Leaf area index inferred from solar beam transmission in mixed conifer forests on complex terrain

Abstract

Forest process models are used to predict forest growth in a broad range of conditions. Because more than a quarter of the world's forests are in mountainous regions, leaf area index (LAI) must frequently be estimated for forests in complex terrain. LAI is often inferred from canopy light transmission using various canopy models. Choice of a canopy model becomes especially problematic in complex terrain because the complex topography changes the path length of the solar beam through the canopy. For example, if solar elevations are expressed relative to the inclined surface, low elevations can occur on steep slopes at any time of the day, especially on surfaces facing north (in the northern h..