Canopy structure and cloud water deposition in subalpine coniferous forests
Lovett, Gary M.
Reiners, William A.
- Publisher: Tellus B
(issn: 1600-0889, eissn: 0280-6509)
The relationship between canopy structure and cloud water deposition is explored using a modelling approach applied to subalpine conifer forests in the northeastern US. The zero plane displacement height was found to decrease monotonically with stand thinning, while the roughness length showed a unimodal pattern, peaking at a value of total surface area index (SAI) of about 5. The cloud water deposition velocity also was unimodal, increasing from 28 to 34 cm s-1 as the simulated stand was thinned from SAI = 13 to SAI = 6, and then decreasing with further thinning. The calculated resistance to cloud water deposition was greater than the resistance to momentum transfer except at very low values of SAI. Evaporation rate also showed a unimodal pattern as a function of SAI, but the pattern was less pronounced than that of cloud water deposition. These results suggest that agents which moderately reduce the SAI of closed forest stands may increase the deposition of cloud water. If some aspect of cloud water deposition causes canopy deterioration in subalpine forests, a positive feedback could occur between the canopy thinning and the cloud water deposition. A calculation of potential deposition on the lee side of gaps in the forest indicates a maximum possible deposition velocity approaching 200 cm s-1, illustrating the expected heterogeneity of deposition rates across the subalpine landscape.DOI: 10.1111/j.1600-0889.1986.tb00257.x