By ERNIE REZENTS
For The Maui News—
Two weeks ago I wrote about pruning hedges and young trees and mentioned some safety precautions a person should take. I cannot over emphasize that it may be cheaper and safer for you to hire a knowledgeable person to do major pruning for you than for you to do the job yourself. Young trees with branches less than 2 inches in diameter, roses, and hedges may be possible for you to prune safely. It has been said that if you need to get on a ladder to prune a tree it is time to call for the help of a professional. However, if you do know good pruning techniques discuss these with the individual you are about to hire. Make certain that your trees are not butchered. Climbing spikes and broadleafed trees don’t mix (See my article dated February 27, 1994). Make sure that the pruner is currently insured (call his agent) so that you are not liable. Inspect some of his recent work, and talk to these tree owners. The kind of work you require will dictate the skill needed by your pruner. Shop around and be selective.
Guiding Principles For Healthy Trees
- Select Healthy Trees. Do not buy or plant trees that have roots crushed or crowded in a bag or container.
- Plant Properly. Do not plant too deeply. I presented proper tree planting in my article dated November 14, 1993.
- Plant the Right Tree in the Right Place. Do not plant large maturing trees near buildings or power lines.
- Prune Branches Correctly. Do not remove branch collars, leave stubs, or make flush cuts. Branch collars are the swollen rings of bark at the base of branches. The size and ease of identification varies with the tree species.
- Prune Trees Correctly. Do not top trees.
Making the Cut
Heading Back, Stubbing, or Topping, are all names given to removing limbs away from their point of origin. “Stubs” or a “hat rack” results. The branches respond with a flush of weakly attached sprouts that convert the tree into a round bush (See Photo #1). If all the shoots are kept they will develop into branches that rub and interfere with each other. Because they are weakly attached, they may become a liability. This is especially true when they get big, support weights (fully leafed, wet from rain), and are exposed to strong winds. The larger the stubbed limb the more unlikely the branches will ever grow to a size where the wound is completely healed and hidden by being incorporated in the growth of a dominant limb. Good examples are the once beautiful trees that line Puunene Avenue traveling towards HC&S mill (Photo # 2). Some of the monkeypods that were transplanted along sections of Hana Highway are candidates for a similar fate.
Thinning Cuts are preferred. These remove a lateral at its origin just outside the branch collar. Leaving the collar, or rings, intact will assist in the formation of callus and wound healing. Three cuts are required. The first should be about 12 inches away from the branch collar, cut from the bottom up and at least one third of the way through. The second should be about 3 or 4 inches away from the first, cutting from the top and going right through the branch. The third and final cut should be outside of the branch collar. (See Figure # 1). Some people make a slight cut below the branch just outside the collar to prevent tearing the bark when the third cut is made.
If the cut is made into or too close to the branch collar, callus and wound healing will be uneven.
Lowering the Height of Trees.
Trees are often “topped” to shorten them. If a smaller type tree were planted initially, the topping would not be necessary. Trees can be shortened by “drop crotching”. Remove the top with the customary first and second cuts used in a “thinning cut” above the lateral you want to develop into the new leader. Then make the third cut. Some decay will result at the top, but hopefully the tree will wall this off and prevent its spread and the lateral branch’s growth will encompass and hide the injury.
- When deciding which branch to remove, keep wide angled lateral branches because they are stronger than those with narrow angles. The angle is measured from the main trunk to the top of the lateral branch.
- Laterals should be smaller than the trunk.
- Lower laterals should not out grow the leader. Maintain the leader’s dominance.
- Remove dead and diseased wood and branches that rub or interfere with each other.
- Remove water sprouts. These are shoots that grow vertically straight up from a bud on a lateral.
- Open the tree to permit light and air through.
- Do not apply wound dressings such as paint and asphalt emulsions. These will trap moisture and encourage fungus and decay. Natural is best.
- If you have to remove a tree replace it with others; preferably not one for one, but with others to equal to the value of the one removed.
I hope you have benefited from this article because “Once you have tamed a tree you are forever responsible for it”. This quote, or something like it, is from Dr. Alex L. Shigo He retired from the U.S. Forest Service as Chief Scientist and Project Leader on the Discoloration and Decay in Forest Trees. I had the distinct privilege of studying under his tutelage, along with about 23 other individuals, for four days in May 1992. My thanks to the Maui Outdoor Circle for sponsoring my attendance.