Oklahoma Midcycle Survey 

Shows Changes in Forest 

Resources 

Cha11e6 E Thomaa 
OKLAHOMA MIDCYCLE SURVEY SHOWS CHANGES IN FOREST RESOURCES 

Chlllef 1. Thomas 

INTRODUCTION 

This forert survey of oklahoma is the fifth ronducfed by the ioreri 

inventory and ~nalyiii (FIA) unit of the 

Southern Fareri Experiment Station. Thp 

pPeviov3 rurvey was made in 1976. 

Narnally the next survey would have been 

1986. but 10 aid the Itote in if5 current forest resource planning an abbreviated 

midcycle survey war made in 1981. A new 

sampling procedure bared on prior survey 

data and current photography war used to 

develop foreit rerource estimate3 for 

this midcycle or 5-year rvivey in Oklahoma. The midcycle technique involves remeasurement of about 10 percent 

of the forest plots and coifs roughly 15 

percent a3 much ar regular ruiveyi. Rcliability of the estimates, however, is considerably lower than iegular rurveyr. 

METHODS 

the quantity 1.1 x number of forested locations) to obtain the sampling 

intervdl. From a random rtait In the 

cumulative list, this rampling interval 

war used ta select 80 forested plots for field renearurenent. Perronnel of the 

Farlrtry Diuirion. Oklahoma state Department of ~giiculfure and the FIA 

unit rDmearvPed the plats using standard FIU plot procedures. 

Volumes 07 individual treer were computed det~rminlrtically fron 

dendrometry data uring algorithmr 

developed as part of SrX (Grorenbaugh 

1967). These volumes were iunmari2.d in lOftw00d and hardwood rafegoriet and 

iompared to 1976 valuer. irrimater of 

volune per acre for both rvrveyr were calculated for each or the rervrveyed 

plots. Volume <hanger then were used to update all permanent plot3 which 

accopding to photointerpretation. wer; still forerfed. 

Growth ~rfimater for east Oklahoma were developed by applyjng relationrhipr 

obtained from remeasured plots to each of 

the forested plots that war nor remeasured. During remeasurement, 

changer . in indiuidu~l rreer, and in other plat dynanlcr rvrh as 

ingrowth. mortality, and renouall, were 

"tounfed for. Net growth per acre per 

year for roftwood and hardwood growing-ltock volume wet computed lor 

each renearured plot. 

Rlg~eltion equationf were developed to predict net growth per acre of softw~nd ~~o~lng-st~ck volume from past 

roftwood growing-stock volume (RZ = .61). 

Equatiani for hardwood growth were developed rimilarly (RZ - .a). Net 

growth per acre af growing-rrook volume war predicted for each plot, expanded and 

then summed to obtain county and itare totair. 

Removal volumes were developed from three componentr. For the firit 

charies i. ~homas is a erea arch ~oreirer with sovthern rorert ~xprrtment station, 

USCIA..iorert Service, Starkv'tlle, MI 
RESULTS 

exfenrive arear and should be interpreted 

with canriderable care. Net growth of 

growjng stork averaged roughly 23 cubic feet per acre per year, down 3 cubic feet 

per acre from the 1975 estimate. Average 

volume per acre was 482 cubic feet, an increase of 5 cubic feet oyer 1976. 

Stocking (ncreared while net growth 

declined. 

werage annual net growth for softwnodl "3% 67.0 million cubic feet in 

east Oklahoma and removals everaged 55.2 

million cubic feet (appendix tabler 25 

and 27). ~ardwood growth, 40.5 million 

cubic feet, ionriderably exceeded the 

12.1 ~-~~ mollon cubic feet averaoe annual 

le.OY.1. The balance in softwood remavalr and 

growth belies the change in inventory 

volume during the p~riod. With growth 

and rut ertsmarer roughly equivalent, the 

inventory could be expected to rmmaln 

stable. Removal rater, howeve?, changed 

drastically just prlor to the 1976 

survey. softwood removali role 37 

percent from 1966 to 1976. From 1976 to 

1982, the inireate wal only about 1 pertent, but with," the period removalr 

varied iubrtantlally. Bared on the output of forest products in 1975 

(Bertelron 1977) and 1978 (Rvdir and 

done5 1981) removals af softwood growing 

stock continued to InrPeare duiins the 

early part of the inter-survey period. 

canversion of "art areas af primarily 

all-age pine stands in Oklahoma to 

even-age management has changed the 

inventow dramatically. 

The current decline in softwood 

inventory may be temporary as the effect 

of even-age management 1s not yet ieflected in lnventary volumes. 

Photoinferpietation of the 1,828 

permanent plots indicated that 335,000 

acres were cur and regenerated to pine in the pair 10 years. one-third of there 

stands are 6 to 10 years old. Although 

there young rtandr ihow little cubic ~olune, virtually all of it war ingrowth 

and contributed to average annual growth 

tor the period. Another third Of the 

acres have been regenerated and these 3 

to 6 year old stands aye nearing the sire 

to contribute to the growing stock. 

These findings are iorrobarated by 

planting vecord~ in eastern Oklahona eve; 

the part 30 yearr (USDA undated). Figure 

2 indicates that the dramatic inrreare in 

acres planted between 1972 and 1974 war sulfdined through 1980. These 

regenerated stands are expected fa contribute ta the inventory at the next rurvey scheduled for 1986. 

-does l. ,.I! :.:>:,.>or 

: : . ' " I,! :o.c,t 

, r . a . ; :<?'-I 

I;-t .,I. :,I ': ".'-: e.<e:t,c.5. ~~ 

Table 4 was omitted because ownership war not resurveyed. Sampling method and rile 

limited the reliability of tabler 22-24 

and 30-34, so they too were excluded. 

Table 9 may be computed directly from 

Table 10, canulrting cubic feet to iordr. 

ApprOpPilfe flCtOP3 can be derived from the 1976 state totals. Table 12 has been 

expanded to 123, IZb, 12c, and 12d to 

g!ve more details of volume by rite 

Cldll. 

 he sampling methods were developed 

to p~ovide suitable survey unit 

estimates. Errinater for imtlle~ arear are pierenied, but the sampling error 

increaser as the area decrearer. sampling errors prcicnied in table I are 

bared on onerfandard deviation or a probability of two chanier out of three. 

TO estimate therampling error far a combinatian of counties one ran use the 

following: 

II = StbndlPd @Pro? Of estimate 

(percent) 

X = variable Of ,nteP.lf (area. 

YoIY~~) 

G = group of iovntiei to be 

combined 

i - total for The unit 

A sample computation of the standard 

error 'or hardwood grawing-irock volume 

for the first five countlei in table 10 

follows: 
ACRES OF FOREST PLANTING BY OWNERSHIP 

OXLIHOMA 

960 1955 960 965 R70 1915 980 

YE/U 

- 388.3 million cubic feet = 2,065.4 million cubic feet SET = 4.6, expressed in percent 

Thus, there are 2 chances out of 3 that the true valve for hardwood growing-stock 

volume is Included in the inteival 347 1 and 429.5 milllon cubic feet (388.3 '! 10.6 pertmt). 

DEFINITIONS OF TERNS 

Standard &US# 

rleaaptdza trars.-iirowing-stack trees 

of commercial species that meet specified 

standards of rlze and quality ar desirable trees. 

heirable ~aas.-4rowing-~tock trees 

that are of commercial species have no 

defects in quality far timber'productr, 

we of relatively high vigor, and canialn 

no pathogens that may result in death or serious deterlaratian belare rotation am=. .~. 

Forset t#p*.-d ~la~sifi~~fisf 

forest land bared upon the species 

forming a plurality of live-free e,"rb*"" 

~o'anooonadai .p.cies.--Tree rprCler of typically small rile, poor fom, or 

inferior quality which normally do not 

develop into tie@. suitable ?or industrial wood producrr. 
~h~~i~~~~hi~ siir--A claiiificatian 

of forest land according to its 

~~itabiliiy for growing CePtain species 

groupi..pinei, upland hardwaodr, or 

baitomland hardwoodr. 

PO~~*~~BI. traas.--6rowing-rta~ treer 

of commercial rpecier at least 5.0 inches 

in diameter at breait height, but smaller 

than sawtimber rim. 

metan trees.--live treer of iomerclal rpecier that do not contain at least one 

12.foot saw log, now or prarpectivel?. 

~iimarily beiaurl Of rot. 

mugh tram--live trees af commercial species that do noi.contain at least one 

12.iooi $3" log. now or prarpectively, 

prinaii~y because of roughness or paor 

foim. (Incl~des all live tieel of 

noncommercial ipecjer.) 

soutimber iraa8.-.Live treer that are ~~~~rcial ipecier, contain at leart a 

12-foot raw log, and meet regional 

ipeclfirafions far freedom from defect. softwoods must be at leart 9.0 inches in 

diameter at breait height and hardwoods 

at ledst 11.0 inches. 

amtinbm uol-.--~et volume of the 

raw.iog partion of live iantimber treer 

in board feet, International 114-inch 

rule. 

sira ozasa.-.~ clarrifiratlon of forest 

land in terms of inherent capacity to 

grow crops of induitrial woods. Sraad.ai#e cZils~.--A claislfi~afi~n of forest land bared on the size class of 

QIOW~~S-S~OCX trees on the area: that is, 

~~~ii~ber, poletimber, or rapling and 

seedling. %dm rsmouals.- he net volume of 

grawing-itork treer removed fion the 

inventory by harverfing, cultural 

operations such ar timber-stand 

inorovement, land clearing, or changer in 

land %mbuinnd.-- (~ormerly connmrcial 

porast i."d.) Forest land producing or capable of producing cropr of industrial 

wand cnd not withdrawn from timber 

~TllizdtiO". 

mtiaol w ~hoto-lntBI.wetatim 2.3 

-Y a or leis denre and extenrive tree 

sofiroodr appear rough in texture 

and are rhader of red to magenta. 

~ardwoods appear very rough in texture 

with toner of light and dark gray. 

8*.nnt aleill-nut.--An area of forest 

duping the 111t inventory and signs of 

logging aitiuitier are present. 

N~ regeneration of roftw~adr ran be 

detected. The image har a very rough 

texture of llght and dark with no visible pink color. 

atilg. I ~~~~~sratim s4.ta.-dn area of 

pine with an average height of 

approximately two feet. The apPe"'"cE 

4% generally moth in texture and with 

very little pink or red color. srnge II rogsneroria sire.-4 pine 

pianratjan in whtch individual trees my 

be on the photography. Trees exceed 

five feet in height. 

Stag# lii l.egonmilt<m site.-4i 

in which pines have reached 

full crown closure in appearance. The 

trees are a bright magenta and have a 

inoother texture than stage 11. 

~~di~idual trees cannot be seen and 

~hadows are not apvarent. 

~l~l~d.-xropland, including improved 

appears very smooth and har road 

d~ce~s. he coloi varies from the white 

~f freshly harvested cropland to a very 

dark freshly plowed field. U growing 

crop appear3 bright red, whereas, young 

pine tree3 aremore magenta or blood 

red. pmnanat nmforaet.-4rban area-. 

highways, pipelines, and other permanent 

felTYnI. vatm.-iiater appears dark blue to 

black. in shades af blue when turbid. 

LITERATURE CITED 

Bertelron, D.F. 1917. Oklahoma forest 

Indurtrler. 1975. USDA. For. Serv. Rer. 

Bull. 10.64. South. For. Exp. Stn.. New 

Orleans, LA. I4 P. ~arlei. J.M. 1976. Forert rtatirtirr for 

Eait Oklahoma caunfler. USDA For. serv. 

~ei. ~ull. ~012. south. For. ixp. 

sfn., new Orleans, LA. 40 p. 

Glorenbaugh. L.R. 1967. STX-FORTRAN-4 

~~ogiam for ettlmater of tree populations from 3-P sample tree meliurementr. USOA, For. Sarv. Rer. 

pap. PSW-13. ~acific iaufhweit Forert 

and Range Exp. stn., Blrkley. CA. 41 


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Thomas. C.E. 

191. Oklthoma midcycle survey shows change in 

forest resource trends. U.S. Dep. ~gric. ior. 

Sl"". Resour. Bull. SO-100. south. For. Exp. 

Sfn., New Orleans, LA., 1%. 

The first 8xtenrlve midcycle update of Oxlahoma's 

forest resouices ~hevi a 61 decrease in inventory 

volume between 1976 and 1981. iorert area drcllned by about 1X durlng the same perlod. Soft- wood inventory declined for the first time since 

1930'1. 

Addiflanal keywards: Area. forert type, stand 

1121 9POWTh. PPrnDVIl.. rnOPT.litl, mIdLyCle IYlYeY, 

In~~ntory.