Canadian Forest Service Publications
Cytospora canker of poplars: Bark wounding in relation to canker development. 1963. Bloomberg, W.J.; Farris, S.H. Canadian Journal of Botany 41(2): 303-310.
Issued by: Pacific Forestry Centre
Catalog ID: 23932
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Cuttings of Populus trichocarpa Torr. and Gray, P. × canadensis Moench 'Regenerata' and P. × canadensis ‘Robusta Bachelieri’ were adjusted to three different moisture contents, then wounded by scorching the bark. The moisture treatments differed significantly in their effects on the histological responses in tissues around the scorch wounds, the greatest contrast being in the mode of tannin deposition. Lignification was also affected by moisture content; however, fewer cells were involved in lignin changes than in tannin deposition. No suberization was observed as a result of wounding. There were qualitative and quantitative differences among the poplar varieties with respect to tannin deposition. When wounds were inoculated with Cytospora chrysosperma (Pers.) Fr., the growth of canker varied inversely as the number of tanniferous cells, the width of the tanniferous zone, and the number of lignified cells. The correlation with tannin deposition was much stronger than that with lignification. These findings suggested that the relationship previously observed between Cytospora canker growth and moisture content may operate partly through the mechanism of tannin deposition.