You'll want to trim trees for various reasons, mainly attributed to tree health, safety and aesthetic reasons. For some trees, particularly fruit trees, trimming may increase fruit production. Tree trimming supplies primarily include the different trimming tools required to trim various diameter branches. You'll only need hand tools for smaller trimming jobs, but use power trimming tools for large branches.
Hand pruners are used to prune the smallest branches, less than 1 inch in diameter. Anvil-style hand pruners work by cutting with a straight blade against an anvil when you squeeze the handles. Bypass pruners have a curved blade that slides against a lower blade, similar to scissors. Both are available in left- or right-handed styles. Most landscapers prefer the results of a bypass pruner because it doesn't crush branches as anvil types tend to do.
Pruning saws cut larger branches up to 4 inches diameter in size. They provide for more leverage and often come equipped with a pull stroke and long teeth for a clean, quick cut. Most offer steel blades that you can sharpen or replace as needed. Handles usually have comfortable foam grips. Some models are battery-operated to make trimming almost labor-free. Extensions are provided with some pruning saws to make it easier to reach higher branches.
Chain saws are typically used for branches more than 4 inches in diameter. This tool proves dangerous to inexperienced operators and should only be used if necessary--trim when branches are smaller--or contact a professional to perform the trimming. Chain saws are available in gas or electric powered models. This powerful tool cuts large branches quickly as it rotates a chain of sharp blades very quickly. Some chain saws are equipped with safety features, such as a chain catcher that protects the operator if a chain breaks, to protect you from the potential dangers of using a chain saw.