by Nancy Penrose
Pruning is the removal of diseased, damaged and dead tree wood. It is an important part of big tree maintenance. When done at the right time and with the right cuts, it can improve the tree’s root system and energy reserves. Pruning will also help your tree produce an abundance of new growth, including more fruits and flowers. Another benefit of pruning is that it keeps pests away and prevents tree disease.
Getting rid of dead wood can be done at any time. However, for most big trees, the best time to prune is late winter, when the coldest part of the season has passed. Pruning is easier in the winter when the tree goes dormant and the leafless branches can be seen more clearly.
Some big trees, like fall birches, dogwoods, elms, and maple tree varieties can also be pruned in the spring or summer. Try to avoid pruning in the fall when the wounds from cuts heal slower. When you prune during the summer, it is easier to see limbs that are carrying too much weight from leaves.
There are three basic types of pruning: raising and reduction, thinning and topping
Raising and reduction is used to create more clearance for utility lines, pedestrian walkways, vehicles and buildings. Reduction is the process of reducing the size of the tree. Raising refers to the removal of the tree’s lower branches.
Thinning a big tree involves the removal of limbs and branches where they join the tree. It can help promote new growth, and increase fruit and flower production. Topping is the removal of all branches down to the tree’s largest branches. Both thinning and topping are considered more aggressive types of pruning.
Before you start pruning, you should also know that tree branches join together in one of three different ways: collar, collarless or codominant. Each has a different type of pruning method that helps prevent regrowth and decay.
A collar is a swollen area surrounding the location where a branch attaches to the trunk. Branches can also be attached to the trunk without a collar (collarless). Never cut off a collar when pruning a big tree. Codominant refers to stems that grow from the same place and have the same diameter.
Major structural pruning should be done when the tree is young, the cuts are smaller and it is easier for the tree to recover from the wounds.
The general pruning starts with a top to bottom inspection of the tree. Any dead or dying branches should be removed, along with diseased limbs.
Make sure you cut the branches at an angle that mirrors the branch collar. Also remember to cut the branch in three parts. The first cut is to reduce the weight. The second cut is to prevent bark from ripping when the stub falls. The final cut is next to the branch collar.
You can get great advice on pruning big trees from a big tree expert or tree nurserys specialist. A tree nursery (Seattle) who is selling big trees will know the best way to prune your tree and can help you avoid mistakes that may cause permanent damage.
Nancy Penrose is owner of Big Trees Inc. (http://www.bigtreesupply.com), tree nursery Snohomish, WA, one of the largest Seattle tree nurseries (see inventory at http://bigtreesupply.com/sales-inventory/), specializing in tree transplanting. See our video at https://www.youtube.com/watch?v=zpactBDUPmQ