FERTILIZING 

      Established trees do not need to be fertilized in order to maintain their health. Established trees growing in a maintained landscape receive enough fertilizer for moderate growth because their root system grows into fertilized shrub beds and turf areas. In most instances, additional fertilizer is not necessary to maintain healthy trees. Some trees with micronutrient deficiencies respond to applications of minor elements.
      Young trees can use more fertilizer while older mature trees have different needs. Young trees can respond favorably to fertilizer applications and be pushed a bit to attain the desirable size in the landscape. But for older, mature trees, slow growth generally means better overall tree health. And tree health is much more important than tree growth.
      Fast growing trees are not necessarily healthy trees. People often equate fast growth to tree health. But this concept is not true. Research has consistently demonstrated that heavily fertilized trees are often more susceptible to insect and disease problems. And research has also shown that heavily fertilized trees are less able to tolerate stress such as from drought. So next time a tree in your yard is having problems, application of fertilizer may not be the best treatment.
      Tree fertilizer does not need to be injected into the soil. Tree roots grow among turf and shrub roots. Most are located within the top 12" of soil. Fertilizer broadcast over the surface reaches tree, shrub and turf roots in adequate amounts. Deep fertilizer injection sounds great but actually puts the fertilizer below the absorbing root zone and out of reach of the tree roots.
      Many trees create their own chemicals that help protect them from insects, disease, decay and environmental stress. These naturally produced chemicals such as terpines, alkaloids, and phenols can protect a tree from some diseases and insects. But the production of these chemicals has a cost to the tree. It requires the expenditure of energy (stored carbohydrates). When a tree is fertilized with high amounts of nitrogen fertilizer, the tree slows the manufacture of defensive chemicals and expends its limited energy reserves in new shoot growth. In other words a sick tree may not benefit from fertilizer and may become even more susceptible to disease, insects or other stresses following a fertilizer application.
     Fertilizing in the fall generally does not stimulate growth in the fall. Many trees and shrubs will not respond to an application of fertilizer until the following year. Fall is an excellent time to fertilize trees and shrubs. But be careful, some plants such as crape myrtle and some other plants may be stimulated to grow in the fall in response to fall fertilization. In this case, spring fertilization is better just after the first flush of new spring growth.
    Tree fertilizer is not tree food. Trees utilize the elements in fertilizer to produce glucose, proteins and other materials, which might be considered food. In other words, trees manufacture their own food. Fertilizers supply some of the elements necessary for plants to produce tree food, but fertilizer is not tree food.
      Mature trees do not require much fertilizer per year to maintain good growth. Established trees probably require little if any fertilizer to maintain their health and moderate growth, particularly if lawn clippings, leaves and mulch are recycled back into the landscape. If you fertilize your lawn, the far-ranging tree roots that extend way out beyond the edge of the tree canopy will pick up some of the fertilizer you put on your lawn. Adding more fertilizer for the tree is unnecessary and wasteful.

TREE TRUNK AND BRANCH STRUCTURE 

      A trunk with a crook in it is just as strong as a straight one. Trunks with slight doglegs, crooks or bends are not weaker than those, which are straight. This is a normal development on many trees. Healthy trees will grow out of this condition and the trunk will appear straighter as it becomes larger in diameter.
      Horizontal oriented branches are better attached to trees than upright branches. Upright branches are poorly attached to trunks. Horizontally oriented branches are usually well secured to trunks. A branch growing in an upright manner parallel to the trunk becomes a second trunk. The tree is said to have a double leader. Double leaders are dangerous because they can easily split from the tree during a storm.
      Topping a tree creates a dangerous tree. Topping is cutting branches or stems to random lengths. Trees should never be topped. Topping creates hazardous trees because the wood inside the cut branch begins to decay. The sprouts, which grow in response to topping, are not well secured to the topped branch and they can easily split from the tree, as they grow larger. To avoid this, always prune a branch back to a living branch crotch. This technique is called drop crotching.
      A tree with multiple leaders (trunks) can become hazardous to people and property as the tree grows larger. Never allow trees to grow with multiple upright leaders. These trees may look handsome when young but will become hazardous as they grow older. Always prune so that leaders or branches are spaced 18-36 apart along the main trunk and be sure they form an angle of more than 40° with the trunk. 

PRUNING