Leaf Litter Mass Loss and C/N for American Chestnut (Castanea dentata) Litter in Central NY: Wild Type Vs. Transgenic and Hybrid.

American chestnut (Castanea dentata) was once an integral component in northeastern US forests, providing many ecological and economic benefits; an introduced fungus rendered the species functionally extinct. Federal (USDA APHIS, FDA and EPA) policies require demonstration that transgenic tree functions are equivalent to native American chestnut. We compared foliar mass loss and elemental concentrations among two transgenic (GM1, GM2), a hybrid (American-Chinese) and wild-type (Zoar) incubated in situ using litterbags retrieved 12, 18, and 24 months. At 24 months, wild-type and GM 2 had less mass remaining (0.06 g, 0.08 g) than GM 1 (0.13 g) (p = 0.004). (p = 0.30). There was a greater range in mass remaining between the two transgenic types (GM 1 and GM 2) than between the transgenic types and wild-type or hybrid type.  There was no interaction between litter type and time.  After 24 months, wild-type leaf litter had a slightly higher C/N ratio (21) than GM 1, GM 2, and hybrid (19, 18, and 19 respectively; p = 0.006). These studies suggest that the process of genetic engineering does not have a large influence of foliar decomposition.