LAI (leaf area index) estimation from direct measurement is tedious or impossible in tree canopies because of the high number of leaves and the large plant size. Methods based on inversion of gap fraction measurements have therefore been proposed, where gap fraction is measured from light sensors (e.g. ceptometer, Cohen et al. 1995, LAI-2000, Stenberg et al., 1994) or fisheye photographs (e.g. ...

Spatial and temporal variation in the below-canopy light environment of tropical forests is not well known and its measurement is technically challenging. Distributions of gap and understory areas in forests are likewise little known because of the resource requirements of forest structural censuses and a lack of consensus over how gaps should be defined. A basic model of forest structure, base...

CONTEXT Due to a long history of intensive forest exploitation, few European beech (Fagus sylvatica L.) old-growth forests have been preserved in Europe. MATERIAL AND METHODS We studied two beech forest reserves in southern Slovenia. We examined the structural characteristics of the two forest reserves based on data from sample plots and complete inventory obtained from four previous forest m...

The creation of gaps in forest canopies can dramatically change the microclimate and soil water balance which strongly influences the process of regeneration and biodiversity within forest ecosystems. Hence, understanding the microclimatic conditions in canopy gaps is a prerequisite in developing and improving techniques for forest management and conservation practices. However, information is ...

Overstory conditions influence understory microclimate and resource availability, leading to gradients in evaporative demand andmoisture availability that influence seedlingwater relations. Partial canopies may either reduce seedling moisture stress by ameliorating environmental conditions, or increase moisture stress by reducing soil moisture availability. This study used stable isotope ratios...

We investigated effects of nitrogen (N) fertilizer and canopy position on the allocation of N to Rubisco and chlorophyll as well as the distribution of absorbed light among thermal energy dissipation, photochemistry, net CO2 assimilation and alternative electron sinks such as the Mehler reaction and photorespiration. The relative reduction state of the primary quinone receptor of photosystem II...

A fundamental property of all forest landscapes is the size frequency distribution of canopy gap disturbances. But characterizing forest structure and changes at large spatial scales has been challenging and most of our understanding is from permanent inventory plots. Here we report the first application of light detection and ranging remote sensing to measurements of canopy disturbance and reg...

Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visib...