Land-use change, primarily from conventional agricultural expansion and deforestation, contributes to approximately 17% of global greenhouse-gas emissions.
Forests sequester carbon from the atmosphere, and in so doing can mitigate the effects of climate change. Fire is a natural disturbance process in many forest systems that releases carbon back to the atmosphere. In dry temperate forests, fires historically burned with greater frequency and lower severity than they do today.
Active 20th century fire suppression in western US forests, and a resultingincrease in stem density, is thought to account for a significant fraction of the NorthAmerican carbon sink. We compared California forest inventories from the 1930s withinventories from the 1990s to quantify changes in aboveground biomass.