In response to data on monocultures: There are monoculture plantations in Tasmania (Australia). In particular I have visited those in Meander. Many are of Eucalyptus Niten a fast growing species, a smaller fraction are of the Tasmanian Blue Gum. The operators are the Tasmanian Forestry Commission and North Forest Products (parent: North Broken Hill, parent: North Broken Hill Peko Ltd). I have seen the plantations around Meander. Some are growing well and some appear retarded. One plantation on fairly level ground did not grow well and after about 15 years was bulldozed this year to make way for an orchard or tree farm. I believe they were Nitens. Before bull-dozing the leaves were all brown and hard, the trees were from about 8 to 12 feet high. A few months before dozing, helicopters were over the plantation. They may have been spraying atrazine, a triazine herbicide often used by the Commission. (The planation across the road did not look dead.) They usually use it to control competition from native plant species and from introduced weeds (which grow around the plantations in Meander). Atrazine can contaminate ground water and remain intercalated in clay soils therefore it is a negative aspect of the plantations. The Nitens can mill well (for saw logs) after about 120 years but are mainly for wood chips. Blue gums are allround useful. One postive aspect of the plantations is that they are usually in neat rows so that walkers don't get lost. The eveness of plantations must also be a benefit during harvesting. The ellimination of undergrowth even when the trees are 25 feet high means that the area is virtually lost habitat for the animal species and numbers of them that previously lived there. The previous forest in Menader was mainly temperate rainforest. The rainfall in the area is high for Tasmania. The hot burning before planting means a substantial loss of natural organic nutrients and possible loss of organisms which produce near surface nutrients. However the potash could help the growth of woody tissue except that the residues are not evenly distributed. A negative aspect of planations is the deletion of animals from the area. This sometimes has an impact on the long term numbers of species. Plantations have not grown tall enough for nests for the Tasmanian wedge-tailed eagle which requires about 200-300 year old eucalypts. A more convoluted negative aspect of plantations is that products from forests grown without forest workers input may actually be incorrectly said to be from plantations (examples avialable on request), this can cause increase in deforestation and subsequent harm to native life. Hope this is of some use to the inquirer. Chris. (cdean1@cs.amc.edu.au)
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