Seedling roots and forest floor: Misplaced and neglected aspects of British Columbia's reforestation effort?

Abstract

Concepts of planted seedling root morphology and root location are discussed in the context of reforestation in British Columbia. Comparison of root form and location between natural and planted seedlings reveals profound differences. Unnatural root morphology and delayed development of nursery-produced rooting systems, coupled with current planting techniques that emphasize vertical orientation of roots in mineral soil horizons, may exacerbate harsh microenvironmental site conditions. Inappropriate root systems may inhibit optimal seedling function and compromise long-term stand stability. The forest floor is seen as an appropriate rooting medium to which planted seedlings should be allowed ready access. A change in the biological geometry (direction and depth of root development) of the planted root system may enhance survival, establishment, and growth. The promotion of more natural, lateral, surface rooting at the organic/mineral soil interface is proposed. Site-specific root morphologies and planting strategies may be required. Key words: regeneration silviculture, tree-planting, target seedling stocktype, root egress, root morphology, root location, forest floor, soil temperature, soil moisture, frost heaving, soil nutrients, mycorrhizae, site preparation, alternative stocktypes