Canopy research in north-central British Columbia: an exploration of lichen communities

Wet temperate spruce-fir (Picea engelmannii/ Abies lasiocarpa) forest communities at high elevations in east central British Columbia are host to an abundance of epiphytic lichens. The distribution and diversity of these appears to be strongly influenced by stand structure and attributes of canopy architecture. We have characterized the distribution of arboreal lichen communities along gradients in canopy structure by combining biomass estimates and subsample verification with single rope access techniques. Integrating newly developed techniques with modified existing methodology results in a reliable and objectively collected data set to describe the abundance of epiphytic lichens. Fruticose lichens respond significantly to vertical gradients separating the two fruticose functional groups (Alectoria and Bryoria) into distinct strata within the canopy. The strength of this vertical influence appears to minimize the response of fruticose lichens to other gradients in the canopy environment. The distribution of foliose lichen, in contrast, does not respond to height, but appears to be more strongly influenced by changes in the substrate availability. The most significant response of this lichen group is therefore to changes in the diameter of the host branch. Although all three functional groups (Alectoria, Bryoria and foliose lichen) show notable responses to gr ~ tand age and size, only the two fruticose lichen groups are influenced by the clumped tree distribution of the ecosystem. The management implication of these responses to canopy architecture and stand structure have been explored.