Harvard Forest >

Harvard Forest REU Symposium Abstract 2015

• Title: Red maple (Acer rubrum) and red oak (Quercus rubra) exhibit spatial and temporal variation in vulnerability of xylem vessels to embolism
• Author: Julia L Fisher (Bates College)
• Abstract:

  Vulnerability to embolism was evaluated along the root to leaf pathway in two common hardwood species, red maple (Acer rubrum) and red oak (Quercus rubra), at the Prospect Hill tract of Harvard Forest in Petersham, Massachusetts, USA. Air seeding pressure analysis was completed on root, trunk, multi-year stem, current-year stem, and petiole tissue of saplings and mature trees of both species. Current year (2015) xylem vessels were measured in all tissue types, and past year (2014) vessels were also measured in multi-year and trunk tissue. There were no differences in air seeding thresholds between saplings and mature trees in either species. While Q. rubra exhibited only a slightly higher resistance to embolism in trunk than in petiole tissue, A. rubrum exhibited higher resistance to embolism in trunk and multi-year tissue than in petiole and current-year tissue. A. rubrum xylem vessels in current year growth ring were also more resistant to embolism than vessels from the past year’s growth rings. There was, however, no difference in air seeding pressure between growth rings in Q. rubra. These data suggest that, although diffuse-porous A. rubrum may better adapted to resist embolism than ring-porous Q. rubra, soft petiole tissue in both species may act as dispensable fuses to embolism. As the threat of embolism will increase with the predicted increase in drought frequency and intensity, these data have important implications for future timber management plans and conservation strategies.

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