Fire history and woody debris

This graph shows the contribution of decaying CWD generated each year by wildfire to an overall estimate of the fire-generated CWD decomposition flux in Canada. (That is, each color shows the carbon flux from a different year's cohort, and the top line shows the estimated total flux.) No pre-1959 national statistics are available, so I've assumed a constant fire rate before then, equal to the 1959-1999 mean.

You can see how the low-fire 1970s resulted in a decline in the overall flux, but then in the 1980s and 1990s some big fire years raised the overall annual flux to around 50 Tg.

Soil respiration

The flux of carbon (mostly CO2) from the soil surface is about an order of magnitude larger than anthropogenic CO2 emissions, and is the second-largest flux in the terrestrial carbon cycle. This graph shows records in the Web of Science database about soil respiration, arbitrarily and approximately separated into "interesting" (field studies examining temperature response and/or fluxes over time) and "not interesting" (modeling, remote sensing, incubations, microbial response).