Open letter on climate change report in NZ

Euan Mason

Professor Euan Mason from the School of Forestry at the University of Canterbury in New Zealand has penned an open letter after the release of the Climate Change report. Professor Mason holds a Bachelor of Science in Forestry from the University of Maine and a Doctor of Philosophy from the University of Canterbury. Source: Timberbiz

“The Climate Change Commission should be commended for making a very helpful, comprehensive report on such a difficult topic. The Commission is right to state that our long-term focus must be on reducing greenhouse gas emissions. With respect to forestry issues there appear to be a number of unsubstantiated assumptions, however:

1. Forest C storage is said to be “impermanent”. What matters is the total area of New Zealand in forest, not whether or not any particular forest stand blows down, burns or is harvested. If we commit to increasing the total national area of forest and to ensuring that the very small areas that blow or burn down, or those areas that may be harvested, will be re-established, we can enlarge a very stable, permanent C store in forests.
2. Forest is said to be risky because climate change will increase the risk of fires. New Zealand’s forests have long been far more likely to blow down than burn down, and the frequency of forest fires has not yet been shown to have increased in New Zealand. Australia, at similar latitudes to the Sahara and with continental climate patterns, has always been subjected to greater forest fires than us, and our opinions on this matter appear to have been strongly influenced by anecdotes from across the Tasman Sea. This is poor evidence on which to base policy.
3. There appears to be an implicit assumption that native forests are more permanent than exotic forests, and to the extent that exotics tend to be pioneer species from an ecological point of view, this is true for unharvested forests, but the conclusions that we must plant native forests and that these forests will greatly help us reach our 2050 target are flawed. Native forests sequester C very slowly compared to our most productive exotics, and areas of native forest required to have the necessary impact on our C accounts by 2050 are simply too large and expensive for us to contemplate. There is abundant evidence that we could take advantage of rapid sequestration rates of exotics to fill gaps in our C accounts (these gaps result from a necessarily slow pace of change in greenhouse gas emissions and are acknowledged by the Commission) while gradually transitioning these pioneer exotic carbon forests to later seral stage native forest over many decades. This latter approach would have substantial advantages.

It

1. a) is much cheaper, in dollars and in land area required, than directly planting native C forest;
2. b) ensures that forests actually fill the gaps in our C accounts; and
3. c) ultimately provides extra native forest which many of us would like to see, but in a more natural way.

Kind regards,

Euan Mason”