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Natural forests

training

Training of field crews in February 2002. While
at the plot, observations for biodiversity assess-
ment are made as well as measurements taken.

Natural, native or indigenous forest covers about 23% of New Zealand’s land area. This area has changed dramatically over the last century (see New Zealand land use page) but has been relatively stable recently.

For carbon accounting, the IPCC base year (1990), and the beginning (2008) and the end (2012) of the first commitment period (CP1) are critical.

LUCAS uses a stock approach in natural forests to estimate carbon storage. Changes in carbon stocks of live biomass (growing trees and roots) and dead organic matter (dead wood and litter) are estimated by:

  1. collecting data related to the volumes of trees, shrubs and dead wood; and processing litter samples to determine carbon concentration, from a large national network of permanent plots
  2. converting these volume data to carbon stocks per hectare, using methodologies developed for this purpose
  3. multiplying the values of carbon stock per hectare by the appropriate areas as determined from land use mapping (from high-resolution satellite imagery and aerial photography).

The methodology for the determination of plots and the recording of plot descriptions, vegetation descriptions and measurements is specified in the Indigenous Forest and Shrubland Data Collection Manual and the Soil Data Collection Manual. A robust forest sampling system includes: statistical design, data collection, measurement protocols and quality control procedures. This ensures representative and statistically robust estimates of total carbon stocks; changes in carbon stocks can then be calculated for natural forests on a national scale.

Locations of the natural forest plots sampled in the period 2002-2007.

Locations of the natural forest plots sampled in the period 2002-2007.

To ensure that measurements for carbon stocks calculations of natural forests are representative, samples are located on a 8 km x 8 km grid projected across New Zealand. About 1400 natural forest plots have undergone this approach between February 2002 and April 2007.

Re-measurement of the plots is expected to occur every 5-10 years after the first measurement. Repeat measurements (and derived carbon levels) will determine the carbon stock changes over time.

Last updated: 3 August 2009