A National Exotic Forest Description (2007) – NEFD
2 Overview
New Zealand’s net stocked planted production forests covered an estimated 1.79 million hectares as at 1 April 2007. This total area is thought to be accurate to about plus or minus 5 percent. For further information refer to Chapter 5, Reliability of data.
The total planted forest stem volume is estimated to be 434 million cubic metres with an average forest stand age (area weighted) of 14.8 years.
Table 2.1 provides key national forestry statistics as at 1 April 2007 and compares these with statistics for 2006.
Of the total forest area, 70 percent is in the North Island and 30 percent is in the South Island. The Central North Island wood supply region makes up 30 percent of the entire planted forest estate.
Table 2.1: National exotic forest estate statistics
| Area and standing volume statistics | As at 1 April 20061 |
As at 1 April 2007 |
|---|---|---|
| Forest area | ||
| Net stocked area (ha) | 1 800 000 | 1 790 000 |
| Harvested area awaiting restocking (ha) | 37 100 | 35 600 |
| Total forest area | 1 837 100 | 1 825 600 |
| Growth characteristics | ||
| Standing volume (000 m3) | 418 152 | 434 039 |
| Average standing volume (m3/ha) | 232 | 242 |
| Area-weighted average age (years) | 14.3 | 14.8 |
| Area by species | ||
| Radiata pine (ha) | 1 603 000 | 1 597 000 |
| Douglas-fir (ha) | 113 000 | 113 000 |
| Cypress species (ha) | 7 000 | 8 000 |
| Other softwoods (ha) | 28 000 | 27 000 |
| Eucalyptus species (ha) | 31 000 | 29 000 |
| Other hardwoods (ha) | 18 000 | 16 000 |
| Radiata pine area by tending regime | ||
| Pruned with production thinning (ha) | 219 000 | 218 000 |
| Pruned without production thinning (ha) | 774 000 | 758 000 |
| Unpruned with production thinning (ha) | 39 000 | 37 000 |
| Unpruned without production thinning (ha) | 571 000 | 584 000 |
| Planting statistics | Year ended 31 December 20051 |
Year ended 31 December 2006 |
| New planting | ||
| Total estimated new planting (ha)2 | 6 000 | 2 6003 |
| Restocking (ha) | 31 900 | 34 4003 |
| Harvesting statistics | Year ended 31 March 20061 |
Year ended 31 March 2007 |
| Harvesting | ||
| Area clearfelled – all species (ha) | 38 800 | 43 0003 |
| Area clearfelled – radiata pine (ha) | 34 300 | 38 7003 |
| Volume clearfelled – all species (TRVIB4, 000 m3) | 17 862 | 190753 |
| Volume clearfelled – radiata pine (TRVIB, 000 m3) | 16 671 | 17 9063 |
| Volume production thinned – all species (TRVIB, 000 m3) | 410 | 251 |
| Total volume removed – all species (TRVIB, 000 m3) | 18 272 | 19 326 |
| Average clearfell yield – all species (m3/ha) | 460 | 444 |
| Average clearfell yield – radiata pine (m3/ha) | 486 | 463 |
| Area-weighted average clearfell age for radiata pine (years) | 28.2 | 28.1 |
| Estimated planted forest roundwood removal (000 m3)5 | 18 962 | 20 038 |
Notes
- Source: A National Exotic Forest Description as at 1 April 2006, Ministry of Agriculture and Forestry, 2007.
- The method used to estimate new planting is described on page 6 of this report.
- Estimates from 2007 NEFD survey and Statistics New Zealand 2007 Agricultural Census.
- Total recoverable volume inside bark.
- Source: Annual Log and Roundwood Removal Statistics (Ministry of Agriculture and Forestry, December 2007). This is an indirect estimate that uses conversion factors for each forestry product to estimate the total roundwood input that would be required to produce total forest product outputs. It is included here as a comparison with the direct estimate of the total volume removed from the 2007 NEFD Survey.
Figures 8.1 and 8.2 in this report show the location of New Zealand’s planted forests as identified in the New Zealand Land Cover Database version 2 (NZLCDB2).
Figure 2.1 shows the age structure of the New Zealand planted forest estate. Very little of the forest area is planted in trees older than 32 years, a reflection of the economic rotation age of the dominant species, radiata pine. Radiata pine is typically harvested between 26 and 32 years old. The figure shows that the areas of forest planted from the late 1970s to the mid-1980s are now approaching harvest age. Also, the large areas of forest planted between 1992 and 1998, now 9 to 15 years old, are very apparent. Harvesting of these areas will begin from around 2020.
Figure 2.1: Total estimated planted production forest area by age class, as at 1 April 20071
Note
- The area is shown for each age in single years up to 35 years. After this, five-year age classes are shown.
Species and silviculture
As seen in Figure 2.2, radiata pine is the dominant species, making up 89 percent of the planted forest area. Douglas-fir is the next most common species, making up 6 percent. The remainder of the area is planted in cypress species, eucalyptus species, other softwood species and other hardwood species.
Figure 2.2: Species distribution – 2007
Figure 2.3 indicates that about 61 percent (976 000 hectares) of the radiata pine planted forest estate is, or is expected to be, pruned to a height of at least four metres. Approximately 12 percent (121 000 hectares) of pruned radiata pine is older than 25 years, while 18 percent (175 000 hectares) of pruned radiata pine is between 21 and 25 years old. About 70 percent (680 000 hectares) of the pruned radiata pine is 20 years old or under.
Figure 2.3: Radiata pine by tending regime – 2007
The area of production thinned forest has declined over the last decade. Approximately 16 percent of the radiata pine planted forest currently is, or is expected to be, production thinned. In 1995, 28 percent of the radiata pine forests was, or was intended to be, production thinned. Production thinning of the radiata resource has decreased in the Central North Island region from 50 percent in 1995 to 22 percent in 2007.
Information collected in the 2007 survey indicates that 60 percent of the forest resource is first-rotation forest, 34 percent is second or subsequent rotation, while information is incomplete for 6 percent of the estate. Of the identified first-rotation forest, 56 percent is aged 15 years or under.
Planting
An estimated 2600 hectares of new forest were established in 2006. It is provisionally estimated that 2000 hectares of new forest were established during 2007.
Figure 2.4 shows new forest planting levels since 1920. The average new planting rate over the last 30 years has been 40 000 hectares per year. In the period 1992 to 1998 new planting rates were high – averaging 69 000 hectares per year. Since 1998, new planting has declined. At 2000 hectares in 2007, new planting is at its lowest level since 1950.
Figure 2.4: New forest planting – 2007
It is estimated that between 1990 and 2007, about 682 000 hectares of new forest were established. New entrants to forestry have carried out much of this post-1990 new planting. While these new owners have planted a significant area of forest during the 1990s, 69 percent (1.24 million hectares) of the entire forest resource is owned by growers with more than 1000 hectares of forest.
Deforestation
The relatively new trend of not replanting forest after harvesting, and in a number of cases converting immature forest to pasture, started on a larger scale in 2004. New Zealand has always had a relatively dynamic landscape so changes in land use are not unusual. However, historically little conversion of planted production forest land has occurred. The 2007 survey indicates that approximately 13 600 hectares of forest were converted to another land use in the year ended 31 March 2007.
Harvesting
An estimated 19.3 million cubic metres of roundwood were harvested from New Zealand’s planted production forests in the year ended 31 March 2007. An estimated 19.0 million cubic metres came from clearfelling 43 000 hectares of planted forest, and 0.3 million cubic metres from production thinning.
The clearfelled area (43 000 hectares) includes the area of deforested land where the logs from the area deforested were utilised for wood fibre.
Of the radiata pine harvest, approximately 13 percent of the volume was sold as pruned logs, 67 percent as unpruned logs and 20 percent as pulp and chip logs. About 34 400 hectares of previously clearfelled planted forest were replanted in year ended December 2006.
Figure 2.5: Radiata pine harvest volume by log grade, year ended 31 March 2007
Source
Estimates from 2007 NEFD survey only.
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