[MAIPC] Castanea dentata PPT at Ecological Society of America, mid-Atlantic chapter meeting

[Richard Gardner]

 This past weekend I presented a PPT at the mid-Atlantic chapter of the Ecological Society of America on the local status of Castanea dentata from walking the Appalachian Trail and other trails near home in central PA. (It can be found at http://www.slideshare.net/rtgardner3.)

 I reached several conclusions, the three most important are:

  1.) that hybridizing the American Chestnut with the Chinese Chestnut is creating a non-native species with little to no ecological utility using invasive plant theory, mostly Enemy Release Hypothesis. Added to this is the apparent back crossing being done adds to the destruction of the ecological utility based on the idea that the further from the wild plant the more changes to the physical and chemical properties of that plant. Along with this my thinking is that native organisms apparently require high genetic heterogeneity to be give enough variation within the species utilized to match the variation in native organisms utilizing them. Annie S. Smith at the University of Vermont is apparently working on this idea with nativars.

  2.) diseases and pests such as Bacterial Leaf Scorch (Xylella fastidiosa), Emerald Ash Borer (Agrilus planipennis) , Gypsy Moth (Lymantria dispar dispar) the Hemlock Wooly Adelgid (Adelges tsugae) and the Elongate Hemlock Scale (Fiorinia externa) are opening up the canopy. C. dentata was a canopy tree. These diseases and insect pests are helping C. dentata grow back into the canopy and again become an integral part of the Appalachian forest. This is an interesting reversal of much of what we see and fear. However, it will be happening at the costs of other plants which are an integral part of our forests.

  3.) the limiting factor in tree reproductive success is not the Chestnut Blight (Cryphonectria parasitica), but rather access to direct sunlight on the apical ends of branches. This was clearly demonstrated locally by the contrast between trees in below the canopy in the local forests which we not reproducing and trees along the gamelands service roads cut by the PA Game Commission which had direct sunlight and were reproducing.

                                                                                                                           Richard Gardner