Topping is perhaps the most harmful tree pruning practice known! Topping will make a tree more hazardous in the long term. Topping often removes 50 to 100 percent of the leaf-bearing crown of a tree. Because leaves are the food factories of a tree, removing them can temporarily starve a tree. A stressed tree is more vulnerable to insect and disease infestations. The preferred location to make a pruning cut is just beyond the branch collar at the branch's point of attachment. The tree is biologically equipped to close such a wound, provided the tree is healthy enough and the wound is not too large. Cuts made along a limb between lateral branches create stubs with wounds that the tree may not be able to close. The exposed wood tissues begin to decay. Stubs left from topping usually decay. The shoots that are produced below the cut are weakly attached and often become a hazard.
Mulching can reduce environmental stress by providing trees with a stable root environment that is cooler and contains more moisture than the surrounding soil. Mulch can also prevent mechanical damage by keeping machines such as lawn mowers and string trimmers away from the tree's base. Further, mulch reduces competition from surrounding weeds and turf. To be most effective in all of these functions, mulch should be placed 2 to 4 inches deep and cover the entire root system, which may be as far as 2 or 3 times the diameter of the branch spread of the tree. An organic mulch layer 2 to 4 inches deep of loosely packed shredded leaves, pine straw, peat moss, or composted wood chips is adequate.
Fertilizing a tree can improve growth; however, if fertilizer is not applied wisely, it may not benefit the tree at all and may even adversely affect the tree. Trees require certain nutrients (essential elements) to function and grow. Urban landscape trees can be growing in soils that do not contain sufficient available nutrients for satisfactory growth and development.
Insect and Disease Control
Recent warmer climates which lessen the dormant cycle of trees and shrubs has enticed diseases and pests not native to our area and have no natural/biological controls to invade our plants. Couple this with soil compaction, competition with grass and extended drought and our urban environment is struggling. About 90% of a tree's roots are in the upper 12 inches of soil and they share this space with grass roots. Grass is the first to absorb rainwater and nutrients. If you combine grass and compaction with extended drought, many trees suffer. Some trees will drop leaves and literally go dormant to survive drought. Others will become severely stressed and vulnerable to insects and diseases. Management of insect pests and disease rarely relies on a single control practice. Tactics used in integrated pest management include the use of pest resistant or tolerant plants and cultural, physical, mechanical, biological, and chemical control. Applying multiple control tactics minimizes the chance that insects will adapt to any one tactic.
The most common reason a tree owner calls an arborist is concern that something is wrong with a tree. It may be that some of the leaves are discolored, a branch has died, or perhaps the entire tree has been dropping leaves. While trees are dominant ornamental features in your home landscape, they share this area with turfgrasses, shrubs, and bedding plants. And all these plants have one resource in common: the soil. The roots of trees, shrubs, turfgrass, and bedding plants intermingle and compete for water and nutrients. In fact, the roots of a single mature tree may extend 60 feet or more out into your lawn or flower beds. Every treatment applied to the lawn (fertilizer and herbicide, for example) can impact the appearance and vitality of a tree. Conversely, treatments applied to a tree, such as pruning and fertilizing, can influence the appearance and vitality of the underlying turfgrass.