Club News

Club meeting, August 9, 2017 - Trees in Philadelphia
Club meeting, August 9, 2017 Ken Leroy, arborist Although the large amount of rain this year has been very beneficial to trees in general, Ken Leroy, local arborist at John B. Ward Co., focused his talk on the insect threat to the ash tree. Ash trees constitute about 10% of the canopy community cover in this area, and every single one of those trees is under attack by the emerald ash borer. Although the individual homeowner may possibly protect his or her ash tree by an annual application of chemicals, Leroy predicts a near total demise of the ash trees in this area and in many areas of the country. The ash borer has been found now in 30 states and in Canada. One may get an image of the destruction already wrought by driving in Horsham on route 202 near route 309. Silhouettes of dead trees are all over the horizon; these are ash trees. There are various ways of protecting other types of trees. For example, a scientist at the State University of New York has used genetic modification to create a new chestnut tree. This tree can be cloned, but any new development must be matched by diversity as well. Leroy thinks it will take about a century to reestablish the chestnut. Other varieties of trees are also threatened by other insects and viruses. Ken does not support the movement of having only native trees; he thinks that some exotics could help save our forests. He also noted the lack of diversity in many areas due to the practices of developers and nurseries. When planting new stock, they choose the fastest growing and cheapest trees, often leading to monoculture areas. Nurseries follow a similar route. An example of this is the proliferation of London plane trees and sycamores on many streets in Philadelphia and the lack of variety of trees in many suburban developments. Ken will coordinate a conference on tree diversity in October in conjunction with several institutions. Contact him for information: