Warmer and drier conditions as a result of climate change are expected to have significant effects on closed cone conifer ecosystems, including changes in disturbance regimes, reduced plant growth, and decreased seedling recruitment. Changes in the fire regime could potentially cause localized extinction by narrowing the fire interval past the point compatible with the reproductive timeframe of the closed cone forest. The “interval squeeze hypothesis” describes the synergistic effects of changes in disturbance regimes, plant growth, and seedling recruitment, and suggests that closed cone conifer ecosystems may face extinction sooner than initially accounted for. California closed cone pine species provide a unique way to test the interval squeeze hypothesis. Their short lifespan and fire return interval allow data to be collected over the lifetime of the forest and quantify changes caused by climate change. Stand structure and composition metrics were measured at six sites in California and Colorado. The univariate comparison of metrics showed that California and Colorado pine species are similar across important aspects of stand structure and composition. As such, there is potential for California forests to serve as a model ecosystem for Colorado forests. Pinus contorta var latifolia (Lodgepole Pine) is one of the most widespread tree species across western North America. A large-scale mortality event of P. contort var latifolia forest could cause significant change to the carbon sequestration and water infiltration capacity of these forests.
Forest ecosystems in the Colorado Front Range have evolved to thrive in the unique climatic conditions of the region and natural disturbance regimes that existed prior to European settlement. Knowledge of how forests were structured in the past and the factors that affect their establishment and growth is essential to their management. Part of Notable Lectures & Performances series, Colorado College. Recorded January 25, 2007.