Learn new tips and techniques for tree care to ensure longevity for your new trees.
The Tree Doctor: A Guide to Tree Care and Maintenance(Firefly, 2017), by Daniel and Erin Prendergast, teaches readers the basics of caring for trees. Learn how to select, plant and care for new trees, diagnose diseases, as well as how to select an arborist for tree removal for the end of a trees’ life. Find this excerpt from Chapter 3, “Planting and Care.”
Since trees are such a visible part of the landscape, care must be taken to ensure that proper growth conditions are maintained. Trees lose 70 to 95 percent of their root mass when transplanted. It usually takes transplanted trees one year for every inch of trunk diameter to regenerate their root mass.
Pruning at the time of planting is not recommended and should be limited to deadwood, broken branches and damaged limbs. Corrective pruning activity — such as pruning interfering limbs, poorly spaced limbs and weak crotches — should wait until the tree is established, after one or two growing seasons.
Help ensure that your trees enjoy a long life by completing the following maintenance tasks:
Stake only when necessary: Most newly planted trees do not need to be staked. However, if you’re planting in an open, windy area, staking a young tree provides it with support until its root system is established in the new location.
Mulch: Use only organic mulch, such as wood chips or bark chips.
Water: Watering is imperative in order for a tree’s roots to grow into its surrounding soil. To test if your tree needs water, feel the soil 4 to 8 inches deep. If it is dry or only slightly damp, add water. Sandy soil will require more water than clay soil, which tends to hold moisture longer. Water the tree around the trunk. A slow trickle from a garden hose left to run over several hours is more beneficial than short, frequent watering, which promotes a shallow root system and makes the tree more vulnerable to environmental stress. Continue watering until mid-autumn, tapering off for lower temperatures that require less frequent watering. Give each of your trees one good long soak before freeze-up. Pay particular attention to evergreens, which lose moisture all winter because they don’t shed their needles.
Fertilize: Fertilizing may be necessary if your soil is deficient in essential macro- and micro-nutrients.
Proper watering practices are vital to the survival of your newly planted tree. Trees need soil moisture to encourage root growth and to supply water to leaves. Watering practices should suit the plant type and its environment, and must be appropriate for soil type and drainage. Young plants that are just getting established need more attention, as do mature specimens with extensive root systems.
Your soil type will also influence your watering schedule. Clay needs less frequent, but deeper, watering for the water to penetrate.
Every newly planted tree should be well watered at planting to eliminate air pockets and settle the tree firmly in place. Moisture should reach 12 inches below the soil surface to encourage ideal growth. Thereafter, water once or twice a week for the first few weeks until the root system becomes established. (Be careful not to overwater. Surprisingly, overwatering kills more trees than underwatering. Too much water will cause the leaves to turn yellow or fall off.)
Check the soil to determine when you need to water. You should water newly planted trees thoroughly when the top inch of soil has dried. For established trees, you may be able to wait until the top 2 to 4 inches of soil have lost moisture. You seldom need to water mature trees, except during periods of drought.
Prolonged rainfall will supply enough water to penetrate deeply. If you use sprinklers to duplicate rainfall, allow the water to soak into the soil over a period of time, which will provide the best penetration with the least waste through runoff and evaporation. You can use a soaker hose, too, a process known as “drip irrigation.”
Continue watering until mid-autumn, tapering off as temperatures drop. In cold-winter regions, water trees well in advance of hard freezes. Give each of your trees one good long soaking before freeze-up. Plants that enter winter with dry soil have no moisture reserves in their needles to thwart drying winter winds. Evergreen plants are especially vulnerable to dry soil.
Staking is often used to re-establish young trees, especially bare-root stock. Some people believe that staking is not necessary and that trees will develop better if they are not staked. However, you might consider staking if your tree is planted in a very windy or exposed location.
Transplanted trees suffer from root loss, which limits a tree’s ability to take in water and nutrients. Once a tree is planted, it will concentrate its energy on standing upright. To keep it straight and to keep it from being blown over, you may want to stake a young transplanted tree for a year or so.
Proper staking will also allow your tree enough room to move with the wind, which will enable it to develop a good trunk taper, which is important for stability. Staking will also help to reduce movement of the root ball, which may cause damage to new fine absorbing roots.
For best anchorage and to prevent damage, at least two stakes should be used for each tree. Stakes should be installed with the following tips in mind:
• Set stakes at equal distances from the trunk.
• Drive stakes into solid undisturbed ground at least 2 feet deep from the trunk to provide adequate stability for the tree and to avoid the root ball.
• Tie the tree to its stakes with suitable biodegradable material, like burlap. Avoid using wire encased in rubber hose, as it will prevent trunk expansion if it is left on too long.
• Leave at least 1 inch of space between each tie and the tree trunk. Remove stakes and ties after one year. If it is too dependent on supports, the trunk will not develop adequate strength.
• If you decide to stake your tree, remember the following tips:
• Stake the tree only until it is able to stand on its own. If it is too dependent on supports, the trunk will not develop adequate strength.
• The staking material should not be too tight. Leave room for the tree to sway in the wind.
• The staking material should not be too loose. The tree should not rub against its stakes.
• Stakes should be buried at least 2 feet deep to provide ample support.
• Place your stakes carefully, so people won’t trip over them.
You may choose to use a plastic tree guard around the trunk to minimize damage caused by mice, rabbits and other animals, and to protect it from mowers and string trimmers. (Wrapping is not recommended. This procedure, where a material such as burlap or crepe paper is wrapped around the bark of young trees, fosters an environment for boring insects.) The guard should fit loosely and allow air to circulate around the trunk. You can also use plastic spirals to prevent mice, rabbits and deer from chewing the bark of young trees throughout the winter months.
Trees growing in the wild get no fertilizer as we think of it. However, annual layers of fallen leaves and animal droppings decompose to release a small but continuous supply of nutrients. In the same way, many trees may grow successfully in yards and gardens without supplemental nutrients. If your tree displays significant new growth with good color each year, it is healthy and strong.
Urban trees, on the other hand, often grow in soil that does not contain sufficient nutrients for satisfactory growth. As trees and shrubs grow and develop, they require nutrients such as nitrogen, phosphorous and potassium. Topsoil is often removed during construction, and leaves and other plant parts are removed in gardening maintenance, robbing the soil of nutrients and organic matter. Consequently, most woody plants in urban areas benefit from the addition of fertilizer.
Fertilizing is not necessary if your tree appears to be healthy and strong — but, in some cases, fertilizing may be beneficial.
Plants can obtain nitrogen, phosphorous and potassium in a couple of different ways.
• Phosphorous and potassium must be present in the soil for it to be useful. Roots extract these two nutrients from films of water surrounding soil particles or from the particles themselves. The best time to apply fertilizer containing these two nutrients is before you plant, digging it well into the soil.
• Plants can obtain nitrogen from the air, from decaying matter in the soil and from fertilizer supplements. Much of the nitrogen that is found in soil is lost due to leaching or to its return to the atmosphere in a gaseous state. Removing leaf litter and other natural sources of nitrogen can disrupt the cycling of nitrogen in the soil.
A fertilizer containing all three of the above nutrients is called a complete fertilizer (5-10-5 nitrogen-phosphorus-potassium). Fertilizers are available in organic or inorganic forms. Inorganic fertilizers are quick releasing when dissolved in water, whereas organic fertilizers dissolve at a slower rate. Examples of natural organics are manures, sewage sludge, blood and bone meal.
When fertilizing trees, use fertilizers with slow-release or controlled-release nitrogen. To determine if a fertilizer is a slow-release one, look for the percentage of water-insoluble nitrogen on the label. If approximately half of the nitrogen is water-insoluble, it is considered slow-release.
In order for fertilizer to be absorbed by a tree’s roots, its nutrients must be in solution, which requires soil moisture. This means that you must water the soil thoroughly after applying fertilizer so the nutrients are released.
• Fertilizers address nutrient deficiencies. Plants lacking in nitrogen display slow growth, small leaves and yellowing leaves (chlorosis). The application of fertilizer can often correct these problems.
• A tree that is growing vigorously is less susceptible to severe injury by certain diseases and insect pests.
Heavy nitrogen fertilization promotes vegetative growth, or green leaf growth, which may delay flowering output. High rates of application in July and August will stimulate growth that won’t harden off properly before the winter, which can result in winter-kill. Heavy nitrogen fertilization can also stimulate the activity of sap-sucking insects and certain diseases.
Trees need nutrients when they are producing new growth. The best time to apply fertilizer is in late winter to early spring, depending on the climate. Fertilizer uptake in deciduous trees corresponds with the time of root growth, which, in general, starts before bud break and ends after leaf drop. Fall is also a good time to fertilize trees; many trees continue to grow roots in the fall after the shoots have stopped growing.
To prevent fertilizer runoff in the spring, do not apply it if the ground is frozen. During drought periods, roots will not readily absorb fertilizers. There is also additional risk of damage from salts.
In mild-winter regions with no frost, you can continue a fertilizer program throughout the summer. In cold-winter climates, discontinue fertilizer application in early summer. The new growth stimulated by later applications will be at risk when temperatures plummet. However, trees can benefit from one final application just before the first frost is expected.
At this point the plants have already stopped producing new growth, but roots are still able to absorb nutrients and store them for spring’s growth push.
Trees in natural settings create their own mulch as they drop their leaves, twigs, fruit and flowers. This litter layer provides many benefits for a tree. In an urban environment, you can mimic this process by using an organic wood-chip mulch around trees. When applied correctly, your tree will benefit greatly.
• Reduces weed problems
• Reduces soil compaction and erosion
• Retains moisture
• Moderates soil temperatures
• Improves soil aeration and structure
• Looks good
Use composted mulch and apply it at a depth of 2 to 4 inches, depending on the soil. For soils that drain poorly, like clay, use 2 to 3 inches of mulch. Use 3 to 4 inches of mulch for better-draining soils. Spread the mulch wide, not deep. To avoid moist bark conditions and prevent decay, take care that the mulch doesn’t touch the trunk of the tree.
The Tree Doctor: A Guide to Tree Care and Maintenance
By Daniel Prendergast & Erin Prendergast
Published by Firefly Books Ltd. 2017
Copyright © 2017 Firefly Books Ltd
Text copyright © 2017 Daniel Prendergast and Erin Prendergast
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