East Coast wood availability forecasts for the period 2007–2040
Introduction
These forecasts show the range of harvest volumes potentially available from the planted production forests in the East Coast Region for the period 2007–2040.
The forecasts have been developed by incorporating harvesting intentions of the region’s large-scale forest owners as outlined below; the results are amalgamated to ensure confidentiality. Large-scale owners (those with 1000 hectares of forest or more) are:
- Hikurangi Forest Farms;
- Ernslaw One;
- Juken New Zealand;
- New Forests;
- Mangatu Incorporated;
- Ngati Porou Whanui Forests (no harvest before 2015).
The small-scale owners’ resource was defined using the most recent National Exotic Forest Description (NEFD) data.
Five scenarios have been modelled to indicate the potential range of future wood availability. The scenarios indicate that there are many different ways for the forest estate in the East Coast to be harvested. A key issue is the timing of harvesting by the small-scale forest owners, which will be driven by a range of factors – including individual forest owners’ objectives, forest age, log prices, demand by local wood processing plants, and perceptions about future log prices and future wood supply.
It needs to be recognised that forests are managed to maximise the benefits to the enterprise that owns them. Each enterprise has its own harvest strategy based on the owners’ objectives, market conditions and the forest estate that it owns or manages. Any change in harvesting strategies by forest owners affects the age-structure and maturity of the forests they own. This in turn feeds back directly into future wood availability.
There are different levels of certainty associated with the wood availability from each component of the estate. The volumes forecast from the large-scale owners’ forests are subject to change because of changes in market conditions or changes in the resource description (areas and yields). Yet, they have greater certainty than those forecast from the small-scale owners’ estate. Not only are harvest intentions less clear for small-scale owners, their resource descriptions are likely to be less accurate also. To improve the levels of certainty, the forecasts incorporate the views of the region’s forest managers and consultants. This feedback was critical for ensuring that the forecasts represent a realistic range of future wood availability scenarios.
Scenarios for radiata pine
Five wood availability scenarios have been modelled for radiata pine. These scenarios indicate the ways the forests in the region could be harvested in the future.
To ensure the scenarios presented here are reasonable, they were developed in consultation with the NEFD Steering Committee and feedback was received from major forest owners and consultants in the East Coast Wood Supply Region.
Listed years are assumed to be to 31 December. For example, 2005 indicates the 12 months to 31 December 2005.
Scenario 1: Harvest all areas at age 30
All owners are assumed to harvest their trees at age 30. This scenario shows the potential future harvest in any given year based on the area of radiata forest that reaches 30 years of age in that year.
Scenario 2: Large-scale owners harvest at stated intentions, small-scale owners harvest trees at age 30
Large-scale owners’ wood availability is assumed to be at stated harvest intentions for 2005 to 2015. After 2015, the large-scale owners’ wood availability is assumed not to decrease. Small-scale owners are assumed to harvest trees at age 30.
Scenario 3: Non-declining yield (NDY) – target rotation 30 years
Large-scale owners’ wood availability is assumed to be at stated harvest intentions (as for scenario 2). The total wood availability of radiata pine from the region is modelled to be non-declining in perpetuity.
Scenario 4: Split non-declining yield – target rotation 30 years
This is the same as scenario 3 except that the total wood availability of radiata pine from the region is assumed to step down from 2034 (at the end of the current rotation). Thereafter, a reduction is assumed.
Scenario 5: Target rotation age variations
This is similar to scenario 4 except target rotation ages of 28 and 32 years are also modelled.
Discussion on scenarios
With the exception of scenario 1, the small-scale forest owners have been modelled separately from the large-scale owners. This is because future harvesting by small-scale owners is generally less certain than by large-scale owners.
In scenarios 1 and 2 (Figure 1A and 1B, respectively), forests owned by small-scale owners are assumed to be harvested at age 30. In scenario 1 all forests (large and small-scale) are harvested at 30 years. In scenario 2, the small-scale forests are harvested at age 30, but the large-scale forests follow their owners’ stated intentions. Both scenarios show the “potential” availability of mature forest in any given year and reflect directly the area of forest in each age class in the East Coast. For practical reasons already described, it is unlikely that the future harvesting would occur this way. The two scenarios simply show the potential magnitude of harvesting under favourable market conditions in any given year.
Scenarios 3 to 5 (Figure 1C and 1D, respectively) are based on yield regulation. Under these scenarios, the future harvesting model is generally constrained to be non-declining; that is, each year the volume must either be the same or higher than in the previous year. Yield regulation provides a more orderly harvesting volume profile that takes logistical and market constraints into account, to some extent.
Scenarios 3 to 5 avoid the large year-to-year fluctuations seen in scenarios 1 and 2. A fundamental property of the forests in the East Coast (like many regions in New Zealand) is the large area of forests established during the 1990s. Scenarios 4 and 5 illustrate the harvesting of these forests by applying a non-declining yield constraint for the period 2006 to 2034. Then once the “bulge” of forests planted during the 1990s have been harvested, the model lets the volume decline again.
The main limitations of scenarios 3 to 5 are that log prices and other market factors significantly determine harvesting in any given year. When log prices go up, harvesting will generally increase. When log prices fall, the level of harvesting will generally decrease. It is beyond the scope of this analysis to predict future timber prices.
Figures 1A to 1D summarise the sequence of models that are presented in the remainder of this report.
Figure 1: The sequence of wood availability scenarios presented in this report for radiata pine. (Scenario 5 is the same as scenario 4 except it shows wood availability profiles of various harvesting ages.)
1A - Scenario 1 example: harvest all trees at age 30
1B - Scenario 2 example: large-scale owners harvest at stated intentions, small-scale owners harvest trees at age 30
1C - Scenario 3 example: non-declining yield with target rotation 30 years
1D - Scenario 4 example: split non-declining yield with target rotation 30 years
Scenarios for Douglas-fir
One scenario is presented for Douglas-fir (all owners) similar to scenario 4 for radiata pine. It is based on the harvest intentions of large-scale owners for 2005 to 2015 with yield regulated in subsequent years. Target rotation age is 45 years for Douglas-fir.
Wood availability from other species has not been modelled.
Contact for Enquiries
Policy Adviser
Pastoral House
MAF Policy
PO Box 2526
Wellington 6140
NEW ZEALAND
Fax: +64 4 894 0741
Contact this person
