BC’s Inland Rainforest – Conservation and Community
Changes in Stand Structure, Vascular Plants, and Ectomycorrhizal Fungi over Stand Age in Forests of the ICH
Craig Delong 1 and Marty Kranabetter 2
A lot of current research has focused on the rich arboreal lichen communities of the inland rainforest, but it is important to understand the dynamics of other biological guilds within these forests. This presentation summarizes work by the authors on changes in vascular plant and ectomycorrhizal fungal communities, as well as stand structure related to wildlife habitat, over stand age in forests of the Interior Cedar Hemlock zone. In the ICHvk2 young (< 50 yrs old) fire origin stands are generally dominated by dense western hemlock, but occasionally spruce on cooler sites or deciduous coniferous mixtures on drier warm sites. In contrast to climax forests, we find understory vegetation very poorly developed in these young hemlock stands. Hemlock stands in the ICHwk3, on the other hand, which have little understory community prior to disturbance, can develop high cover of red raspberry and elderberry in response to hemlock looper mortality and it’s beneficial effects on light and nutrients. Ectomycorrhizal fungi comprise a diverse community in the ICH that is profoundly affected by disturbance. Reestablishment of ectomycorrhizal species is influenced primarily by dispersal rates and habitat suitability, and many species do not persist in young stands until after canopy closure. Recovery of climax species assemblages took approximately 75-100 years in the ICHmc2, and diversity peaked in mixed, mature stands before declining slightly as early-seral host tree species (paper birch, lodgepole pine) died out. Green tree retention in disturbed areas were very effective in maintaining ectomycorrhizal species of mature stands, and these biological legacies will facilitate succession during stand development. Stand structure differences between old (>120 yrs) and very old (>250 yrs) forests within the ICHwk3 were significant, with more wildlife habitat attributes found in very old stands. This includes higher number of trees with cavities, cracks, loose or deeply furrowed bark, as well as the number of tree stubs, the number of large (> 50 cm diameter) trees, and the number of CWD pieces important as den habitat or hiding cover. The results of these studies emphasize the value of mature and old-growth ICH forests in maintaining a wide diversity of plant, fungal and wildlife communities.
1 Research Ecologist, Northern Interior Forest Region, Ministry of Forests and Range, 1011 4th Ave., Prince George, B.C. V2L 3H9. Email: firstname.lastname@example.org
2 BC Ministry of Forests and Range, Smithers, BC. Email: email@example.com
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