CARBON SINKS / 9 Oct 2019
The Life and Death Question of Forest Carbon
Our greenhouse is warming up. The year 2019 is foreseen to be the warmest year in the recorded history of global temperature measurements. The latest IPCC report released in August underlines the need for accelerated action to cut down emissions. This time IPCC places particular emphasis on land use, highlighting the need to focus more on increasing CO2 sinks and absorption in forests. So how can we make this happen?
A simple answer is to plant new forests on open land. Ideally, this land would be productive, facilitating moderate-to-fast growth of trees, and would not be used for food production. If food production would be unavoidable, agroforestry models would need to be adopted, that facilitate food production and growing trees on a same area. New forests absorb carbon and create new carbon sinks, thus mitigating climate change. Agroforests can also increase food productivity, thus, creating a win-win situation for land owners.
The big question is what will happen to these forests in the future? If the objective is to maximize the short term carbon sink, we would need to protect these forests from any interference and let them mature and grow very old, which also entails exposing them to disease and damage, which will eventually kill the trees and, in the worst case, the whole forest. Damaged or dead wood cannot be used commercially and will rot and go back to the atmosphere as CO2. Then we would replant and re-start the natural cycle. Sounds like the garden of Eden – but is this really the best solution for mitigating climate change?
There is also another option. Following the planting of new forests, we could manage these forests sustainably and use the wood for multiple end uses. Instead of just waiting for the inevitable death that all living organisms face sooner or later, we can do intermediary harvests in the forests, removing weaker trees that would otherwise die, and using them for furniture or other long-lived biomaterials.
When the forest grows old, we could harvest the forest for regeneration and use the trees for construction and other products. And at the same time, we could regenerate the forest to start a new natural cycle. CO2 in harvested trees would not be released to the air by rotting, but would be restored for much longer time in the products that we need for everyday life. The harvested wood would substitute steel in furniture, or concrete in construction, and we would not need to use so much steel or concrete, which would reduce CO2 emissions of producing these materials. And these benefits that come from substitution are expected to increase in the future. The industry is actively developing new bio-based products, which could substitute many materials such as plastics and, thereby, decrease overall CO2 emissions.
Now, which option would be better? In both of the above mentioned cases, forests absorb CO2. In the second case, the CO2 sink has a longer life, since it is bound also in products. Let’s imagine that this forest would be planted in Africa, Asia or South America, where local people need employment, income, construction wood etc. Would they be more committed to plant trees that they cannot use, or trees that they can harvest sustainably and benefit from? Which type of forests would they be more committed to protect from fires and other damages? These are the life or death questions of forest carbon.
The article was initially published in magazine Suomen Kuvalehti in Finland.