Light competition

TOC

Description

Light competition is one of five factors determining mortality - the others being low growth efficiency, negative annual carbon balance, heat stress, and PFT bioclimatic limit overshooting.

Details

Light competition among neighbouring individuals happens when increased biomass results in:

1 - gridcell FPC of more than 1, when summed across all PFTs; or
2 - gridcell FPC of more than 0.95, when summed across woody PFTs.

Mortality is imposed such that summed woody FPC is reduced to 0.95, and/or total grid cell FPC is reduced to 1.

Herbaceous plants are assumed to be inferior to woody plants in competition for light, and can occupy, at most, that proportion of the gridcell (1-FPCwoody) not occupied by woody plants.

Shading mortality is partitioned among woody PFTs in proportion to the FPC increment resulting from their biomass increment for that year. The same rule is applied for herbaceous plants.

light.c, light_tree.c, light_grass.c

See Also

mortality, Wiki, Plant functional types, vegetation dynamics

Reference

Sitch S, Smith B, Prentice IC et al. (2003) Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Global Change Biology, 9, 161–185.