Table 1. – Annual estimates and uncertainty

Figure 1. – Area of timberland and forest land by year.

Figure 2. – Area of forest land area by top seven forest 

type groups and stand size class, 2004-2007.

West Virginia’s Forest Resources, 2007 Research Note NRS-60

This publication provides an overview of forest resource 

attributes for this state based on an annual inventory 

conducted by the Forest Inventory and Analysis (FIA) 

program at the Northern Research Station of the U.S. 

Forest Service. These estimates, along with web-posted 

core tables, will be updated annually. For more 

information please refer to page 5 of this report.

1

Figure 3. –Area of timberland by stand size class and 

year.

* Data for growth, removals, and mortality are not available for this report.

Note: When available, sampling errors/bars provided in figures and tables 

represent 68 percent confidence intervals.

8

9

10

11

12

13

14

1948 1968 1988 2008

Area (1,000.000 acres)

Year

Timberland

Forest land

0 1 2 3 4 5 6 7

Oak/hickory

Maple/beech/birch

Oak/pine

Elm/ash/cottonwood

Pitch/Virginia pine

White/red/jack pine

Spruce/fir

Forest land (1,000 acres)

Forest type groups

Large

Medium

Small

0

2

4

6

8

10

1940 1950 1960 1970 1980 1990 2000 2010

Area (1,000,000 acres)

Year

Large Medium Small

Estimate 

2007

Sampling 

error

(%)

Forest Land Estimates

Area (1,000 acres) 12,005 0.8

Annual mortality of live trees 

(1,000 ft3

/year) NA* --

Timberland Estimates

Area (1,000 acres) 11,737 0.8

Annual mortality of growingstock trees (1,000 ft3

/year) NA* --

Annual harvest removals of 

growing-stock trees (1,000 

ft3

/year) NA* --

Annual other removals of 

growing-stock trees (1,000 

ft3

/year) NA* --

Annual harvest removals of live 

trees (1,000 ft3

/year) NA*

--

Number of live trees 1-inch 

diameter or larger (million trees) 6,010 1.8

Number of live trees 1-inch 

diameter or larger (million trees) 6,153 1.7

Dry biomass of live trees 1-inch 

diameter or larger (1,000 tons) 781,286 1.3

Net volume in live trees 

(1,000,000 ft3

) 26,915 1.3

Annual net growth of live trees 

(1,000 ft3

/year) NA* --

Net volume of growing-stock 

trees (1,000,000 ft3

) 24,811 1.5

Annual net growth of growingstock trees (1,000 ft3

/year) NA* --

Dry biomass of live trees 1-inch 

diameter or larger (1,000 tons) 761,349 1.3

Net volume in live trees 

(1,000,000 ft3

) 26,192 1.4

--

Annual other removals of live 

trees (1,000 ft3

/year) NA*
Table 2. – Top 10 tree species by statewide volume estimates 2004-2007

Figure 4. – Area of forest land by major owner group (2007) and size of private forest landholding (2006).

2

Private forest land – 87 percent of all forest land 

Public forest land – 13 percent of all forest land

(Of the 10.4 million acres of privately owned forest 

land, 7.2 million acres is held by family forest owners 

with the remainder held by a combination of 

corporations, partnerships ,and other forms of 

ownership.)

Rank Species Sampling Sampling 

Error error

(%) (%)

1 Yellow-poplar 3,844 4.6 14.3 15,483 5.4 17.9

2 Red maple 2,422 4.3 9.0 5,766 6.0 6.6

3 Chestnut oak 2,405 4.9 8.9 7,567 5.8 8.7

4 White oak 2,327 4.6 8.6 8,256 5.5 9.5

5 Northern red oak 2,107 5.6 7.8 8,853 6.6 10.2

6 Sugar maple 1,922 5.0 7.1 5,188 7.2 6.0

7 Black oak 1,286 6.3 4.8 5,246 7.6 6.1

8 American beech 1,082 6.9 4.0 3,458 9.2 4.0

9 Black cherry 1,030 8.5 3.8 3,214 10.7 3.7

10 American basswood 790 9.9 2.9 3,157 11.5 3.6

Other softwoods 1,378 7.2 5.1 4,033 9.3 4.7

Other hardwoods 6,323 2.4 23.5 16,486 3.6 19.0

All Species 26,915 1.3 100.0 86,707 2.0 100.0

Proportion of 

total sawtimber 

volume (%)

Volume of live trees 

on forest land 

(1,000,000 ft3

)

Proportion of 

total live tree 

volume (%)

Volume of sawtimber 

trees on timberland 

(1,000,000 bdft)

-

500 

1,000 

1,500 

2,000 

2,500 

Private forest land (1,000 acres) 

Landholding size (acres)
3

Continuous Improvement Process for Volume, Biomass, and Carbon Estimation

Implementation of the annual inventory requires ongoing evaluation of existing methods and implementation of 

improved system components as they become available. Recently, significant changes were made to the 

methods for estimating tree-level volume and biomass (dry weight) for Northeastern states, and the calculation of 

change components (net growth, removals, and mortality) was modified for national consistency. These changes 

have focused on improving the ability to report consistent estimates across time and space--a primary objective 

for FIA.

Tree-level Volume Estimation

As the remeasurement phase of the annual inventory was implemented, “noise” (random variation in the data) 

began to outweigh the signal (detectable change in volumetric variables), thus limiting the ability to track real 

change over time. Sources of noise include: measurement variability, field protocol changes, field crew cohort 

changes, definition changes, processing algorithm changes, and model error. This noise impacts estimates of 

volume, biomass, carbon, and associated change component estimates.

Volume estimation is critically important because individual tree volume estimates form the basis for biomass and 

carbon estimates. In the past, estimates of individual tree gross volumes (cubic foot and board foot) were 

estimated using equations based on field-measured diameters and lengths (bole and saw log). Net volume of the 

tree was computed by subtracting field-measured cull (Scott 1981, Scott 1979). Over time, it was found that noise 

in the measurements of tree lengths and cull outweighed the true signal. To ameliorate this, a taper model was 

used to estimate length (Westfall 2009). In addition, a model was developed for determining the percent of total 

tree volume represented by cull. The modeled length and cull estimates are used in conjunction with Scott’s 

volume equations, thus providing a consistent estimation procedure across the Northeast. In general, the new 

volume estimates will be higher because previous estimates were based on length measurements that included 

reductions based on merchantability, e.g., prior to 2007, the measurement of the top of the bole may have been 

below the 4-inch top due to form deficiencies that prevents use for pulpwood. In 2007, the merchantability limits 

were removed from the field protocols. In conjunction with the removal of merchantability limits, changes in cull 

measurements were implemented, such that net tree volume would continue to represent only the merchantable 

portion of the tree. The modeled lengths and culls are aligned with these new measurement protocols.

Component Ratio Method (CRM) for Biomass/Carbon Estimation

Biomass and carbon have become increasingly important to FIA clients as demand for bioenergy has increased 

and carbon sequestration has emerged as a vital component of climate change analyses. As such, a method for 

harmonizing volume, biomass, and carbon estimates was needed. Prior to implementation of the CRM method, 

volume and biomass were estimated using separate sets of equations. The CRM method is comprised of the 

following steps (Heath and others 2009):

• Conversion of sound-wood volume in the merchantable bole to biomass using species-level specific gravities 

(dry mass per unit of green volume)

• Calculation of bark biomass using a set of percent bark and bark specific gravities

• Calculation of biomass in tops and limbs as a proportion of merchantable bole biomass based on component 

proportions using equations from Jenkins and others (2003)

• Calculation of stump biomass using equations from Raile (1982)

• Summation of biomass components to obtain total aboveground biomass

Estimates of carbon are derived through simple conversion of the biomass variables.
Additional West Virginia Inventory Information

4

Citation for this Publication

Widmann, R.H.; McCaskill, G.M.; McWilliams, W.; Cook, G.W. 2010. West Virginia’s forest resources, 2007. 

Res. Note NRS-60. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research 

Station. 5 p.

FIA Program Information

Bechtold, W.A.; Patterson, P.L. 2005. The Enhanced Forest Inventory and Analysis Program: national sampling 

design and estimation procedures. Gen. Tech. Rep. SRS-80. Asheville, NC: U.S. Department of Agriculture, 

Forest Service, Southern Research Station. 85 p.

Smith, W.B. 2002. Forest Inventory and Analysis: a national inventory and monitoring program. Environmental 

Pollution. 116: 233-242.

USDA Forest Service. 2005. Forest Inventory and Analysis national core field guide, Vol. 1, field data collection 

procedures for phase 2 plots, Ver. 3.0. Available at http://www.fia.fs.fed.us/library/field-guides-methods-proc/ 

(verified Aug. 1 2008). 

Bones, J.T. 1978. The forest resources of West Virginia. Resour. Bull. NE-56. Broomall, PA: U.S. Department 

of Agriculture, Forest Service, Northeastern Forest Experiment Station. 105 p.

DiGiovanni, D.M. 1990. Forest statistics for West Virginia—1975 and 1989, Resour. Bull. NE-114. Radnor, PA: 

U.S. Department of Agriculture, Forest, Service, Northeastern Research Station. 172 p.

Ferguson, R.H. 1964. The timber resources of West Virginia. Resour. Bull. NE-2. Upper Darby, PA: 

U.S.Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 123 p.

Change Component Estimation

Change components are perhaps the most important volumetric variables reported by FIA because they are 

indicative of sustainability (net growth-to-removals ratio) and forest health (mortality). To summarize, gross 

growth is equal to ingrowth (volume of trees reaching the 5.0-inch minimum diameter threshold for 

merchantable volume) plus accretion (growth of surviving trees that were above the threshold at previous 

measurement). Net growth is equal to gross growth minus mortality (volume of trees meeting the threshold at 

previous measurement that died). Removals are equal to the volume of trees meeting the threshold at the 

previous measurement that were harvested or on forest land that changed to nonforest land. Net change in 

inventory is equal to net growth minus removals.

The National Inventory Management System (NIMS) is the compilation system for all FIA estimates. 

Implementation of NIMS has included some adjustments to regional change-component algorithms to achieve 

national consistency. A new method, termed the “midpoint method,” has introduced some fundamental 

changes in methods (Westfall et al. 2009). Essentially, the new approach uses models to “grow” trees to the 

midpoint of the inventory cycle (2.5 years for a 5-year cycle). Although the overall net changes are equivalent 

under the previous and new evaluation methods, estimates for individual components will be different. For 

ingrowth, the midpoint method produces a smaller estimate because volumes are calculated at the 5.0-inch 

threshold instead of using the actual diameter measurement, which may be larger. The estimate for accretion 

is higher because growth on ingrowth, mortality, and removal trees are included. As such, the removals and 

mortality estimates will also be higher than before.
5

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 file a complaint of 

discrimination, write to USDA, Director, Office 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.

Lead Analyst: Richard Widmann, (610) 557-4051, rwidmann@fs.fed.us

Data processing/access: Carol Alerich, (610) 557-4068, calerich@fs.fed.us

Field data collection: Mike Effinger (304) 285-1593, meffinger@fs.fed.us

Estimates, tabular data, and maps may be generated at: www.fia.fs.fed.us/tools-data 

Contact Information

Heath, L.S.; Hansen, M.H.; Smith, J.E.; Smith, W.B.; Miles, P.D. 2009. Investigation into calculating tree 

biomass and carbon in the FIADB using a biomass expansion factor approach. In: McWilliams, W.; Moisen, 

G.; Czaplewski, R., comps. 2008 forest inventory and analysis symposium; 2008 October 21-23; Park City, 

UT. Proc. RMRS-P-56CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station. CD.

Jenkins, J.; Chojnacky, D.C.; Heath, L.S.; Birdsey, R.A. 2003. National scale biomass estimators for United 

States tree species. Forest Science. 49(1): 12-35.

Raile, G.K. 1982. Estimating stump volume. Research Paper NC-224. St. Paul, MN: U.S. Department of 

Agriculture, Forest Service, North Central Research Station. 4 p.

Scott, C.T. 1979. Northeastern forest survey board-foot volume equations. Res. Note NE-271. Broomall, PA: 

U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 2 p.

Scott, C.T. 1981. Northeastern forest survey revised cubic-foot volume equations. Res. Note NE-304. 

Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 2 p.

Westfall, J.A. In press. Taper models for tree species in the Northeastern U.S. Forest Science.

Westfall, J.A.; Frieswyk, T.; Griffith, D.M. 2009. Implementing the measurement interval midpoint method for 

change estimation. In: McRoberts, R.E.; Reams, G.A.; Van Deusen, P.C.; McWilliams W., eds. Proceedings 

of the eighth annual forest inventory and analysis symposium; 2006 October 16-19; Monterey, CA. Gen. 

Tech. Rep. WO-79. Washington, DC: U.S. Department of Agriculture, Forest Service: 221-236.

Literature Cited in Continuous Improvement Section

Griffith, D.M.; Widmann, Richard H. 2003. Forest statistics for West Virginia: 1989 and 2000. Resour. Bull. NE157. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 

119 p.

Widmann, R.H.; Dye, C.R.; Cook, G.W. 2007. Forests of the Mountain State. Resour. Bull. NRS-17. Newtown 

Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 28 p.