10/2007 NEW: We now use earth friendly Bio-deisel.

9/21/2007 

DECAY CAN CAUSE HAZARDOUS DEFECTS IN TREES

     Tree failure is a major cause of residential property damage, as well as the leading cause of power outages nationwide. An ice storm can overload all the branches on a tree, a hurricane or high wind can blow down a tree if its roots are restricted, or a cracked tree can fail under its own weight.

     "Homeowners worried about trees falling and damaging property should call a professional arborist in for an inspection," advises Peter Gerstenberger, senior advisor for safety, standards and compliance with the Tree Care Industry Association.

     Gerstenberger notes that trees are designed to withstand storms, but all trees can fail - and defective trees fail sooner than healthy trees. A sound tree becmes potentially dangerous when the tree's woody structure is weakened by one or more defects. During storms, pre-existing defects predispose trees to failure.

     "To a professional arborist," notes Gerstenberger, "defects are detectable signs that a tree has an increased potential to fail."

     Broadly defined, there are seven categories of defect: decayed wood, cracks, root problems, weak branch unions, cankers, poor tree architecture, and dead trees, tops or branches.

DECAY

     Healthy, well-maintained trees growing on suitable sites will be able to minimize the extent of decay and other defects. Trees that are stressed have reduced energy reserves, and therefore, have less ability to deal with wounds and the ensuing decay.  

     Most urban trees survive on construction-altered soils that may be compacted, poorly drained, high in clay, sand, or gravel, very alkalilne or littered with construction debris. Additionally, many urban trees are subjected to chemicals such as deicing salts, herbicides and fertilizers commonly used in landscape maintenance. Poor tree maintenance is another contributor to stress. These cumulative stresses all take a toll on tree vitality and structural integrity, increasing the risk of failure.

     All defective trees cannot be detected, corrected or eliminated. Although a professional arborist can readily recognize most defects, there are root problems and some internal defects that are hidden. These trees may require in-depth assessments and specialized diagnostic tools. Homeowners should also keep in mind that defects change with time. A tree that looked fine three years ago may have severe problems today. By doing regular inspections arborists can successfully manage the risk of tree failure.

     Advanced decay and cavities result in less structural strength and reduced stability. Indicators of advanced decay are rotten wood, fungal fruiting bodies, cavities, holes, open cracks or bulges in the wood. Decayed wood is the result of the long-term interaction between a tree and decay-causing fungi. Wood decay is an internal process with just a few external indications, such as mushrooms, conks, rotten or punky wood, cavities, hollows, holes, inrolled cracks, and bulges in the wood.

     The undecayed layer surounding the decay column is called the shell. If the shell thickness is thin relative to the size of the tree, the shell is likely to fracture causing the tree to fail. A tree can have internal decay and an opening and still be structurally sound provided that the shell is thick enough and the opening is not too wide.

     If a tree is repeatedly wounded by the presence of inrolled cracks, included bark, canker-rot fungi, or equipment (mowers, plows, and weed whips), decay occurs in every annual ring of wood. These trees should be carefully inspected by a professional arborist because they do not form a sound shell of wood. The tree is likely to fail at or near the location of the crack or wound because a large and ever-expanding column of decay is present there. Again, a professional arborist can evaluate shell thickness and opening width to help determine the tree's potential for failure.

     Visual assessment by a trained arborist of the extent of decay can often be a reliable means of predicting potential risk. However, invasive techniques may be needed to quantify the thickness of the sound shell of wood in comparison to the size of the tree. Use of a probe or another tool may be needed to test several areas in order to find the location of the thinnest shell of sound wood.

     In-depth assessments, using specialized diagnostic tools, may be warranted when additional information about the location and extent of internal decay is critical to assessing the probability of tree failure.

WHAT CAN YOU DO?

     Homeowners who would like a professional arborist to assess their trees should contact the Tree Care Industry Association (TCIA), a 67-year-old public and professional resource on trees and arboriculture. It has more than 2,000 member companies who recognize stringent safety and performance standards, and are required to carry liability insurance. An easy way to find a tree care service provider in your area is to use the "Locate Your Local TCIA Member Companies" program. You can use this service by calling 1-800-733-2622 or by doing a ZIP code search on the TCIA Web site, www.treecareindustry.org.

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9/1/2007 - Newsletter

Ten Tree Myths

Much of what we hear about tree care is actually incorrect, based on myths and misconceptions. Here are what the International Society of Arboriculture considers the top 10 myths of tree care.

MYTH #1: When a tree is planted it should be securely staked to ensure the development of a stable root system and a strong trunk. Although it is sometimes necessary to stake trees to keep them upright and allow establishment, there are some adverse effects of staking. Compared to staked trees, unstaked trees tend to develop a more extensive root system and better trunk taper. Allowing a small amount of movement can help root and trunk development. Of course, the worst effect of staking is the possibility of trunk damage from the staking wires or ties. Staking materials usually should be removed after one year to avoid girdling the tree.

MYTH #2: Newly planted trees should have their trunks wrapped with tree wrap to prevent sunscald and insect entry. Studies using most common tree wraps have shown that they do not prevent extreme fluctuations in temperature on the bark. In some cases, the temperature extremes are worse. Also, tree wraps have proven quite ineffective in preventing insect entry. In fact, some insects like to burrow under it.

MYTH #3: Trees should be pruned back heavily when they are planted to compensate for the loss of roots. Tree establishment is best on unpruned trees. Although pruning the top can reduce the amount of water that evaporates from the leaves, the tree needs a full crown to produce the much-needed food and the plant hormones that induce root growth. The tree will develope a stronger, more extensive root system if it has a fuller crown. Limit pruning at the time of planting to structural training and the removal of damaged branches.

MYTH #4: When removing a branch from a tree, the final cut should be flush with the stem to optimize healing. First of all, trees don't "heal" in the sense that wounds on people heal. Our bodies regenerate tissues in much the same form of the tissues that were removed. Trees compartmentalize wounds, generating woundwood over the wounded area. Flush cutting removes the branch collar, creating a larger wound than if the branch were removed outside the collar. Also, it is likely that some of the parent branch tissue will be removed. The spread of decay inside the tree is greater with flush cuts.

MYTH #5: Pruning wounds greater than three inches in diameter should be painted with a wound dressing. Research has shown that the common wound dressings do not inhibit decay, do not prevent insect entry and do not bring about faster wound closure. In fact, many of the commonly used dressings slow wound closure.

MYTH #6: Certain fast-growing, weak-wooded trees such as silver maple and Siberian elm should be "topped" to make them less hazardous in the landscape. While topping these trees may reduce the potential hazard at first, they will likely be more dangerous in the future. Topping stimulates growth of twigs below the cuts. Growth of many, vigorous shoots leads to branches with weak attachments. Also decay spreads inside the stubs and branches that were topped. Within 2-5 years after topping, the tree will have regained its height, but will be more hazardous than before the topping. Besides, topping makes trees ugly. Alternatives include thinning, cabling, or removal and replacement with a more suitable species.

MYTH #7: If certain species of trees are pruned early in the spring, they will "bleed", stressing the tree and causing health problems. True, some trees such as maples and birches will "bleed" or lose sap from pruning cuts made early in the spring. This bleeding does not hurt the tree, and the loss of sap is inconsequential. With a few exceptions, most routine pruning can be done any time of the year. The worst time is just as the tree has leafed out in the spring. The best time is when the tree is dormant. To maximize flowering for the following year, prune just after bloom this year.

MYTH #8: The root system of a tree is a mirror image of the top. Many people envision a large, branching taproot growing deep into the soil. Actually, taproots are very uncommon in mature trees. If taproots do develop, they usually will be forced into horizontal growth when they encounter hard subsoils beneath the surface. The entire root systems of most trees can be found within the top three feet of soil. The spread of the root sytem however, can be very extensive, often extending 2-3 times the spread of the crown.

MYTH #9: Trees require "deep root fertilization" to reach their root system. In most U.S. soils, the vast majority of a trees fibrous, absorbing roots are in the top eight inches of soil. Roots grow where conditions are best for root growth, where water and oxygen are available. When we place fertilizer 12 -18" deep in the soil, we are putting it too deep.

MYTH #10: When a tree has lost a significant portion of its root system such as in construction damage, the crown should be cut back to compensate for root loss. While this is a common recommendation, research has not supported it. Following root loss, unpruned trees seem to respond better than pruned trees. Obviously, any removal of branches will reduce the capacity of the tree to produce food in the leaves. Although the tree will probably lose some branches as a result of the root damage (if the tree survives the trauma), it is best to let the tree decide which ones. Thus, pruning should be limited to hazard reduction at first. Later, after the tree has responded to the damage, further pruning would be in order.

 HORT NOTES, UMASS EXTENSION, Volumn 17, Number 8 (May 29, 2006). Article by H.Dennis P.Ryan, Arboriculture & Community Forestry, UMass Dept of Natural Resources Conservaton.

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