Tree Care Information
Skip Navigation LinksHome > Tree Care Information > Mature Tree Care

Mature Tree Care


Think of tree care as an investment. A healthy tree increases in value with age—paying big dividends, increasing property values, beautifying our surroundings, purifying our air, and saving energy by providing cooling shade from summer’s heat and protection from winter’s wind.

Providing a preventive care program for your landscape plants is like putting money in the bank. Regular maintenance, designed to promote plant health and vigor, ensures their value will continue to grow. Preventing a problem is much less costly and time-consuming than curing one once it has developed. An effective maintenance program, including regular inspections and the necessary follow-up care of mulching, fertilizing, and pruning, can detect problems and correct them before they become damaging or fatal. Considering that many tree species can live as long as 200 to 300 years, including these practices when caring for your home landscape is an investment that will offer enjoyment and value for generations.

Tree Inspection

Tree inspection is an evaluation tool to call attention to any change in the tree’s health before the problem becomes too serious. By providing regular inspections of mature trees at least once a year, you can prevent or reduce the severity of future disease, insect, and environmental problems. During tree inspection, be sure to examine four characteristics of tree vigor: new leaves or buds, leaf size, twig growth, and absence of crown dieback (gradual death of the upper part of the tree).

A reduction in the extension of shoots (new growing parts), such as buds or new leaves, is a fairly reliable cue that the tree’s health has recently changed. To evaluate this factor, compare the growth of the shoots over the past three years. Determine whether there is a reduction in the tree’s typical growth pattern.

Further signs of poor tree health are trunk decay, crown dieback, or both. These symptoms often indicate problems that began several years before. Loose bark or deformed growths, such as trunk conks (mushrooms), are common signs of stem decay.

Any abnormalities found during these inspections, including insect activity and spotted, deformed, discolored, or dead leaves and twigs, should be noted and watched closely. If you are uncertain as to what should be done, report your findings to your local ISA Certified Arborist or other tree care professional for advice on possible treatment.

 

 

Mulching

Mulching can reduce environmental stress by providing trees with a stable root environment that is cooler and contains more moisture than the surrounding soil. Mulch can also prevent mechanical damage by keeping machines such as lawn mowers and string trimmers away from the tree’s base. Further, mulch reduces competition from surrounding weeds and turf.

To be most effective in all of these functions, mulch should be placed 2 to 4 inches deep and cover the entire root system, which may be as far as 2 or 3 times the diameter of the branch spread of the tree. If the area and activities happening around the tree do not permit the entire area to be mulched, it is recommended that you mulch as much of the area under the drip line of the tree as possible (refer to diagram). When placing mulch, care should be taken not to cover the actual trunk of the tree. This mulch-free area, 1 to 2 inches wide at the base, is sufficient to avoid moist bark conditions and prevent trunk decay.

An organic mulch layer 2 to 4 inches deep of loosely packed shredded leaves, pine straw, peat moss, or composted wood chips is adequate. Plastic should not be used because it interferes with the exchange of gases between soil and air, which inhibits root growth. Thicker mulch layers, 5 to 6 inches deep or greater, may also inhibit gas exchange.

Fertilization

Fertilization is another important aspect of mature tree care. Trees require certain nutrients (essential elements) to function and grow. Urban landscape trees can be growing in soils that do not contain sufficient available nutrients for satisfactory growth and development. In these situations, it may be necessary to fertilize to improve plant vigor.

Fertilizing a tree can improve growth; however, if fertilizer is not applied wisely, it may not benefit the tree at all and may even adversely affect the tree. Mature trees making satisfactory growth may not require fertilization. When considering supplemental fertilizer, it is important to know which nutrients are needed and when and how they should be applied.

Soil conditions, especially pH and organic matter content, vary greatly, making the proper selection and use of fertilizer a somewhat complex process. When dealing with a mature tree that provides considerable benefit and value to your landscape, it is worth the time and investment to have the soil tested for nutrient content. Any arborist can arrange to have your soil tested at a soil testing laboratory and can give advice on application rates, timing, and the best blend of fertilizer for each of your trees and other landscape plants.

Mature trees have expansive root systems that extend from 2 to 3 times the size of the leaf canopy. A major portion of actively growing roots is located outside the tree’s drip line. It is important to understand this fact when applying fertilizer to your trees as well as your turf. Many lawn fertilizers contain weed and feed formulations that may be harmful to your trees. When you apply a broadleaf herbicide to your turf, remember that tree roots coexist with turf roots. The same herbicide that kills broadleaf weeds in your lawn is picked up by tree roots and can harm or kill your broadleaf trees if applied incorrectly. Understanding the actual size and extent of a tree’s root system before you fertilize is necessary to determine how much, what type, and where to best apply fertilizer.

Pruning

Pruning is the most common tree maintenance procedure next to watering. Pruning is often desirable or necessary to remove dead, diseased, or insect-infested branches and to improve tree structure, enhance vigor, or maintain safety. Because each cut has the potential to change the growth of (or cause damage to) a tree, no branch should be removed without a reason.

Removing foliage from a tree has two distinct effects on its growth. Removing leaves reduces photosynthesis and may reduce overall growth. That is why pruning should always be performed sparingly. Overpruning is extremely harmful because without enough leaves, a tree cannot gather and process enough sunlight to survive. However, after pruning, the growth that does occur takes place on fewer shoots, so they tend to grow longer than they would without pruning. Understanding how the tree responds to pruning should assist you when selecting branches for removal.

Pruning mature trees may require special equipment, training, and experience. If the pruning work requires climbing, the use of a chain or hand saw, or the removal of large limbs, then using personal safety equipment, such as protective eyewear and hearing protection, is a must. 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. They also are able to determine which type of pruning is necessary to maintain or improve the health, appearance, and safety of your trees.

Removal

Although tree removal is a last resort, there are circumstances when it is necessary. An arborist can help decide whether or not a tree should be removed. Professionally trained arborists have the skills and equipment to safely and efficiently remove trees. Removal is recommended when a tree

  • is dead, dying, or considered irreparably hazardous
  • is causing an obstruction or is crowding and causing harm to other trees and the situation is impossible to correct through pruning
  • is to be replaced by a more suitable specimen
  • should be removed to allow for construction

With proper maintenance, trees are attractive and can add considerable value to your property. Poorly maintained trees, on the other hand, can be a significant liability. Pruning or removing trees, especially large trees, can be dangerous work. It should be performed only by those trained and equipped to work safely in trees. For more information on mature tree care, contact your local ISA Certified Arborist.

The PHC Alternative

Maintaining mature landscapes is a complicated undertaking. You may wish to consider a professional Plant Health Care (PHC) maintenance program, which is now available from many landscape care companies. A PHC program is designed to maintain plant vigor and should initially include inspections to detect and treat any existing problems that could be damaging or fatal. Thereafter, regular inspections and preventive maintenance will ensure plant health and beauty. Refer to our Plant Health Care brochure for more information.


E-mail inquiries: isa@isa-arbor.com


(c) 1998, 2004 International Society of Arboriculture.
UPDATED JULY 2005

Developed by the International Society of Arboriculture (ISA), a non-profit organization supporting tree care research around the world and is dedicated to the care and preservation of shade and ornamental trees. For further information, contact:
ISA, P.O. Box 3129, Champaign, IL 61826-3129, USA.
E-mail inquires: isa@isa-arbor.com

© 2007 International Society of Arboriculture.
UPDATED SEPTEMBER 2005

News

What is an Arborist and How Can You Find One?
From Planet Green a Discovery Company MORE >>

Green Parking II: Putting Parking Lots to Work
Green parking lots are defined as those that are designed to do environmental work. Parking lots should be designed to reduce the use of energy, improve environmental quality and to ensure more healthy conditions for people. Further, parking lots should be planned and designed to reflect regional landscape types. Plant materials and other materials of construction must be used in ways that will support this objective. MORE >>

NADF Hardiness Zone Map
Find out the right tree to plant where you live MORE >>

Hot Topics
"Hot Topic" press releases fro the USDA newsroom ranging from current pest alerts for specific regions of the United States to new trends in disease prevention and tree and plant care. MORE >>

Don't Move Firewood!

Camping Season is fast approaching. Please remember to not transport firewood. Tree-killing insects and diseases can lurk in firewood. These insects and diseases can't move far on their own, but when people move firewood they can jump hundreds of miles. New infestations destroy our forests, property values, and cost huge sums of money to control. MORE >>

National Tree Benefits Calculator
Make a simple estimation of the benefits individual street-side trees provide. With inputs of location, species and tree size, users will get an understanding of the environmental and economic value trees provide on an annual basis. For more detailed information on urban and community forest assessments, visit the i-Tree website. MORE >>

National Register of Big Trees
Big trees are symbols of all the good work trees do for the quality of the environment-and our quality of life. MORE >>


"A society grows great when old men plant trees whose shade they know they shall never sit in." - Greek Proverb

Resources

Mature Tree Care Brochure

Available through the ISA Web store

Careful Planning, Gradual Pruning Essential for Flowering Trees
As summer approaches, many trees and shrubs are flowering into greenery that highlights any outdoor picnic or barbecue. However, with the flowering of summer comes the challenging responsibility of pruning - MORE >>

© International Society of Arboriculture 2009
P.O. Box 3129, Champaign, IL 61826
Email comments & questions to isa@isa-arbor.com