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Tree Care Homeowners and community staff can use these tree care tips to plant and maintain trees. Trees require sunlight, sufficient water, moderate temperatures, well drained soils and adequate nutrients to become established.
Roots of mature trees extend far beyond the extent of the branch tips (drip line). With adequate soil, tree roots may extend as far as 2 1/2 times the diameter of the drip line. The majority of nutrient absorbing roots exist in the upper 12 to 16 inches of soil. During construction, tree conservation efforts require that a large portion of the tree's root system, the critical root zone (CRZ), be protected for all trees to survive. Consider removing trees that have sustained CRZ loss in excess of 30%. Tree species, health, structure, soil type, vegetation competition, proximity to structures, future planned impacts, and planned maintenance all contribute to the determination of which trees should be removed and how remaining trees can be protected. Trees may not die immediately, but could decline over several years. With this delay in symptom development, you may not associate the loss of the tree with construction. SCFP Foresters can provide assistance by identifying trees that should remain on construction sites, offering technical assistance with tree protection methods, and referring developers to educational programs offered in Georgia. How to Conserve Natural Resources on Construction Sites (publication)
Water is the single most limiting essential resource for tree survival and growth. Drought conditions can severely affect young and old trees alike leading to tree decline, pest problems, and non-recoverable damage as well as decreased rates of diameter and height growth. More than eighty percent of the variation in tree growth is because of water supply.{1} Although providing adequate water to newly planted trees is essential, replacing older, more valuable trees lost or damaged due to lack of water can be especially difficult since they can take decades to grow to the same size. With the many social, economic and environmental benefits that trees provide, it is important to continue caring for our trees even in times of drought and tightening water restrictions.
The signs of drought stress can be observed mostly in the foliage of trees. Symptoms such as leaf drop and curling, wilting, or discolored leaves as well as dead branches are all signs of dry roots. Many people may not realize that their mature trees are stressed since these symptoms first appear in the top center portion of the canopy which may be far from view.{2} However, it is better to apply water preventatively before these symptoms even appear. Considering that state and local watering restrictions may be in place, here are some tips to help weather the dry conditions: Tips for Watering Trees During a Drought
What Not to do during drought conditions:
Additional tips on watering trees {1} Coder, Kim D. 1999 {2} Gilman, Edward F. 2007 Fertilization aids in tree growth, reproduction and development. Before you fertilize, it is best to have a soil analysis test. Tests are available through the University of Georgia Cooperative Extension Service. Fertilization is not a “cure-all” for declining trees, but may be used to complement other tree maintenance activities, such as watering and mulching.
The ideal time to fertilize is late winter or early spring just as the leaves begin to expand. Fertilizer is not plant food, but a mix of essential elements necessary for plant survival. The most common nutrients found in fertilizers are nitrogen, phosphorus and potassium.
Fertilizer should always be applied to moist soil and watered in afterward, to improve uptake and to reduce the chance of root injury.
Application rate In the absence of a soil analysis, a fertilizer ratio of 3:1:1 or 3:1:2 should be used. These numbers refer to the percent content of nitrogen, phosphorus and potassium respectively. Slow-release nitrogen fertilizer and a salt index of less than 50 percent is preferred.
A soil test is the best method for determining what is lacking in the soil. For most areas, the following guidelines based on the distance to the edge of the branches may be used for fertilizing established trees.
Step 1: Measure the distance from the trunk to the edge of the branch spread; this is the crown radius.
Step 2: Use the table below to determine the amount of fertilizer to apply. Find the crown radius in the left column, then look in the appropriate column for the type of fertilizer that you are using to determine how many pounds of the fertilizer to apply.
Best Ratio Good Ratio 3:1:1 3:1:2 N:P:K N:P:K
One pound of fertilizer is approximately two 8 oz. cups.
Fertilizer Application Rate Table
If the area under the branches is restricted by sidewalks or driveways, or the root system has been damaged by construction, this area should be subtracted from the fertilization application area and the rate should be reduced by an equal percentage to avoid damage to the tree.
Application method for mature trees A broadcast method may be applied to the soil surface, starting near the tree trunk and extending several feet beyond the furthest branch tip. If the soil is compacted or grass is present, you may want to consider the drill hole method of fertilizer application.
The drill hole method requires that holes be dug in a grid pattern starting near the trunk and extending slightly beyond the edge of the branches. Holes should be 4” – 8” deep and 2” – 4” in diameter, and may be made with a drill auger, pipe, or post-hole digger. Fill holes with specified amount of fertilizer leaving a space 2” from the top of the fertilizer to fill with soil. The total amount of fertilizer should be divided evenly among the holes. The increased amount of air available to the roots is often as beneficial as the fertilizer.
Grid pattern spacing and number of holes 2’X2’ grid pattern = 250 holes 3’X3’ grid pattern = 111 holes
***Warning*** Do not use herbicide-type fertilizers or soil sterilants in the area beneath the branches of trees which may cause tree damage or mortality.
Arborists frequently apply liquid fertilizer through a probe into the soil which results in faster uptake by trees, and a more visible response. Injecting or implanting fertilizer into the trunk is useful for specific nutrient deficiencies or where root area is limited. But since injection and implants wound the tree, their use should be limited. Insect pests and diseases often attack trees which are already under stress or weakened. Drought, improper planting and disturbance of the root system through digging, trenching, construction activity or addition of soil to the root area can make trees more susceptible to attack. First, find out why the tree is weak and then treat the primary cause of the stress.
Examine your tree regularly, looking for anything out of the ordinary: sap coming out of the bark, smaller leaves that are less green than usual, leaf spots, branch die-back in the canopy or leaves changing color early. Mushrooms at the base of a tree can sometimes indicate root rot and may warrant removal. Consult a Certified Arborist.
Always identify the pest or disease before applying sprays to control it. Some tree pests do not require control measures and some diseases have no practical control. A fungicide will never control an insect problem. If you cannot diagnose a problem, get professional assistance from a local nurseryman, professional arborist, the Georgia Forestry Commission or the University of Georgia Cooperative Extension Service.
Mulch is a material placed over the soil surface of the trees’ root zone to maintain moisture and improve soil conditions. Mulching is one of the most beneficial things that can be done for the health and growth of a tree. A thin layer of mulch (2-4 inches deep) can improve soil structure, oxygen levels, temperature, and moisture availability.
Recommended Mulch Materials Good quality mulch materials are usually readily available. Organic materials are preferable over inorganic materials (rock, stone, shredded rubber). When organic mulching materials decompose, they must be replenished.
When to Mulch
How to Mulch
Benefits of Mulch
Nursery Stock - Tree Selection The successful growth of a tree to maturity depends on the quality of the tree itself. Do not choose a tree that has:
Do plant and maintain a tree that:
Pruning Young and Mature Trees Pruning controls the appearance, shape and growth patterns of the tree and keeps branches from harming structures or people. Improper pruning can cause damage that will last for the life of the tree, or worse, shorten the tree’s life.
Pruning Young Trees What to Prune
When to Prune
How to Prune
Pruning Mature Trees Pruning mature trees may require special equipment, training and experience. If the pruning work requires climbing, the use of a chain or hand saws, or the removal of large limbs, the use of personal safety equipment, such as protective eye wear and hearing protection is a must. Certified Arborists can provide a variety of services to assist in performing the job safely and reducing risk of personal injury and damage to your property. Trained crews will have all of the required safety equipment and liability insurance. They are also able to determine what type of pruning is necessary to maintain or improve the health, appearance and safety of your trees.
Avoid using the services of a company that:
If branches have broken, stubs remaining on the tree should be pruned back to the next largest branch. Correct Steps to Pruning
Topping is a harmful pruning practice in which tree branches are cut back to stubs. Topping trees will make them more hazardous in the long term. Proper pruning methods exist to reduce tree height versus topping, which can cause decay of the branches and attract insects and disease.
Water is the single most limiting essential resource for tree survival and growth. Drought conditions can severely affect young and old trees alike leading to tree decline, pest problems, and non-recoverable damage as well as decreased rates of diameter and height growth. More than eighty percent of the variation in tree growth is because of water supply.{1} Although providing adequate water to newly planted trees is essential, replacing older, more valuable trees lost or damaged due to lack of water can be especially difficult since they can take decades to grow to the same size. With the many social, economic and environmental benefits that trees provide it is important to continue caring for our trees even in times of drought and tightening water restrictions. Newly planted trees should be regularly watered for the first three years. Water newly planted trees every few days initially, then once a week depending on soil conditions and rainfall. Weekly to monthly watering should continue until the tree is established in the landscape. Established, mature trees should be watered every 2 to 4 weeks during drought conditions by thoroughly wetting the top 12 inches of soil under the tree’s canopy. This may takes several hours or more depending on what type of application devices are available to you. If you have limited time to devote to your trees, it is better to completely wet a small area than to only wet the surface few inches over a large area. Limit pedestrian, mower and vehicle traffic under the tree. {2} A good slow soaking over several hours is the most efficient way to water trees. Using a soaker hose, drip irrigation, a Tree gator watering bag, or slow drip bucket which applies water at ground level is the best way to accomplish this and to avoid water loss due to evaporation or runoff. This method also focuses the water over the root area and keeps the leaves and trunk dry which can prevent opportunities for harmful pests and diseases. Don’t over water. Too much water can kill a tree by eliminating the air from the soil and suffocating the roots. The soil should not stay saturated, but have time to dry out between waterings.
As a general rule, 2 gallons of water should be applied for every 1” of tree diameter.
{1} Coder, Kim D. 1999 {2} Gilman, Edward F. 2007 |
