Caring for Your Trees

Useful Information on Caring for Your Trees
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Benefits of Trees

Among the direct economic benefits of trees are lowered energy costs to homeowners--lower air conditioning costs and lower heating costs when trees are planted as windbreaks--and value added from landscaped vs. non-landscaped homes (from 5-20% value difference). The net cooling effect of a young, healthy tree is equivalent to 10 room-size air conditioners operating 20 hours a day, according to the U.S. Department of Agriculture.

     According to Pepper deTuro, certified NJ arborist:

  • One mature tree provides enough oxygen for four people.
  • A single maple tree with a diameter of 30 cm can extract between 5 and 10 grams of heavy metals from the soil each year, which helps decontaminate urban lands.
  • A healthy mature tree can absorb between 2.5 and 5.0 kg of carbon each year, which slows down climate change, and about 7,000 fine particulates in each liter of air, which decreases the incidence of respiratory diseases.
  • Trees protect us against the heat island effect by creating shade and pulling water out of the soil and into the atmosphere; a large oak tree can transpire more than 400 liters of water a day.

     Trees serve as noise barriers. Birds are attracted to the area. Leaves filter the air we breathe by removing dust and other particulates. Rain then washes pollutants to the ground. Leaves absorb carbon dioxide from the air, as well as other pollutants, ozone, carbon monoxide, and sulfur dioxide. They give off oxygen.  Temperature near trees is cooler than it is away from them. Trees moderate the heat effects of pavement/concrete in urban settings.   Wind speed and direction can be affected by trees. Trees reduce stormwater runoff and the possibility of flooding.

     Trees improve air quality, moderate the climate, conserve water, and harbor wildlife.

     Tree Benefits Calculator.

Invasive Species List

NJ Invasive Species Strike Team invasive species do not plant list.

Resolution 16-364 recommending invasive species do not plant list.

Caring for Trees

The Community Forestry Program of the NJ State Dept. of Environmental Protection has advice on caring for trees and other topics.

Brochure on tree decay.(pdf)

Native Shade Trees - NJ

Question:  I want to plant a tree in my Princeton yard. I hear native (not imported) trees perform the best. What are the names of some native trees that grow well in our New Jersey climate?

Answer: Take this list of recommended native trees with you to the tree nursery.

Tree-Related Links

Urban-tolerant trees. This link to the New Jersey Tree Foundation website includes related articles.

Landscape plants rated by deer resistance. A comprehensive list, including trees, can be found on this Rutgers University fact sheet. See also the same information on this website, in the "Useful Info" drop-down menu, under the heading "Deer Resistant Plants."

What are the best trees to plant under utility wires? The PSE&G website, under the heading "Right Tree, Right Place," presents a list of trees compatible with overhead distribution facilities.

Tree owner information. This link to the International Society of Arboriculture website presents many tree care topics and directs you to related brochures.

Mulching Your Trees

Spring is a great time to mulch your trees, but not if you are using mulch "volcanoes." The practice of creating mulch volcanoes, while a popular landscaping practice, actually is most harmful to trees. Piling mulch at the base of a tree traps moisture around the trunk and root flare, leading to decay and often structural damage. Excessive and improper use of mulch can also rot bark surfaces and prevent deep supporting root development. Further, excessive mulch placed around the bark of trees prevents moisture from penetrating the roots. The best shape is a donut that keeps mulch several inches away from the base of the tree to avoid rot and diseases but encourages moisture to enter the root system.

Trees with mulched root zones are usually larger and more vigorous, develop faster, and have higher rates of survival than plants surrounded by turf grass or bare dirt. Mulches retain soil moisture, reduce erosion, and prevent soil compaction. Mulching under trees but away from the tree trunk results in fewer weeds to compete with tree roots for water. Soil under mulch is likely to stay warmer in winter and warms faster in spring, helping extend the growing season for roots.

Organic mulches are a favorite among professionals, who view wood chips as an effective, attractive mulch for trees. Avoid fine mulch, which can become matted and prevent penetration of water and air. A good mulch bed should extend out at least three feet from a tree's trunk in all directions, though extending to the drip line is preferred. The drip line is defined as the area where the tree branches end. The mulch depth should be 2-3 inches.

Don't keep adding new mulch on top of what is already under the tree. Mulch does decompose, but you don't want to accumulate excessive mulch year after year by adding fresh mulch every spring. If you want the look of fresh mulch, and there is a depth of mulch fewer than three inches under the tree, break up the old with a rake and add only a thin layer of new on top.

--Condensed and edited summary of a 2011 Town Topics article written by Pepper deTuro, certified NJ arborist.

Hazards to Your Trees

Bacterial Leaf Scorch in Oaks

Deer Resistant Plants

Additional Resources

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