Dysfunctional Root Systems and Brief Landscape Lives: Stem Girdling Roots and the Browning of Our Landscapes

摘要

That’s a sobering thought—a tree with a normal life span of 65 to 250 years may live less than 10 years when planted in any American city’s downtown landscape. Admit- tedly, that fgure represents tree placement in the worst of our urban landscape sites: sidewalk cut-outs. These inhospitable planting sites are also known as tree coffns, tree burial mounds, or urban tree disposal units to frustrated urban foresters. When the mortality rate of downtown trees is compared to tree losses from Dutch elm disease, oak wilt, sudden oak death, and gypsy moth, it doesn’t take too long to realize that there’s an epidemic of urban tree loss going on and it’s largely under the radar (Figure 1)