Tall vegetation and complex terrain create difficult conditions for measuring and modeling net ecosystem– atmosphere exchanges of carbon, water vapor, and pollutants. The instability of canopy flow regimes over complex terrain is critical for understanding what factors are essential to control exchanges between different canopy flow regimes. In this paper, an analytical criterion of instability...

The analysis of hemispherical photographs is nowadays an established method for assessing light indirectly and describing canopy structures. In this article, we present an automatic threshold algorithm for separating canopy and sky by edge detection. The algorithm was evaluated under different canopy conditions by comparing its results for canopy openness, fractal dimension and diffuse transmit...

almond is among some of the most important nut crops requiring improvement in many aspects of its production. to do that, the first step is an evaluation of the genetic diversity of the existing germplasm. towards this end, 56 vigorous almond seedlings were evaluated with recording eight morphological characteristics (trunk diameter, height of main trunk, canopy density, canopy angle, branch nu...

Dry forests represent a large percentage of tropical forests and are vulnerable to both anthropogenic and natural disturbances, yet important aspects of their sensitivity to disruption remain poorly understood. It is particularly unclear how changes in land-use or tropical storm patterns may affect the resiliency of phosphorus (P)-limited neotropical forests. In these systems, vegetation is sus...

Among the plant factors, canopy geometry plays a crucial role in deciding the driving force for leaf biological processes since it modulates canopy interception of short-term radiation fluxes and it controls their distributions throughout the foliage (Monteith and Unsworth, 1990; Jones, 1992). In particular, it is recognized the biological role of PhAR (400-700 nm waveband) in driving the photo...

1. Research on habitat selection has focused on the role of vegetative and geologic characteristics or antagonistic behavioural interactions. 2. Conspecifics can confer information about habitat quality and provide positive density-dependent effects, suggesting habitat selection in response to the presence of conspecifics can be an adaptive strategy. 3. We conducted a manipulative field experim...

The currently prevailing view is that saplings require gaps or larger disturbances in order to grow into the canopy. This study documents an exception. In California's Pseudotsuga-mixed hardwood forests, crowns of Pseudotsuga menziesii (Douglas fir) are within those of angiosperm trees (Arbutus menziesii and Quercus species). In the forests we examined, every Pseudotsuga was younger and all but...