An effective tree maintenance program, including regular inspections and the necessary follow-up care of mulching, watering, and pruning can detect problems and correct them before they become damaging or fatal.
Tree Inspection
Tree inspection is an evaluation tool to call attention to any change in the tree’s health before the problem becomes too serious. By providing regular inspections of mature trees at least once a year, you can prevent or reduce the severity of future disease, insect, and environmental problems.
A reduction in the extension of shoots such as buds or new leaves, is a reliable cue that the tree’s health has recently changed. To evaluate this factor, compare the growth of the shoots over the past three years. Determine whether there is a reduction in the tree’s typical growth pattern.
Further signs of poor tree health are trunk decay, crown dieback, or both. These symptoms often indicate problems that began several years before. Loose bark or deformed growths, such as trunk conks (mushrooms), are common signs of stem decay.
Any abnormalities found during these inspections, including insect activity and spotted, deformed, discolored, or dead leaves and twigs, should be noted and watched closely.
Common Tree Diseases and Insects
There are several insect pests and diseases that contribute to health decline and death of trees and shrubs. Following is a list of those common to the area, as well as a link to further information and treatment.
- Aphids can cause damage to all trees and shrubs by piercing the tender plant tissue and drawing large quantities of plant sap.
- Browning of evergreen trees can occur for various reasons.
- Cankers are a common fungal disease of poplar trees, killing the outer wood and bark of stems and branches.
- Fireblight is a highly destructive disease of several members of the rose family.
- Forest tent caterpillar damage can range from a thinning of the crown to the complete defoliation of aspen, poplar and other trees and shrubs.
- Spider mites infect Colorado and white spruce trees.
- Spruce Budworm is a native pest larvae feed on the new buds, needles, flowers and cones of spruce trees, resulting in the defoliation of the trees. Although one year of defoliation can weaken trees, it generally takes 4-5 consecutive years of infestation before they are likely to die.
- Spruce gall adelgid are aphid-like insects that produce galls or abnormal outgrowths on spruce trees.
- Yellowheaded spruce sawfly larvae feed on the new needles of Colorado and white spruce, leaving only short brown stubs.