Calcium Restoration and Forest Decline

ca application by helicopter
J. Hornbeck/Hubbard Brook Research Foundation

Acid deposition has depleted calcium in forest soils throughout the northeastern US, a pattern tied to forest declines in the region. But through a fifteen year experiment at Hubbard Brook Experimental Forest that restores this lost calcium, John Battles and colleagues have shown that forests can recover from the damaging impacts of acid rain. The study compares forest growth and productivity in a pair of watersheds. The experimental addition of more than 40 tons of calcium silicate to one watershed allowed comparison of the forests’ responses: the restored forest showed higher aboveground NPP, increased photosynthetic surface area, and a rebound in tree biomass increment. It was also faster to recover from a severe ice storm that affected the area in 1998.