Biology 2483A Lecture Notes - Lecture 19: Leaf Area Index, Normalized Difference Vegetation Index, Spectral Signature

• School: Western University
• Department: Biology
• Course: Biology 2483A
• Professor: Hugh Henry

Document Summary

Ecosystem: refers to all the compounds of an ecological system, biotic and abiotic, that influence the flow of energy and elements. Integrates ecology with other disciplines such as geochemistry, hydrology, and atmospheric science. Primary production: the chemical energy generated by autotrophs during photosynthesis and chemosynthesis. Energy assimilated by autotrophs is stored as carbon compounds in plant tissues, thus carbon is the currency used to measure primary production. Gross primary production (gpp): total amount of carbon fixed by autotrophs. Photosynthetic rate if influenced by climate and leaf area index (lai) - leaf area per unit of ground area. Less than 0. 1 in arctic tundra (less than 10% of the ground surface has leaf cover. 12 in boreal and tropic forests (12 layers of leaves between the canopy and the ground, on average) Because of shading, the incremental gain in photosynthesis for each added leaf layer decreases. Eventually, the respiratory costs associated with adding leaf layers outweigh the photosynthetic benefits.