Large-scale watershed manipulations have been a hallmark of the Hubbard Brook Ecosystem Study since 1965.  Such experimental manipulations can test important questions of relevance to Human-Accelerated Environmental Change and provide key information to resource managers and policy makers. 

Results/Conclusions

Based on long-term research and monitoring, the northern hardwood forest on experimental watersheds of the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire has stopped accumulating biomass (stopped growing!).  Recent data suggest that not only is this forest no longer sequestering carbon, but now it is releasing carbon to the atmosphere, primarily as a result of the effects of acid rain, climate change and disease.  An experimental addition of Wollastonite (CaSiO₃) was initiated to a watershed-ecosystem of the Hubbard Brook Experimental Forest in 1998 to test this question.  The early results of this long-term experiment are clearly beginning to elucidate the coupled interactions among the biogeochemical cycles of carbon, nitrogen, hydrogen ion and base cations within the Hubbard Brook Valley.