Long-term forest data links acorn crops to Lyme disease risk

A 35-year ecological study conducted in New York's Dutchess County suggests that acorn crops may be a better predictor of Lyme disease risk than deer populations. Researchers from the Cary Institute of Ecosystem Studies and Bard College analyzed long-term data from a 2,000-acre forested site, finding no statistical relationship between deer abundance and the density of nymphal ticks, which are the life stage most responsible for spreading the disease to humans.

The study highlights a food-based chain where oak trees periodically drop heavy acorn crops in synchronized events known as masting. These crops support mouse populations, which in turn influence tick density. Lead author Richard Ostfeld noted that while short-term data subsets showed a weak positive relationship between deer and nymph abundance, the full 35-year dataset refuted that connection, cautioning against relying on single-season tick counts.