FORESTS OF 

1

This resource update provides an overview of the forest 

resources of Oklahoma based on an inventory conducted by 

the U.S. Forest Service, Forest Inventory and Analysis 

(FIA) program at the Southern Research Station (SRS), and 

Oklahoma Forestry Services (OFS). Data collection and 

estimates are based on the FIA annualized sample design, 

and are updated yearly, creating a moving average. The 

2016 resource update highlights how the moving average 

has been updated since the 2015 report (Dooley, 2017). The 

data used in this publication were accessed from the FIA 

Database between May 1 and June 15, 2018.

Over view

Oklahoma’s 77 counties are divided into seven survey units 

(fig. 1): Southeast (unit 1), Northeast (unit 2), North Central 

(unit 3), South Central (unit 4), Southwest (unit 5), High 

Plains (unit 6), and Great Plains (unit 7). Units 1 and 2 

make up East Oklahoma, while West Oklahoma comprises 

units 3 through 7. West Oklahoma was not surveyed by 

FIA until 2009. West Oklahoma is on a 10-year cycle and 

2016 marks 80 percent of the cycle complete. For West 

Oklahoma, 2015 estimates comprise inventory years 2009-

2015, and estimates for 2016 are based on inventory years 

2009-2016. Eastern Oklahoma is on a 5-year cycle, and has 

8 previous complete measurement cycles, the first taking 

place in 1936. For East Oklahoma, 2015 estimates comprise 

years 2011-2015, and 2016 estimates comprise years 2012-

2016 (table 1). 

Oklahoma was allocated 6,307 plots, of which 6,091 were 

sampled, 4,443 field sampled. Estimates of current data, 

such as area of forest land or standing volumes, are derived 

from these plots. Estimates on change variables such as 

growth, mortality, and removals are based on a subset of 

1,709 plots which were remeasured. Until West Oklahoma 

completes a cycle and begins remeasurement, all of the 

growth, mortality, and removal data are from East 

Oklahoma. 

Forest Service | October 2018

R E S O U R C E U P D A T E F S -1 7 7

Oklahoma, 2016 

Table 1 – Oklahoma forest statistics, change between 2015 and 2016 

Forest statistics

2015 

estimate 

Sampling 

error 

(percent) 

2016 

estimate 

Sampling 

error 

(percent)

Change 

since 2015 

Area (thousand acres ) 12,284.18 1.244 12,158.89 1.181 -125.29

Number of live trees >1 inch d.b.h. (million trees ) 5,469.34 2.091 5,532.21 2.049 62.86

Net volume live trees >5 inches d.b.h. (million cubic feet ) 9,632.09 1.966 9,752.23 1.912 120.14

Live trees aboveground biomass (thousand oven-dry tons ) 281,634.26 1.655 284,746.00 1.601 3,111.74

Net grow th live trees >5 inches d.b.h. (million cubic feet per year )

a

131.973 7.563 139.888 7.453 7.91

Annual removals of live trees >5 inches d.b.h. (million cubic feet per year) a102.315 13.151 95.875 12.551 -6.44

Annual mortality of live trees >5 inches d.b.h. (million cubic feet per year) a99.066 5.755 99.611 5.504 0.55

Area (thousand acres ) 6,949.11 1.901 6,888.23 1.852 -60.88

Number of live trees >1 inch d.b.h (million trees ) 3,585.22 2.871 3,607.16 2.846 21.94

Net volume live trees >5 inches d.b.h. (million cubic feet ) 7,187.74 2.755 7,265.24 2.696 77.5

Live trees aboveground biomass (thousand oven-dry tons ) 203,709.52 2.478 205,240.55 2.418 1,531.02

Net grow th live trees >5 inches d.b.h. (million cubic feet per year )

a

139.895 7.324 149.194 7.203 9.3

Annual removals of live trees >5 inches d.b.h. (million cubic feet per year )

a

116.807 11.846 110.769 11.303 -6.04

Annual mortality of live trees >5 inches d.b.h. (million cubic feet per year )

a

87.575 6.345 87.513 6.178 -0.06

aNet annual grow th, removals, and mortality based on units 1 and 2 only.

Forest land

Timberland
2

Forest Area

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In the Oklahoma 2016 

FIA survey, an estimated 

12.2 million acres of land 

was forested, 27 percent 

Figure 1—Counties and FIA survey units in Oklahoma.

of total area. Land that can produce at least 20 cubic feet of 

wood per acre per year, and which is not prohibited from 

timber extraction by law or statute is called timberland. In 

Oklahoma, 6.9 million acres of the forest land qualified as 

timberland. The 5.3 million acres of other forest land are not 

prime for timber extraction, but provide wildlife habitat, 

recreation opportunities, and ecosystem diversity. The remaining 32.6 million acres of Oklahoma area was water or 

accounts for 17 percent of timberland area. 

Most of the forest land in Oklahoma is naturally regenerated, with only 6 percent being planted (11 percent of timberlands). But, this is not uniform across forest-types. 

Most of the forest-type groups have no artificially regenerated stands, while loblolly-shortleaf pine is in planted 

stands 51 percent of the time (54 percent on timberlands).

nonforest land. Though the overall percent of forest land 

was 27, it was not uniformly distributed across the State. 

In Unit 1 (Southeast) more than 60 percent of the area is 

forest land, more than 50 percent being timberland, while 

98 percent of unit 6 (High Plains) is nonforest (fig. 2). 

Of the lands that are forested, oak-hickory forest-types 

accounted for more than half of the area (fig. 3). Timberlands had close to the same proportions by forest-type 

group, with the exception of loblolly-shortleaf pine, which 

Nonindustrial private owners, which include all nongovernmental groups, individuals, or corporations which 

do not operate a primary wood processing plant, own the 

vast majority (88 percent) of forest land in Oklahoma (fig. 

4). About half (53 percent) of the forest land owned by 

nonindustrial private landowners is timberland. Similar 

proportions are seen in State and local government owned 

forest land (50 percent timberland) and other federal (59 

percent timberland). Conversely, the vast majority of forest lands owned by U.S. Forest Service, and forest industry are timberland (85 and 99 percent respectively).

Loblollyshortleaf 

pine

10.0%

Other 

eastern 

softwoods

4.5%

Pinyonjuniper

0.8%

Oak-pine

7.8%

Oakhickory

55.5%

Oak-gumcypress

1.6%

Other 

hardwoods

0.6%

Maplebeech-birch

0.2%

Elm-ashcottonwood

11.5%

Woodland hardwoods

3.4%

Exotic hardwoods

0.5%

Nonstocked

3.6%

Figure 3—Proportion of forest land by forest-type group, 

Oklahoma, 2016. Total area 12.2 million acres.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Area (million acres)

Ownership group

Timberland Other forest land

Figure 4—Timberland and forest land area by ownership 

group, Oklahoma, 2016. Total area 12.2 million acres.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Area (million acres)

Survey unit

Timberland Other forest land Nonforest

Figure 2—Area of timberland, forest land, and nonforest land 

by survey unit, Oklahoma, 2016. Total area 44.7 million acres.
3

Including unknowns collected to the genus level, 95 species 

of trees were recorded on Oklahoma forest land during the 

2016 survey, 19 more than in 2015. Post oak, winged elm, 

and eastern redcedar were the most common species by 

number of live trees (table 2). Most of the 95 species are 

relatively uncommon. The three most common species 

account for more than a third of the total tree count, and the 

10 most frequent species accounting for nearly two-thirds. 

Nine of the 10 most common species were also most 

common on timberland (green ash replaced sugarberry on 

timberland) though ranking within the top 10 was different.

Oklahoma forest lands contained a net live volume of 9.8 

billion cubic feet (table 3). As with number of trees, post 

oak was the top contributor, accounting for 22 percent of 

the volume. In this category, shortleaf and loblolly pines 

ranked next. 

Volume, Biomass, and Trends

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Table 2—Number of live trees ≥1.0 

inch diameter on forest land, Oklahoma, 2016.

Table 3—Net merchantable volume 

of live trees ≥5.0 inches diameter on 

forest land, Oklahoma, 2016.

Table 4—Aboveground, dry biomass 

of live trees ≥1.0 inch diameter on 

forest land, Oklahoma, 2016.

Species Million cubic feet

Post oak 2,142.06

Shortleaf pine 1,154.02

Loblolly pine 845.35

Black oak 481.59

Eastern redcedar 430.50

Pecan 354.61

White oak 315.90

American elm 305.20

Blackjack oak 266.91

Green ash 240.31

All others 3,215.79

Total 9,752.23

Species Million trees

Post oak 759.96

Winged elm 604.60

Eastern redcedar 494.38

Blackjack oak 369.60

Shortleaf pine 325.26

Loblolly pine 305.46

Black hickory 216.61

American elm 200.94

Mockernut hickory 141.26

Sugarberry 127.07

All others 1,987.05

Total 5,532.21

Species Million short tons

Post oak 69.43

Shortleaf pine 24.78

Loblolly pine 18.45

Black oak 13.98

Blackjack oak 11.70

Eastern redcedar 10.67

Pecan 10.52

White oak 9.38

Winged elm 9.31

Black hickory 9.18

All others 97.36

Total 284.75

Close to 285 million short tons of oven-dry biomass were 

present in the aboveground portion of trees on forest land 

in Oklahoma (table 4). Biomass is closely related to 

volume, so it is no surprise that the top four contributing 

species were the same for volume and biomass, and eight 

of the top 10 species by volume were also in the top 10 

biomass contributors. 

In units 1 and 2 where data from previous years is 

available, change components (growth, mortality, and 

removals) can be evaluated in addition to current volumes. 

After years of decline, the average annual net growth 

volume increased in 2016 (fig. 5). At 13.9 million cubic 

feet, it is still well below the 21.6 million cubic feet in 

2010, but it is promising. Average annual mortality is still 

increasing, but at a much reduced rate. Compared with 

2015 the average annual mortality on forest land in 2016 

increased by about 0.05 million cubic feet, the increase 

between 2014 and 2015 was 0.97 million cubic feet, nearly 

20 times the increase seen this year. This is a good sign, 

but continued monitoring of this volume is important, as at 

9.96 million cubic feet, the average annual mortality of 

2016 is still 1.73 million cubic feet greater than the 2011 

level of 8.24 million cubic feet (fig. 5). 

Removal volume can include trees taken out of the landuse category sample (e.g., land changing from timberland 

to other forest or from forest to nonforest) as well as 

harvest removals for timber use. The harvested removals 

can be summarized separately. Total removals were about 

9.6 average annual million cubic feet. Average annual 

harvest removals for forest land were 9.2 million cubic 

feet. Since 2012, total removal volume and harvest 

removal volume have both reduced; 2.0 and 1.5 average 

annual million cubic feet, respectively. 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

2012 2013 2014 2015 2016

Volume (million cubic feet)

Inventory year

Net growth Mortality Removals Harvest removals

Average annual volume changes on forest land, East Oklahoma, 2012-2016.
4

Forest Fires

FIA field crews collect “fire disturbance” data on all 

accessed forested plots. The data is collected at the stand 

level, and includes ground and crown fires, prescribed or 

wild. Though the term disturbance is used, it is important to 

note that the fires do not have to be damaging. To be 

considered disturbed, at least 25 percent of the area must be 

affected by fire—which can include reduced undergrowth, 

charring on trees, ash/char on the soil surface, etc. For 

remeasured plots—those which were part of earlier 

inventories—crews will record evidence of fire since the 

last field visit. For plots being measured for the first time—

such as the plots in central and western Oklahoma—crews 

will record fires that occurred in the previous five years. 

The total estimated acres disturbed by fires across the entire 

timeframe is 1.1 million, or about 9 percent of forest land. 

This works out to an average of 114,000 acres annually. 

Although dividing the data into sub-categories will 

generally increase sampling error rates, it can still be 

enlightening to look at the data filtered this way. More than 

40 percent of the estimated acres were located in the 

Southeast survey unit (fig. 6). As Oklahoma has a variety of 

ecosystems and land uses, it is important to note that this 

How to Cite This Publication

Dooley, Kerry. 2018. Forests of Oklahoma, 2016. 

Resource Update FS–177. Asheville, NC: U.S. 

Department of Agriculture Forest Service, 

Southern Research Station. 4 p.

Contact Information

Kerry Dooley, forester

Forest Inventory and Analysis

Southern Research Station, USDA Forest Service

4700 Old Kingston Pike

Knoxville, TN 37919

Phone: 865-862-2098 / Fax: 865-862-0262

Email: kjdooley@fs.fed.us

Southern FIA: https://srsfia2.fs.fed.us

National FIA: https://www.fs.usda.gov/srsfia/

Carri Abner, FIA Coordinator

Oklahoma Forestry Services

Oklahoma Dept. of Agriculture, Food, & Forestry

2800 N. Lincoln Blvd.

Oklahoma City, OK 73105-4298

Phone: 918-290-9208 / Fax: 405-522-4583

Email: carri.abner@ag.ok.gov

http://www.forestry.ok.gov

The published report is available online at http://treesearch.fs.fed.us

Literature Cited

Dooley, Kerry. 2017. Forests of Oklahoma, 2015. Resource Update FS–

126. Asheville, NC: U.S. Department of Agriculture Forest Service, 

Southern Research Station. 4 p.

USDA is an equal opportunity provider and employer

R E S O U R C E U P D A T E F S - xxx

www.fia.fs.fed.us

data is only collected on forest land . Because the units 

vary in amount of forest land acres, it is also useful to 

compare the proportion of forest land affected by fire. 

Using this evaluation, the North Central unit shows the 

greatest amount of fire disturbance evidence (fig. 6).

In addition to location, we can compare fire occurrences by 

forest types. In Oklahoma, the oak-hickory forest type 

group is by far the most common; therefore, it is not 

surprising that it had the most acres with fire evidence as 

well (fig.7). 

0

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50

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300

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400

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500

Proportion (percent)

Area (thousand acres)

Survey unit

Area of forest land with fire disturbance

Proportion of forest land with fire disturbance

Figure 6─Prevalance of fire disturbance by survey unit, in 

total area and as proportion of forest land.

Nonstocked forest land was proportionally highest. 

Nonstocked means land that does not currently have 10 

percent tree cover or 40 seedlings per acre, but which is 

staying in forest use—for example land that is surveyed 

post-harvest but before replanting. 

0

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Proportion (percent)

Area (thousand acres)

Forest-type group

Area of fire disturbance Proportion fire disturbance

Figure 7—Prevalance of fire disturbance by forest-type 

group, in total area and as a proportion of forest land.