Every time we prune our trees, we take a chance on carrying disease from one to another, so cleaning equipment is very important. The fungus diseases causing bud rot of palms are examples. Citrus trees are subject to viruses spread by unsanitary pruning practices.
But in Hawaii by far the most devastating disease spread by pruning is rapid ohia death or ROD. This disease can be spread from one area to another by transporting infected ohia logs and green waste. Apparently, it also can be spread by mud on shoes or vehicles from infested areas, so sanitation is critical.
Even though we have been aware of ROD for more than three years, many folks did not become aware of the disease until recently. The ideal situation would be to have arborists on the staff of county and state maintenance departments. That way, folks responsible for tree maintenance would be the first to know when crises such as ROD occur. Fortunately, University of Hawaii scientists such as J.B. Friday are now working with utility companies, Hawaii County and state maintenance personnel to make sure they understand the importance of sanitation as they prune trees on roads around the island.
Scientists Lisa Keith with USDA-ARS and Flint Hughes with the USDA Forest Service are studying the disease complex to understand what else can be done to save our ohia. Wade Heller and Marc Hughes are assisting in this effort as they work on their postdoctoral programs. However, more resources will be needed if we are to find solutions to this devastating disease.
Landscape gardeners and homeowners also need to be aware. At this time of year, folks begin to think about the potential for summer storms. Because of climate change, we are getting those tropical blasts from May-November.
Before the storm flag is hoisted, inspect your trees for dead branches that seem to be ready to fall. Also look for dead branches that are firm but brittle. A gust of hurricane-force wind can snap an arm-size branch from a tree and send it at missile speed through a picture window.
A low hanging branch over a roof can wreak havoc. Powerful winds can turn the limb into a tool of destruction. This tool can remove shingles as easily as a fish can remove scales.
Removing dead and out of place limbs is a good idea even if there is no storm.
Fan-like fungus growing on the side of a tree trunk indicates rotten spots that need attention. A hole made by poor pruning, damage from earlier storms or the gouge of an auto bumper can start rotten spots. The auto-made wound can easily be filled with a water tight material as it is not more than kneeling height. But other rotting areas will require experience at climbing to dizzy heights on a trembling ladder.
Often it is cheaper in the long run to call a professional to handle the treetop jobs.
Some older trees with Y-shaped crotches are prone to cleave apart. Check the trees in this category. If necessary, place temporary props in the appropriate places or make the tree one unit again with steel rods and turnbuckles.
Remove decayed trees that are too weak to hold up under the strain of a storm. This action will save you grief later.
Palm fronds are wicked to deal with if propelled by an 80-mile-per-hour wind. So, clean away all loose palm leaves at the first hint of a storm. Be careful not to overprune the palms. Overpruning will weaken and even kill them.
Actually, even 100-mile-an-hour wind is not as dangerous as it sounds, if necessary measures are taken before the wind reaches gale force.
As soon as the storm is past, it is a good idea to inspect the trees and other plants around the house. Usually, all the plants will show signs of wind damage. But with a little trimming, propping, resettling of root systems and fertilizing and watering, nearly all plants that were shaken loose from the ground can be salvaged.
Many of our tropical trees grow rampant with extensive root systems. That is why we prune — to keep them from getting out of hand — but let’s prune the correct way. After hurricane season, you might want to consider some root pruning.
Here is a scheme to keep lawns and flowerbeds healthy, too. The trouble with roots of many big trees, banyans (Ficus species) and monkeypods, especially, is that they are too greedy. Their roots will fill a flowerbed or a new lawn in just a few years after the trees are planted. When this happens, you can be sure they are not doing the smaller plants any good. It is very likely the tree roots are competing so fiercely for the soil’s available water and nutrients that grass, shrubs and flower roots suffer.
With lawns, this action often demonstrates itself right before your eyes. If big trees grow at one side of a large lawn, notice that whenever the lawn goes without water for any period of time, the grass nearest the trees is always the first to show the bluish cast and lifelessness that indicate wilt. Ultimately, the grass will fade out under the tree until none is left.
The countermeasure is to cut tree roots that grow into the bed or lawn and then make it impossible for new roots to grow back into the area. You have to assume the tree roots grow out in more or less straight lines that radiate out from the trunk.
Whether you are pruning branches or severing hungry roots, it is always a good idea to clean your equipment. Bleach or alcohol will do the job, but the former is less expensive.
Just keep in mind that an injury to a tree can be just as life threatening as an infected wound on a person. The best solution is preventing disease through sanitation.
