Wooden buildings and fuels may drag us to another gulf

We used to burn trees for energy, and we stopped doing that after we had fossil fuels (ugh), then now people thought, oh maybe we should go back to wood fuels again!

This article written by my supervisor: Why Burning Trees for Energy Harms the Climate? explains that this could be a wrong idea. There are three major reasons:

1. When burned, trees generate more CO2 emissions per unit of energy generated than fossil fuels.
2. Harvesting trees for energy releases carbon that would otherwise have remained stored in the forest. It also forgoes future carbon sequestration that otherwise would have occurred had the trees been allowed to continue growing.
3. The re-sequestration of the released carbon back into biomass is not instantaneous.

We also need to rethink how "green" it is to replace concrete with timber products for construction materials.

I read two articles on the pros and cons of using wood to substitute concrete for buildings:
Article 1: TO SAVE OUR CLIMATE WE NEED TALLER TREES NOT TALLER WOODEN BUILDINGS
Article 2: As Mass Timber Takes Off, How Green Is This New Building Material?

It is easily understood that the standing trees can absorb CO2 and capture carbon for decades and centuries. It is also well known that the production of concrete building materials generates CO2 and pollution. Wooden products are always regarded as green and environmental friendly materials. These are the major incentives of the mass timber building projects (Article 2):

"... many want nothing less than to turn the coming decades of global commercial construction from a giant source of carbon emissions into a giant carbon sink by replacing concrete and steel construction with mass timber. That ...would avoid the CO2 generated in the production of those building materials and sequester massive amounts of carbon by tying up the wood in buildings for decades or even longer..."

However, both articles question this theory. Firstly, from the perspective of ecology, when wood is cut off, the timber starts to emit carbon to the atmosphere instead of absorbing it (Article 1):

"Wood buildings release carbon, they don’t store it. Wood is half carbon by weight and once cut off the stump is emitted into the atmosphere at rates that are well known but vary with species and end use."

There is a common wrong belief that wooden materials are carbon neutral, and the carbon in the timber product won't go away and we keep the carbon in hand. Actually, not only that the tree is no longer living and accumulating carbon, but also that the wood piece also releases carbon gradually (Article 1):

"Increased emissions and diminished carbon sequestration capacity - these two effects make conventional wood production very carbon intensive. "

So in one sentence, trees are green because they are living, and they are no longer "green" when they become chairs, desks, housing materials... Okay, now that both concrete and timber are carbon intensive. Which one is better off then?

Compared to the natural forests, plantations have a higher growth rate and shorter cycle. They also stock less carbon than natural forests because of those. The major concerns are two folds. (A) the plantations will replace natural forests to meet the demand and induce clearings given the advocacy of mass timber. (B) Monoculture tree plantations are found to be less resilient to climate change and subject to loss of biodiversity.

The key point is how sustainable the management of plantations is. We surely want to have market-based strategy and make the adaptation practice more diverse and lively. But before getting into that risky direction, we should build a assessment system to reward the good (low carbon emission) and punish the bad (high carbon emission). Article 1 has a great discussion on this, which is quite thought provoking. We certainly need a broader and deeper discussion on this.