Effects of intensity and frequency of harvesting on abundance, stocking and composition of natural regeneration in the Acadian forest of eastern North America
Silva Fennica 30(23): 301314
In a silviculture experiment in east-central Maine, USA, natural regeneration was sampled to measure the effects of: (1) a range of partial harvest intensities, and (2) repeated partial harvest at one intensity. Under the first objective, five treatments were compared with residual basal areas ranging from 15 to 24 m2 ha–1 for trees ≥ 1.3 cm diameter at breast height. For the second objective, regeneration was evaluated after four harvests at 5 year intervals. Prior to harvests, the overstory of all the treated stands was dominated by Tsuga canadensis (L.) Carr., Picea spp. A. Dietr., and Abies balsamea (L.) Mill. Eleven species or species groups were identified among the regeneration: A. balsamea, T. canadensis, Picea spp., Thuja occidentalis L., Pinus spp. L., Betula papyrifera Marsh., Acer rubrum L., Betula populifolia Marsh., Populus spp. L., Fagus grandifolia Ehrh. and Prunus serotina Ehrh. Regeneration abundance was measured as counts of seedlings or sprouts taller than 15 cm but with diameters less than 1.3 cm at breast height (1.37 m). Regardless of harvest treatment, total regeneration was profuse, ranging from over 25 000 to nearly 80 000 trees ha–1. Regeneration was dominated by conifers with a total angiosperm component of 10 to 52 percent approximately 5 years after harvest and 11 to 33 percent after 10 years. Consequently, in forests of similar species composition, tree regeneration following partial harvests should be sufficiently abundant with an array of species to meet a variety of future management objectives.
Received 22 September 1995 Accepted 13 June 1996