Edge Modification Study - Treatment Effectiveness
Results of Chuck Rowan’s Edge Modification Study in Coastal BC
- Compared to damage in controls, pruned, topped, and feathered treatment
units had 30–50% less wind damage during the first winter after treatment.
- Treatment units with combined feathering plus crown modification had
65% less damage than untreated controls.
- For the blocks with more than one year of post-treatment measurements,
the majority of damage occurred during the first winter. There is a
slight increase in standing tree mortality in the fourth year after
treatment in some of the pruned/topped treatment units.
- Untreated trees in the pruned and topped treatment units are more
vulnerable than treated trees of similar size in these units.
- In the control units – slender trees were more vulnerable, trees with
rotten branches or mistletoe were more vulnerable.
- Stands with a higher amabilis fir component were more vulnerable than
stands with a higher cedar component.
- Only 30% of new leaners blew down over the second winter.