Projections of Growth of Loblolly Pine Stands Under Elevated Temperatures and Carbon Dioxide

Abstract

Over the past 200 years, the concentration of carbon dioxide (CO₂) in the atmosphere has increased from about 280 ppm (Neftel et al., 1991) to 360 ppm. An eventual doubling of the present-day ambient concentration along with increases in atmospheric concentrations of other greenhouse gasses are expected. Predictions that these higher concentrations will cause alterations in climates in many regions of the world have been widely disseminated by atmospheric physicists and others (e.g., Houghton et al., 1990). Tree physiologists have indicated that an increase in CO₂, by itself, may foster faster growth and more efficient use of water by trees. Conversely, if the rise in CO₂ is accompanied by an altered climate, gains that might otherwise accrue from CO₂ fertilization could be either partially or entirely negated. Plant geographers have predicted changes in forest types in given regions under various climatic change scenerios, and concern has been voiced that if change is too rapid, some species will not be able to migrate fast enough to remain with those environmental conditions to which they are adapted.