Disturbance severity and canopy position control the radial growth response of maple trees (Acer spp.) in forests of northwest Ohio impacted by emerald ash borer (Agrilus planipennis)

Abstract

Key message. Radial growth of silver and red maples was investigated across three forests in northwest Ohio following the outbreak of the invasive emerald ash borer. The growth response of maples was driven by an advancement in canopy class and disturbance severity. Context. Forest disturbances resulting in species-specific diffuse mortality cause shifts in aboveground and belowground competition. This competition may differentially affect nonimpacted trees, depending on crown class, disturbance severity, and species-specific responses. Aims. The purpose of this study is to elucidate the primary drivers of silver and red maple (Acer saccharinum and A. rubrum) growth following emerald ash borer (EAB, Agrilus planipennis)-induced ash tree (Fraxinus spp.) mortality in riparian forests of northwest Ohio. Methods. Using dendroecological approaches, we analyzed the pattern of radial growth in red and silver maples in conjunction with the EAB outbreak. Results. This study revealed growth rates of maples increased 72% following EAB arrival and trees advancing in crown class grew 41% faster than those not advancing. The growth response varied by initial crown class, with trees in the intermediate class responding most dramatically. Furthermore, the positive correlation between relative basal area of ash and the radial growth response of maples indicates the important role of disturbance severity in post-disturbance dynamics. Conclusion. These findings suggest that, although advancement in crown class may allow predictions of "winners" in forest succession post-disturbance, even trees not changing crown class benefit from decreased competition. Results from this study provide a detailed account of radial growth responses in maples following EAB-induced ash mortality and lend insight into the future canopy composition of ashdominated riparian forests.

Keywords

Silver maple (Acer saccharinum), Red maple (Acer rubrum), Growth release, Emerald ash borer (Agrilus planipennis), Diffuse mortality, Disturbance

Citation

Costilow, K.C.; Knight, K.S.; Flower, C.E. 2017. Disturbance severity and canopy position control the radial growth response of maple trees (Acer spp.) in forests of northwest Ohio impacted by emerald ash borer (Agrilus planipennis). Annals of Forest Science. 74: 10. 10 p. https://doi.org/10.1007/s13595-016-0602-1