Keeping Trees Healthy and Safe

Many trees have life spans that any human would envy. But in residential areas, these impressive life spans are often cut short by the rigors of the urban environment. With attention to a few key management practices, this doesn’t have to be so.

Proper watering is critical when transplanting a new tree. Water regularly, but be careful not to overwater. After a tree is established, normal rainfall usually will provide an adequate amount of water. But you still need to water during droughts or extended dry periods during the summer.

Once a tree is established, apply up to 6 pounds of nitrogen per 1,000 square feet over the tree’s rooting area to maximize tree growth. Every 3 years, apply 3.6 pounds of phosphorus and 6 pounds of potash per 1,000 square feet. Apply fertilizer to an area that extends several feet beyond the canopy drip line.

Be on the lookout for warning signs that may indicate your tree is under stress. For example, are the leaves off-color, undersized, withering, or showing dark blotches? Are many of them missing?

Are the branches dying at the ends? How much have the tips of the branches grown in the past year? You can tell by looking at the ‘bud scale scars.’ In general, twig growth on most trees should be at least 9 inches.

Are there cracks or holes in the tree trunk or cankers (localized dead areas) on the bark? Do you see insect activity or signs of insect presence: curled leaves, chewed leaves, missing leaves, holes in branches, buds that don’t sprout, webs, sawdust, holes in the trunks, or galls, which are tumors that form on the plant tissue?

Has a storm broken limbs or done any other damage? And is the soil compacted, or packed down? Compaction, one of the major killers of trees in urban areas, reduces the availability of air in the soil, suffocating tree roots.

Some of these warning signs can have a number of causes, so you may need to call in a professional arborist to determine the problem. For instance, yellowed, undersized, or withered leaves can be caused by diseases, insects, inadequate moisture, or lack of nutrients.