Acorn Production
Acorns are considered a keystone resource in upland hardwood ecosystems. Acorn abundance influences rodent populations and the populations of their predators. Populations of many game species including squirrels, bear and deer are also affected by annual acorn production. Even forest structure and hardwood regeneration are indirectly affected by acorn production by influencing densities of deer – which in turn browse heavily on woody vegetation. And, of course, oak regeneration comes from their seeds – acorns!
Working with collaborators and partners our research shows
- Acorn production varies among years, species, and individual oak trees.
- Acorn production among individual oak trees is not “all or none.”
- A good crop = more trees with acorns + more acorns per tree.
- Acorn density is correlated with the proportion of fruiting trees.
- Good producers produce more acorns more frequently.
- Good producers constitute <50% of population, but produce most of the acorns.
- Good producers are hard to identify because a similar proportion of good and poor producers produce in all years.
- The proportion of trees bearing acorns is a good predictor of crop size.
- A fast, simple estimate of the proportion of trees bearing acorns in any given year can be substituted for the current labor-intensive hard mast indexing techniques.
- State and Federal agencies can easily standardize their hard mast surveys using this technique, thus ensuring that acorn production data are comparable at local and regional scales.