softwood than for hardwoodspecies. In many instances, the smaller treesthat died were understory trees that werecrowded out by larger trees. As trees becomelarger, fewer can grow on each acre of forestland.

Potential Supply of Timber

New Jersey has untapped potential with respect to itstimber resource. In 1999, the potential amount ofsawtimber available for harvesting totaled 8.1 billionboard feet, an increase of 44 percent since the 1987inventory. This total is equivalent to the amount of woodin a half million houses. The large increase in volume wasattributed primarily to the many poletimber-size treesthat grew to sawtimber size. Hardwood species accountfor 83 percent of the total board-foot volume. Yellow-poplar and pitch pine were the leading species insawtimber volume; the oak species accounted for a thirdof the volume.

Despite the use of state-of-the-art equipment andtechnology, wildfires have burned thousands ofacres of New Jersey’s forests during drought years.

Courtesy of New Jersey Forest Fire Service

Components of Annual Volume Change on

Timberland 1987-1999

-16.8

22.6

75.158.3

-35.7-60.0

-40.0

-20.0

0.0

20.0

40.0

60.0

80.0

100.0

Gross Growth Mortality Net Growth Removals Net Change

Mill

ion

cubi

c fe

et

68% due to land use changed to nonforest use27% due to land use changed to reserved forest land 5% due to harvesting

Trees 5 to less than 11 inches

d.b.h.

Trees 11 inches and

larger in

All trees 5 inches and

larger in d.b.h.Softwood species 80.00% 70.00% 0.80%

Hardwood species 100.00% 0.30% 0.50%

All species 0.90% 0.40% 0.60%

Mortality Rates

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Forest HealthForests are continually stressed by insects, diseases andother factors that reduce growth and increase treemortality. How forests withstand them is a measure oftheir overall health. To a great extent, New Jersey’s forestshave overcome these stresses as trees have continued toincrease in number, size, and volume. An increasingthreat to forest health is the introduction of exoticinsects, diseases, and plants from overseas. Introducedspecies typically have few natural enemies in this country,

so unchecked populations can explode under the rightconditions.

The loss of the American chestnut to the chestnutblight in the early 1900’s and the demise of theAmerican elm to the Dutch elm disease later in thecentury demonstrate the destructive nature ofnonnative exotic species. Introduced diseases that arenot as well known are the butternut canker, which isslowly eliminating butternut trees from the Nation’seastern forests, and dogwood anthracnose, which hasgreatly reduced the populations of dogwood trees inthe forest understory. Since the late 1960’s, periodicoutbreaks of the gypsy moth caterpillar havedefoliated thousands of acres of forest, resulting inlarge losses of tree growth and extensive tree mortality.White oak is particularly susceptible to gypsy moth.

The hemlock woolly adelgid (HWA) and the elongatedhemlock scale, introduced to the United States fromAsia, are causing widespread mortality of easternhemlock trees. The HWA has been destroying hemlockstands in New Jersey for more than two decades. Manyhemlocks grow in nearly pure stands in ravine forests inthe northern part of the State. The loss of dense shadeprovided by these trees can alter the ecology of streams in

Potential Available Sawtimber Volume, 1987 and 1999, With Percentage Change Between Inventories

0 200 400 600 800 1000 1200

Atlantic white-cedar

Sweetgum

Other white oaks

White oak

Ash

Northern red oak

Red maple

Other red oaks

Pitch pine

Yellow-poplar

Sp

ecie

s

Million board feet

1987

1999

+28%

+65%

+26%

+95%

+59%

+36%

+23%

+29%

+41%

+63%

The hemlock woolly adelgid, anintroduced pest, is killing hemlocktrees in northern New Jersey.Without the dense shade providedby hemlocks, streams warm in thesun and become unsuitable for trout.

Above, courtesy of USDAAPHIS, image 2652087(www.forestryimages.org)

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ravines. Because the HWA and hemlock scale feed on thejuices in the hemlock needles, chemical spraying tocontrol these pests is ineffective. Currently, a predatorybeetle that is a natural enemy of the HWA in Asia isbeing released in the State. Another destructive forestinsect pest, the Asian longhorn beetle, was detected inJersey City in 2002. Thought to have arrived in theUnited States in the wood of shipping pallets, the beetlefeeds on a variety of hardwood trees, including maplesand ash. Intense efforts are underway to prevent thisspecies from establishing itself in the State. To date, theAsian longhorn beetle can be eliminated only byremoving infested trees and destroying them by chippingor burning.

Air pollution and climate change are long-term threats tothe health of a forest. Air pollutants such as ozone candistress foliage and acid deposition can alter the soilchemistry. A warming of the climate could result in ashift in the range of certain tree species that thrive in coolweather. Species such as sugar maple would migratenorthward out of New Jersey, making growing conditionsfavorable to other species.

To assess long-term forest health, the Forest Servicecarefully measures selected indicators that can helpscientists detect when trees are under stress and whichspecies are most susceptible. These include crowndieback, ozone injury, lichen communities, and soilconditions. The accumulate data from these annualmeasurements should provide increasingly accurateassessments of the health of New Jersey’s forests.

The Future of New Jersey’s ForestsIn general, New Jersey’s forests are healthy and resilient,and will continue to mature. Current trends indicate thatthe State’s future forests will have larger trees, highervolumes per acre, and more old-growth characteristics.But these forests will be vastly different from the originalforests that confronted the early settlers. As the GardenState’s economy and population grow, the impact on theforest resource will only increase. Land cleared fordevelopment will remain in this condition permanentlyeven as more land is cleared. Fragmentation of forestsinto ever smaller patches will continue, rural areas will

become more urbanized, and the introduction ofunwanted invasive insect, disease, and exotic plantspecies will continue to threaten native species. Onceestablished, many nonnative species become a permanentpart of the ecosystem they inhabit. The adverse effects ofthese changes may not be immediately evident, and theoverall impact may be difficult to assess because forestschange slowly.

High deer populations are causing changes in speciescomposition and hindering the ability of forests toreproduce. Natural processes within the forest aredisrupted by interference by humans. For example,increased efforts to control wildfires as homes and newdevelopments encroach on forests, breaking the naturalfire cycle to which the State’s pinelands are adapted. As aresult, in the Pine Barrens, pine eventually could lose itsdominance to hardwood species.

Threats to New Jersey’s forest from beyond its bordersinclude pollutants carried into the State by wind, andpossible changes in climate. These and other factors willmake it increasingly difficult to manage the GardenState’s forests. As threats to forest health increase, themonitoring and tending of forest land will become moreimportant. Attempts now underway to keep hemlocktrees from disappearing and to control Asian longhornbeetles are examples of management activities that willbecome more common in the future.

Attention to the urban forest will increase ourunderstanding of how trees benefit society. Programsdesigned to build, maintain, and enhance the urbanforest likely will expand, as will communitycommitments to protect the State’s urban-suburbanforests. Regarding trees as a valued element of the urbaninfrastructure will result in a better managed resourcethat will improve the aesthetics and livability of NewJersey’s cities and towns.

The area of forest in the State has peaked as the area ofnew forests from abandoned agricultural lands now isbeing outpaced by development. In reaction to this,forests in public ownership probably will continue toexpand. Land trusts, nonprofit organizations, and public

19

agencies and government entities are actively pursuingprotection strategies. Conservation easements allowlands to remain in private ownership and protect criticalhabitats for wildlife while providing a continuedmechanism for forest use. The pace of forest loss will bedetermined by the effectiveness of efforts to identify and

target for protection undeveloped land that is critical forproviding benefits such as clean drinking water andrecreational and aesthetic enjoyment. Should these andother programs be successful, New Jersey will become aleader in integrating people into a functioningecosystem.

Before Thinning

After Thinning

Thinning understory vegetationconcentrates future growth on a fewlarge trees and reduces the risk ofdestructive crown fires.

Photos courtesy of New Jersey Division of Parksand Forestry - New Jersey Forest Service

20

For additional information contact:

Forest Inventory and Analysis, USDA Forest Service,Northeastern Research Station11 Campus Boulevard, Suite 200Newtown Square, PA 19073(610) 557-4051; www.fs.fed.us/ne/fia/

New Jersey Forest ServiceDivision of Parks & ForestryPO Box 404Trenton, NJ 08625-0404Tel. 609-292-2531www.state.nj.us/dep/parksandforests/forest/

Printed on Recycled Paper

Widmann, Richard H. 2005. Forests of the Garden State. Resour. Bull. NE-163.Newtown Square, PA: U.S. Department of Agriculture, Forest Service,Northeastern Research Station. 20 p.

A report on the fourth forest inventory of New Jersey conducted in 1998-99 by theForest Inventory and Analysis unit of the Northeastern Research Station. Discussesthe current condition and changes from previous inventories for forest area, timbervolume, tree species, and growth and removals. Graphics depict data at the statelevel and by county where appropriate.

Keywords: New Jersey; forest inventory; volume; biomass; growth and removals

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Headquarters of the Northeastern Research Station is in Newtown Square,Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

Burlington, Vermont, in cooperation with the University of Vermont

Delaware, Ohio

Durham, New Hampshire, in cooperation with the University of New Hampshire

Hamden, Connecticut, in cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Parsons, West Virginia

Princeton, West Virginia

Syracuse, New York, in cooperation with the State University of New York,College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs andactivities on the basis of race, color, national origin, gender, religion, age, disability, politicalbeliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to allprograms.) Persons with disabilities who require alternative means for communication ofprogram information (Braille, large print, audiotape, etc.) should contact the USDA's TARGETCenter at (202)720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W,Whitten Building, 14th and Independence Avenue SW, Washington, DC 20250-9410, or call(202)720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.

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