Pine Stem Rust Management Guidebook
Table of Contents
Appendix 3. Guidelines for pruning white pine
Surveys indicate that older and larger trees are more likely to have stem cankers. Therefore, trees should be pruned as early as possible in order to maximize their probability of survival. Pruning is usually performed in two lifts. The first lift is for survival; subsequent lifts are for value although future survival is a consideration.
- Prune when mean white pine height is 1.0 to 2.5 m for plantations.
- Prune when mean white pine height is 1.5 to 3.0 m for natural regeneration.
- Prune to 50 per cent of total tree height. On coastal sites or vigorous interior sites, pruning may be conducted to 65 per cent of total tree height. While some growth loss may result, rapidly growing white pine will usually recover in two or three years. On interior sites with leader growth of less than 50 cm per year, growth loss should be avoided by restricting pruning to 50 per cent of total tree height.
- Selectively prune infected branches above target pruning height.
- In areas with high hazard, consider pruning as early in the tree's life as possible (this may result in the necessity for a third lift).
- Prune when mean white pine height is 5.0 m or greater.
- Prune to 3.0 m height or 50 per cent of total height (2.5 m is usually sufficient for control, but 3.0 m is better and is desirable for additional wood quality benefits).
- Prune any smaller white pine to 50 per cent of total tree height.
- You may combine this treatment with pruning of other species to improve wood quality.
A 3rd lift (to approximately 5.5 m) may be performed later to improve wood quality. A three-lift system is mainly recommended when white pine is used in reforesting a root disease area.
- Prune all branches, both live and dead, below target pruning height.
- Prune flush with branch collar (not flush to the bole); avoid leaving long stubs.
- Look for ground level branches that may be obscured by needles, duff, or vegetation.
- Trees less than a specified minimum height (will vary) may be excluded from pruning at the time of the 1st lift; they should be tall enough to prune at the time of the 2nd lift. Trees less than the minimum height at 2nd lift will likely not form part of the overstorey.
- Trees with stem cankers (including lethal branch cankers) should be treated as follows:
– on pruning contracts, fall or leave unpruned
– on spacing or brushing contracts involving power saws, fall.
Refer to the Pruning Guidebook for more detail on proper pruning techniques.