Technical Resources
Trees SC has created a series of simple, yet informative fact sheets on successfully caring for trees. Please contact us if you would like to request a color copy of a fact sheet
How to Buy a Tree
Trees SC was founded in 1991 as a non-profit organization to foster the stewardship of South Carolina’s urban and community forests through education, advocacy and networking.
Urban and community forests include all the trees in your community: tree-lined roads, parks, neighborhoods, and commercial building sites. Taking care of the trees in these areas benefits the environmental, social and economic well-being of your community.
The Golden Rule of Tree Buying – Always Select Trees Yourself
When buying trees, there are four issues to settle: tree species, size, price, and condition. You can settle three of them over the telephone (species, size, and price). You should assess tree condition with your own eyes.
Inspect the Crown
- Be extra careful to inspect for structural defects on large-maturing shade trees like oaks and maples. Young shade trees with structural defects (poor brand attachments, for example), become serious safety hazards as they reach maturity. This is not as much an issue with smaller ornamental trees.
- For large-maturing shade trees, beware of trunks that fork low to the ground, tight (V-shaped) branch crotches with the bark rolled inward, and multiple branches arising from one place on the trunk. These are structural weaknesses.
- Look at the branches-this is where the leaves (the food factories of the tree) will be. You’re looking for a general covering of small-to-medium size branches. Beware of large branches that are low on the trunk.
Inspect the Trunk
- Avoid trees with large bark injuries (deer rubbing, mechanical wounds, etc.). Large bark injuries can develop into cracks and the wood behind these injuries can develop decay.
- Avoid trees with sprouts around the base-this is a sign of biological distress and is probably an indication that the tree was planted too deep.
- Learn to recognize proper pruning-avoid trees with branch stubs or flush cuts. Improper pruning can cause a number of problems, including “frost cracks,” “sun scald,” excessive sprouting, and decay.
- Trunk wrap is unnecessary and can hide decays. Some nurseries us a cardboard shield to protect the trunk from injury during handling. Always remove it to inspect the trunk before you accept the tree. It can be reattached for further handling.
Inspect the Roots
- For bailed and burlapped trees, avoid undersized root balls. Trees are sold by caliper (trunk diameter 6” above the ground), or height. The American Association of Nurserymen maintains a set of standards for nurseries selling trees (see table below). You should insist that the root ball meets these specifications.
- For container-grown trees, avoid trees with large circling roots. Very gently remove the container to inspect the root system.
- For bare-root trees, avoid trees with dried up or mechanically damaged roots.
Standards for Nursery Stock
How to Establish a Tree
Location
Use common sense when deciding where to plant a tree. Large-maturing shade trees should be planted away from buildings and utility lines. Give trees a chance-don’t plant them in the wrong place.
Planting Depth
Do not plant trees and shrubs too deep. The root collar (where the first main roots branch out from the trunk) should be even with or slightly higher than the final grade of the surrounding soil.
Should Trees Be Staked?
Not necessarily, even though it is a common practice. Trees are often staked unnecessarily and improperly, even by professionals. It is a practice that is best saved for very open, windy areas. If trees need support in strong winds, brace them properly (improper staking is a leading cause of damage to new trees). Here is the proper way to branch trees:
- Use broad, belt-like materials that won’t injure the bark. DO NOT STAKE TREES WITH A WIRE IN A HOSE.
- Don’t apply tension-allow the trunk to sway slightly in a moderate wind.
- Remove all bracing materials after the first summer and before the beginning of the second growing season.
Pruning Trees
Don’t worry about pruning until next year-research shows that it is better to wait until after the first growing season to prune newly planted trees. The old theory to “balance the top with the roots” has been shown to prolong the establishment period. Here’s why: Removing branches removes leaves. Leaves are the food factories of the tree! Dead or deceased branches are the exception to this rule and should be properly pruned away as soon as they are discovered.
Mulch
Always mulch newly planted trees properly. Composted organic material (leaves, twigs, wood chips) is best. Cover a large area under the tree wit a layer 2-3 inches deep, making sure not to pile it against the trunk. Although proper mulching will suppress some weed growth, you will still have to control weeds in the mulched area by hand pulling or applying an appropriate herbicide.
Watering
Always provide water during the establishment period. Larger trees require a longer establishment period. For each inch of trunk caliper at planting time, the tree needs approximately one year to become established. (One year for a 1-inch tree, 2 years for a 2-inch tree, etc.)
A good rule of thumb is to provide water twice a week during the summer. In sandy areas, water more often. Five or 10 gallons per inch of trunk diameter is a good amount of water. A five-gallon bucket with a small hole in the bottom and placed near the trunk is an easy way to deliver water slowly to the root zone.
To keep water from running off, build up a ring of soil around the root zone when you plant the tree. This “water ring” helps keep the water where it is needed.
How to Fertilize a Tree
When Do You Fertilize?
The time to fertilize trees is in the late winter before the buds begin to break open. Avoid fertilizing during periods of drought or excessive moisture. Applying fertilizer to dry soil will burn the roots or break down before it can be watered in by natural rains. During wet periods the fertilizer will be washed away before it can be utilized by the tree. Fertilizers should be applied when the soil is moist. This optimizes the chances that the nutrients you are supplying will get to the tree.
Where Do You Fertilize?
Trees have roots spreading far from the trunk of the tree. These roots reach in all directions from the trunk. The roots which do the actual work of taking up the water and nutrients are the tiny “feeder” roots. These are hair-like roots located in the top layer of the soil. Most of these tiny roots are concentrated under the canopy of the tree. This is where fertilizer should be applied.
How Do You Fertilize?
Fertilizers may be applied in two forms, wet or dry. Liquid fertilizer is usually injected into the soil. Dry fertilizer comes in powdered and granular forms.
Granular fertilizers are easy to obtain and to apply. Broadcasting granules on the soil surface works but does not deliver the material directly to tree roots. If there is grass under the trees instead of mulch, the grass will get much of the benefits. To deliver more of the fertilizer to the tree roots, the fertilizer must be placed under the surface of the soil. Apply the fertilizer into small holes placed two to three feet apart in a grid pattern under the canopy of the tree. The holes should be dug with a pipe, tire tool, steel prybar, or bulb planter. The holes should be 8-12 inches deep and one to two inches in diameter. Mix the fertilizer with peat moss or other bulky organic matter. This will help reduce burn and add airspace to the soil. Liquid fertilizer should be injected in the same grid pattern.
How Much Do You Fertilize?
Very light applications are ideal. With a light approach, more fertilizer can always be added later. Heavy applications of fertilizer can severely damage or kill trees, especially stressed trees.
How to Protect a Tree
The following steps will help to preserve trees on your site that will enhance your property value, provide wildlife habitats, reduce energy bills and provide an environment you will enjoy for years to come.
Start Before Constrction
If you start before construction begins, protecting trees on construction sites can be inexpensive, simple, and yield very satisfying results. The following steps will be helpful in planning the development of your site.
Walk the Site
Before your architect or engineer designs your site on paper, walk the site with them and a certified arborist. Pick the trees you would like to save and have the arborist assess their overall health. Different species of trees vary in their ability to overcome the stresses associated with construction and environmental change; the arborist will be able to provide guidance in these matters.
Accurate Location is Essential
Once you have chosen the healthiest and best species of trees on your site, mark these trees and have a surveyor locate them on your site plan. Accurate location is essential, as the entire site will be designed around these trees. Inaccurate location can lead to expensive redesign and damage to or removal of otherwise healthy trees.
Protecting Trees With Buildings
Sit down with the architect or engineer to discuss and sketch the placement of all buildings and associated structures that best protect the trees. Don’t forget things like asphalt or concrete drives or patios, pools, and underground utilities such as telephone, water, sewer, cable TV and electrical lines. All of these can cause severe root damage if not located at a reasonable distance from the tree. The tiny feeder roots, which take in water and nutrients, require oxygen to live and function properly. Because they need oxygen, they are located in the top layer of soil and organic matter on the forest floor. It is absolutely critical to protect this layer (and the roots that live there) from disturbance. Since a great percentage of these roots occur within the drip line (the edge of the canopy), trees are best protected by having all construction and trenching done outside this canopy.
Compaction: The “Silent Killer”
Have the architect or engineer specify tree barricades around protected trees on the site plan. These fences are critical in protecting feeder roots from being crushed by the compaction of the soil from driving or parking vehicles near the trees. Compaction is the “silent killer” of trees on construction sites. Make sure barricades are made from sturdy, high visibility material (such as orange safety fence attached securely to 2×4 posts) and are placed as close to the drip line as possible.
Specify Tree Protection
Put a clause in your building contract specifying tree protection and penalties if protected trees are damaged or removed. Meet with your contractor and walk the site to review which trees are protected.
Take Care Installing Additional Landscaping
When you landscape, don’t forget that installing irrigation lines and plant material can also damage root systems; therefore, it is best to install them beyond the area(s) protected during construction. Ask your landscaper to follow the seven principles of xeriscape when designing the landscape and irrigation, and be sure to put a rain gauge on your irrigation system. Both of these measures will help conserve water. Saving understory plants during construction helps preserve our native plant species and protects wildlife habitat.
Monitor the work being done on your site to be sure that tree protection guidelines are followed. A certified arborist should be consulted to help with problems due to damage during construction.