Agenda - Environmental Policy Board - 07/19/2021

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FOREST SAMPLING METHODS 55 time -efficient and produced the most accurate estimates of all stems in a stand regardless of size. The QUAD produced 1. slightly more accurate estimates of larger stems, but produced less accurate estimates of small stems and was also less time - efficient. The VRP was extremely time- 2. efficient and produced precise estimates of larger stems, but tended to underestimate the actual number of stems. The PCQ 3. method also produced time -efficient and precise estimates of larger stems, but underestimated actual stem density. Fur- thermore, the PCQ may produce biased 4. estimates depending on stem distribution in a stand. Both the VRP and PCQ pro- duced precise estimates, regardless of stem 5. density; therefore, these methods are usable when the manager takes into account that the estimate obtained may be low. By calculating the appropriate sample 6. size from a preliminary field size, estimates may be closer to the true mean and may reflect unbiased estimates of stem density when applying the VRP method. 7. We recommend using a combination of an FRP method and VRP method when sampling stems of all sizes in variable - density forested communities. FRP meth- ods provide relatively accurate and time - efficient results on small stems (DBH 2.54- 11.42 cm), while the VRP method is time- 8. efficient and relatively accurate at sampling larger stems (DBH >11.43 cm). The number of samples should be based on the standard deviation or coefficient of variation of a preliminary field sample. The combination of these methods will provide accurate and time -efficient results for sampling woody species regardless of size. ACKNOWLEDGMENTS Funding was provided through the Okla- homa State University, Department of Forestry and Oklahoma Agricultural Ex- periment Station. We thank M. Stewart for field assistance and T. Lynch for review of an earlier draft. This article is published with the approval of the Director of the Oklahoma Agricultural Experiment Sta- tion. 9. 10. 11. REFERENCES Curtis JT, McIntosh RP. The inter- relations of certain analytic and syn- thetic phytosociological characters. Ecology 1950; 31:434-455. Shanks RE. Plotless sampling trials in Appalachian Forest types. Ecology 1954; 35:237-244. Beasom SL, Haucke HH. A comparison of four distance sampling techniques in South Texas live oak notes. J of Range Manag 1975; 28:142-144. Cottam G, Curtis JT. The use of distance measures in phytosociological samp- ling. Ecology 1954; 37:451-461. Oosting HJ. The study of plant com- munities: an introduction of plant ecology. 2nd ed. San Francisco: W. H. Freeman and Co.; 1956. 440 p. Grosenbaugh LR, Stover WS. Point - sampling compared with plot -sampling in southeast Texas. Forest Sci. 1957; 3:2- 14. Masters RE. Effects of timber harvest and prescribed fire on wildlife habitat and use in the Ouachita Mountains of eastern Oklahoma. [Unpublished Ph.D. dissertation] Stillwater (OK): Oklahoma State University; 1991. 351 p. Available from: OSU Library. Masters RE. Effects of fire and timber harvest on vegetation and cervid use on oak -pine sites in Oklahoma Ouachita Mountains. In: Nodvin SC, Waldrop A editors. Fire and the environment: ecological and cultural perspectives. USDA, Forest Service, Southeast Forest Experiment Station, General Technical Report SE-69; 1991. p.168-176. Masters RE, Engle DM, Robinson R. Effects of timber harvest and prescribed fire on soil chemical properties in the Ouachita Mountains. South J Appl For 1993; 17:139-145. Masters RE, Engle DM, Robinson R. Effects of timber harvest and prescribed fire on white-tailed deer forage pro- duction. Wildl Soc Bull 1993; 21:401-411. Grosenbaugh LR. Plotless timber esti- mates —new, fast, easy. J For 1952; 50:32- 37. Proc. Okla. Acad. Sci. 82:49-56(2002)