New Growth Forest vs Old Growth Forest
Trees are one of the best and easiest options we have to reduce atmospheric CO2. There are two main categories of forest with different benefits.
Old growth forests have trees ranging from 120-1000 years old. Over the course of their lifetime, the CO2 they have removed from the atmosphere (via photosynthesis) is stored in organic matter in soil litter and live woody tissue. This is known as carbon sequestration. Globally, these old growth forests store approximately 30 times annual fossil fuel emissions, or 300 billion tons of carbon (Craggs 2016).
These forests are large carbon sinks.
As a tree grows, it becomes more susceptible to drought, lightning, storms, soil nutrient deficiency and loses efficiency in transporting water. Hence, these old trees become less efficient at taking up CO2 with age, and even reach net zero uptake (Pugh 2020).
New growth forests are generally younger than 120 years and take up more CO2 than old growth forests. However, the amount of carbon stored in these forests is less than old growth forests due to their age.
In today’s world, new growth forests are typically replacing, or aiming to regenerate areas of old growth forest that have been destroyed. Deforestation is extremely damaging to the old forest carbon sink as locked up carbon is released back into the atmosphere as CO2. Thus, contributing to global climate change (Craggs 2016). Hence, although younger trees take up CO2 at a greater rate than old forest, this is countered by the loss of stored carbon (Pugh 2020).
Many of us have heard some variation of the old saying where the only thing better than a tree planted today, is one planted ten years ago. This is still true. But we also need to be looking at protecting what remains.
There has been some progress in recent years with the UN 2015 Paris Climate Conference which set out to “halve de-forestation by 2020 and eliminate it by 2030”. However, more than 30% of old-growth forests are still unmanaged and unprotected (Craggs 2016).
These old growth forests sinks are integral to our future climate. So, let’s do some tree hugging.
References:
Craggs, Geoffrey. 2016. “The Role of Old-Growth Forests in Carbon Sequestration” Accessed 11 June, 2021. https://www.futuredirections.org.au/publication/role-old-growth-forests-carbon-sequestration/
Pugh, Tom. 2020. “Are young trees or old forests more important for slowing climate change?” Accessed 25 June, 2021. https://theconversation.com/are-young-trees-or-old-forests-more-important-for-slowing-climate-change-139813
Author: Sienna Blanckensee | Jul 30, 2021