You are here

Harvard Forest >

Harvard Forest REU Symposium Abstract 2019

  • Title: Limits to growth in Carya ovata due to climate and competition
  • Author: Danielle Holt (Portland Community College)
  • Abstract:

    Both climate change and the ongoing shift in forest composition due to changes to land use can have a dynamic impact on the growth of Shagbark Hickory (Carya ovata). While several studies have investigated Shagbark’s response to light patches and canopy accession strategies, little attention has been paid to how climate, canopy position, or stand density simultaneously or independently impact growth. In this study I used a combination of field survey data, tree-ring records, competition indexing, and time-series analysis to investigate how these factors impacted two populations of Shagbark Hickory near a poleward limit at the Harvard Forest in Massachusetts. I found that Shagbark Hickory growth is positively correlated to total June, July, and August precipitation, negatively correlated to June and July maximum temperatures, and positively correlated to average minimum February temperatures. While trees in the overstory or understory were both sensitive to summer precipitation, overstory C. ovata growth was more negatively impacted by extreme summer temperatures than understory trees. Additionally, the sensitivity to February minimum temperature has decreased in recent years, which is likely caused by increasing winter temperatures due to climate change. 1953 and 1954 were marker rings with extreme damage, followed by a growth release, likely caused by a tornado and late frost event. These rings indicate Shagbark is vulnerable to extreme cold events, and able to respond rapidly to stand disturbance. Understanding how Shagbark Hickory responds to climate, competition, and disturbance will help predict which factors will decide Shagbark Hickory’s success in this region.

  • Research Category: Physiological Ecology, Population Dynamics, and Species Interactions