Trees of life

Forestry will be vital to New Zealand’s transition to a low-emissions economy, according to a new report from the Productivity Commission.

It says 1.4-2.8 million hectares will need to shift from pastoral farming – principally marginally profitable sheep and beef – to forestry. However, forestplanting is not a long-term method of emissions reduction because suitable land for continued planting will eventually run out. The commission says it will “buy time” between now and 2050 for the development of low-emission technologies.

Between 44,000 and 90,000ha of new forests will need to be planted annually over the next 32 years – far higher than the average 18,000ha a year planted between 1990 and 2015. Changing the land use from pastoral farming to horticulture is also required. The commission says such a rate of land-use change is feasible and is comparable to the massive changes over recent decades from sheep and beef to dairying and other purposes.

Many observers would prefer to see a large expansion of native forests rather than exotics such as Pinus radiata, but the commission says natives are more expensive to plant and in the first 30 years soak up only about a third or a half of the carbon radiata absorbs.

Agriculture contributes about half of New Zealand’s total greenhouse-gas emissions. The commission favours bringing agriculture into the Emissions Trading Scheme and says emissions pricing should be the main driver of land-use change to forestry and

horticulture.