Planting trees to offset carbon emissions is seen as one of many strategies to deal with rising CO2 levels in the atmosphere. This ranges from a small scale, where members of the public are encouraged to plant trees, to well organised initiatives planting millions of trees. There has also been a growth in standards for offsetting carbon through tree planting, creating a sub-industry that was not foreseen only a few decades ago.
While planting trees has been shown to be an effective method to bind carbon, it has it’s limits. For example, depending on factors such as tree species and local climate, it can take from 31 to 46 trees to compensate for just one tonne of CO2.
A paper published in September by researchers from the University of Gothenburg reports that trees planted in nutrient poor soil take up less CO2 over time. This would make trees planted in nutrient poor soils poor long-term candidates for carbon sequestration programmes. They further report that trees grown in these conditions may die earlier and release their stored carbon reducing the total amount of carbon stored.
The paper is open access and can be found here.