Question
We have two mature 20+ yrs old Shumard red oaks.  What is the production capacity iif these trees for acorns and how often do they produce acorns?

Answer
Shumard oak is a red oak. The minimum seed-bearing age for Shumard oak is 25 years and optimum production is about 50 years. The interval between seed crops is 2 to 3 years. Of course this will depend on the weather in the spring when the oaks are flowering. The variability in acorn production is often a result of poor pollination, late spring frosts or drought. Late in the season, acorn weevils can also be a factor. In addition, individual trees will be good, moderate or poor acorn-producers and may have genetic differences that affect their reproductive maturity.

Acorns of trees in the red oak group take 15 months, two growing seasons, to mature and are bitter because they are high in tannic acid.  Each fall, trees in the red oak group will have a combination of small, immature acorns on the current year抯 growth and mature acorns on the previous year抯 growth. Thus, species in the red oak group can provide an acorn crop in years with a late spring freeze that might have destroyed the white oak acorn crop. However, in both groups, acorn production remains very unpredictable from year to year. Research has shown that, on average, most species produce a good crop of acorns only one year out of three or four. Some oak species are inherently better acorn-producers than others, and these different species will tend to produce a good acorn crop in different years. Environmental factors, such as a late spring frost or summer drought, can contribute to the cyclic nature of unfavorable acorn production during any particular year.