We know: How to Prune Trees

What is tree pruning?

Tree pruning means to cut away or remove dead or living parts of a tree, usually the branches.

What's the purpose of pruning a tree?

The more common reasons for pruning trees are to improve the health and shape of the tree, as well as cutting away potentially dangerous branches. Pruning can also stimulate fruit production and increase the value of timber.

What are the general natural shapes of trees?

Trees have many forms, but the most common types are shaped like a pyramid or a sphere. Trees with pyramid crowns, e.g., most conifers, have a strong central stem and lateral branches that are more or less horizontal and do not compete with the central stem for dominance. Trees with spherical crowns, e.g., most hardwoods, have many lateral branches that may compete for dominance.

What are the different approaches to pruning?

Proper pruning cuts are made at a node, the point at which one branch or twig attaches to another.

The most common types of pruning are:

Crown thinningprimarily for hardwoods, removes branches to increase light penetration and air movement throughout the crown of a tree. Branches with strong U-shaped angles of attachment should be retained . Branches with narrow, V-shaped angles of attachment should be removed
Crown raising means removing branches from the bottom of the crown of a tree to provide clearance for pedestrians, vehicles, etc. On young trees "temporary" branches may be retained along the stem to encourage taper and protect trees from vandalism and sun scald.
Crown reduction pruning, sometimes called drop crotch pruning, is used on trees that have grown too large. A method of last resort, it results in large pruning wounds to stems that may lead to decay. This method should never be used on a tree with a pyramidal growth form. A better long term solution is to remove the tree and replace it with t will not grow beyond the available space.

When should I prune?

Different types of trees should be pruned at different times.

Conifers may be pruned any time of year, but pruning during the dormant season may minimize sap and resin flow from cut branches.
Hardwood trees and shrubs should be pruned in the dormant season. However, trees that flower in the early spring should be trimmed immediately after flowering. Other flowering trees should be pruned in the dormant season.

Tell me about pruning tools.

Hand pruners are used to prune small branches (under 2.5 cm diameter)

Slightly larger branches may be cut with small pruning saws (up to 10 cm) or lopping shears (up to 7 cm diameter) with larger cutting surfaces and greater leverage. For larger branches, use larger pruning saws.

Chain saws are preferred when pruning branches larger than about 10 cm.

Pole pruners must be used to cut branches beyond reach.