Pruning

Abstract

Pruning involves removal of branches for some distance up the stem of plantation trees. The most common reason is to limit development of knots in logs that are ultimately to be sawn to produce high quality timber; knots are the chief source of defect in sawn timber. Pruning often involves the removal of both live branches, that is branches with leaves still attached, and dead branches. As long as no more than about 30–50 % of the leaves on a tree are removed, the remaining leaves are able to increase their photosynthetic rate so there is no loss of growth after pruning. Often pruning is done in one or two ‘lifts’, allowing the crown of the tree to recover its former size between lifts. Pruning is usually done manually, from the ground or with the aid of ladders, using saws or shears carried on long poles. It is usually done to a height above which no logs will be produced that are large enough to produce high quality sawn timber. A pruning regime for a plantation involves decisions about when and how often pruning should be done, how far up the stem branches should be removed and how many and which trees should be pruned. These will all be chosen to ensure the cost of pruning is more than offset by the higher prices that can be obtained for pruned logs.