The role of forests
Trees absorb carbon dioxide and use it to produce oxygen and carbohydrates through photosynthesis. Forests store large amounts of carbon which is released into the atmosphere during deforestation or as a result of forest degradation. Deforestation has contributed significantly to the increase in atmospheric carbon dioxide. According to the Intergovernmental Panel on Climate Change (IPCC), about 22% of the rise in atmospheric carbon dioxide since pre-industrial times has come from loss of forests. Protection of existing forests and planting of new forests are therefore important tools in countering global warming.
New Zealand has contributed to this global trend of forest destruction. The area of natural forest in New Zealand has reduced from approximately 85% of total land area before human arrival to 29%, only partly offset by the planting of exotic forests which currently cover 7% of land area.
Offsetting your carbon footprint by planting trees
In New Zealand, there is considerable interest in planting trees for carbon sequestration. While most of the focus is on establishing fast-growing exotics such as pines and eucalypts, there is also increasing interest in planting native species which provide many benefits in addition to storing carbon. These include restoration of indigenous biodiversity, improvements in water quality, and enhancement of landscape and land use values in productive landscapes. Substantial areas of native shrubland and emerging native forest have been established by the planting of nursery-raised seedlings of a wide range of native species. These native stands store carbon which can be quantified to demonstrate the role of restoration plantings as carbon sinks.
A comparison of native and exotic forestry
None of the native species can compare in early sequestration rates with the fastest growing exotics such as radiata pine. Beyond about age 20 years, however, the fastest growing native species such as kauri, red beech and black beech can approach exotics in terms of current annual increment. Ultimately, all forest, whether exotic or native, if left to mature will reach a maximum carrying capacity for carbon.
The Emissions Trading Scheme (ETS)
The New Zealand Emissions Trading Scheme (ETS) puts a price on greenhouse gas emissions. This encourages people and businesses to reduce greenhouse gas emissions and to establish forests to remove greenhouse gases from the atmosphere.
The primary unit of trade in the ETS is the New Zealand Unit (NZU), also called a carbon credit. One NZU represents 1 tonne of carbon dioxide (or the equivalent of other greenhouse gases). Read more about the ETS to enable post-1989 forest owners to receive carbon units through the creation of new permanent forests on the Te Uru Rakau Forestry New Zealand website.