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Dig This
Friday, June 16, 2000
By Ken Ige, Star-Bulletin
In the Trees of Hawaii classroom, Abner Undan
demonstrates a resistograph, used to detect hollows
or rotten interiors of trees that could threaten the life
of the tree and endanger people and nearby buildings.
The problem with talking to Abner Undan is you begin to hear the screaming of the trees. Wounded trees
never healWhat butchers armed with sharp objects euphemistically call pruning this certified arborist and president of Trees of Hawaii calls mutilation.
The urban jungle is a brutal world where more than 90 percent of trees have been damaged by improper pruning, according to Undan, a world where property owners, out of ignorance or wilfulness, hire people to kill their trees.
The question "What are some of the more common mistakes people make when pruning trees?" brings a long, deeply felt sigh. It's followed by a lesson in the basics.
"People forget that trees make their own food through a process called photosynthesis. If you cut a lot of the leaves off the tree, you limit its ability to survive," says Undan. He's not trying to be pedantic. Sure we all learn that in grade school. But the evidence he sees suggests most of us forget it.
"Educating our customers on the importance of proper pruning, that's the biggest challenge we have," he says.
Wounded trees
Topping persists in Hawaii despite widespread criticism of the tactic, which the International Society of Arborculture calls the most harmful pruning practice known. Topping is the indiscriminate cutting of tree branches, often eliminating 50 to 100 percent of foliage.The dangers of topping are many. No foliage means no food, see Botany 101 above. Trees that have stored enough energy to cope with topping grow faster afterward in self-defense, which defeats the purpose of containing growth. Trees that have not stored enough energy die. Sun can damage bark exposed by the removal of foliage. Cuts are vulnerable to water, insects, bacteria and fungus. Finally, even if the tree is not killed or diseased, its natural structure is compromised, making it potentially dangerous.
"We do not top trees. We don't want people to pay us to destroy trees," says Undan.
However, he will sometimes make sacrifices to prove his point.
Undan tells of a condominium board that wanted several trees topped. One board member stood fast against Undan's objections. Finally, Undan agreed to top one, prune the rest in the fashion he would prefer and let the board examine the results; with the caveat that while he would do what he could for the topped tree, he would not take responsibility for its performance. Slowly and painfully, the tree died. Undan got to do the rest of the trees his way. And the stubborn board member was billed for the removal and replacement of the dead tree.
Then there are the customers who want to take a 50-foot mango tree and make it 10-feet tall. "I like those calls," says Undan with a mischievous glint in his eye. "So I ask, 'Mrs. A, do you really want to pay us to destroy that tree?' It's a direct question."
Taking a mature tree and reducing it to nothing is not possible without harming the tree, says Undan. "The problem is people don't understand trees. They think they are indestructible."
Proper pruning
If the damage is not too severe, trees can be redeemed over time. The problem is, a wound suffered by a tree never really heals, it's just covered over, says Undan.Good pruning techniques take this into account and do as little damage as possible.
The appropriate method for reducing the size of a tree is to remove branches to the parent limb or a lateral limb that is at least one third of its diameter, a process called drop crotching. It is important not to remove more than 30 percent of the foliage at any one time, says Undan.
The placement of the cut and its clean execution also are important. There is a narrow window between cutting too close to the parent or lateral limb and damaging its tissue; and cutting too far from it and leaving a stub.
The best way to find this spot is to go out and look at some trees. The places where branches are missing that have bark growing over or all around them are probably healthy. The cuts that have not been covered over are vulnerable.
Undan says hand tools make the cleanest cuts on small branches. For large limbs, chainsaws are better. However, he adds, large trees are more safely left to professionals. He offered this guide: If making the desired cut means leaving the ground, hire help.
Let's return to Mrs. A, the customer who wants a 10-foot tree where the 50-foot mango stands.
After poor pruning, Undan says, the second largest problem he sees in the urban forest is wrong tree, wrong place.
Two things to keep mind when choosing a tree are its mature size and function: shade, privacy, etc.
Mrs. A has two options, if she really can't live with a full-grown mango tree. One is to replace it with a tree that grows to a more acceptable natural height. The other, if she likes mangos but wants them closer to the ground, is to replace it with a young mango tree and prune it consistently to contain its size.
Sighs and head shaking aside, Undan enjoys his work. He's done it for a quarter century, starting at Trees of Hawaii in 1976 as a $3-an-hour groundsman.
"I love this industry," he says. "I wish I could dedicate my life to just going out and doing training."
If he ever gets to do that, maybe the screaming will subside.
Gardening Calendar in Do It Electric!
Stephanie Kendrick's gardening column runs Fridays in Today.
You can write her at the Star-Bulletin, P.O. Box 3080, Honolulu 96802
or email skendrick@starbulletin.com
