Stand dynamics of Pinus flexilis-dominated subalpine forests in the Colorado Front Range
Article first published online: 24 FEB 2009
1991 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 2, Issue 4, pages 445–458, August 1991
How to Cite
Rebertus, A. J., Burns, B. R. and Veblen, T. T. (1991), Stand dynamics of Pinus flexilis-dominated subalpine forests in the Colorado Front Range. Journal of Vegetation Science, 2: 445–458. doi: 10.2307/3236026
- Issue published online: 24 FEB 2009
- Article first published online: 24 FEB 2009
- Received 15 January 1991; Revision received 30 April 1991; Accepted 14 May 1991; Final revision received 19 June 1991.
- Age structure;
- Limber pine;
- Weber (1990)
Abstract. Population age structure and succession were investigated in subalpine forests in the Colorado Front Range dominated by Pinus flexilis (limber pine). Age, size, and spatial data were collected from three recent burns (<100 yr old), six ca. 240 year-old post-fire stands, and two old-growth stands (individuals > 400 yr old). The sequence of colonization of now extant trees on these post-fire sites appeared to be consistent: first Pinus flexilis, then Picea engelmannii (Engelmann spruce), and later Abies lasiocarpa (subalpine fir) with a delay between the first Pinus flexilis and Abies of as long as 140 yr. The advantage of Pinus flexilis on post-burn sites can be attributed to avian seed dispersal and the exceptional drought tolerance of its seedlings. The three recent burns were not extensive, and the delay in establishment of Picea and Abies appeared to be limited by harsh site conditions rather than lack of seed dispersal.
Spatial analysis indicated a consistent, although sometimes weak, attraction between Pinus flexilis and Picea and Pinus flexilis and Abies at a scale of 1–4 m, suggesting that Pinus flexilis may facilitate establishment of Picea and Abies seedlings by providing shade or protection from wind. On xeric to slightly xeric sites, Pinus flexilis appeared to form broadly even-aged, non-regenerating populations that were gradually being replaced by Picea and Abies. Replacement is proceeding at a faster rate on the least xeric sites (north aspects, valley bottoms) compared to the most xeric sites (south aspects). On the most extreme sites, Pinus flexilis formed all-aged, self-maintaining populations with no evidence of replacement by Picea and Abies. In these old-growth forests with occasional trees aged at > 1300 yr, recruitment is continuous or episodic.