Here’s the next instalment of the Sequestering Carbon in Native Forests series. It’s fairly acedemic (I have to be serious sometimes), so get your acedemia on! If you haven’t read any of the previous posts in the series maybe check them out first; they are best read in order.
Pre-existing forests can be managed to sequester carbon through measures such as having a mix of species, managing fire regimes and keeping the forest at an ideal mix of age-classes. A mixture of species in a forest makes the system more resilient and overall better at storing carbon (Böttcher and Linder, 2010).
As outlined above, different species react differently to factors such as water availability so in this way a resilient tree community would be made up of a variety of species so that whatever the rainfall pattern at least one species was still able to actively sequester carbon.
In the Australian bush the constant possibility of fire means that landholders with a large number of trees on their property need to have a fire management plan with efforts such as controlled burning to reduce fuel loads. (Böttcher and Linder, 2010).
Although this releases carbon dioxide, it can greatly reduce the risk of large, uncontrolled fires later and can actually help with the sequestration process if the ash goes back into the soil. For the purposes of sequestration the ideal age-class structure of a forest is fairly mixed (Böttcher, 2007).
If a system cannot self-regulate to achieve this, the forest should be managed; trees that are all relatively young and still growing sequester large amounts of carbon but there will be a lesser extent of the natural process that use dead roots, branches and twigs to lock up carbon in the soil as these processes take decades to fully establish.
However, if the forest comprises only of mature trees that have stopped growing the sequestering potential for that forest will largely have been reached.
Thus, once a forest has been established it should be managed (if it can’t self-regulate) so there is a mixed age-class with a mind to disturbing the ecosystem as little as possible. While it takes around 100 years for this point to be reached (possibly longer in low rainfall areas) the potential of forests to mitigate against climate change, even in those low rainfall areas, is good.