2.b Total growing stock and annual increment of both merchantable and non-merchantable tree species in forests available for wood production

Rationale

This indicator measures the growing stock and annual increment of forest area available for wood production to meet society’s needs. The annual increment and growing stock can be related to the volume harvested each year to provide a means to demonstrate the sustainable management of forest resources.

Current state

Despite a small reduction in the area available for wood production over the last decade, the standing volume of New Zealand’s planted forests, as estimated by the National Exotic Forest Description, has increased by an average of 9 million cubic metres per annum. The increase in standing volume is reflected in the average age of planted forest stands, which has increased from 13.7 to 16.4 years over the same period.

Stem vollume and stand age in planted forests available for wood production

Total standing volume is the volume of wood contained in stems of all age classes. It includes some non- recoverable volume (commonly about 15 percent), but excludes bark.

Radiata pine (90 percent) and Douglas-fir (6 percent) are the main planted species in New Zealand.

Mean annual increment of total recoverable volume

The forest resource is distributed throughout New Zealand, but with a significant proportion of the planted estate in the Central North Island.

Plantation forests by location

Trends

Despite a 3 percent reduction in the area available for wood production, between 2007 and 2013 the standing volume of planted forests has increased by 18 percent due to the large areas in the 1980s and early 1990s and now in mid-rotation.

Recent estimates suggest that the standing volume of indigenous forests has remained stable over the last decade at a little over 3200 million cubic metres.

Radiata pine by age class

Trend Status

Data Quality M / H

Supporting Material:

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