Spatiotemporal variation in black spruce cone and seed crops along a boreal forest - tree line transect.

摘要: To assess the relationship between regenerative potential of black spruce (Picea mariana (Mill.) BSP) and latitudinal thermal gradients, cone crop was monitored in same selection trees during 1989-1995 period northern boreal forest (sites A, n = 49, B, 48), southern forest-tundra transition zone (site C, 35), at tree line D, 21). The size crop, amount seeds extracted per cone, along with percentages filled seed germination were measured on each tree. There no south to north trend associated crop. not significantly lower than either southerly sites six seven observed years. number percentage seeds, showed significant decrease northward according year. Although there temperature production over study...