Agenda - Environmental Policy Board - 07/19/2021

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50 J.C. SPARKS, R.E. MASTERS and M.E. PAYTON the time required by these methods to obtain a 10% sample (by area). STUDY AREA We conducted this study on the Pushmataha Forest Habitat Research Area (PFHRA) on the 7395 ha Pushmataha Wildlife Manage- ment Area, approximately 6 km southeast of Clayton, Oklahoma (7). The PFHRA was protected from logging, grazing, and fire until 1984 when a comprehensive study on the effects of fire and timber harvest began (7-10). We selected three different stands in the research area to represent varying stand densities in both understory and overstory. Stands included 1. High density stand —unmanaged stand, no fire or timber harvest, 0.92 ha in size. 2. Moderate density stand —removal of 1/2 of the hardwood basal area, annual winter burn since 1985, 0.56 ha in size. 3. Low density stand —harvest all mer- chantable pine, annual winter burn since 1985, 1 ha in size. The high density stand was dominated by post oak (Quercus stellata), shortleaf pine (Pinus echinata), with occasional blackjack oaks (Q. marilandica) and mockernut hickory (Carya tomentosa) (7). Shortleaf pine dom- inated the moderate density stand while the low density stand was dominated by post oak with occasional blackjack oak and mockernut hickory. Study area soils and vegetation on these sites were previously described by Masters and Masters et al. (7- 10). METHODS We delineated the area to be sampled in each stand by using a compass and hip chain. We sampled experimental stands >20 m from stand boundaries to minimize edge effects from adjacent stands. After stand bound- aries were surveyed and marked, we obtained a total count of stem density from each stand. We recorded species and diameter at breast height (DBH) of all stems with a DBH >2.54 cm. After a stem was tallied we marked the bark or foliage with paint to ensure that all trees were counted accurately. We selected sampling points at random distances along a base line through the long axis of the stand after the method of Beason and Haucke (3). We then selected a random distance from the random point on the base line for location of plot center. This process continued until the desired number of samples had been taken (Table 1). Sampling Methods: The six sampling methods compared with total census counts included VRPs, 3.64 m fixed -radius plot (FRP-AC), 5.64 m fixed -radius plot (0.01 ha; FRP-HA), QUAD, PCQ, and BT. We prac- ticed each sampling method prior to samp- ling to familiarize ourselves with the methods. We performed only one sampling technique on a plot at a time. Sampling time was recorded with a stopwatch. We sampled approximately 10% of the area of each experimental unit using all methods except VRP. For VRP, we used the same plot centers as those used in the PCQ method. We tallied all woody species with a DBH >2.54 cm, except when applying the PCQ, for which only stems >11.43 cm were tallied. We recorded species and DBH for all sampling methods. We counted all stems of appropriate DBH in a given area for the FRP-AC, FRP- HA, QUAD, and BT. We used a 10-factor prism when applying the VRP method (2,11,12). We tallied trees that subtended an angle equal to or greater than that of the prism. When using the PCQ method we divided sampling points into four quarters (3,4). In each quarter we tallied the nearest tree >11.43 cm. We did not sample small stems when using the PCQ method. We then measured from the sample point to the nearest tree in each quarter (quadrant) and recorded this measurement. We placed BTs on randomly located lines running the length of the stand by using a transect width of 1 m (Table 1). We tallied all trees within the 1 m transect width and tallied every other border -line tree. Proc. Okla. Acad. Sci. 82:49-56(2002)