California Agriculture

Blue gum eucalyptus (Eucalyptus globulus) is a large tree native to Australia that was widely planted throughout California for reforestation, building and timber, but in some areas has spread beyond its planted borders and substantially altered wildlands. Due to its fast growth, large size and reproductive potential, blue gum's impacts on native vegetation, wildlife and ecosystem processes are of concern, particularly in areas with reliable year-round rainfall or fog, where it is most likely to spread. Depending on levels of invasion and rate of spread, blue gum may have negative, positive or neutral impacts on fire regimes, water and nutrient availability, understory vegetation and higher trophic levels. Additional research on the abiotic and biotic impacts of blue gum, quantitative estimates of area covered by blue gum, and weed risk assessments that allow for region-specific climatic information and management goals to be incorporated are needed to guide management of blue gum populations.