Specific goals include determining current levels of gene exchange between poplar plantations and wild stands, characterizing establishment of hybrid poplars, simulating potential spread of transgenic trees, and evaluating potential impacts. Forest trees pose difficult obstacles for genetic risk analysis because of their long generation times, large size, and potential for long-distance dispersal of pollen and seed. We must therefore use established stands for retrospective studies of gene flow, and simulation models to explore the consequences of introducing new genes into the environment. Using data from these gene flow studies and a spatial database derived from digitized air photos, I am developing a spatial simulation model to explore the complex processes involved in gene escape. I have also begun developing the spatial simulation model by obtaining a digitized map of cottonwood populations in the vicinity of plantations in my study area.
Data structures are in place and model preprocessing is complete.
All functions are outlined, and coding is underway. The entire project will be completed by the end of the year. I expect habitat creation, propagule pressure, and hypothetical transgenic fitness to be the primary factors affecting modeled transgene movement. S.Leonardi, S. Cheng, and S.H. Strauss. Assessing potential risks of transgene escape from fiber plantations.