Understanding Carbon Drawdown of Trees

Carbon drawdown is the process of taking carbon from the atmosphere and storing it in the landscape (usually in trees or soil). According to the World Market Institute, across the world, trees and forests collectively absorb around 7.6 billion metric tonnes of carbon every year. Keep reading to understand exactly how trees store carbon and how they can help you earn carbon credits. 

How? You may be asking.

To cut a long chemistry lesson short, a small amount of the carbon dioxide that a tree absorbs is transferred to the soil, and the rest is converted to glucose (sugar) through photosynthesis when combined with water and sunlight. Glucose is used to build leaves, stems, branches, and trunks. The glucose that isn’t used right away is stored as starch in the middle layer of a tree, also known as sapwood, or xylem. The tree is able to access this store of starch when it needs to and continuously stores excess glucose here. As the tree ages, some of this starch moves into the tree’s heartwood store. This store is the final layer of the tree trunk before the central pith and is permanent, meaning that once the starch transitions here it is no longer accessible for the tree to use.

It’s important to remember that each plant species varies in how it stores the carbon that it captures through photosynthesis. Generally though, carbon stored in tree biomass can be broken down to the figure below:

Carbon distribution throughout a tree (Sources: Forest Learning)

Standing the test of time

As trees age, their carbon sequestration rate increases until eventually levelling off when the tree is full-grown. The rate at which trees store carbon also depends on a range of changeable factors – availability of nutrients, rainfall, and wood density. Recent research in this area has shown that allowing trees to reach their full growth potential (by extending forest harvest rotations or just allowing trees to grow on your property) can enable them to store the maximum about of carbon. More on this here.

We are family

Trees in the natural world don’t tend to exist alone, they grow in forests or stands of trees. This enables them to establish stronger root systems that connect to each other underground so they can share nutrients and improve the overall health of the ecosystem they are a part of.

A strong and larger root system also comes with an array of ecological benefits, including managing groundwater and reducing soil salinity. When considering the carbon drawdown of trees, this whole ecosystem needs to be considered, including the surrounding leaf litter and soil which also play a key role in storing carbon. Areas with a mixed age range of trees, and multiple species, are widely considered to be the healthiest. 

Trees = healthier farm

With all this in mind, you can see how the benefits of revegetation efforts for improving the health of your farm.  There are proven benefits to the health of the soil, livestock, and crop vigour by strategically integrating belt plantings such as windbreaks for crops or shelterbelts for livestock.

Strategic block plantings can be implemented and transformed into a silvopastoral system- i.e. livestock can move under the establishing tree canopy providing shelter, with added understory plants to provide fodder (such as tagasaste or saltbush).

Plant trees to diversify income

Undertaking an environmental planting carbon project can be a diversification opportunity for your farming business. For every tonne of CO2e you store in your registered & compliant environmental planting carbon project, you generate one Australian Carbon Credit Unit (ACCU). The beauty of carbon credits is that they can provide your farm with another revenue stream for 25 years. The key is to strategically integrate tree plantings into existing livestock or cropping operations or optimise the use of underutilised land! Find out more about how you can earn carbon credits by planting trees here.

Ready to find out more?

Explore our range of educational resources in our Carbon Farming Education Hub where we frequently publish educational articles, webinars, and guidebooks. 

When you’re ready to explore the feasibility of undertaking a carbon project on your property, email us at [email protected] or give us a bell at (08) 6835 1140 to be connected with one of our project facilitators.