Predicting harvestability of existing Pinus radiata stands: 2013-2030 projections of stumpage profits from pre-90 and post-89 forests

Our goal is to predict which forests are harvestable in New Zealand each year, and the stumpage profits attained from harvesting. We begin by documenting how Motu updates the 2008 Land Use in Rural New Zealand map to match the 2013 National Exotic Forest Description planted forest dataset. We then produce forest stand maps for the years 2013-2030. Last, we describe how we assign stumpage profits, and the distribution of stumpage profits over the simulation years (2013-2030).

We find that stumpage profits are: always positive; increasing through time (2013-2030); lowest (on average) in the West Coast; and highest (on average) in the North Island East Coast. Our results suggest that forest owners will always harvest given that they have already incurred planting and growing costs.

Limitations in data, including the need to use averages of yields and some costs across wide areas, and the effect of market conditions, and their role in determining the pace and average age at which the estate is harvested, mean that the true distribution of stumpage profits is likely to be wider. Those most likely to not harvest would be those with low estimated stumpage.