A fully grown healthy tree can store up 5 tonnes of carbon.

Forests are an integral part of Irish ecosystems, as well as being an incredible carbon-capturing mechanism. Here is a brief summary of why we are planting native woodland in Ireland.

A home for animals, insects, and plants

Our native woodlands hold a significant percentage of our biodiversity. For example, oak can support almost 300 species of insect, birch and willow about 250 and hawthorn around 150 while many dozens more can be found on each of our other trees species.

These range from the deadly Devil’s coach-horse to the bumbling cockchafer and some real beauties like the purple hairstreak, silver-washed fritillary and the white prominent.

These, in turn, support the dozens of bird species that inhabit our woods as well as the many mammals we are more familiar with including badger, deer, fox, hare, pine marten, stoat and red squirrel.

Trees store carbon and clean our air

Trees’ leaves break down carbon dioxide in the air during photosynthesis storing carbon in the timber and releasing oxygen. 

Plants, big and small, take in carbon every day. It is an amazing system, and it is exactly what we need right now.

How much CO2 is stored in a tree?


  • About 35% of the green mass of a tree is water so 65% is solid dry mass.
  • 50% of the dry mass of a tree is carbon.
  • 20% of tree biomass is below ground level in roots so a multiplication factor of 120% is used.

So, if the weight of the tree above ground is just 100kg – it contains about 39kg of carbon that might otherwise be in the atmosphere. For context, this is about as much CO2 equivalent as is produced by flying for 10 minutes in a Boeing 737.

What this means is that we need to plant a lot more trees if we want them to be able to suck in as much carbon as we are pushing out in our daily lives.

Th good news is that there is plenty of potential for planting native woodlands in Ireland.

The potential for new forests that do not encroach on cropland is high in the UK, Ireland and central Europe.
Guardian graphic. Source: Bastin et al, Science, 2019