Branch stubs from 12 red maples (Acer rubrum L.) were studied to determine differences in tree response to such injuries. Two basic patterns emerged from the 110 stubs dissected. Some stubs (type A) had a clearly visible green-colored boundary, which separated the discolored and decayed wood of the protruding stub from sapwood inside the stem. Other stubs (type B) lacked this boundary, and discolored wood extended into the stem. Fungi and bacteria were more abundant in sapwood and discolored wood of type B stubs than type A stubs. The green-colored boundary was enriched with phenols, and appeared to prevent movement of bacteria and fungi into the stem. This boundary should not be removed when a tree is pruned. Forest Sci. 27:519-522.
Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.