Litterfall and fine woody debris production and chemistry (DP1.10033.001)

Each qualifying tower plot in forested ecosystems has 0-2 elevated traps and 1-2 ground traps deployed. Ground traps are sampled annually. Sampling interval of elevated litter traps is variable by dominant overstory vegetation. Deciduous forests are sampled once in the spring then multiple times during fall senescence; evergreen and coniferous forests are sampled year round at monthly intervals. Traps are consistent with those used by the Smithsonian Center for Tropical Forest Science (CTFS). Mass data for each collection event are measured separately for functional groups: Leaves, Needles, Twigs/branches, Woody material, Seeds, Flowers and other non-woody reproductive structures, Other, and Mixed (unsorted). Once every five years, leaf and needle samples from elevated traps from a single collection event are analyzed for carbon and nitrogen concentrations and stable isotopes as well as lignin concentrations.