Leaf to landscape

One fundamental problem for maximizing carbon gain at the leaf and higher organizational levels entails the link between light aperture and leaf energy budgets. The balance between the two processes, however, depends on the environment. For example, shade environments limit carbon gain due to low light levels, and so we would expect plants to display traits that maximize light interception and traits that facilitate survival in a low-resource environment (relative to photosynthesis). These topics have received wide attention and have been reviewed numerous times (for the most relevant contributions in the context of this book, see Ackerly 1996, Poorter 1999, Poorter and Werger 1999, Valladares 1999, Walters and Reich 1999; see also Chapter 2). Conversely, in high-light environments, leaf energy balance becomes the driving force for structural traits. This is particularly true for environments that are at the same time limited by water availability. Similarly, although in the opposite direction, leaf energy balance is a major factor in carbon gain in cold environments. A third significant environmental axis is nutrient availability which, when limiting, can result in evergreen, often sclerophyllous, leaves which have potentially low photosynthetic capacity but high efficiency of resource utilization