Significant Emissions From Forest Drainage Ditches—An Unaccounted Term in Anthropogenic Greenhouse Gas Inventories?

Forestry is a natural climate solution for removing atmospheric carbon dioxide (CO2) and reaching net zero emissions. Managed boreal forests typically have extensive drainage ditch networks, these can be hotspots of anthropogenic greenhouse gas (GHG) emissions, potentially offsetting the terrestrial gain. However, there lack data detailing GHG emissions from ditches on mineral soils, where most forestry occurs. Here, we address this knowledge gap using two approaches. First, conducted synoptic campaign to measure summer fluxes 109 forest draining soils within one local region. We found clear control water level methane (CH4), with dry variable, but often high, water-filled ditches. Almost all acted as sources CO2, regardless status. Second, reanalyzed published set streams across three regions concentrations had been repeatedly measured detailed catchment information was available. Within categorized 76 into peatland catchments detected no difference in mean CH4 CO2 between soil types. large those Using literature values uptake demonstrate that are particularly important offset uptake. Ignoring which origin, will lead incorrect estimates landscape-scale budget.