Aldo Leopold provides the inspiration and points out the importance of planting trees. To plant well and assure the splendid trees envisioned for the school’s future, homework is needed. Planting trees varies from climate to climate, soil to soil. These are things to keep in mind in the Research Triangle area to achieve vigorous trees.

The establishment period for many trees is over several years, so the first step for a successful planting project is a thorough plan to oversee the tree or trees during that period. Establishing responsibility and a plan of work beginning with planning, through planting, to watering and removal of stakes, wires, and root dams, provides a sound beginning.

The most common need for successful planting in the Triangle area and on Cary Academy grounds specifically is a good air moisture ratio in the soil. The soils are generally heavy clay soils, formed during the Triassic Period, that tend to shrink when they are dry and swell when they are wet. These have been compacted during the construction process of grading and building the school. Compaction reduces the air space in the soil and reduces the flow of water out of the soil. Unsuccessful plants are quite often the result of drowning of the roots. In large areas of planting, ripping the soil provides an excellent result in thriving plants. This is not easy work to do but it is the most important step in achieving long term success on the school’s grounds.

Planting in late fall through February is ideal in terms of establishing root systems for the long term. This is the period of lower risk for many tree species when less intensive watering is required. When plants are dormant, they lose less water through transpiration. While successful planting can be done in the Triangle throughout much of the year, it is done at higher cost, and higher risk, and success varies by species. "Fall" in Triangle planting terminology may not begin until about the end of November if the months between September and November have been dry and a killing frost has not occurred. Many plants have late dormancy and continue to grow late into the year. The tree planting should be well planned to be sure the planting site will be ready in order that trees will not have to be stored while waiting to be planted.

Select quality trees well adapted to conditions of individual planting sites. Poor quality and/or poorly sited plants are doomed from the start, no matter how carefully they are planted. Seek out trees from reliable sources grown in soils similar to the site on which they will be planted.

Container plants should be chosen with no roots circling around the root ball. These may eventually girdle the trunk and make the tree susceptible to falling over. Select trees grown in containers with vertical ribs or a copper-treatment on the interior container wall. These container modifications and treatments minimize circling root formation. Balled and burlapped plants should be freshly dug. Request that no synthetic material or treated burlap be used to wrap balled and burlapped trees.

Ask that plants be handled carefully during shipping and protected from drying out by shipping in covered trucks and under tarps. Moving trees from the delivery truck to the ground should be done with care to prevent damage to the bark and rootballs. Dropping trees on the pavement is not a desirable practice.

Locate all of the utilities in the area of the proposed planting before the site is finalized and be sure the planting is well away from the utilities. If underground rock obstructs planting, remove small quantities. If the rock is too large, change the planting site to a more favorable location.

Obtain a NC Department of Agriculture soils test for all areas to be planted. Recommended pH adjustment amendments should be incorporated during planting.

Test soil drainage before planting. Dig a test hole as deep as the planting hole and fill with water. If water drains at a rate of less than one inch per hour, consider installing drainage to carry water away from the planting hole base, or moving or raising the planting site with berm construction. Consider using water-tolerant species. Avoid plants that don’t like "wet feet" where drainage is poor.

It takes more than digging a hole to plant a great tree. The preparation of the planting area is critical to tree survival and vigorous growth. Prepare a planting area 4-5 times larger than the diameter of the rootball by ripping the soil to a depth of 24" using a backhoe mounted frost ripper or a tractor mounted rotovator. In the center of this prepared area, dig a flat bottomed hole. Carefully place the tree upright in the hole on undisturbed solid ground, so that the upper surface of the root ball is higher than the surrounding grade or even higher in poorly drained soils. Take care that the trunk is straight. Walk around and look at the tree from different sides and if the tree is not straight, carefully move the ball, not the tree.

Closely inspect the wrapping around root balls of B & B (balled and burlapped) trees. Many growers use synthetic materials, as well as burlap treated to retard degradation, to wrap root balls. Many of these materials will not degrade. To insure root growth into surrounding soil, remove pinning nails or rope lacing, then cut away or drop the wrapping material to the bottom of the planting hole, backfill over it. Pull back burlap from the top 18" of the ball. Cut this off and again, drop material to the bottom of the planting hole.

Wire baskets used to protect root balls degrade very slowly underground. Remove the top 8-12 inches of wire to keep equipment from getting caught in wire loops, and surface roots from girdling.

Remove all rope, whether jute or nylon, from trunks. Again, degradation is slow or nonexistent, and ropes can girdle trunks and roots.

Remove plastic containers from container-grown trees. For plants in fiber pots, break away the top or remove the pot entirely. Many fiber pots are coated to extend their shelf life, but this slows degradation below ground and retards root extension.

Score or rough up the walls of machine-dug holes to prevent glazing. Till all of the soil which had been removed. Remove the very large clumps and rocks so that air pockets are eliminated.

Mix ph amendments at rates specified in the soil tests reports, as the backfilling proceeds since ph amendments do not move easily through the soil.

Lightly compact the backfill material. Do not place soil on top of the root ball.

When backfilling is complete, form a 2-3" high earth mound outside the outer edges of the root ball. This "dam" will aid in watering by capturing the water and letting it seep into the root area. This dam should be removed after the grow-in period.

Remove tags and labels from trees and shrubs to prevent girdling branches and trunks.

Researchers are continuing to study the effects of fertility on newly planted trees. The current thinking that has evolved with experience is that accelerated root growth is a desirable result. Nitrogen(N) is often the most needed nutrient in the Triangle soils since there are frequently sufficient amount of phosphorous(P) and potassium(K). Nitrogen also leaches through the soil faster. Research indicates the most effective method is using slow release granular fertilizer broadcast under the tree canopy.

Mulch, but don’t over mulch newly planted trees. Two to three inches of mulch is best. Use organic mulches such as pine bark mulch or pine straw. Mulches, in addition to providing benefit to the soil, provide a measure of protection against errant maintenance equipment damage. Black plastic beneath mulch around trees and shrubs should not be used because it blocks air and water exchange. Keep the mulch from touching tree trunks. This helps prevent disease and rodent problems.

Trees should only be staked if support is needed. Trees with large crowns, or those situated on windy sites or where people may push them over may require staking. Allow trees a slight amount of flex rather than holding them rigidly in place. Use guying or attaching material that won’t damage the bark. To prevent trunk girdling, remove all guying material as soon as roots are established, or at the end of the first growing season.

Wrapping

Most trees should not have their trunks wrapped. This practice started with the aim of preventing sun scald but research now shows wrap does not protect trees. Moisture can be trapped, heat held near the bark, and insects, especially borers, are provided a haven under what is supposed to be a protective wrap.

Good follow-up watering is the most important need of newly planted trees to promote root growth. New trees are best watered manually with a hose to obtain sufficient quantity since rainfall and automatic irrigation are often ineffective during the most critical first three months. Direct the water to the top of the root ball and fill the area created by the soil dam. The frequency of watering will depend on the soil type and the temperatures and wind which affect evaporation. A dependable way to monitor the soil moisture in and around the now hidden root ball is by using a soil probe which, when removed from the ground brings up a small column of soil. The moisture or lack of moisture can be felt when the soil is poured out in the hand. Watering based on soil probe results eliminates most of the guessing if water is getting were it is needed and prevents over watering.

Thinking through the logistics of watering is very important before planting the tree. Drip irrigation systems and water reservoir devices such as the now popular "Gator bags" can facilitate watering. Establish a calendar for watering. Determine the source of water and who will do the watering? Are there hose connections nearby or will water need to be transported to the site?

Summary

The School can make a meaningful contribution to the Triangle’s canopy of trees by planting well. The results of the careless planting of trees is not an infrequent sight throughout the community. Struggling trees are often the reflection above ground of an unhealthy root system resulting from poor planting. The stunted growth, gangly form, yellow or pale green leaves, or dying back of the tips of the branches are not inspiring.