|Abstract or Summary
- This thesis is an observational study that examines relationships between disturbance, forest stand development, and big huckleberry (Vaccinium membranaceum) fruit productivity and growth by combining ecological methods with the traditional ecological knowledge of Warm Springs ceremonial huckleberry pickers. Shrub fields of fruiting big huckleberry develop in early seral subalpine environments such as forest burns. With fire suppression, the abundance of big huckleberry fields on the Mt. Hood National Forest and Warm Springs Indian
Reservation has declined, though mechanical disturbances, such as timber harvests, have occasionally created productive fields. During summer and fall 2000, characteristics of forest overstories (canopy cover, basal area, stand density) and huckleberry understories (fruit productivity, stem height, leaf cover) were measured in 25 huckleberry fields representing a range of initial disturbance types and stand ages. Data were analyzed with univariate and linear regression techniques. Forest Steven R. Radosevich stands on huckleberry fields created by historic fires were older and had greater stand development than fields created by mechanical disturbances. Though once extremely productive, at the time of this study huckleberry fields created by historic fires produced less fruit than fields created by mechanical disturbances.
Huckleberry field fruit production was negatively associated with overstory canopy
cover and basal area, suggesting that sexual reproduction in forest understories is
resource-limited. Regressions on stand age indicated that huckleberry shrubs take over a decade to recover from disturbance and begin abundant fruit production in open environments. Huckleberry stem height and leaf cover were not associated with forest stand characteristics that change with successional time; therefore, big huckleberry appears tolerant of extended periods in closed canopy forests. Huckleberry fruit production and stem height were correlated, and both variables were greater on ridges than on slopes, perhaps due to slowed stand development on ridges. Future yields of big huckleberry will require management practices that mimic past disturbance regimes and slow stand development.