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Six elements are required in small amounts for the growth and development of plants. These are referred to as micronutrients: iron (Fe), manganese (Mn) copper (Cu), zinc (Zn), molybdenum (Mo), and boron (B).
Needlecast and needle blight are terms applied to a variety of foliage disorders of many coniferous species. These diseases are usually more severe on young trees or on trees growing outside of their natural range.
Sonic tomography, or the use of sound waves to detect decay in trees, is a relatively new technology available to arborists.
Thousands of trees are struck by lightning every year. These trees will have varying degrees of damage ranging from complete shattering and destruction of the tree, to a slow lingering death, to virtually no apparent damage at all (Figure 1).
Conifers are commonly planted in North America to provide year-round screening, as windbreaks or as focal trees in the landscape.
Oak decline is a slow-acting disease complex that involves the interaction of biotic and abiotic factors such as climate, site quality and advancing tree age.
Ice or snow loads can cause branch breakage or failure of entire trees and shrubs. Branches or entire trees that fall in storms can impact homes, vehicles, power lines and block roads.
ManagementEmerald ash borer (Agrilus planipennis) was first discovered in southeastern Michigan in 2002.
Insect and disease infestations pose major threats to several North American forest tree species.
North American forests and forest management institutions are experiencing a wide range of significant ecological disturbances and socioeconomic changes, which point to the need for enhanced resilience.