Discoloration and Decay in Severed Tree Roots

Roots of honeylocust (Gleditsia triacanthos var. inermis), pin oak (Quercus palustris), tuliptree (Liriodendron tulipifera), and green ash (Fraxinus pennsylvanica) trees were severed at the root flare and 1, 2, or 3 m (3.3, 6.6, and 9.9 ft) from the trunk. After 5 years, the severed roots were excavated and all discolored and decayed portions were removed. The furthest extent of decay development ranged between 4.5 cm (1.8 in) in green ash and 10.8 cm (4.3 in) in honeylocust. The furthest extent of discoloration also varied between 6.3 cm (2.5 in) in green ash and 77.1 cm (30.8 in) in honeylocust. The root severing location producing the greatest decay or discoloration varied among species. Natural defect development as a result of severing roots of any size root at any distance is not likely to result in a threat to the health or stability of a tree.