Disturbance dynamics of old-growth Picea rubens forests of northern Maine
Article first published online: 24 FEB 2009
2005 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 16, Issue 5, pages 597–610, October 2005
How to Cite
Fraver, S. and White, A. S. (2005), Disturbance dynamics of old-growth Picea rubens forests of northern Maine. Journal of Vegetation Science, 16: 597–610. doi: 10.1111/j.1654-1103.2005.tb02401.x
- Issue published online: 24 FEB 2009
- Article first published online: 24 FEB 2009
- Received 4 March 2005; Accepted 9 September 2005
- Canopy gap;
- Canopy structure;
- Choristoneura fumiferana;
- Dendroctonus rufipennis;
- Patch dynamics;
- Spruce bark beetle;
- Spruce budworm
How have the spatial and temporal aspects of past disturbance shaped the current structure and composition of old-growth Picea rubens forests?
Northern Maine, USA.
We established three 50 m × 50 m plots in old-growth Picea rubens forests and mapped the location of trees and saplings. We extracted increment cores from canopy trees, and recorded growth releases indicating past disturbance. By linking spatial data (tree positions) and temporal data (dated growth releases), we reconstructed the location and size of former canopy gaps back to 1920, and determined a more general disturbance chronology extending as far back as 1740.
We found no evidence of stand-replacing disturbances. The disturbance dynamic includes pulses of moderate-severity disturbances caused by wind storms and host-specific disturbance agents (spruce budworm, spruce bark beetle) interposed upon a background of scattered smaller canopy gaps. Consequently, rates of disturbance fluctuated considerably over time. Reconstructed canopy gaps were temporally and spatially scattered; during disturbance peaks, they were both larger and more numerous.
Despite peaks in disturbance, several of which created relatively large gaps, this system has experienced no significant change in species composition. Instead, the shade-tolerant Picea rubens has maintained canopy dominance. The patch dynamics described here consist of dramatic structural, not compositional, changes to the forest. The persistence of Picea rubens is attributed to a combination of traits: (1) abundance of advance regeneration; (2) ability to endure suppression and respond favourably to release; and (3) longevity relative to ecologically similar species.