Polk County Conservation

Acorn Mast Years

  • Why do oak trees produce a lot of acorns one year and hardly any in other years? I have tons of acorns to rake up under my bur oak trees this fall.

    When a tree produces a huge crop of nuts, it is called a "mast" year and this year is a mast year for bur oak and white oak trees. However the acorn crop for pin oak, swamp white oak, and red oak is poor. There aren’t any good predictors as to why acorn production varies from year to year or from species to species. On average, most oaks produce a good crop of acorns every three to four years. Environmental factors can influence a tree’s ability to produce acorns. For example in warm wet years, trees have more resources to produce a large crop. While in cold, dry years, not many acorns are produced. Late frosts in the spring can also affect the acorn productivity. If an oak tree produces a good crop of acorns one year, it is likely that the following year will not yield as many. Acorns are an important source of food for deer, squirrels, turkeys, and other wildlife.

  • Contact Us

    Administration Office
    11407 NW Jester Park Drive
    Granger, IA 50109

    P: (515) 323-5300
    F: (515) 323-5354
    pccb_info@polkcountyiowa.gov

    Monday – Friday, 8:00 a.m. – 4:30 p.m.

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