New results on water quality in pines
From the Spring 2006 edition of Bush Telegraph Magazine.
Forests NSW latest forest hydrology research has shown that significant groundcover remains in pine plantations after harvesting, limiting the impacts on water quality in downstream catchments.
A study carried out by Forests NSW research scientist, Dr Ashley Webb, and forest assistant, Brad Jarrett, in two catchments in Canobolas State Forest, near Orange, found site disturbance from logging equipment and trucks makes little difference to groundcover, as ‘slash’ (tree branches
and leaves left over from logging) remained on-site.
“We found there was little reduction in groundcover after harvesting and this was reflected positively in the results of our water quality monitoring,” Ashley said.
“Cover provided by post harvest slash left on the ground is high in comparison to the extent of soil disturbance.
“We also found that there was likely to be an increase in groundcover from continuing growth of vegetation on exposed soil.”
Vegetation acts as a filter for water entering into creeks and streams. Ashley said the study’s outcome meant that the water quality of streams in the area was only slightly affected by the harvest, and soon returned to pre-harvest conditions.
The study examined the harvest area for soil disturbance in the general harvest area, on forwarder tracks, roads, log landings, cable logging furrows and other areas such as creek beds and road batters.
The study found that the least groundcover was on roads, but as these comprised only a minor area and were largely armoured with gravel, there was little impact from them on water turbidity.
“Forests NSW road building incorporates the latest techniques in protecting waterways, so their impact was minimal,” Ashley said.
Public Affairs & Media, Coffs Harbour
