Conceptualizing the ‘old-growth’ stage of development along chronosequence and productivity gradients in the coastal maritime boreal forest

Abstract

I investigated stand development along chronosequence and site productivity gradients in Nova Scotia’s coastal black spruce (Picea mariana) forests. I determined if gap-phase dynamics was contributing to uneven-aged structures, which is indicative of the ‘old-growth’ stage of stand development and increased structural complexity in lowland and upland ecosites. I found that small-scale disturbances were resulting in uneven-aged structures as the age of the oldest 30 % basal area increased. The upland sites had a higher growth rate, which was resulting in increased susceptibility and faster development of uneven-aged structures compared to the lowlands. Larger structural features and increased species diversity were not observed as stands aged. Older aged stands did exhibit decreased snag volume in the lowlands and increased snag density in the uplands. The onset of the ‘old-growth’ stage of development in the coastal boreal forest appeared to occur earlier than inland boreal forests located in Ontario and Quebec and other climax forest types in Nova Scotia. Because coastal black spruce forests are climax communities that exhibit unique structural features later in stand development, they should be included in regional old forest management practices.