New Zealand's carbon accounting rules: What's changing for forestry in 2026

From 1 January 2026, New Zealand’s forestry sector will see a series of important updates to the Climate Change (Forestry) Regulations 2022. These amendments focus on technical changes aimed at improving accuracy in carbon accounting. While technical in nature, these changes could have financial implications, so it is important to consider the changes carefully.

The big change: how forest area is measured

One of the key changes is the introduction of ellipsoidal measurement for land area calculations. This method, which takes into account the curvature of the earth, replaces the previous, simpler definition of “area” (that assumed the Earth is flat) to provide a more precise and standardised approach to measuring forest land and making accurate carbon stock assessments.

Participants who have been using Tupu-ake system-generated emissions returns have already been having their areas calculated on an ellipsoidal basis. Those who have been submitting a manual emissions return on the planimetric basis, will now be forced to re‑map on the ellipsoidal basis. While technology may have been moving that way anyhow, this change will crystallise impacts on unit entitlements driven simply from re-mapping, which could cause some initial consternation.

Simplified rules for forest sub-areas

The rules around how forest sub-areas are defined for carbon stock calculations have also been refined. The definitions now cover cases in which the predominant forest species of decaying trees are of the same forest type (instead of only covering cases in which all decaying trees are of the same forest type). The requirement for small areas to be merged into sub-areas is also revoked.

These changes aim to resolve current complexity and confusion, and create a simplified approach and more logical workflow when working towards identifying sub-areas. As with the move to ellipsoidal mapping, there could be some transitional impacts on unit count for some participants from the change in approach.

Other key updates:

New requirements for transmission notices for the transfer of post-1989 forest land interests to include the transferee’s holding account name and number, to assist in the timely processing of notices; and
Adding to the circumstances where previously planted land can nevertheless be considered to have “first rotation forest status” under averaging accounting, to include land on which first rotation forest trees are cleared and the nominal average age of relevant trees immediately before clearing was 0 years;
Changing the deadline by which an input return for an emission return may be submitted from seven days before the deadline for submitting the emissions return to, in effect, one hour before that deadline.

Under the transitional provisions, for any periods ending on or before 31 December 2025, the previous definitions and methods for sub-areas, small area merging, and area measurement will continue to apply

What is happening next?

Further changes to forest types and default carbon tables have also been consulted on recently, but regulations have not yet come out to reflect those proposals. A report on submissions indicate support for most proposed changes, so we expect to see regulations to implement most consultation proposals in due course.