|Forest codes of practice. Contributing to environmentally sound forest operations. (FAO Forestry Paper - 133) (1996)|
|New Zealand forestry and the forest code of practice|
In about the year 800, when the first Maori people arrived from Polynesia, forest covered over 75% of New Zealand. The Maori people burned some of this forest, not only to create living space, but also as a hunting technique. When the European colonists starting arriving in considerable numbers not long after the turn of the 19th century, vast areas of native forest were converted into pasture.
Pastoral agriculture has been, and continues to be, New Zealands dominant land use. In 1994, the countries 27 million hectares is predominantly in pasture and arable land (52%) and native forest (23%), 5% is under exotic forest and the remaining 20% under mountains, water bodies, cropland and urban areas. A summary of the history of land-use change in New Zealand is illustrated in Figure 1.
State-organised planting of production (exotic) forests began in the late 1920s (depression years), particularly on volcanic plateaux where pastoral farming was marginal. The Kaingaroa Forest between Rotorua and Taupo is a good example of the extensive planting of this time; over 100,000 hectares of continuous exotic plantation forest.
A number of factors have combined over the last thirty years to encourage further planting, including: the need to stabilise eroding farmland; an increase in log prices; and improved harvesting techniques and efficiencies. In 1994, an additional 100,000 hectares were planted (in addition to restocking), most of it on relatively steep farmland.
Although in the early years many different tree species were planted, experimentation showed that Pinus radiata (also known as Monterey Pine, originally from California) excelled in the New Zealand conditions. With continual genetic improvement, Pinus radiata continues to out-produce any other species by far, accounting for 90% of our 1.4 million hectares in exotic trees (other main species include 5% Douglas-fir and almost 2% Eucalypts). With an average growth rate of 24 m3/ha/yr, a single tree will grow to 35 metres in 30 years, yielding 2.4 m3 of timber. Nearly all of our pine forests are clearcut harvest at age 30 (Douglas-fir at age 50). The current annual harvested volume is 16 million m3/yr a.
a All data are from Forestry Facts & Figures, 1994, published by the New Zealand Forest Owners Association and the Ministry of Forestry.
It is important to note that close to 99% of the volume of timber harvested in New Zealand comes from these exotic plantations. An encouraging trend for the environmentalists is that more of our remaining native forests are permanently being protected through park and reserve status, and the remainder through legislation, cannot be regulated as an industry: what goes for forestry must apply to all land-users.
The more traditional, and still the most common way of harvesting is using ground based machinery. A typical ground-based operations might consist of a gang of eight people, operating a skidder or a tractor and a loader/fleeter, being able to harvest on average about 260 tonnes per day. The total extraction cost for such an operation is usually between NZ$10 to $12 (about US$8).
Expansion onto steeper land in recent decades has meant that 35% of all harvesting is now carried out using cable systems. An average cable harvesting gang of 10 people, with a hauler, processor and loader/fleeter, can harvest about 200 tonnes per day (extraction cost NZ$18 to $20).