Abstract
I studied an invasive tree species black locust (Robinia pseudo acacia L.), in BC's Lower Columba Valley (LCV). Black locust has invaded forests and open lands since its introduction to revegetate disturbed slopes in the 1940's. I conducted research to help my partners Teck Metals Ltd. achieve three goals: (1) assess the ability of aerial imagery to support visual identification of black locust stands and recommend strategies for improving black locust identification, (2) identify abiotic conditions and native vegetation species associated with risks of black locust invasion, and (3) develop strategies to contain new black locust invasions in the LCV and remediate sites invaded by black locust. Aerial imagery successfully helped identify flowering black locust trees but did not help identify non-flowering trees and black locust shrubs and recruits. Black locust cover increased in association with increasing temperature, light availability, moisture availability, and soil disturbance, but black locust did not occur on sites with permanently saturated soils. Black locust was associated with early-seral deciduous tree species including black cottonwood and trembling aspen and the native conifer species western white pine and Douglas-fir. Black locust was not associated with later-seral coniferous species associated with either hot and dry conditions (including ponderosa pine) or cool conditions (including western hemlock). Black locust invasions may be able to be contained and restored by physically remediating disturbed sites, removing black locust on disturbed sites, and planting native tree and shrub species to stabilize soils and reduce black locust seedbank and rootstock establishment and maturation success by outcompeting black locust for light, space, and moisture. Native forests may be able to be re-established on sites invaded by mature black locust stands by protecting sites from further disturbances, restoring native tree species throughout the region to increase propagule availability and re-colonization success, and planting native tree and shrub species to replace maturing black locust stands with native mid- and later-seral forest species.