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Lite: A Model for Estimating Light Interception and Transmission Through Forest Canopies

Author(s): P. Comeau
Source: Research
Subject: Forestry General
Series: Working Paper
Other details:  Published 1998. Hardcopy is available.
 

Abstract

LITE is a software package developed to provide both instantaneous (hourly average) and seasonal estimates of photosynthetic photon flux density beneath tree canopies. The model provides utilities for estimating the leaf area contained in each cubic metre of canopy space from either a grid of directional LAI-2000 Plant Canopy Analyzer (PCA) measurements or from tree list data (including stem location, lean, height, height to crown base, crown extent, diameter at breast height, leaf area (if available)). Directional PCA measurements are taken using view restrictors supplied with the instrument (a common approach is to take a reading in each of 4 cardinal directions using a 90o view restrictor). When using PCA data, the user provides information on the location of each grid point (x and y coordinates) and the height to the top and the base of the canopy. The model calculates the location of the sun, partitions open sky total PPFD into diffuse and direct components, and estimates the penetration of each through the canopy to the selected point of interest. Direct PPFD is assumed to come from the location of the sun, diffuse PPFD is assumed to be evenly distributed across 480 segments of the sky. The software provides maps of LAI and PPFD across the study site and provides information on the light regime at selected locations. Routines for entering, merging, and editing data are also provided. The model is written for use with MS-Windows.

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Updated November 05, 2009