Hemlock woolly adelgid (Adelges tsugae) infestation affects water and carbon relations of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana)
Article first published online: 8 APR 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 199, Issue 2, pages 452–463, July 2013
How to Cite
Domec, J.-C., Rivera, L. N., King, J. S., Peszlen, I., Hain, F., Smith, B. and Frampton, J. (2013), Hemlock woolly adelgid (Adelges tsugae) infestation affects water and carbon relations of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana). New Phytologist, 199: 452–463. doi: 10.1111/nph.12263
- Issue published online: 19 JUN 2013
- Article first published online: 8 APR 2013
- Manuscript Accepted: 7 MAR 2013
- Manuscript Received: 13 SEP 2012
- USDA Forest Service (EFETAC)
- DOE – BER Terrestrial Ecosystem Sciences program. Grant Numbers: 11-DE-SC-0006700, ER65189
- carbon isotope;
- hydraulic conductivity;
- soil–plant–atmosphere model;
- stomatal conductance;
- traumatic resin canals;
- water potential;
- wood anatomy
- Hemlock woolly adelgid (HWA) is an exotic insect pest causing severe decimation of native hemlock trees. Extensive research has been conducted on the ecological impacts of HWA, but the exact physiological mechanisms that cause mortality are not known.
- Water relations, anatomy and gas exchange measurements were assessed on healthy and infested eastern (Tsuga canadensis) and Carolina (Tsuga caroliniana) hemlock trees. These data were then used in a mechanistic model to test whether the physiological responses to HWA infestation were sufficiently significant to induce changes in whole-plant water use and carbon uptake.
- The results indicated coordinated responses of functional traits governing water relations in infested relative to healthy trees. In response to HWA, leaf water potential, carbon isotope ratios, plant hydraulic properties and stomatal conductance were affected, inducing a reduction in tree water use by > 40% and gross primary productivity by 25%. Anatomical changes also appeared, including the activation of traumatic cells.
- HWA infestation had a direct effect on plant water relations. Despite some leaf compensatory mechanisms, such as an increase in leaf hydraulic conductance and nitrogen content, tree water use and carbon assimilation were diminished significantly in infested trees, which could contribute to tree mortality.