May 10, 2023

<aside> 💬 “Unmanaged and unharvested stands will cumulatively sequester and store more total ecosystem carbon than harvested stands, even when harvested wood products are included." Forest Carbon for Commercial Landowners Report, March 2023

</aside>

Debate about the real impact of improved forest management (IFM) on carbon dioxide removal seems to be hot among forest carbon groups. The fundamental question seems to be “How much harvesting is too much?”

Last fall, Verra, AFF, TNC, and TerraCarbon collaborated on a new protocol to quantify the additionality of Improved Forest Management. The theory is that a forest manager can harvest wood in ways that sequester additional CO2. Here are activities that in theory can get a forest to remove more CO2:

• Enrichment planting
• Release of natural regeneration via management of competing vegetation
• Stand irrigation and/or fertilization
• Reducing timber harvest levels
• Deferring harvest/extending rotations or cutting cycles
• Designating reserves
• Altering fire severity via fuel load treatments

I’ll first touch on why we can’t just let forests grow, and then walk through some visuals I made to help myself better understand the impact of two specific Improved Forest Management practices: extending rotations and reducing harvest levels. Hopefully you find them helpful too!

Why “Leave it alone” isn’t enough

We can’t “leave forests alone” because

• We consume wood (and it plays a role in cutting fossil fuel consumption)
• We need to get the wood somewhere, and if we don’t get it locally then we pay transport costs in emissions and money to import it from somewhere else
• Invasive species need mitigation to cultivate biodiversity and forest health
• Wildfires and insect outbreaks can jeopardize forest productivity

Trees, being the biggest carbon sink in the US, don’t just store their carbon in forests: We harvest them for wood products. A forester who I spoke with this spring mentioned that Americans consume about 1.5 pounds of wood per day. I tried to find similar figures, including digging into a North Carolina Forestry Association study that found Americans used about 44 cubic feet of wood per capita in 2013, but it turns out that converting cubic feet of wood to pounds gets complicated based on wood type and moisture content. If anyone has a source for annual per capita consumption of wood in the US in weight, please let me know!