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www.arborage.com ARBOR AGE n SPRING 2015 25 TRAINING & EDUCATION once again, some knowledge of proper pruning and a willingness to get in the proper position can eliminate this problem. Chain saws: "Bringin' the power" is certainly needed in some pruning operations, particularly in larger trees, but chain saws should only be used in pruning cuts that require their power and chain speed. The reality is that even with the best of saw control, small-diameter pruning cuts done with a chain saw are going to be ragged and very poor quality. Larger diameter pruning cuts that require a chain saw also require the operator's utmost attention to detail and saw control to result in an adequate fi nished cut; and, should time allow it, might best be "fi nished" with a hand saw cut in the proper location once the weight of the piece is removed via the chain saw. LOCATION, LOCATION, LOCATION The most important thing to understand and implement when pruning is the location of the fi nal cut. The fi nal cut should be made just outside the branch collar in order to allow the tree to respond properly to the newly created wound. Cuts in the collar of the branch itself will slow the process wherein the tree puts tissue over the wound, possibly leading to decay into the trunk of the tree or parent branch itself. Cuts too far from the branch collar will leave a stub that the tree will have diffi culty covering with tissue, and once again perhaps leaving access for decay or pathogens. In the event of a dead branch where the collar has extended outward on the dead branch tissue, often seen in oaks, the cut should still be made right at the edge of the collar regardless of whether it seems to leave an unsightly protrusion or not. BASIC STRATEGIES Pruning a tree may be done for many reasons — some have to do with the health of the tree, some have to do with the desires of humans. Regardless of the inspiration for the pruning, it should be done in a manner to cause the tree the least stress possible. While an individual tree's response to pruning will depend on condition, site, and species, in general, a younger tree will tolerate pruning more readily than a mature tree. A basic guideline is that no more than 25 percent of a tree's living canopy should be removed at any one time; and pruners should keep in mind that pruning is certainly a case of "less is better" if possible. Unless human-required pruning needs are involved, most trees are well served by simply removing deadwood, broken, and crossing branches — with the 25 percent rule in mind of course. Trees that are pruned at a younger age for good structure will require less pruning as they mature, which is an excellent point to make to the customer at that new tree installation. Pruners should attempt to keep in mind the "pruning cycle" the tree Regardless of the inspiration for the pruning, it should be done in a manner to cause the tree the least stress possible. While perhaps hard to believe, the vaguely circular area is where a previous pruning cut has been covered over. An example of the branch collar-pruning cut interaction.