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10 Most Frequently Asked Questions to the Arborist?
1) What is a Certified Arborist?
Arborists are knowledgeable about the needs of trees, and are trained and equipped to provide proper care. An arborist by definition is an individual who is trained in the art and science of planting, caring for and maintaining trees. ISA Arborist Certification is a non-governmental, voluntary process by which individual can document their base of knowledge. Certified Arborists are individuals who have achieved a level of knowledge in the art and science of tree care through at least three years experience and have passed a comprehensive examination developed by some of the nation’s leading experts on tree care. Certified Arborists must also continue their education to maintain their certification. Provided by the ISA, “Why Hire an Arborist” pamphlet.
2) Do I need to fertilize my trees every year?
Fertilizing at least once a year helps to compensate for the broken nutrient cycle, depleted soils and confined root areas. Using a controlled release mineral fertilizer below the grass roots, ensuring the lawn does not interfere, will slowly release nutrients over many seasons, the way Mother Nature intended. Providing proper nutrition ensures that your trees have the nutrients needed to build defenses against disease, insects and unfavorable weather. Trees remove large quantities of nutrients from the soil each year, utilizing them for growth and development. In a forest setting, trees have a natural nutrient cycle where the nutrients they remove are returned when leaves, twigs and debris fall to the ground and decompose. This natural cycle is self-sustaining, and has allowed forest trees to grow large and healthy for centuries. In our urban environments, the natural nutrient cycle is broken, as the organic forest floor has typically been replaced by turf grass. Falling leaves, twigs and fruit are quickly removed to maintain a healthy lawn. Competition with lawns and other underlying plants further deplete the nutrients from our soils. If this weren’t enough, our trees roots are confined by smaller spaces. Roads, driveways, patios and houses all limit the area urban trees have to find nutrients. Urban trees grow to be less healthy and live much shorter lives then those in the forest.
3) How much mulch should I put around my trees? I see mulch piles high against the trunks, is this right?
Mulch beds and rings need to have their mulch level checked each year. The mulch layer should be between 3-4” of material under the tree out to the dripline. If there is a sufficeient layer of mulch, it can be turned over to give it a fresh look. It is not necessary to add more mulch each year. Mulch wide, not deep. Keep mulch away from the trunk of the plants. Piling mulch high against the truck can cause disease, decay, and eventual death.
4) How much should I water my trees and how?
How much a plant should be watered depends on a lot of factors. Some factors that need to be considered are plant size, location, weather, recent precipitation amounts, and the age of the plant (newly planted or established). The following are general guidelines for watering plants. It is very important to remember to always test the soil moisture first before watering. Too much water can be as harmful as too little water.
Newly transplanted trees or shrubs lose around 85-90% of their roots during transplanting. It is critical that they be watered regularly for 2-3 years until their root systems become fully established. For the first several months after transplant, the tree or shrub draws its moisture only from the root ball. If the root ball dries out the tree or shrub will die. Water both the root ball and the surrounding area so roots expand carefully.
For established trees or shrubs the top 8-12 inches of soil holds 80% of a tree/shrub’s root system and should be kept moist during periods of drought as far out as the branches spread (drip line). The amount of water required will vary depending on the site. Without adequate rainfall, established trees may need watering as often as every 10-14 days, especially during the hot summer.
Watering Techniques: If the ground is level, simply let an open hose slowly run on the surface and move it around to different locations to get good distribution. If the ground slopes, water may easily run off the surface, in these cases, a soaker hose or sprinkler can distribute the water more slowly. Infrequent deep soakings encourage a deeper root system and more drought tolerant plants. Frequent shallow watering encourages surface roots, which make the plants vulnerable to wilting in dry conditions. The most beneficial time to water is in the early morning. Avoid sprinkler watering in the evening as moisture left on the leaves can lead to fungal problems.
5) There is “green - grey growth” on the side of my tree. Is it harmful? Will it kill my tree?
The “green-grey growth” that is on the trunks of the trees is called lichen. It is not harmful and will not kill the tree. Removing the lichen is not recommended because it may cause damage to the tree. Lichens are living organisms composed of algae and fungus. It can be found growing on a variety of surfaces, including: tree branches, trunks, rocks, fences, gutters, and roofs, and come in many different forms and colors. Lichen do not absorb food from the tree or any source it is attached to or growing on, and prefer moist and shady conditions. There is no need for any control measures for lichen.
6) I have heard about Emerald Ash Borer. Should I be concerned?
Yes. Emerald Ash Borer is a devastating insect to all ash trees, healthy or declining. Currently, Emerald Ash Borer has been found in Lily Lake, Wilmette, Winnetka, and Evanston. There are treatment options that can help control emerald ash borer. Contact one of our certified arborist for more details. (See insect section for more information and pictures.)
7) Why is my pine tree dying? All of a sudden there are brown needles on the inside of the tree. What is going on?
Brown needles on the inside of the tree, generally in fall, are from a natural occurrence called Seasonal Needle Drop. Pines do not keep all their needles for the life of the tree. Seasonal needle drop is caused by weather and season. The change can be gradual or quick. Spruces and fir trees also go through seasonal needle drop, but the change is less noticeable. As long as the brown needles are on the old growth, and not the current years growth at the outer branch tips, the condition is seasonal needle drop. If the current season’s growth is brown than the tree may be suffering from a more serious problem, and one of our certified arborists should be contacted to determine the cause.
8) My crabapple tree looked fine earlier this spring, now all the leaves are spotted and falling off. Is this normal?
No, the crabapple tree has a disease called apple scab. Apple Scab is a common disease of crabapple and apple trees. Fungi spores from the air infect newly forming leaves during cool-wet spring conditions. Symptoms first appear as olive-green lesions on the leaves, blossoms, and fruit. Severe infections cause leaves to shrivel and drop prematurely, placing the tree in serious stress. Preventative treatments can control this disease. (See disease section for more information and pictures.)
9) The leaves on my linden tree are being eaten and look lace like. What is happening to my tree?
Japanese beetles are feeding on the linden tree. Adult Japanese beetles can be very destructive. They feed on over 300 species of ornamental plants. Some of their favorite plants are roses, lindens, crabapples, elms, and birches. Beetles feed in large groups eating leaves, flowers and fruit, defoliating your trees and shrubs. (See insect section for more information and pictures.)
10) Why is topping my tree bad?
Topping is the removal of branches and stems, leaving long stubs with disregard for tree structure and form. Pruning is the selective removal of branches and stems with regard to tree structure and form. There are several reasons topping is bad for trees. Topping removes a majority of the trees ability to make food. It can result in “burning” of the tissue under the bark because new areas of the tree are now exposed directly to sunlight and heat that would normally be shaded. “Burning” of tree tissue can also lead to cankers, splitting, or death of some branches. Large branches and stems are slow to heal or may not heal from the topping cuts. Plus these cuts are vulnerable to insects and decay. Topping results in rapid growth, often called water sprouts. Water sprouts occur below the cuts will need to be pruned again soon because of their rapid growth. Topping loses the natural form of the tree, and the tree will never regain its natural form. Trees that are topped are more likely to break and be considered hazardous. The International Society of Arboriculture considers topping an unacceptable practice. Proper pruning with cuts made correctly are the best for the care of a tree. Consult one of our certified arborists for more information about pruning.
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