On forest culture
Gary Blake, New Zealand Tree Grower August 2009
J C Firth was a prominent Auckland and Matamata business man who, in 1874, presented a paper to the Auckland Institute on the state of New Zealand forestry. It provides an excellent reference point for assessing the situation in 2009. The first part ‘Forest Conservation’ concerns native forests, the second part ‘Forest Creation and Culture’ concerns Firth’s awareness of the declining native resource and the need to look at exotics.
What trees ought we plant? Native trees or deciduous trees and evergreen trees not native to New Zealand? Native trees have not been planted extensively, and have not succeeded well. Firth agreed that natives could be grown given shade and respect for the tap root system. He noted that at least 100 years was needed for a saw log with a diameter of two feet, and he thought the kauri supply would dry up by about 1900. He was very concerned about future timber supplies and said current trees being felled were at least 200 years old.
Firth was most knowledgeable about the Auckland area and felt it was too humid and soils to acid for deciduous trees like oak, elm, sycamore, ash, and beech. They would do better south of the 38th parallel. The fern covered northern plain soils required sweetening before deciduous trees could be attempted. North of Lake Taupo, Firth saw the potential for a vast totara forest. He considered that ‘belts of Coniferae must be planted as ‘nurses’ to shelter the plantations of native and deciduous trees.’ He saw the shelter trees as resting places for seed carrying birds and the importance of corridors.
‘If judicious and well-sustained efforts are made to create forests of our most valuable native trees, it is not unreasonable to hope that we shall be able to transmit to our descendents the wealth of timber suitable for every industrial and economic purpose which our native trees possess.’
However with regard to trees to be planted for use in the immediate future, he favoured eucalypts and conifers. A future coal mining industry would need this timber and of the 150 species of eucalypts few grew well, Eucalyptus globulus was the best.
Unlike the deciduous species conifers established well in the soils. He germinated Pinus insignis, P. radiata and P. maritima and planted them in scarified rows. Six men planted two acres a day. Three years later only five per cent had failed and P. insignis reached three metres in height. Firth realised that if the tap root was severed in the nursery the seedlings were easier to transplant but thought it could make the standing tree less stable.
If you want to see the full paper, all 15 pages, look on the Royal Society website at http://rsnz.natlib.govt.nz. It is well worth the read.