Carbon sequestration

Process of natural regeneration and carbon storage

During the process of natural regeneration, abandoned pasture slowly reverts to native forest, as long as the conditions are right. There needs to be a source of native seeds from a forest near enough to reach the pasture naturally. To have good growth rates there needs to be adequate rainfall; altitude, aspect and soil type are also very important.

As the trees grow, they absorb CO2 from the air and convert it into carbon-based products such as wood; this process is called sequestration. Carbon comprises approximately half of the dry mass of wood; therefore, the bigger the forest grows, the greater the carbon storage potential. If a forest grows quickly the rate of sequestration is higher than where a forest grows slowly. However, forests that grow quickly at the beginning of their life cycle usually store less carbon overall than forests with trees that live a long time and grow slowly.

Protection of the regenerating forest (through a PFSI covenant) confers ‘additionality’ to the process of forest regeneration because protection allows the succession to proceed to tall forest in perpetuity, whereas standard agricultural practice involves a burn/regrowth cycle.

Co-benefits of natural regeneration

There are some initial costs involved with trading carbon from natural forest regeneration, such as registration to obtain credits and, in some cases, fencing. However, for marginal pasture, forest regeneration can save money in the longer term. This is particularly true if you are currently spending money on keeping the pasture from reverting to mānuka or even gorse or broom.

If you commit to long-term natural forest regeneration you can expect to gain native biodiversity not only in flora but also in fauna. The number of native bird species visiting your forest may increase as may the number of species of insects and other invertebrates. Even native fungal species will increase! In addition, you may notice a decrease in erosion and the number of slips, particularly on steep country, and an increase in water quality from streams that run through the naturally regenerating forest.

The carbon cycle

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