A study of wood wastes: Utilisation of bark on horticulture and its possible uses as a growing media for containerised plants : A thesis submitted as the requirement for the National Diploma of Horticulture

Abstract

As suitable soil becomes scarcer nurserymen have turned to soil-less composts for raising their container grown plants. Many are using variations of the University of California composts. Problems of transport and costs are making peat expensive. Much of the peat used in New Zealand comes from Ireland, as this is considered of better quality than the local peats and there is little difference in cost. Both Hauraki peat and Irish cost $25 per m3 . One alternative to peat is bark, which is a waste product from the pulp mills with no economic use at present. Work that has been carried out overseas seems to indicate that bark is a suitable alternative. This Thesis is the result of investigations into the possibilities of using bark from New Zealand pulp mills. The Thesis is divided into three sections as follows:- a) A review of overseas work. (b) Result of Hawkes Bay trials. (c) Review of future prospects and future trials needed. The demand for timber has increased dramatically over the last few years and with newer methods of bonding particles together more timber, which would have been uneconomic a decade ago, is now being utilized. The only part that has little use is the bark. It is possible to bond bark but the end product is of poor quality. Therefore most bark is dumped and this then is a potential source of pollution and unless the dump is well sited, a scar on the environment. How much bark horticulture would be able to use remains to be seen. Transport costs would probably limit its use to areas near pulp mills and demand would be for only a small amount of annual production.