Present address Forest Ecology Lab., School of Resource and Environmental Science, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Canada
Differential survival among life stages contributes to co-dominance of Abies mariesii and Abies veitchii in a sub-alpine old-growth forest
Article first published online: 29 JAN 2009
2008 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 19, Issue 2, pages 239–244, April 2008
How to Cite
Mori, A. S. and Komiyama, A. (2008), Differential survival among life stages contributes to co-dominance of Abies mariesii and Abies veitchii in a sub-alpine old-growth forest. Journal of Vegetation Science, 19: 239–244. doi: 10.3170/2008-8-18364
Nomenclature: Kitamura & Murata (1994).
- Issue published online: 29 JAN 2009
- Article first published online: 29 JAN 2009
- Received 26 June 2006; Accepted 16 July 2007
- Canopy dominance;
- Vertically-stratified forest
Questions: Are there interspecific differences in mortality and recruitment rates across life stages between two shade-tolerant dominant trees in a sub-alpine old-growth forest? Do such differences in demography contribute to the coexistence and co-dominance of the two species?
Location: Sub-alpine, old-growth forest on Mt. Ontake, central Honshu, Japan.
Methods: From 1980 to 2005, we recorded DBH and status (alive or dead) of all Abies mariesii and A. veitchii individuals (DBH ≥ 5 cm) in a 0.44-ha plot. Based on this 25 year census, we quantified mortality and recruitment rates of the two species in three life stages (small tree, 5 cm ≤ DBH < 10 cm; subcanopy tree, 10 cm ≤ DBH < 20 cm; canopy tree, DBH ≥ 20 cm).
Results: Significant interspecific differences in mortality and recruitment rates were observed in both the small tree and sub-canopy tree stages. In this forest, saplings (< 5 cm DBH) are mostly buried by snow-pack during winter. As a consequence, saplings of A. mariesii, which is snow and shade tolerant, show higher rates of recruitment into the small tree stage than do those of A. veitchii. Above the snow-pack, trees must tolerate dry, cold temperatures. A. veitchii, which can more readily endure such climate conditions, showed lower mortality rate at the subcanopy stage and a higher recruitment rate into the canopy tree stage. This differential mortality and recruitment among life-stages determines relative dominance of the two species in the canopy.
Conclusion: Differential growth conditions along a vertical gradient in this old forest determine survival of the two species prior to reaching the canopy, and consequently allow co-dominance at the canopy stage.