If your clients ask for help with maintaining their valuable trees, is your crew ready to handle the job?
Houses become homes and streets become boulevards thanks to the trees in our landscapes. And they are workhorses for humans, too. They shade homes and lower energy bills, increase the property values and provide shelter and shade. Making sure trees are healthy and well cared for is critical to their continued service around homes and along streets.
“Trees in the landscape make life healthier, more pleasant and safer, so their care is central to our well-being,” says R.J. Laverne, urban forester for The Davey Tree Expert Company. “Proper pruning is the first and most important step of tree care.”
If your company offers tree care services, including pruning, it’s critical to know why, when and what to prune—and how to do it safely.
“Pruning has a purpose,” says Laverne. “Cuts made to a tree without a clear intention actually jeopardize its health and growth,” he adds.
Over time, weather conditions and environmental factors can leave tree branches diseased and broken to the point where they can no longer be saved. Pruning eliminates the risk of having this inferior material in a tree’s canopy.
“Removing dead, broken and diseased branches has two purposes,” says Laverne “First, it’s for the tree’s own good and prevents further damage or disease from entering the tree. Second, it prevents branches from falling unexpectedly and injuring people and property below.”
Selectively removing branches—whether healthy or not—also allows for wind and light to pass through the canopy.
“Again, this is two-fold,” says Laverne. “It lessens resistance to wind passing through, thereby lessening the chances for limb damage. It also brings more light to the inner part of the canopy, benefiting the tree.”
Pruning can help create clearance, as well. Whether it’s to clear a nearby power line, residence, fence or other structure, some cuts may be needed to properly shape the tree and prevent damage to the interfering object.
In addition, a tree’s flowering and fruiting can be improved with proper pruning. “Left unpruned, fruiting and flowering trees especially can go through cycles of feast or famine,” Laverne says. “Too much fruit one year leads to too little the next. Proper pruning can even the flowering and fruiting production from year to year.”
Last but not least, trimming branches can improve a homeowner’s view. “Perhaps Mr. and Mrs. Smith want to see the sunset from their dining room window,” Laverne says. “A branch here, a branch there, removed correctly, can ensure they see the sunset for years to come.”
When to prune
Although it may not be a time of comfortable working conditions, fall and winter are the ideal seasons to prune trees. Leaves have fallen, and the tree has become dormant.
“This allows you to see what arborists call the scaffolding of the tree, its branches and their condition and position,” says Laverne.
Broken limbs and those that are diseased are visible. In addition, the dormancy of the tree lessens the likelihood that pathogens will spread through the wounds exposed by pruning.
“The tree’s flow of nutrients has essentially stopped,” says Laverne, “and it is much more difficult for diseases to enter and take hold of the tree.” He adds that the dormant season also holds insects at bay, as they are either hibernating or not present during this time.
Pruning is also appropriate as a preventive measure prior to major storms, particularly before summer storms and hurricane season. “It might not be the ideal time, but it’s certainly good for the tree,” Laverne notes. “Thinning the canopy reduces the resistance high winds will encounter, and so it reduces the forces that could break off branches.”
Laverne adds that preventive pruning is also good for home safety. “Remove dangling, injured or dead wood now before the winds starts blowing,” he says. “It’ll not only prevent property damage but also personal injury.”
Protection from personal injury is job No. 1 when it comes to any type of tree work. Being prepared for the job is as simple has having three items in your toolbox, Laverne explains.
- Hard hat: “Any work done under a tree canopy requires you to wear a hard hat,” he says. “In case anything from above drops, you won’t get conked on the noggin.”
- Safety glasses: “This is especially important when using a saw,” Laverne says. “Wood chips and bark will fly, and safety glasses will protect your eyes.”
- Leather gloves: “One accidental pull of a saw across the skin could turn an otherwise productive day into an unfortunate trip to the emergency room,” Laverne warns.
As for equipment, Laverne says there is no need for power tools such as chain saws for pruning smaller branches that could be easily removed with a hand saw. If branches are thick and require more powerful equipment, Laverne has this advice: Don’t use a chain saw to cut above your shoulders. “That is a serious accident waiting to happen.”
The tree expert has one more very critical piece of safety advice, especially if your crew does not include a trained and certified arborist: “If you can’t reach a branch while standing safely on the ground, call in a professional licensed arborist to do the job,” he says. “They have the ropes, saddles and climbing equipment to do the job correctly and safely. And if the pruning is anywhere near power lines, call the power company and have them come to do the work since they are specially trained for that situation.”
How to prune
Before the first cut, Laverne advises to take a general assessment of the tree in question. Mentally map where the work has to be done and have a game plan for the work within the tree. “Look for the main trunk.” Laverne says, “and base any directional pruning on that strong center to maintain a healthy shape for the tree.”
Once the branch to remove has been selected, stop for a moment to find where your cuts will take place. “On the top of the branch there is a saddle of bark along the branch-bark ridge, where the bark from the trunk and the bark from the branch meet,” he says. “The bark layers here are being pushed up and outside of that branch union and are easily seen.”
The base of the branch is a swollen area where the wood tissues from the trunk and branch overlap. “You don’t want to cut into the wood tissues of the trunk,” Laverne explains. “That trunk wood tissue is the place where new wood grows to cover up the pruning wound.” Therefore, the cut will not be flush with the trunk but with the base of the branch, outside the swollen area that is the branch collar.
Next, make the cuts. “It’s more than just sawing through a limb,” Laverne says. “It’s actually a series of three well-placed cuts.”
- First cut: Depending on the length of the branch, the first cut is positioned one foot or more from the branch-bark ridge. This cut – the undercut – is from the underside of the branch upward and about a quarter of the way through the branch. “Its purpose is to relieve the compression tension on the bottom end of the branch,” Laverne says.
- Second cut: The next cut is positioned just a few inches down the limb from the undercut and is started on the top of the branch. This top cut removes the length of the hanging limb. “The reason for these two offset cuts is to remove the limb without its weight creating tearing or ripping stresses in the wood and bark,” Laverne explains.
- Third cut: The third and last cut removes the remaining stub of limb. “Find the branch-bark ridge and make sure the final cut is outside those two features,” Laverne says. A correctly positioned cut will be perpendicular to the branch, not to the trunk itself.
As the third cut reaches the opposite side, Laverne says to slow down the speed of cutting. “Slowing down ensures you pay attention to creating a clean cut. And in just two to three years’ time, a healthy cut will be closed over from the trunk wood growing over it.”
A word on equipment
The quality of a completed job is only as good as the equipment used. “Pruning with dull, rusty and dirty blades and saws can do more harm than good by leaving ragged cuts and points of entry for disease or insect infestations,” says Laverne. He advises using only sharp saws and to clean them after each use. “Keep the saws and blades in contact with a 10 percent bleach solution for about a minute, then rinse off the solution and wipe down with a dry cloth. That should do the trick.”
With an eye on the tree’s health, form and proper pruning techniques, the landscape’s trees can bring beauty and benefit to an entire community for generations to come.
Jennifer Lenox is in the Corporate Communications division of The Davey Tree Expert Company. Visit the company’s site at http://www.davey.com.