Acorn production has important implications for wildlife and overall forest ecosystem health. Acorn crop size estimates have thus become an important component of assessment tools for land managers and researchers. We used 9 years of acorn production data to develop predictive models that estimate average annual acorn production for five common oak species, using tree diameter and projected crown area as prediction components. Sampled oak trees were located throughout the Pisgah National Forest in the Southern Appalachians. As a case study, we applied our prediction models to inventory and monitoring data from the US Forest Service to derive estimates of average annual acorn production across the state of Virginia.
Results/Conclusions
The number of acorns produced varied among species (p<0.0001). Of the five oaks studied, white oak (Quercus alba L.) produced the most acorns per tree per year (2,093) and chestnut oak (Q. prinus L.) the least (274). At the landscape level, white oak also produced the most acorns (7,098 acorns/ha/yr). Chestnut oak, however, was the third highest producer of acorns (1,618 acorns/ha/yr). These differences between tree and landscape-level acorn production among species are partly due to differences in their relative abundance across the landscape in Virginia. Chestnut oak was concentrated in the mountains, primarily on ridge tops, where acorn production for this species averaged nearly 6,100 acorns/ha/yr. White oak, although somewhat evenly distributed, produced the most acorns (10,749 acorns/ha/yr) in the northern piedmont region of the State. These distributional differences have potential implications for both forestry and wildlife management given the differing acorn production cycles and nutritional differences between the red and white oak subgenera. This study presents the first estimates of acorn production at a landscape scale.
