Tiny mite may boost plantation profits
	Tiny mite: indicator of forest health
By Julian Lee Some insects may help in efforts to speed timber-growing on plantations using sewage fertilisers, an ANU biologist believes. "Sewage added to trial plantation sites produces timber in a fraction of the time. Pine, for example, can be grown from seedlings in five years instead of 15 to 20 years," Geir Fokstuen, a Master's student at the Department of Forestry, said. "This arrangement is extremely beneficial as it produces timber while lowering water tables, reducing greenhouse gases, erosion and waterway pollution," he said. Mr Fokstuen has found that one species of Histiostoma mite, previously found in effluent ponds, is now living in plantation sites treated with sewage. He believes the mites could be used as a living indicator of the conditions in the plantation, assisting forest managers to make sustainable and profitable decisions. The mites live on fungus growing on rotting plant matter such as fallen leaves and branches. Depending on the soil conditions, different fungi grow, determining the species of mites which live there, he said. The presence of different species of mites indicates the relative amounts of nutrients and minerals in the soil and the health of the trees. Mr Fokstuen's study will identify different species of mites and their particular living conditions - which could then be used as a rapid and simple indicator of the conditions in an area. "Forest managers would be able to intervene before the trees show visible signs of stress, by which time there could already be economic loss in productivity or sustainability," he said. Mites could also play an important role in "reading" the soil prior to establishing a plantation. The different types of mites present would indicate the most appropriate seedlings to be planted. Mr Fokstuen believes that it would be possible to use mites to prepare and improve soils before tree plantings, in much the same way that farmers improve pasture with clover and bacteria. As the study discovers further species, the potential for creating a diagnostic chart or introducing suitable preparatory species increases. Mr Fokstuen has already identified a new species of Oribatid mite which plays an important role in breaking up decaying materials into smaller particles. Managing tree resources is a complicated task and Mr Fokstuen believes researchers have been ignoring a crucial aspect - the soil. "It's time to look at what happens below ground," he said.