Height and diameter measurement of spruce in response to harvest: 1993 - 2002

To document possible soil nitrogen mosaics before timber harvesting on three Alaskan boreal forest sites, maps of the distribution of understory green and Sitka alder stems were made. Understory alders were regularly distributed throughout the northernmost site (Standard Creek), and very irregularly distributed at the southernmost site (Cooper Landing). There were no consistent relations between alder stem location and total soil nitrogen. In undisturbed forest, soils collected beneath alders tended to have more nitrogen than soils without alder, but after the sites were harvested, soil chemistry differed. To examine the interactions of alder (Alnus crispa (Ait.) Pursh and A. sitchensis (Reg.) Rydb.) and white spruce (Picea glauca (Moench) Voss) on secondary successional sites, mixed plantations of white spruce and alder were established after each site was harvested. Despite good survival, the planted alder grew poorly. There were no differences between nursery-grown alder seedlings and alder wildlings in either growth or survival. Though fifth-year survival and growth of white spruce were excellent on all sites, they were not related to either the pre-harvest distribution of naturally occurring alder or to alders planted in the mixed plantations. Locational information and site maps are provided to encourage future evaluation of these plantations.