Decline in forest cover – it is happening and it does matter

Each year the Ministry for Primary Industries (MPI) surveys the 29 forestry nurseries around New Zealand. Provisional figures have recently been released. They show:

  • Tree stock sales declined 18.4 million from 2012 to 2013 (see table below). The years 2010, 2011 and 2012 all had year-on-year increases in new plantings levels. This is most likely a function of the emissions trading scheme (ETS) and a price on carbon that increased forecast returns on forest growing. This is contrary to Tim Groser's view that recent forest planting is driven by the timber markets and over-zealous speculation by tree stock nurseries. In fact, during 2013, the timber market was stronger than 2011 or 2012.

Tree Stock Sales from 2006 to 2013 (millions)

Radiata pine 28.8 36.7 36.2 37.7 46.4 58.9 64.6 48.5
Douglas fir 2.8 2.9 2.3 3.0 3.6 5.1 4.0 3.1
Other softwoods 1.8 1.7 1.5 1.5 1.3 1.3 1.3 0.7
All hardwoods 0.6 1.1 1.2 1.0 1.9 2.3 2.6 1.9
TOTAL 34.0 42.4 41.2 43.2 53.2 67.6 72.5 54.1
        p = provisional


  • It is provisionally estimated that 49,000 hectares of forest was planted in 2013. 92% of the planting was in Radiata pine.
    • Of this, it is estimated 4,500 hectares of new forest was planted. This contrasts with an estimated 12,000 ha in 2012.
    • Of this, it is estimated 44,500 hectares of forest was replanted (after harvesting).

New planting and replanting since 1991 is shown on the graph below.

Replanting trend

Total harvesting in New Zealand in 2012 was 27.5m m³ and in 2013 a record 29.7m was harvested. Taking the average of both years (28.6m m³) and dividing by an estimated average yield of 500 m³/hectare provides a proxy for harvested area available for replanting in 2013, i.e. 57,200 hectares. The difference between this and the estimated area replanted (above, i.e. 44,500 hectares) is 12,700 hectares and likely to comprise a mixture of deforestation (conversion to pasture) and land lying around fallow and unproductive.

Whilst some of the conversion to pasture may be an obvious economic choice based on economic profitability, if the total cost of externalities such as soil erosion, water quality and green-house gas emissions were recognised, the highest- and-best land use choices could look quite different.

But I guess for this to matter, you have to believe that climate change is happening and believe that New Zealand should pull its weight in doing something about it.