Seasonal prediction models for understory production from simple overstory measurements were developed using regression analysis. During the summer of 1976 and winter of 1976-1977, production of understory vegetation was recorded by species or species groups in timber stands on the Savannah River Plant using a 100% clip method. Overstory density and basal area were also recorded. Sampled timber stands ranged from pine regeneration sites with measurable overstory (stems > 3 cm dbh) to immature sawtimber of pine and upland hardwoods. Quadratic equations using basal area of all stems yielded seasonal regressions for woody leaf and twig production and combined woody production. Variation in the total understory forage yield (fungi, grasses and sedges, herbaceous plants and woody plants) was also explained with quadratic equations using either basal area of all stems or basal area of only large stems. No sacrifice in model stability was observed when basal area of large stems (> II cm dbh) was used. Therefore economy and efficiency in sampling can be achieved using standard plotless sampling methods.
