A Macroscopic and Microscopic Study of Compartmentalization and Wound Closure after Mechanical Wounding of Black Walnut Trees


  • J. E. Armstrong
  • A. L. Shigo
  • D. T. Funk
  • E. A. McGinnes
  • D. E. Smith


Juglans nigra, wound response, discoloration, compartmentalization, anatomy, pathology


Compartmentalization is a concept developed to explain tree response to injury. To study this concept, uniform mechanical wounds were made in fifty black walnut trees. Each tree was wounded at two different heights, 0.5 and 1.4 m, and at two different times, fall (November 1975) and spring (March 1976). The amount of wound closure was noted after one complete growing season, as were several macro- and microscopic characteristics of compartmentalization. Wound closure and compartmentalization were separate responses. Most of the wounds were closed after a single season's growth.

The eight trees with one or more open wounds were among the smallest and slowest growing trees in the study. This suggests a positive relationship between growth rate and wound closure, but statistically the relationship was not significant. Wood discoloration was the most prominent wound-related defect. Greater volumes of discolored wood were associated with fall wounds than with spring wounds. Similarly, fall and spring upper wounds were associated with larger volumes of discolored wood than their lower counterparts. Prior fertilizer treatments had no effect on wound closure or compartmentalization. The compartmentalization of wound-affected wood in black walnut agrees with the generalized model of compartmentalization of decay in trees (CODIT). The outer tangential and lateral compartment walls are the strongest, and the inner tangential and top and bottom compartment walls are the weakest and most easily overcome by invading microorganisms. The initial wood discoloration process did not appear to be associated with microorganism activity. Effective compartmentalization was positively correlated with growth rate. Some results of this study suggest that the relative ability to compartmentalize is under genetic control.


Armstrong, J. E., W. H. Kearby, and E. A. McGinnes, Jr. 1979. Anatomical response and recovery of twigs of Juglans nigra following oviposition injury inflicted by the two-spotted tree-hopper, Enchenopa binotata.Wood Fiber11(1):29-37.nArmstrong, J. E., and E. A. McGinnes, Jr. 1979. Wound reactions in twigs of black walnut. Pages 83-87 in: Walnut insects and diseases workshop. Proc. USDA For. Serv. Gen. Tech. Rep. NC-52. 99 pp.nBlock, R. 1941. Wound healing in higher plants. Bot. Rev.7:110-146.nClark, F. B. 1955. Black walnut responds to pruning. J. Forestry53:362-365.nClark, F. B. 1961. Climatic injury found on planted black walnut in Kansas. USDA For. Serv. Cent. States For. Exp. Stn. Note 147. 2 pp.nGagnon, C. 1967. Polyphenols and discoloration in the elm disease investigated by histochemical techniques. Can. J. Bot.45:2119-2124.nMaeglin, R. R., and N. D. Nelson. 1970. Surface soil properties of black walnut sites in relationships to wood color. Soil Sci. Soc. Am. Proc.34:142-146.nMcGinnes, E. A. Jr. 1968. Extent of shake in black walnut (Juglans nigra L.). For. Prod. J.18:80-82.nMcGinnes, E. A. Jr. 1975. Response of black walnut to environmental mishaps. 66th Ann. Report North. Nut Growers Assoc. Pp. 102-107.nMcGinnes, E. A. Jr., and A. L. Shigo. 1975. Electronic technique for detection of discoloration, decay, and injury-associated ring shake in black walnut. For. Prod. J.25:30-32.nNeely, D. 1970. Healing of wounds on trees. J. Am. Hortic. Sci.95:536-540.nPhelps, J. E. 1980. Color variation in black walnut veneer: A macro- and microscopic study. Ph.D. Dissertation. University of Missouri, Columbia. 93 pp.nShigo, A. L. 1975. Biology of decay and wood quality. Pages 1-15 in W. Liese, ed. Biological transformation of wood by microorganisms. Springer-Verlag, Berlin.nShigo, A. L. 1976. Compartmentalization of discolored and decayed wood in trees. Mater. und Org., Dunker and Humbolt, Berlin, 3:221-226.nShigo, A. L., and W. E. Hillis. 1973. Heartwood, discolored wood, and microorganism in living trees. Ann. Rev. Phytopath.11:197-222.nShigo, A. L., and H. G. Marx. 1977. Compartmentalization of decay in trees. USDA For. Serv. Agric. Inf. Bull. 405.nShigo, A. L., E. A. McGinnes, Jr., D. T. Funk, and N. F. Rogers. 1979. Internal defects associated with pruned and nonpruned branch stubs in black walnut. USDA For. Serv. Res. Paper NE-440, 27 pp.nShigo, A. L., N. F. Rogers, E. A. McGinnes, Jr., and D. T. Funk. 1978. Black walnut on Kansas stripmine spoils. Some observations 25 years after pruning. USDA For. Serv. Res. Paper NE-393. 14 pp.nShigo, A. L., W. C. Shortle, and P. W. Garrett. 1977. Genetic control suggested in compartmentalization of discolored wood associated with tree wounds. For. Sci.23(2):179-182.nSmith, D. E. 1980. Abnormal wood formation following fall and spring injuries in black walnut. Wood Sci.12(4):243-251.nSucoff, E., H. Ratsch, and D. Hook. 1967. Early development of wound-initiated discoloration in Populus tremuliodes Michx. Can. J. Bot.45:649-656.n






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