Aboveground Autotrophic Respiration

Abstract

Understanding the autotrophic respiratory activity of living tissues in a forest provides useful insights into the responses of the forest to its environment. Respiration measurements also contribute essential data for evaluating and constructing carbon budgets and models. Historically, studies have shown that the primary factors that control autotrophic respiration include temperature, phenology, and species. More recently, studies by (1989), (1995), (1998), (1999), (1999), and (2001) have shown that nitrogen content plays a key role in autotrophic respiration rates. Above-ground autotrophic respiration can be conveniently divided into woody-tissue respiration and foliar respiration. Foliar respiration accounts for from about 30% of aboveground autotrophic respiration in some temperate deciduous forests (Edwards et al. 1981) to as much as 75% in some forests, such as in northern coniferous sites (Lavigne et al. 1997). Woody-tissue respiration is important because the bulk of the biomass in a mature forest stand is in woody tissue, and respiration in the living cells of this tissue occurs continuously, even when trees are “dormant.” Woody-tissue respiration is also a good indicator of growth phenology and can be used to calculate growth rates if the respiration required for maintenance is taken into consideration. Woody-tissues account for from about 25% of the total aboveground autotrophic respiration in some forests, such as in northern coniferous sites (Lavigne et al. 1997), to more than half of the aboveground autotrophic respiration in some temperate deciduous forests (Edwards et al. 1981).