National Tree Day 2013

The Seedy Lot group in conjunction with Transition Action Group hosted a National Tree Day activity on Sunday 28 July 2013 at three sites - Hicks Road (Armagh) and Benbournie Road and Lookout Road (Benbournie). These locations are very important.  

At the first site there's a need to introduce blue gum trees to replace those that have died or are under stress nearby, from the effects of mistletoe infestations. 

This is a very serious problem in the Clare Valley area, and the threat of ecosystem collapse is increasing as the years pass by. Unfortunately, there is scant work being done to arrest tree decline in the district. 

Dead & dying blue gum trees

Dead & dying bluegum trees near Hicks Road, Armagh


On death row! Bluegum tree near Hicks Road, Armagh

A small roadside planting with Bluegum trees and native shrubs was carried out near to these dead and dying trees. This is our tiny contribution to … Mistletoe Action … and more will be done in future years. 

Here are four strategies that must be implemented throughout Clare Valley to counter the mistletoe problem.

  • Replace trees that have died from the effects of mistletoe
  • Extend the planting of SA bluegum on a broad scale, both on private land and public land
  • Introduce understorey plants in woodland areas
  • Remove mistletoe from trees that are threatened by too much of the mistletoe growth

The second and third sites were road reserves in cleared and eroded agricultural land. There's a need to provide a semblance of native vegetation cover in the landscape. We would like to see on-farm native vegetation plantings in the future to re-establish biodiversity, vegetation corridors and connections, windbreaks, and landscape repair, so it's hoped that our work may kickstart a long term plan for the area.

Here's an aerial view of the landscape that we went to.

NTD sites 2013

Under-used road reserves in the area will be our primary source of land for revegetation. 

How do you interpret this photograph? Why not do your own search on Google Earth or Nature Maps and see for yourself how the landscape looks from the air.

This type of landscape is exactly what my discussions is all about at Landscape and Biodiversity.

CLICK HERE for some photos of "landscapers" doing their stuff.

Now for the shock and horror story

Look at the aerial photo above. Do you see the erosion scars across the land? They were caused when large rainfall events occurred after native vegetation was cleared from the surface for farming. Once the land was cleared, there was nothing to prevent surface runoff from gathering speed as it ran out of the foothills (on the right in the photo above), accumulating in a small stream that grew ever bigger, and faster. 

The two photographs below show what happened when a small culvert was placed across Lookout Road many years ago. People thought they were doing the right thing, but in fact it was an absence of knowledge and a poor connection with natural forces that resulted in this environmental devastation. 

Let's look at what happened.

Surface runoff entered the pipe (left photo) and became a concentrating force of higher velocity, which then became a highly erosive force as it charged out of the pipe. The concrete slab that was placed over the pipe in the roadway would also have increased the velocity of flows from high rain events. The slab was obviously to allow unimpeded travel of vehicles across the watercourse and to accommodate flows that would not be able to enter the pipe. 

The result - devastating erosion at the downstream end (right photo). 

Cosmetic actions in years past at the discharge end have included concrete work and substantial stone walling - undoubtedly at huge cost. 

The cause of the problem has never been fixed, and it's doubtful that the symptom has either. The gully depth is 6m to 8m. There has been massive soil loss in this landscape.

These erosion scars spread like fingers across the cleared land. They are very common throughout the farming region of the "Mid North" of South Australia.

Should they be rehabilitated? Could they be reverted to native vegetation corridors that provide many benefits in a landscape devoid of native vegetation? 

Should cropping right up to the edge of the banks of these scars continue? 

Have your say. What do you think?

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