The life of a County Extension Agent is always fun. On any given day, I might get questions about lawn fertilizer recommendations, the best plants for our area, or a fungus growing on a tree. Sometimes, I get a fun question from someone who is just curious about something they observed in nature. I usually get to learn something new while I’m finding an answer!
Last week, I got a call about why there are so many acorns this year. While I was tempted to offer to send squirrels from my neighborhood to take care of any acorn abundance, that would not have satisfied the caller!
Oaks and several other species of trees occasionally produce a huge crop of acorns. This is called a mast event
or masting. For many of our oaks, masting events might happen every two to five years, followed by small or moderate acorn crops. Interestingly, masting events are not synchronized among trees of the same species. One tree might have a masting even, while the tree next to it has very few acorns in a given year.
Production of acorns in a masting year takes a tremendous amount of energy and resources from the tree. Trees may not be able to maintain that level of production every year without causing deficits in the tree’s resources.
Weather plays a large role in acorn production. Bad weather such as late spring freezes, extremely high summer temperatures, drought, and other stressful weather events can reduce pollination and acorn production. For most oaks, the male catkins produce pollen first, then the female flowers open to receive it. This ensures cross pollination within a species. If a late spring freeze damages the flowers at the wrong time, trees will have poor pollination and a low acorn crop. Or a drought in the summer can cause a tree to drop acorns early because it does not have the energy to put into acorn production.
Wildlife can also reduce the number of acorns that we see. Squirrels, deer, turkeys and other wildlife may eat up all the acorns. Weevil larvae might also reduce acorn production as they eat the acorns from the inside out. Oaks may produce an abundance of acorns at irregular intervals to ensure the next generation of seedlings. If a tree can produce more than the wildlife can eat, some acorns will survive long enough to germinate and produce a seedling. That’s a smart oak tree!
For more information about lawn and garden topics, contact Kate Hajda, Horticulture Extension Agent for Williamson County, at 512-943-3300.
