japanese maple branch - Illustration by Helen KrayenhoffA neighbor recently asked which trees he should plant to act as carbon sinks. Now, for those readers who don’t already know about global climate change (are there any?) carbon sinks are natural systems that suck up and store carbon dioxide from the atmosphere. Gardening practices can certainly help in this process but as you know it isn’t simple.

During the process of photosynthesis, plants break down atmospheric carbon dioxide into oxygen, which is released back into the air. Captured carbon, which gets combined with water, is then converted into carbon sugars the plant uses to fuel itself. Plants also release carbon, as do humans in the process of breathing. Plants, especially forests can also store massive amounts of carbon, but when forests release more carbon than they absorb, such as during a forest fire or when there are more dead than living trees, it becomes a carbon source.

Soil is also an important part of this equation. The over-application of synthetic NPK fertilizer shuts down production of nitrogen and slows down or even halts humus formation and carbon storage. And finally, while it’s not something gardeners have a direct tie to, oceans play a key role in this carbon cycle, both absorbing and releasing carbon.

The human-influenced increase in atmospheric carbon and other greenhouse gasses is undeniable. It is a crying shame that global power structures still deny the facts about climate change. Every day that passes leaves me wondering what can be done to help. Of course reducing our extraction and use of fossil fuels is a good start. Promoting the use of alternative energy sources is still relevant. Boycotting forest-clearing companies is huge. But still, even as small-scale gardeners we can help.

As kings of the plant world, trees have much more woody biomass to store carbon than smaller plants. As a result, trees are considered nature’s most efficient carbon sinks. It is this characteristic which makes planting trees a form of climate change mitigation. Ultimately, trees of any shape, size or genetic origin help absorb carbon. And, my research shows that evergreen or deciduous doesn’t really matter. Real scientists agree that the least expensive and perhaps the easiest way for individuals to help offset the carbon that they generate in their everyday lives is to plant a tree…any tree, as long as it is appropriate for the given region and climate.

Spread the word. Be fearless. Be active. Did I mention trees that feed us?