Climate scientists may have overlooked Earth’s secret weapon.
One study of tropical forests in Panama found that most of the forest’s biomass consisted of fast-growing, bulky trees. These trees sequester more carbon dioxide than other trees, and this had not been predicted in climate models.
The study, published in the prestigious journal Science , reveals that trees that grow fast, live longer and reproduce slowly sequester by far the largest proportion of carbon dioxide in forests.
These “long-lived trees”, such as mahogany or walnut trees, grow up to twice as fast as other trees and can tower over all other treetops in the forest for centuries.
How trees convert CO2
The roots of the trees get water from the ground and the leaves absorb carbon dioxide from the air and light from the sun. The carbon dioxide, light and water are converted into sugar and oxygen through photosynthesis.
The oxygen is then released back into the atmosphere, but the sugar combines with nutrients from the soil and forms biomass for the tree. As biomass builds, the trees grow.
All trees convert carbon dioxide into biomass – but not all are equally efficient.
Trees grow in their own way and each has its advantages and disadvantages. Trees that grow fast often do not age as well as other trees that grow more slowly. Trees also have to choose and reject, so to speak, either they reproduce quickly or grow quickly.
As for this, the aged trees have to make sacrifices. They grow fast and get old. On the other hand, they multiply much more slowly than their shorter neighbors.
Current climate models have so far equated all trees, regardless of their different growing conditions, and for the sake of taste, the effects of long-lived trees have been rather underestimated, but scientists today believe that we should protect these trees early in their life cycle.
Old trees stop sequestering carbon dioxide
Of course, more plays a role than just size and age. In another study published in the journal Nature, it was shown that some trees stop growing and sequestering carbon dioxide when they reach a certain age, regardless of the level of carbon dioxide in the environment.
This is due to the fact that the growth of trees is also determined by the available nutrients. The scientists studied Australian eucalyptus trees that stopped growing because the soil around them was low in phosphorus.
From the point of view of carbon dioxide farming, nothing is done by allowing old eucalyptus trees to stand still. In fact, one could rather see that there would be more benefit in demolishing them, if it were possible to ensure that they were used in the construction industry, for example instead of concrete.
The scientists also point out that other rules may apply to other tree species and other more nutritious areas.
What does this mean for the tall trees? Sure, they may not continue to absorb carbon dioxide from the atmosphere forever, but they absorb many times more than the neighboring trees do throughout their lifetime.
