Evidence of soil nutrient availability as the proximate constraint on growth of treeline trees: Reply

Abstract

The most common hypothesis to explain low growth of treeline trees is that cold temperatures limit investment of photosynthetic carbohydrates in growth (Korner 1998). This is known as the sink limitation hypothesis, which is often pitted against an alternative hypothesis that trees are limited by photosynthate supply, known as the source limitation hypothesis. Source limitation could come about through drought-induced stomatal closure (e.g., McDowell et al. 2008), low nutrient availability (e.g., Sveinbjornsson et al. 1992) or defoliation (Susiluoto et al. 2010), among other possibilities. This article is protected by copyright. All rights reserved.