Of course you can, when there is demand and market. In reality, less than 10% of original raw wood becomes furniture. The furniture costs many times more than raw wood, and only certain types of tree species are desirable as furniture. So there is still plenty of wood available for carbon sequestration. At the end of their normal useful life, old furniture and construction wood can also be buried for carbon sequestration, thus making a ‘waste’ into something valuable.

We consider this from several angles.

1. On the longer time horizon, WHS is a negative emissions technology (NET) that actually removes CO2 from the atmosphere, while burning is not. NETs will be needed to keep climate at a safe level, in addition to reduce fossil fuel emissions.

2. Compared to fossil fuel, wood contains less energy per unit of carbon. The carbon:energy ratio is approximately wood:coal:oil:gas = 6:5:4:3. For instance, burning natural gas for energy while storing wood for carbon sequestration is twice as efficient as vice versa. For this same reason, burning gas instead of coal has been the major driver of reduction in CO2 emission in the United States over the last decade.

3. On a shorter time horizon, there is currently large quantities of wood residuals that can not be utilized economically, and would otherwise release CO2 into the atmosphere.

4. There is an opportunity cost for not doing it. The sustainable rate of wood production by the world’s trees for WHS-style sequestration is estimated at 2-10 GtCO2 per year. If this ‘stream’ of opportunity is not utilized on an ongoing basis, the potential would be simply lost. For example, a 20-year delayed action for 2 GtCO2 per year sequestration would add to 40 GtCO2 lost opportunity.

Globally, WHS can achieve a sustainable potential rate of 1-10 GtCO2 per year. A 1 GtCO2/yr rate can be achieved by utilizing wood residuals alone from fire thinning, forestry residues, storm and insect damage, and urban wood trimming. The rate can also be achieved by harvesting wood at a moderate harvesting intensity of 5 tonne biomass per hectare each year, over a forest area of 1 million square kilometers (100 million hectares), 1/10 of the area of the US. To achieve the higher value of 10 GtCO2/y, forests need to be managed this way on a quarter of the world’s forested land, or on smaller area with higher harvest intensity and fast growing tree species. Thus, while the high value of 10 Gt depends on the society’s sense of climate emergency, the lower 1 Gt potential can be implemented immediately with many co-benefits.

They can stay for hundreds of years or longer without decay if they are kept in anaerobic conditions, for example, buried under a sufficiently thick layer of clay soil or sunk into stagnant anaerobic water bodies, as evidenced by numerous archaeological discovery of well-preserved ancient tree trunks, wood structures, and even ‘bog man’. Wood can persist very long also in dry or cold conditions. Scientists studying wood buried inside landfill found no or little decay after several decades. We now also have results from a pilot project that shows an inferred durability of greater than 1000 years.

This long lifetime is fundamentally because wood consists of cellulose fibers interlinked by hemicellulose and covered by lignin, a complex polymer that is highly resistant to decay. Most natural decomposers don’t have the ability to ‘eat’ lignin, except for few species such as white rot fungi and termites, but they need oxygen to live. Even in open air, the decomposition of wood is slow. There is an evolutionary reason why vascular (woody) plants evolved with strong wood support in order to grow tall to compete for light.

Actually, methanogenic bacteria do not like wood.

1) Anaerobic bacteria do not digest lignocellulose, the main component of wood, due to the complex polymer structure of lignin.

2) While a small fraction of woody biomass that is carbohydrate may generate small amounts of methane, this methane will be consumed by methanotrophic bacteria in the layer of biologically active soil above a properly engineered burial chamber (Wood Vault);

This notion of methane generation may come from landfill where food scrap provides the fuel, but this is not the case in a properly engineered Wood Vault where only clean coarse woody biomass is buried. It is critical to make certain that biomass burial does not generate methane – which is why monitoring and measurement of methane is a key component of Wood Vault MRV.

The space occupied will increase cumulatively over time, and eventually there will be a limitation. However, the footprint is very small: a one-hectare Wood Vault can bury 100,000tCO2 equivalent of wood. This is 250 times the standing biomass of a typical forest of the same size. Another way to visualize this is to think that we put wood back to all the coal mines humans have dug, and it won’t take more space than the original space occupied by coal. Moreover, because wood is buried sufficiently deep underground, the area above can be utilized for natural vegetation regeneration, grazing, crop, park, or solar farm.