BRYOPHYTES IN OLD-GROWTH FORESTS OF WESTERN MASSACHUSETTS

Old-growth forests constitute rare habitat that may support rare bryop hytes (mosses and liverworts) or provide refugia for populations once more widely distributed. This study was undertaken to determine what d ifferences, if any, can be found between the bryophyte flora of old-gr owth and nearby second-growth forest sites matched for elevation, slop e, aspect, and forest type. Bryophytes were censused on trees, logs, r ocks and exposed soil in four western Massachusetts old-growth stands and in four second-growth stands. Ninety-one bryophyte species were id entified; the majority of species were sparsely distributed. Several s pecies either occurred only in old-growth or were most abundant in old -growth, although no species was strictly associated with old-growth. The total number of species on trees in old-growth is nearly twice tha t of species on trees in second-growth, and Acer saccharum in old-grow th hosted more bryophyte species than Acer saccharum of same diameter in second-growth. Abundances of substrate available for bryophyte colo nization were similar in old-growth and second-growth. Although old-gr owth and second-growth plots had similar bryophyte floras, there may b e important differences in habitat provided by these forest types, and some less common species may be slow to recolonize cleared areas.