Species richness on logged sites remained relatively flat across the stages. Species turnover was greater between stages on burned sites than between stages on logged sites. Surface organic layer was twice as deep on logged sites in each stand development stage compared to burned sites, suggesting that element availability may be lower on logged sites. Logged sites appear to initiate succession with substantial patches of the original older forest understory and its complement of species intact, and appear not to support a set of specialist fire-dependent species. Burned sites appear to be more uniformly disturbed, to support several fire-dependent species, and to experience more complete turnover of species between successional stages than logged sites.
Forest structure is the key to species diversity.
Figure x is a synthesis of the contributions and consequences for species diversity of the entire life cycle of the white spruce ecosystem. Key structural features control species richness, mediate competition, and influence processes which can feed back into species controls. For example, arboreal lichen abundance is inferred to be largely a function of time for canopy development. Vascular richness appears to oscillate and turn over, at least partly, in composition from early to later succession. I represented the BNZ site at a September 1996 workshop on the relationship of species diversity and productivity at the National Center for Ecological Analysis and Synthesis.