Discoloration following bark stripping wounds on Fraxinus excelsior

A total of 101 Fraxinus excelsior trees 8-32 cm in d.b.h. with bark strippi ng wounds caused by Alces alces and Cervus elaphus in Lithuania were cut, d issected and examined. The injuries ranged in age from 5 to 18 years, when the trees were 22-40 years old and were in the size range 6-24 cm d.b.h. Fo r 5-10 years old wounds, the mean length of associated wood discoloration w as 804 +/- 201 cm, while in 16-18 years old wounds it was 912 +/- 144 cm. T here was no correlation between wound age and extent of discoloration in th e stems examined (r=0.11). Tree d.b.h. and Mound size (initial width x leng th) were correlated with the extent of discoloration (r=0.43 and r=0.20, re spectively). The presence of complete wound occlusion had no significant ef fect on the length of columns of discoloration associated with wounds of 10 or more years old. The average occlusion rate during the first 10 years wa s 128 +/- 28 mm or 13 mm/year, correlating positively with the radial incre ment (r = 0.42). Amongst a total of 500 F. excelsior trees with wounds, 29 trees (5.8%) bore basidiomycete fruiting bodies. Most common was Phellinus punctatus, found on 12 (2.4%) stems, followed by Coniophora puteana (1.6%), Peniophora limitata (0.4%) and Datronia mollis (0.4%). Fungi most commonly isolated from discoloured wood were ascomycetes Phaeoacremonium rubrigenum , Phialophora malorum, Hypoxylon rubiginosum, Coniothyrium sporulosum, Libe rtella spp., Ophiostoma sp., and basidiomycetes Ischnoderma benzoinum, Isch noderma resinosum, Tyromyces sp.