Wednesday, 31 October 2007

Forest And Field

Following on from my recent post about building forests, I had the scientific department out doing some research ( :-P ) and they came up with the following:

From the ABC's News In Science: Native trees key to cooling climate

Some excerpts below:

Extensive clearing of native trees is making Australian droughts hotter and is an under-recognised factor in climate change, research shows.
And, my favourite:

He says native vegetation plays an important role in moderating climate because it is deep rooted, which leads to more moisture evaporating into the atmosphere over a longer period.

This is then recycled into the environment as rainfall.

Native vegetation also reflects less short-wave solar radiation into the atmosphere than crops, which keeps the surface temperature cooler and helps in cloud formation.

I agree with the general aim of the proposed measures of course, but I feel it hasn't been taken to it's logical conclusion, possibly due to political and social factors. I think we can do better, at least in some areas.

Drawing on the previous post, many natives actively resist evaporating moisture into the air as part of their evolved survival mechanism. Rather than planting these natives, put in other trees that are deep rooted, and evaporate more moisture than their Australian cousins, whether this be rainforest plants or non-indigenous plants from other areas of the world. Rather than returning to the sunburnt country, go the next step and move to a moister country all round.

Put in trees that build up humus that works to improve moisture retention and infiltration. Plant trees that face their leaves to the sun and thus cool the earth beneath them more, rather than Eucalypts that hang their leaves down in an attempt to avoid catching (and therefore collecting and/or reflecting) the sun.

I think the idea of open pastures, orchards and vineyards is perhaps a bit of a throwback to the European origins of our practices. The lower light and heat levels there required that the plants have more access to sunlight. Here at the top of the earth (if you're holding the globe up the right way!) we get more intense sunlight, so a little bit of shading comes in handy. Take a browse through some of the Aussie gardening blogs and see how many put up shade covers in summer so the plants in their vege gardens can survive.

It's obviously a trade-off, as the start and end of the growing season would be adversely affected to a degree, but I think there is room to fit trees into our grazing land with benefit to the entire system. If soils are improved, and cooler, and more moisture is retained, then growth during the peak of summer should make up for that lost at either end of the season. Cooler grazing animals should also require less water (and moister feed should also assist with that) and be happier if they aren't standing in the sun all day, or fighting one another to occupy the one tiny bit of shade in a big paddock. Lamb chops may also be tastier if they aren't coming in from the paddock already sun-dried.

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