Silicon content of canopy foliage along an elevation gradient near W6 at the Hubbard Brook Experimental Forest, 1998-2008

Leaf tissue was collected for the three dominant tree species; sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Erhr.), and yellow birch (Betula alleghaniensis Britt.) at the full-grown stage in August of each year. Individual leaves were collected from manually cut branches throughout the canopies of trees at different elevations in the Bear Brook area west of, and representative of, W6. Fifteen trees (five per species in the low, middle and high elevation zones) were sampled each year from 1998-2008. Leaf samples were handled with nitrile gloves at all stages. The leaf samples were composited by species, dried (60C) and ground (mortar and pestle) before analysis. Total biogenic silicon (SiO2) content was measured for every second year using a single-step chemical extraction. Measurements were aimed to estimate annual Si uptake, and standing Si stocks in living biomass for northern hardwood forest. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.