Leaf area index of boreal forests: Theory, techniques, and measurements

Leaf area index measurements

Leaf area index (LAI) is a key structural characteristic of forest ecosystems because of the role of green leaves in controlling many biological and physical processes in plant canopies. Accurate LA1 estimates are required in studies of ecophysiology, atmosphere-ecosystem interactions, and global change. The objective of this paper is to evaluate LA1 values obtained by several research teams us...

Temporal variability of probability density functions of the leaf area index for boreal and temperate forests

Measurements of leaf orientation, light distribution and sunlit leaf area in a boreal aspen forest

A new instrument called a Multiband Vegetation Imager (MVI) (Kucharik et al., 1997), which uses a 16-bit charge-coupled device (CCD) camera and ®lter exchange mechanism to capture 2-band (visible and near-infrared) image pairs of plant canopies, has been used to measure the light distribution over sunlit leaves and indirectly infer leaf area index (LAI), sunlit LAI and leaf angle distribution (...

Methane measurements in Tropical and Boreal forests

Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the re-5 sults of high frequency (ca. 1 min −1) methane measurements cond...

Radiation, temperature, and leaf area explain ecosystem carbon fluxes in boreal and temperate European forests

[1] We analyzed measurements of net ecosystem exchange of CO2 (NEE) over 15 European forests (the EuroFlux data set) to investigate which climate and forest characteristics explain temporal and intersite variations in NEE and its components, gross primary production (GPP) and respiration (R). Informed stepwise regression was used to derive a parameter-efficient, empirical model that was consist...