HERBACEOUS LAYER COVER AND BIOMASS IN A YOUNG VERSUS A MATURE STAND OF A CENTRAL APPALACHIAN HARDWOOD FOREST

This study examined herb layer vegetation (all vascular plants less-th an-or-equal-to 1 m in height) of two montane watersheds of different s tand ages in the Fernow Experimental Forest, in north-central West Vir ginia (WS3, approximately 20 yr; WS4, >80 yr). Mean herb layer cover w as 19.3 and 26.4% for WS3 and WS4, respectively. Herb layer biomass wa s significantly (P < 0.001) correlated with herb cover for both waters heds. Mean herb layer biomass was 8.1 and 11.6 g/m2 for WS3 and WS4, r espectively. Herb cover responded positively to elevation on both wate rsheds. Within WS3, herb cover was only weakly correlated with canopy characteristics, but was positively correlated with soil pH, organic m atter, sand content, cation exchange capacity, Ca, K, Mg, and NO3-N. W ithin WS4, herb cover was negatively correlated with understory basal area and density, but not significantly correlated with any soil varia bles except Ca. From these data we suggest a hypothesis that in early forest succession in these ecosystems, early herb layer development is influenced greatly by allogenic factors (such as soil fertility) but that autogenic factors, such as canopy closure, become more important as the stand matures and becomes more stratified.