Wednesday, September 22, 2010

Workshop on Fomes Annosa (Heterobasidion annosum)

Yesterday, Sept 21, 2010, I attended a workshop on Fomes Annosa (Heterobasidion annosum) (FA) which was put on by Richard Wilson Phd. a tree pathologist with the Ontario Ministry of Natural Resources based out of Sault Ste Marie. It was held at the Larose Forest which is located about 50 kilometres East of Ottawa.

FA is a fungus that attacks particularly red pine (Pr) trees and only affects injured trees since it gets in through the wound.

The morning consisted of technical presentations including an Overview of Forest Health in Ontario, Fomes Root Rot in Ontario, and Overview of the Pesticides Act and Regulations: What You need to know in order to apply pesticides. The first two presentations were provided by Dr. Wilson while the pesticide presentation was given by Scott Olan, Pesticide Specialist with the Ontario Ministry of the Environment.

In the afternoon we proceeded out to the forest to observe signs and symptoms of Fomes Annosa, discussion on Red Pine management, and various management methods and options.

Heartwood includes a number of small red pine (Pr) groves. FA effects mainly the Pr and what makes it so unique is that Pr roots will graft together with roots of neighbouring Pr trees and share nutrients.

What I learned from this workshop was how trees are exposed to the FA and methods to identify the disease and to minimize its spread. A Pr becomes particularly susceptible when it is cut down. The stump then becomes a scar where the fungus can take hold and it then can travel to the neighbouring trees through the grafted root system killing the neighbouring trees. 

One of the interesting methods of controlling this spread it to dig a trench around an affected area thus effectively cutting off the root connections with neighbouring trees. This technique was used in the Larose Forest long ago and it proved to be quite effective since healthy neighbouring trees outside such a trench survived well. We looked at three such trenches which looked like meteor craters or imitations of Stonehenge.

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