WATER S.O.S TASMANIA - Climate
HOME
Forests
Bio-mass
Catchment Stability
Sediment & Nutrient Loss
Climate
Plantation Effect
Chemicals
Fire
Carbon
Science of Forestry
Stability / Instability
Social Impact
M.I.S. Assault
Tourism
Other Links
Community Links
Climate Tasmania
The micro and macro climate around the world is being altered as deforestation for agriculture and forestry destroy or change the nature and structure of forests and water catchments forever.
Australian National University
carbon storage going up in smoke is much more than previously thought
THE MELBOURNE AGE 4/8/08 | SYDNEY MORNING HERALD 5/8/08
Climate Tasmania
Multiple canopies of the different species within native forests form complex layers of leaves which have a very large combined surface area and are integral to a number of functions within those old forests. These complex layers help to filter the suns ray’s which in turn helps to keep the under story moist while at the same time retaining the warmth of the day. Leaves of the over story eucalypts largely hang downwards, so any moisture runs off more easily than the under story leaves which are more splayed out or horizontal. With their greater surface area and the associated surface tension, moisture retention within those forests is maximized. Around day-break when the right conditions exist and the atmosphere above old forests is at it’s coolest, moist tree top clouds (which is not fog) often form as the moisture in these forests together with rising warm air condenses creating the wet drizzly conditions which form the classic water cycle of wet forests. The effects of vertical and horizontal turbulence within and over the uneven canopies of old forests, are important factors in distributing pollens and spores into the atmosphere above those forests, which in turn provide the nuclei for rain drops.

These phenomenon do not occur where mono-culture re-growth or plantations have replaced complex undisturbed native forests.
Old Growth / Regrowth Forest Tasmania
The phenomenon also has become less frequent or non existent as ever shrinking and more isolated areas of old forest are subjected to drying out as the edge effects caused by extensive de-forestation has substantially altered the structure of the vegetation and overall landscape. The remaining undisturbed native forest is not extensive enough to support a reliable and relatively stable water cycles and micro-climate. Changing the nature and structure of forests impacts dramatically on the micro-climate. The effects of land clearing on the climate has been vividly outlined by research carried out in Western Australia  in the early 90’s.
“Contrasting land use practices on either side of the Rabbit Fence are clearly visible from space”.

“Local suspicions of rainfall changes are supported by measurements of albedos and atmospheric convection and lifting condensation levels. Regional rainfall changes observed over half a century correlate with land clearance activities”.

Map of S.W. Western Australia, showing the “Rabbit Fence” and climate data.
Cloud Formation
This picture clearly illustrates the difference in atmospheric moisture between the cleared farmland and native vegetation.
Ref: Peter Schwerdtfeger Emeritus Professor of Meteorology, Flinders University S.A., RABBITS AND CLIMATE
Ref: Plantation Effect.