American chestnut (Castanea dentata) was once a major component of eastern North American forests. It provided more food and habitat for wildlife than oaks. The timber is valuable, and the growth rate exceeds other hardwood species. Blight resistant hybrid chestnuts share most morphological characteristics with C. dentata, so studying C. dentata establishment and early growth will help develop more effective methods for establishing blight resistant hybrids. This study examined the effect of shade levels (open, 33% tree canopy cover, and 50% canopy cover) and a novel leaf spray fertilizer supplement, Accele-Grow-M™ (Accelegrow Technologies), on the first year growth of C. dentata seedlings. The fertilizer supplement has demonstrated promising results from agriculture, but no studies have been published on hardwoods. Unlike standard soil fertilization, it has a targeted delivery system to individual plants through the leaves, so off target fertilization and soil pollution are minimized. Standard fertilization of C. dentata is correlated with increased root necrosis, and we hope to avoid this by using the leaf spray.  

Results/Conclusions

About 65% of the trees were alive and unbrowsed at the end of the 2009 growing season. Comparison of the marginal means shows that the growth are significantly different among some of the treatments. Relative basal area and root collar diameter growth of seedlings treated twice with fertilizer supplement was approximately 25% greater than control trees. The relative basal area and root collar growths were about 60% greater in the open than under the 50% canopy cover. The effects were non-significant for relative height growth. Control and single application trees did not differ significantly in any growth measures. There was some root collar swelling due to disease that was not distinguished from growth. Survival did not differ significantly among fertilizer or shade levels. A higher incidence of P. cinnamomi was observed in the seedlings growing in the open than those under tree canopy.