Experts and BHG readers answer.
Is a streetlight causing my maple tree problems?
Bright streetlights can affect a plant's perception of day length. The plants are tricked into perceiving that days are longer than they really are by the artificial light from the street lamp. Because declining day length is one of the triggers that induces dormancy in a plant, leaf color changes and leaf drop may be delayed by proximity to a bright light. In most cases, plants will continue to grow with no ill effects. But should an extremely early cold snap hit, branch tips that have not hardened off properly may suffer dieback. Or, as in the case of your maple tree, the leaves may hang on an extra-long time. Usually as buds begin to swell next spring, the old leaves will be pushed off, and no permanent damage will be evident. Some trees are more sensitive to the effects of security lights than others.
Norway maple (Acer pla-tanoides), paper birch (Betula papyrifera), sycamore (Platanus Yacerifolia), American elm (Ulmus ameri-cana), and Japanese zelkova (Zelkova serrata) are some of the more sensitive. Those with low sensitivity include American holly (Ilex opaca), sweet gum (Liquidambar styraciflua), southern magnolia (Magnolia grandiflora), Austrian pine (Pinus nigra), callery pear (Pyrus calleryana), and willow oak (Quercus phellos). K: landscaping, trees, maple, acer, leaves, street lights, day length, dormancy, paper birch, betula, sycamore, platanus, elm, ulmus, zelkova, holly, ilex, sweet gum, liquidambar, magnolia, pine, pinus, callery pear, willow oak, quercus