Map of the small-scale forest estate of New Zealand

Abstract

From 2015 to 2021, final-year Bachelor of Forestry Science (BForSc) students at the University of Canterbury have developed, region by region, a map of the small-scale forest estate in New Zealand. Forest boundaries were mapped in a geographic information system (GIS), based on visual interpretation of aerial photography and satellite imagery. It was found that the mapped area is less than the National Exotic Forest Description (NEFD) estimate of area in eight wood supply regions and exceeds the NEFD area in the other four regions. The total nationwide mapped area is over 90,000 ha less than the NEFD area. The level of NEFD over-estimation is substantial for Central North Island, Canterbury, East Coast, Hawke’s Bay and Southland. The map of the small-scale estate allows the distribution of small-scale forest attributes to be explored, including site productivity (site index and 300 index) and attributes that affect delivered wood cost (slope, distance to public road, distance to port). If combined with LiDAR data, where available, it is also possible to estimate age and forest structure for the small-scale estate. The study confirms the urgent need for an accurate and up-to-date spatial database of New Zealand’s plantation forests. Not only would this provide accurate estimates of plantation area for wood availability forecasting, it would also enable detailed transportation and logistics planning, as well as quantification of the potential wood supply within specified distances from current and potential wood processing sites.