Carbon Calculator for planted native forests

More information about carbon sequestration

• The role of forests in mitigating climate change

  In New Zealand, the interest in planting trees for carbon sequestration is considerable.

  While most of the focus is on establishing fast growing exotics such as pines and eucalypts, there is also increasing interest in using native species. The Waikato Regional Council supports landowners and communities involved in planting of native shrubs and trees throughout the region as part of various initiatives to restore indigenous biodiversity, improve water quality and enhance landscape and land use values throughout their region. Substantial areas of native shrubland and emerging native forest have been established over many years based on the planting of nursery-raised seedlings of a wide range of native species. These stands are sequestering carbon which can be quantified to demonstrate the role of restoration plantings as carbon sinks in the Waikato region.
• Measurement of planted stands

  To determine the potential of a species for carbon sequestration, both tree measurements and models for predicting carbon sequestration from these measurements are required. Tane’s Tree Trust has recently completed a survey of native tree plantations throughout the country including growth measurements (refer to articles in Section 10 of the Tane’s Tree Trust Technical Handbook – e.g. Bergin and Kimberley 2012). These planted stands of a wide range of commonly planted native shrub and tree species have been established from 10-100 years. These measurements have been used to develop growth and carbon models to determine typical carbon sequestration rates of planted New Zealand native tree and shrub species (Kimberley et al. 2014).

  Additional stands of natives planted in the Waikato region have been measured to ensure the national database is well represented with growth data from this region. This includes over 50 planted stands of natives sampled in the Waikato region including the tree species kauri, totara, kahikatea, tanekaha, rimu, matai, miro, silver beech, puriri, kanuka and broadleaf; and the widely grown shrub species manuka, karamu, kohuhu, akeake, tarata, koromiko and whauwhaupaku.
• Estimating carbon sequestration in native forests

  Equations for predicting carbon sequestration for New Zealand native trees have been derived by Scion Research for the Ministry of the Environment using biomass and tree measurements from a database of felled or fallen trees (Beets et al., 2012). These equations predict the carbon stored in a tree from readily obtainable measurements of tree diameter and height. These can be converted into a per hectare carbon value by multiplying by the stand stocking.

  The equations were mainly developed using measurements from old-growth natural forest stands. The only biomass study performed on a native plantation in New Zealand appears to be a study conducted by Scion of trees thinned from a 69-year old Taranaki kauri stand. The estimate of CO₂ sequestration obtained from the biomass measurements in this stand was 1306 t/ha. Applying the carbon equations to the tree height and diameter measurements from the stand gave a very similar estimate of 1326 t/ha giving confidence that the carbon equations developed from natural stands can also be applied to planted native stands.