『Abstract
　Increases in soil freezing associated with decreases in snow cover have been identified as a significant disturbance to nitrogen (N) cycling in northern hardwood forests. We created a range of soil freezing intensity through snow manipulation experiments along an elevation gradient at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains, NH USA in order to improve understanding of the factors regulating freeze effects on nitrate (NO3^- leaching, nitrous oxide (N2O) flux, potential and in situ net N mineralization and nitrification, microbial biomass carbon (C) and N content and respiration, and denitrification. While the snow manipulation treatment produced deep and persistent soil freezing at all sites, effects on hydrologic and gaseous losses of N were less than expected and less than values observed in previous studies at the HBEF. There was no relationship between frost depth, frost heaving and NO3^- leaching, and a weak relationship between frost depth and winter N2O flux. There was a significant positive relationship between dissolved organic carbon (DOC) and NO3^- concentrations in treatment plots but not in reference plots, suggesting that the snow manipulation treatment mobilized available C, which may have simulated retention of N and prevented treatment effects on N losses. While the results support the hypothesis that climate change resulting in less snow and more soil freezing will increase N losses from northern hardwood forests, they also suggest that ecosystem response to soil freezing disturbance is affected by multiple factors that must be reconciled in future research.

Keywords: Climate change; Dissolved organic matter; Methane; Microbial biomass; Nitrate; Nitrous oxide』

Introduction
Methods
　Experimental design
　Plot instrumentation
　Microbial biomass and activity measurements
　Statistical analysis
Results
Discussion
　Variable response to soil freezing
　Coupling between C and N as a regulator of freeze response
　Vegetation composition as a regulator of freeze response
　Annual variation in C and N dynamics as a regulator of freeze response
Conclusions
Acknowledgments
References