Relationships Between External Features and Trunk Rot in Living Yellow Birch
1968
Lavallée, André | Lortie, Marcel
Although broken branches and branch stubs are the most frequently encountered external signs of defects in the trunk of yellow birch, they were found to be less important than mechanical injuries as indicators of the incidence and volume of decay. Frequency and extent of decay were directly related to the extent of wood surface exposed after an injury. Presence of decay, as related to size of wounds, differed in the two localities studied. The rate of linear extension of decay was higher when the causal organism had penetrated through larger wounds, especially in older trees. Heartwood discoloration was found in similar amounts at all the sites studied, and trees with extensive columns of discoloration usually showed numerous visible injuries. A pathological classification of yellow birch, based on external signs, and which seems to be adequate for the selection of high quality trees in a stand, is presented.
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