The Effect of Periodical Cicadas on Growth of Five Tree Species in Midwestern Deciduous Forests

Periodical cicada emergences in the eastern United States are one of the largest biomass fluctuations in the world, providing a unique opportunity to study if a root parasite can affect broad-scale patterns of forest growth and succession. We used dendrochronology to examine the direct effect of Brood X (17 y cicada) and Brood XXIII (13 y cicada) periodical cicadas on 89 individual trees from five species (Acer saccharum, Fraxinus americana, Quercus palustris, Q. velutina and Sassafras albidum) in Indiana. Standard dendrochronological techniques were used to date the tree-ring samples and our chronologies ranged from 63 98 y in age, spanning from four to eight cicada emergences. We removed the main climate variable from each species chronology by conducting a regression, analysis and using the residuals for the remainder of the analysis. Significant climate models were developed for all five species. Acer saccharum growth correlated highest with Jun. temperature (r = -0.392), Fraxinus americana growth correlated with summer Palmer Drought Severity Index (PDSI) (r = 0.338), Quercus palustris growth correlated with summer precipitation (r = 0.366), Q velutina growth correlated with Jul. PDSI (r = 0.527) and Sassafras albidum growth correlated the highest with Jun. precipitation (r = 0.406). A superposed epoch analysis was used to examine the effect of periodical cicadas on each tree species before, during and after multiple emergences on the stand level. No effect from root parasitism prior to emergence was evident in any of the species, but three of the species chronologies showed a significant reduction in growth the year of or the year after the emergence year. Three chronologies showed an increase in growth 5 y following the cicada emergence event.