Trees and climate change – it’s complicated

The scenario of planting trees to halt global warming is a popular one that some researchers warn is a little specious.

Put simply, global warming is due to the sun’s energy being trapped in our atmosphere by so-called greenhouse gasses such as carbon dioxide. Our petrol driven cars and aeroplanes and coal-fired power stations etc, are the prime cause of increased carbon dioxide in the atmosphere.

(Other greenhouse gasses include methane, nitrous oxide and even water vapour. Pound for pound, methane is the worst – best? - gas in the atmosphere for trapping the sun’s energy and warming the planet. Methane is produced in the production of natural gas, coal mining, decomposition of rubbish, even cows produce a measurable amount of atmospheric methane.)

Trees, (all vegetation in fact), absorb carbon dioxide from the air and store the carbon in their trunks, branches, leaves and roots and give off life-sustaining oxygen.

Part of a Greening Australia re-vegetation project in East Gippsland

So, it would seem that it is a ‘no brainer’ – plant more trees and save the planet.

However, when trees die, (all vegetation in fact), their stored carbon is returned to the atmosphere. Also. their carbon is released to the atmosphere when they burn.

When forests burn the carbon in the trees is returned to the atmosphere

The carbon in rotting vegetation returns to the environment.

Added to this, recent calculations estimate that if we continue to produce carbon dioxide at today’s rate, the number of trees needed to just barely hold steady the rise in global temperature would be many millions. These millions of trees would require billions of hectares of land and not all of the currently available land is suitable for growing trees. It is estimated that about 10% of the world’s most productive agricultural land would be required as well, reducing the calories available to the global food system by as much as 40% - not a good outcome for the nearly 8 billion humans on the planet!

Should arable agricultural land be sacrificed for planting trees?

China’s Green Great Wall is a tree planting project that has planted more trees than the rest of the world combined. It has been blamed for absorbing precious ground water reserves in arid regions and for creating worse smog conditions in Beijing!

Yefu Mountain National Forest Park in Lujiang county, Anhui province. (Photo – theasian.asia)

The unmistakable conclusion is that we cannot halt global warming without reducing emissions and we cannot plant our way out of climate change.

 

National Tree Day Sunday July 28th Come and meet the ‘friends’ at Clifford Dr, Drouin, 10 – 12noon All of Australia’s capital cities and many regional centres are conducting urban tree planting projects to provide a multitude of benefits to the environment, the economy and the community.

Is it a crim or an eastern?

Crimson Rosellas and Eastern Rosellas are two of Australia’s most common and colourful parrots. 

Crimson Rosella - note full crimson belly and rump, blue cheeks, etc.

Ever since first settlement, both these birds have been recognised for their beauty. 

Eastern Rosella - white cheeks, yellow belly, black and yellow back, etc.

There are two theories on the derivation of ‘rosella’.

The artist John Gould, (who named the Gouldian Finch, Erythrura gouldiae, after his wife, hence the feminine gouldiae rather than gouldii but pronounced the same), is believed to have used the name Rose Hill Parakeet after early settlers using that term for Eastern Rosellas often seen in the Rose Hill area. Rose Hill Parakeet was thought to be shortened to ‘Rose-Hiller’ and eventually ‘Rosella’.

Gouldian Finch or sometimes Lady Gouldian Finch (Image - Wikipedia)

Another story is that in 1830, John Gilbert named the birds ‘Rosetta Parrots’, (in a list of wildlife commonly shot!), and a slip of the pen resulted in ‘Rosella’.

Who knows? Doesn’t matter, both the Eastern and Crimson Rosella that inhabit our parks and gardens in Drouin are welcome visitors simply for their attractive plumage.

Next time you see an ‘eastern’ or a ‘crim’, take a good look, you may notice something a bit different about the odd individual bird.

Eastern Rosellas belong to the ‘white-cheeked’ branch of the ‘rosella’ family and Crimson Rosellas are ‘blue-cheeked’ birds. (I don’t want to confuse matters too much further, but there are also Yellow Rosellas, Northern Rosellas, Green Rosellas, Pale-headed Rosellas and Western Rosellas but not around here). 

Yellow Rosella, South Australia - note blue cheeks.

Anyway, every now and then a bird will come along that looks very like an Eastern Rosella but has blue cheeks, (and is more extensively crimson than red, less yellow on the back, etc).

Crim or eastern? Blue(ish) cheeks, etc. (Drouin backyard)

Crimson and easterns will sometimes hybridize. Also, it is suspected that colour variation in some Crimson Rosellas is due to a virus.

Eastern and 'Crim-eastern' beside one another.

I know, I am a sad individual!

Why is tree canopy important?

National Tree Day
Sunday 28th July 10am - 12noon Clifford Dr Drouin (External link)
Come and meet the 'friends' and plant a tree.

All of Australia’s capital cities and many regional centres are conducting urban tree planting projects to provide a multitude of benefits to the environment, the economy and the community.

Urban tree cover can:-

·      Remove pollutants from the air, soil and water.

·      Reduce the urban heat island effect. (Internal link)

·      Save energy and reduce greenhouse gas emissions

·      Mitigate the effects of run-off.

·      Sequester carbon. (Internal link)

·      Increase property values.

·      Encourage physical activity through recreation.

·      Provide habitat for wildlife

·      Conceal unattractive areas and soften buildings and developments.

Research around the world suggests that urban tree cover can reduce crime rates, reduce stress levels, improve academic performance and lower infrastructure maintenance costs.

The ACT is the best urban area in Australia for tree cover – about 56%. Melbourne’s tree cover varies greatly between the local government areas but averages out at about 14%. Many other world cities have greater tree cover than ours – Singapore with a population about the same size as Melbourne (5+ million), has a tree canopy coverage of nearly 30%.

Without the aid of 3D laser scanning equipment or orthophotographic techniques, and rather crudely but simply by drawing polygons on Google Earth Pro, Drouin has a tree canopy cover of about 10%.

The unprecedented development that Drouin is currently experiencing would almost certainly mean we are losing our tree canopy.

We should be modifying development to suit the environment rather than modifying the environment to suit development!

Drouin Significant Tree Register

Now available online from the Baw Baw Shire website. (External link).

Click on a tree on the map and the citation details will appear.