Native trees preferred as carbon sinks
NATIVE trees will make better long term carbon sinks than simply planting pine trees to counter climate change, Associate Prof Janice Lord says.
Prof Lord, of the University of Otago botany department, commented yesterday in an 11am campus talk titled ‘‘One billion trees for carbon sequestration’’.
‘‘The most critical conversation we need to have, at a national level, is what do we want this country to look like in 100 years’ time, as we are planting for our children and their children after them,’’ Prof Lord added in an interview.
‘‘The afforestation decisions we make today will affect our landscape for generations, so should not be based simply on the easiest way to meet international carbon commitments.’’
Radiata pines clearly grew faster, as young trees, than any of our large native species.
‘‘However, when grown for harvest, radiata provides little in the way of a carbon sink.’’
The waste material, called ‘‘slash’’, left on the site released carbon as it decayed, and much of the harvested timber went into products such as woodchip and paper that ended up as fuel or waste.
The One Billion Trees Programme had been established in part to offset New Zealand’s carbon dioxide emissions.
More than half of these trees were expected to be rapidlygrowing exotic conifers.
The rapid early growth of pines was not surprising as considerable time and money had been spent over the last 60 years optimising cultivation methods and developing fastgrowing cultivars.
There had been virtually no investment in optimising methods for growing native trees, but newlyplanted native trees could still overtake the carbon sink ability of radiata pine within 80100 years.
‘‘Our longlived native trees will continue to take carbon out of the atmosphere for centuries and recent studies have shown that the forest giants are particularly effective at storing carbon.’’