The Precision and Repeatability of a Leaf Biomass Sampling Technique for Mixed Hardwood Stands

Abstract

ground plots. The work reported here was concerned with the assessment of the contributions to variance of the levels of a sampling design and with what effect these sources of variance have on the precision of estimates of certain stand attributes. If the method is sufficiently reliable, it can be used to compare treatments in other studies. The sampling method is similar to the one used by Olson (1971) in thinned stands of pure, even-aged yellow-poplar. Some comparisons of the variance components will be made with the earlier published work to ascertain how and to what extent the variance contributions to the response variable changed from stands with a single species to stands of mixed hardwood species. In this research, we sampled four unmanaged, even-aged stands of second-growth mixed hardwoods located in the Southern Appalachian Mountains near Asheville, North Carolina, U.S.A. Age of the sampled stands ranged from 67 to 97 years, site index for oak ranged from 72 to 82 ft at age 50 (21 9 to 25 0 m), and stand basal area ranged from 18 4 to 27 0 m2/ha. The stands were composed primarily of upland oaks (northern red, Quercus rubra L.; black, Q. velutina Lam.; scarlet, Q. coccinea Muenchh.; white, Q. alba L.; southern red, Q.falcata Michx.; and chestnut, Q. prinus L.), and smaller amounts of yellow-poplar (Liriodendron tulipifera L.), hickory (Carya spp. Nutt), red maple (Acer rubrum L.), sweet birch (Betula lenta L.), black gum (Nyssa sylvatica Marsh.), American beech (Fagus grandifolia Ehrh.), and black locust (Robinia pseudoacacia L.). Each stand contained ten to twelve of the above species.