RT Journal Article SR Electronic T1 Anatomical Features of Girdling Root Injury JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 29 OP 32 DO 10.48044/jauf.1981.008 VO 7 IS 2 A1 Hudler, G.W. A1 Beale, M.A. YR 1981 UL http://auf.isa-arbor.com/content/7/2/29.abstract AB The root system of a Norway maple affected by girdling roots was excavated, dissected, and examined microscopically. Cross-sectional area of vessels in the stem xylem affected by the girdle was only 10% that of unaffected wood. Rays in the stem wood were skewed and contained few pits. Bark on the girdled stems was compressed from a normal thickness of about 2.5 cm to 1 mm. The offending roots sustained slight compression of cells where they were in contact with the stem and appeared to remain functional. Thus, girdling roots apparently cause tree decline by reducing stem conductivity and radial communication between tissues.