Douglas L. Airhart & Guy Zimmerman III

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Right Tree / Right Place

Selecting Trees

Transplanting Trees

Mulching & Staking

Summary Diagram 

Pruning Trees

Topping Hurts!

Protecting Trees

Tree Root Myths

Pine Bark Beetles

Live Christmas Trees


List of Figures

List of Video Vignettes

Related Links




It is far too easy to make mistakes about managing landscape trees, and seemingly little mistakes can jeopardize the health of your trees.

By following proper planning, planting and maintenance practices, you will allow trees to become established and grow into healthy assets in your landscape. As the trees grow and increase in value, your property will increase in value. These tutorial articles and video vignettes are intended to help you ensure good structure and strength, the continued best health and highest value of your landscape trees.

Trees Save Energy: Anonymous (1992). Tennessee Department of Agriculture, Forestry Division.

Trees in the landscape can be a great way to save money, or just make your yard cooler in the summer, because the shade of trees reduces air temperatures and reduces home and business energy use for air conditioning. In summer sun, bare ground temperatures can become as high as 136F to 152F, and the top of a tree canopy can be 25F higher than the ground level. The air temperature at ground level has been shown to drop 36F after ten minutes of being in the shadow of a tree. It has been said that if you combine the factors of shade, evaporation, transpiration and convection, a single mature tree will get rid of as much heat as five 10,000 BTU air conditioners.

Trees also can divert winds over and around buildings, reducing winter energy costs.

In addition, trees clean the air. Concerning air pollution, a 1992 study showed that air above a street without trees carried 10,000 to 12,000 dust particles per liter, but air above a nearby tree-shaded street had only 1,000 to 3,000 dust particles per liter. Clearly trees contribute to controlling our air pollution problems.

Good Planning creates Good Trees:

The successful completion of any task begins with good planning, and the same is true with the task of establishing landscape trees. Success in this case means continued growth into healthy maturity, which begins with proper selection of trees for the desired use and site conditions. But success also requires that proper transplanting skills and establishment techniques be applied as the tree matures. Young trees must be nurtured to ensure their complete establishment into the landscape. Watson & Himelick (1997) stated "To be considered fully established, the partial root system in the root ball, or the confined root system of the container, must develop into a normal spreading root system that can utilize soil moisture and nutrient resources from a large soil volume. This usually takes several years of root growth."

The tree roots need adequate moisture throughout the year for growth, and each canopy must be pruned for structure and strength as it develops. Established mature trees need regular maintenance and need intermittent pruning to ensure their health.

ALL trees must be protected from the improper treatment known as topping or ‘rounding-over’.

ALL trees must be protected from two main landscape hazards:


damage to the trunk by mowers or string trimmers, and


damage to the root zone by compaction of the soil.

Mower blight occurs when a mower comes too close to a trunk and scrapes off bark, or when a mower clips off the top of an exposed root.

(Figure 1-1) Severe Mower Blight. 

New callus and bark is forming on both sides, but tree growth will be restricted.


Used with permission of Tennessee Tech University, (Photo courtesy of J. Plant, 2002).

In the spring the bark of actively growing trees will ‘slip’ easily, and large chunks of bark can be knocked off with only a slight bump of the mower wheels or frame. These wounds near the ground are particularly likely to become infected with diseases. Some soil borne diseases can kill a tree in a matter of days (Hartman, 2000). Keep mowers away from the tree by killing the grass or mulching the root zone near the trunk (but not up it!) and in the areas of exposed roots.

Soil compaction occurs by pedestrian and vehicle traffic over the root zone, especially on wet soil. Roots are not located deep in the soil, but grow at shallow depths much farther out than the branches. Most homeowners would realize that because the packed soil could not absorb or hold water, the roots will die of dehydration. But more importantly the air-holding pores are squeezed out, and roots no longer have the oxygen they need to survive.

The information in these segments is just a short summary for each of the many considerations affecting the health and successful establishment of landscape trees. We have attempted to mention the primary concerns and main factors to consider in the progression from selection to maturity, but these are just brief and convenient summaries. Homeowners who want the complete explanation of these concerns are recommended to review the excellent references we have in our bibliography.


Purpose    Right Tree / Right Place    Selecting Trees    Transplanting Trees    Mulching & Staking    Summary Diagram     Pruning Trees    Topping Hurts!      Protecting Trees     Tree Root Myths     Pine Bark Beetles     Live Christmas Trees     Glossary     List of Figures    List of Video Vignettes    Related Links     Bibliography


TLCforTrees.info is maintained by: Douglas Airhart, Ph.D. Certified Arborist & Jeff Plant, Ph.D, Last Updated on: 07/11/03