Variation in the Constitutive Defensive System of Loblolly Pine in Relation to Bark Beetle Attack

Abstract

Total flow over a 4-hr period, rate of flow, and relative viscosity were measured on 13 full-sib families in 1987. Significant differences between families were detected for all parameters measured. These parameters have been suggested as being useful in predicting relative host susceptibility to bark beetle attack. Certain families are suggested to be potentially more resistant to bark beetle attack than other families based on these parameters of interest. During 1988, 1989, and 1900 trees of unknown parentage (woods run) were wounded at different times during the day and total resin flow measured hourly for 24 hr. Rate of flow was calculated. Significant differences in flow were found at the beginning of the 24-hr period for all years. Nineteen eighty-eight was the only year that these differences continued for the entire 24 hr. Patterns of flow were similar for all years with 70% to 87% of flow occurring within the first 8 hr after wounding. Findings presented here, although preliminary, are encouraging in that it may be possible to incorporate potential bark beetle resistance information into tree improvement programs. For. Sci. 38(2):457-466.