Light distribution in scattered-trees open woodlands in Western Spain |
| |
Authors: | María Jesús Montero Gerardo Moreno Manuel Bertomeu |
| |
Institution: | (1) Centro Universitario, Forestry School, Universidad de Extremadura, Plasencia, 10600, Caceres, Spain |
| |
Abstract: | We have studied the percentage of radiation transmitted through the tree canopy to the underlying pasture and crops in dehesas
of Southwest Spain by means of fish-eye photographs taken at different distances from the tree. Thirty-six trees were studied
covering all the diametric classes (0.1–14 m canopy width) of two stands, with mean density of 19 mature trees ha−1. Intercepted light decreased with distance following an logistic curve, indicating a rapid increase in the light availability
with distance from the tree. For mature trees, radiation was constant beyond 20 m. Applying a multivariable regression light
equation, distance, stem diameter and canopy width explained more than 88% of the light variability for each orientation studied.
A simple model was built up from light equations, tree growth curves and allometric relationships. From this model, we have
estimated that radiation available for crops and pasture decreased up to 21% due to the presence of trees in a standard dehesa
with 24 mature trees ha−1 and 13% of canopy cover. In addition, we have generated different radiation maps of virtual dehesas differing in tree age,
density and arrangement, which could be useful to determine optimal tree planting schemes and consequent pruning and thinning
regimes. |
| |
Keywords: | Allometric relationships Dehesa Fish-eye photograph Light transmittance Quercus ilex Radiation map |
本文献已被 SpringerLink 等数据库收录! |
|