ASK THE ARBORIST

Our ISA certified arborist answers all your tree care questions. To send us your question, email us at askthearborist@cowarttreeexperts.com. We’ll post the answer here, so come back and visit often!

Question: Why should trees be pruned?

Answer: You should prune trees to maintain the health of the tree. Pruning protects against disease and fungus by allowing air movement through the tree. Pruning also helps the tree callus over wounds to close off to protect from insects. By pruning your tree limbs on a regular basis, you minimize the chance of injury or property damage caused by falling tree limbs.

Question: Is fall the best time of year to prune my trees? **

Answer: I have been pruning trees for more than 18 years and the answer to the “pruning” question is that you can prune any time of the year if you know what to prune and where to make your cuts.

The basic rule of thumb is not to over-prune – no more than 25 percent of the tree’s foliage should be removed. This will keep the tree from getting stressed out; putting the tree into shock can cause dieback or worse. Fall is a good time to prune live limbs for building clearance, elevation and thinning out. This helps air movement, which can help prevent fungus and disease.

When pruning, you should look for crossing and rubbing limbs, limbs touching other limbs and dead wood. This will help reduce problems as the trees grow. You should also look at the top of the tree to make sure there is only one central lead or enough room for multiple leads to grow and mature. Branch attachment is very important, also. Branches should have more of a “u” shape attachment, not a “v” shape. A more rounded attachment is better than a tighter attachment. A more rounded is much stronger and will be less likely to break or split, like Bradford pears do after 10-15 years of growth.

In protecting your trees, it’s best to enlist in the help of a professional arborist when it comes to the proper way to prune them. Improper pruning can cause irreparable damage to your trees.

**As featured in the November 2005 edition of Atlanta Home Improvement magazine.

Question: What is tree topping?

Answer: Tree topping is the removal, or cutting back, of large branches in mature trees.

Question: Should I have my trees topped?

Answer: Tree topping is the worst thing you can do to the health of a tree. Tree topping throws out sucker growth which is weakly attached to the tree. Since sucker growth is so fast, it creates a safety hazard as the new, weaker growth is subject to easy breakage. Tree topping also leaves open wounds that are subject to decay and disease, and can even cause early death of the tree.

Question: Why should I fertilize my trees? And when?

Answer: Trees growing in an urban society are not the same as those in a forest. In the forest, trees live in a natural, balanced environment where leaves, needles, branches and even other plants break down to create organic matter that returns nutrients to the earth. In an urban setting, we rake up all the leaves and organic debris, bag it and discard it. In order for trees to thrive in our urban environment, we should fertilize them regularly. Fertilization should be done from October to the beginning of June. Root stimulant can be applied any time of the year, but the fall is the best time. By applying the stimulant in the fall, it allows the nutrients to be absorbed prior to new spring growth.

Question: What are the signs that my tree is nutrient-deficient?

Answer: The signs that you should look for, to detect if a tree is nutrient deficient are:

• A slow rate and lower amount of annual growth on twigs and trunk
• Increase in dead branches
• Smaller than normal foliage
• Dull or off-color foliage
• Increased disease and/or insect problems