According to the Council of Tree Landscape Appraisers, a sound, mature tree can add from $1,000 to $10,000 to the value of a home. In addition, tree canopies serve to catch precipitation before it reaches the ground, allowing some moisture to drip down, and the rest to evaporate. This function lessens the force of storm damage and reduces runoff. Trees also help trap and hold many pollutants such as dust ash, pollen and smoke, as well as absorbing CO2 and stroing it as cellulose in the trunk. In turn, they replenish the atmosphere with oxygen. Research suggests that shade from two large trees on the west side of a house and one on the east side can save up to 30% of a typical residence’s annual air conditioning costs.
Because of all the benefits of a landscape dotted by mature trees, it is important to regularly review the health of trees growing in the yard.
Some trees may appear to be falling, when they are experiencing normal seasonal dieback. Firs and Cedars are among tree varieties that can exhibit evidence of normal browning and dieback. However, if a tree is showing more pronounced symptoms of decline, there are steps a homeowner can take to restore a tree, or remove a diseased or dead tree that has become a hazard.
Some problems are obvious and the diagnosis is fairly simple. For example, wilting during a drought may mean the tree needs water, and this can be easily remedied. Unfortunately, wilting can also be caused by root injury, soil contamination, insect feeding, soil compaction, or fungal pathogens. Even fertilizer can be too much of a good thing, and may cause leaf edges to turn brown.
Since root and soil problems are among the leading causes of urban tree decline and death, it is best to review these causes first. (Because problems today may cause damage to surface five to six years down the road, reviewing soil around trees every other year is a good practice).
Soil Compaction can be an issue and cause serious complications, even for mature trees. Digging, grading, or construction near a distressed tree within the last decade can bring about eventual tree decline. To check root structure of a tree, look for healthy brown or grey roots, with hard, white centers. Dying roots are soft.
When casually reviewing tree health, easily observable symptoms may be preset on a tree including whether the foliage has been chewed or eaten; are needles bent or swollen; are there tiny black spots on the undersides of the foliage or light colored pustules; are insects or insect eggs present; are insects or animals chewing or clawing around the tree stem or individual branches?
Any of these signs may indicate a problem, and research on-line can help decipher the warning signs. Many agriculture extension sites offer on-line answers to tree questions, and taking a quick picture of the tree issue can help with diagnosis.
What about storm damage or lightning strikes? To provide the best storm protections and recovery for trees, removing branches from the end of long limbs and retaining interior branches is most effective.
Leaning trees or trees with a cracked or multiple trunks may also need review and remediation. A tree that may fall over time might be indication instability through cracked or heaving soil or through exposed roots around the base. Pruning branches or bracing the tree with cables can help, but a professional arborist may provide the best plan of action. The International Society of Arboriculture (ISA) maintains a directory of certified arborists searchable by state.
On the bright side, there may be no immediate, practical action necessary to address a tree health issue. Tree health problems are not like problems with garden pests, which can be ameliorated by a spray application. In many cases, it is a matter of letting the problem run its course (often trees will recover, although with some loss of growth).