ENVIRONMENTAL FACTORS AFFECTING TREE HEALTH IN NEW YORK CITY

A major problem facing the arborist is choosing tree species suitable for urban plantings. A wide variety of biologically important stresses limit tree growth in cities. Because metropolitan tree planters tend to choose only those species com-monly known to be tolerant of urban stresses only a few species of trees are found in cities. Urban areas are very heterogeneous, and dif-ferent stresses or different degrees of stress may be present even at adjacent planting sites. For example, a tree beside a wide, heavily travelled city street may be subjected primarily to high salts and high winds while around the corner, on a street with less vehicular traffic, soil compaction may be more critical. The disturbed nature o