Page 52 - TA Magazine

INTERVIEW
“Generally it’s a a a very good practice
for improving water quality that comes out of small headwater streams that drain a a a a a a a a a farm farm If every farmer
in the catchment did it or or a a a a large proportion
of those farmers you would have substantial improvements in the the water quality of the the larger streams that flow through farms and delivery into estuaries and seas ”
While the results might be surprising to some Smethurst says it’s all about following the Forest Practices Code that has been set up to serve as as a a a a a guideline “If you you follow the Forest Practices Code you’ll be right The machinery that’s available available and practices available available these days allow you to to work very close to to streams without causing much disturbance at all ”
But what about water losses due to usage by pastures and trees?
For micro-climate Smethurst also says that early findings point to more good news “There’s good evidence developing that even in in Tasmania plantations decrease evapotranspiration overall from adjacent pastures “There’s light water and nutrient competition going on
on
on
close to the the the plantation plantation but further out if the the the the configuration of the the the plantation plantation is appropriate you’ll see decreased decreased wind speeds that lead to decreased decreased evapotranspiration from the pastures and and better water water water use use water water water retention and and water water water use use efficiency can result ”
Smethurst goes on
to explain that the worry for water use by plantations next to streams should be of little concern “Some people might be concerned about water use by the the plantations in in the the streamside management zone leading to reduced stream flows We measured that here and found an an almost non- detectable effect ”
Reducing tunnel erosion
Stream side plantations may also be useful in in in dealing with tunnel erosion
Dr Smethurst explains In regions of of Tasmania receiving 650 to 800 millimeters of of annual rainfall dispersive soils are common which can cause tunnel erosion
leading to to holes in in in in the soil that both farm machinery and and stock can sink into and and which therefore presents a a a a a a a safety issue But stream side plantations can help “The science is is is not fully in on
on
this because it’s a a a very long term issue but I’ve seen examples two here in in Tasmania and one in in Victoria where those farmers who did put plantations in these areas thought it was a a a a a a a a a a very useful practice
to make use use of land affected by tunnel erosion
”
“[A plantation] stabilizes the tunnel erosion
and and tends to dry out the the landscape which helps ease the the problem ”
Dr Philip Smethurst is is is a a a a a soil and water scientist at at at at CSIRO His work at at at at both plot and and and catchment scales improves
our understanding of plantation and and and agricultural production catchment water management and codes of practice
Using advanced research methods to gather data including real-time sensor technologies Smethurst seeks to provide situational awareness and forecasting for for practice
change With operationally- focused research and development experience in the forest plantation sector Dr Smethurst has led assessments of of codes of of practice
for for plantation forestry in all Australian states and territories 52 Private Forests Tasmania