Annual Imagery Mosaics

Details

The Forestry Emissions Trading Scheme (ETS) relies on satellite imagery captured near the end of each year and mapping derived from this imagery to determine the areas of annual forest presence and loss. Sentinel satellite imagery collected by the European Space Agency has been identified as the appropriate imagery source. The objective of this procurement is to obtain biannual (twice yearly) Sentinel satellite images captured near the 31st of December each year from 2015 and mask cloud cover and create national cloud free mosaic images. Relevant Sentinel images will be acquired, processed and converted into biannual national imagery mosaics from 2015 to 2021 and then each year thereafter through to at least 2023/24.

The national mosaics will be used as the inputs to then produce annual forest presence and forest loss spatial datasets using automated or semiautomated imagery change detection techniques. The change required to be identified is a loss of forest species through anthropogenic or natural causes. This imagery and spatial data will further enable Te Uru Rākau – New Zealand Forest Service to determine the extent of forest establishment and other land use changes when analysing multiple images captured over time. An accurate spatial representation of land cover and land use, for example the presence or absence of forest species, is required for all New Zealand at the end of each calendar year. Forestry ETS participants can use these data to inform their mapping and resulting carbon stock calculations. These calculations are used by applicants to calculate provisional emissions returns and final emissions returns and by Te Uru Rākau – New Zealand Forest Service to monitor ETS compliance.

Regularly captured multispectral imagery is the most cost effective and efficient method to determine the spatial extent of forest presence/loss and other types of land use change. Increasing the accessibility of the imagery and associated forest presence/loss data will help Forestry ETS participants provide more accurate ETS applications and carbon calculations.