Stem maps of the 4rees on 8.16 ha of Donaldson's Woods were used to help identify logs and estimate their ages on the forest floor. I collected 162 samples from 126 different logs representing 10 different genera. Logs were assigned to age classes based on information from the stem maps and assigned to decay classes by physical appearance. Total log frequency was 37.6 logs/ha. Mean log input rate was 2.52 log/ha/year. Oak-log biomass, area and volume were calculated. Oak-log decay was calculated as Y = .5402 exp (-0.0295 t), where Y = density in g/cc, t = time in years (n = 62, r2 = 0.949). An average oak log takes ca. 75 years to decay to 1/10 its original density. INTRODUCTION An essential step in ecosystem nutrient cycling is the decay of plant litter, and since logs represent a relatively large pool of nutrients temporarily stored on the forest floor (Lang and Forman, 1978), studies of log accumulation and decomposition are important to estimates of total nutrient budgets (Bormann and Likens, 1979; Waring and Franklin, 1979). However, tree death and subsequent decomposition of woody material is a largely unknown component in forest nutrient cycles. There are considerable data on leaf-litter decomposition and nutrient cycling in both deciduous and coniferous forests (e.g., Edwards et al., 1970; Duvigneaud and Denaeyer-DeSmet, 1970), but there is much less information on decomposition and nutrient turnover from larger woody inputs such as downed tree trunks (Bormann and Likens, 1979; Waring and Franklin, 1979). Estimates of woody litter production were reported by Bray and Gorham (1964), McFee and Stone (1966), Cromack (1973), Cromack and Monk (1975), Grier and Logan (1977), Lang and Forman (1978), Bormann and Likens (1979) and Waring and Franklin (1979). Woody litter accumulation is widely variable, depending on climatic conditions, density of stand stocking, availability of nutrients and decay rates. Decay rates of woody litter are difficult to measure. In three studies that have been done, McFee and Stone (1966) described decay of logs over 100 years old, but they did not report a decay rate. J. E. Means (pers. comm.) reported a decay rate for Douglas fir logs in Oregon, and Odum (1970) reported a decay rate for logs in a Puerto Rican rain forest. Like decay of leaves and small branches, log decomposition appears to be correlated with climate and with substrate quality of the wood (Fogel and Cromack, 1977). Since summers in southern Indiana are warm and wet, decomposition rates are expected to be rapid (cf. Olson, 1963). The objectives of this study were to measure the number of logs/ha, and to calculate input rate, woody biomass and decay rate of logs found in a deciduous forest in S-central Indiana. A secondary objective was to test the applicability of a five-class scheme that allowed categorization of logs into different decay classes. SITE DESCRIPTION Donaldson's Woods, the site of this study (38?45'N and 86025'W) is a nearly classic example of Braun's (1950) western mesophytic deciduous forest, or using Bailey's (1976) classification, it is on the border between the beech-maple and oakhickory forests, and contains white oaks (Quercus alba) over 90 cm diam and tulip trees (Liriodendron tulipifera) over 112 cm diam. Because the Woods is an Indiana State Nature Preserve, and living trees cannot be cut or harmed, I could not increment-bore any trees to estimate the age classes. The area studied was 3.35 ha at the northern end