Compression wood was measured by placing thin (3mm), waterlogged, slices of wood on a light box. The compression wood was located by its darker colour. The position of the compression wood was marked on tracing paper, and then digitised into an ARC/INFO coverage. The proportion of the cross-sectional area of the stem occupied by compression wood was calculated using an AML. Weighted compression wood area (where greater emphasis is given to compression wood at near the bark than to similar wood near the pith) was also calculated but the results were generally very similar to those reported here.
Each bar represents data from a different height in the tree.
A consistent pattern of a greater proportion of compression wood in the snapped trees, tha in either the overturned or undamaged trees was found. The differences were not however quite significant, presumably because of the relatively small sample size. However, a similar trend was found in the trees from Grizedale and in the snow damaged trees from Blackhall Forest. It appears therefore that compression wood, may be associated with the determination of whether an individual tree will snap, rather than blowing down or remaining undamaged. .
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