They’re essential for clearing fallen trees and limbs quickly, but few hand-held tools can wreck your day — and relieve you of fingers and limbs — faster than a chain saw. About 30,000 people are injured by chain saws each year, with many suffering disfiguring injuries that require an average of 110 stitches and leave lifelong scars.

Safe chain saw operation starts long before the saw does, with a combination of the right equipment, good saw maintenance and knowledgeable cutting technique.

What to wear

Experts recommend that even occasional chain saw operators should take safety cues from commercial loggers and arborists and dress in appropriate safety gear.

  • A helmet and face shield are essential if you’re felling trees or working under branches after a storm. A Minnesota study found that falling trees or limbs cause nearly 90 percent of chain saw-related deaths.
  • A good set of safety goggles is important eye protection when working with downed limbs or logs on the ground to protect eyes from sawdust and splinters.
  • Ear muffs or ear plugs offer protection from engine noise, especially if you’re looking at several hours of work. Some gas-powered chain saws can easily top 100 decibels. At that volume, Occupational Safety and Health Administration (OSHA) rules limit unprotected exposure to two hours per day to avoid permanent hearing damage.
  • Gloves are critical, as injuries to the hands and arms are the most frequent chain saw mishaps. Look for a set of well-fitting gloves made with a combination of leather and cut-resistant ballistic fabric. Choose a pair that’s not too bulky to allow for better saw control.
  • Cut-resistant chaps are strongly recommended because legs are the second most frequent sites for chain saw injuries. The multi-layer fabric is designed to catch in the teeth of the saw, stopping it from advancing into the leg. They’re a bit bulky and cumbersome to move in, but OSHA rules make chaps mandatory for commercial tree workers.

Before starting the saw

Know the different parts of the saw and how they operate. (This would be a great time to read the full owner’s manual, and not just the quick start guide.)

Check that there’s enough bar oil in the reservoir, and that the chain guide bar is applying the correct amount of tension to the chain. Too much, and the saw will work harder to slide the chain along the bar, increasing the risk of overheating. Too little tension, and the chain will sag too far below the bar, increasing the risk of the chain breaking or whipping off the bar. Most saws should come with a tool for adjusting chain tension, usually by screws at the base of the bar.

With the saw on the ground, make sure the saw’s safety features are secure. A hand guard in front of the top handle should apply pressure on a chain brake. Many newer saws come with a guard at the bar tip to prevent kickback, which is when the tip of the saw grabs into the wood and recoils violently upward. It can happen without warning, catching the operator unaware and sending the moving chain into the face, neck or chest. About 85 percent of chain saw injuries happen from contact with the moving chain, and kickback is the leading cause.

The right way to cut

Proper cutting technique also will help reduce the chance of injury. There are entire courses devoted to tree felling, but most people who aren’t commercial loggers just need to know a few important steps.

  • Start the saw and get it to full speed before cutting.
  • To avoid kickback, try to cut with the base of the saw and not the tip.
  • Brace the saw’s lower bumper spike against the wood to prevent the chain from wrenching the saw away from you.
  • When cutting, stand to the left of the saw, never directly over it. Any kickback should be directed off to the right.
  • Don’t cut above shoulder height. It’s much harder to maintain control and increases the chance of an upper-body injury. If you need to remove limbs above your head, consider renting a small pole saw.

Know when to call the pros

Felling a broken or leaning tree raises the degree of difficulty and presents additional safety hazards. Avoid working on any standing tree that’s partially caught in branches of other trees or has large broken limbs suspended by other branches. Loggers in the Pacific Northwest call these trees “widowmakers” for a reason.

Mike Saunders is a former Boston Globe writer who spends entirely too much time in his garage.