Did it get hot where you were?

One feels for the residents of Walpeup and Hopetoun where the temperature almost reached 50°C on Tuesday 27^th January. All the science tells us that these events are increasing in severity and frequency.

The science also tells us what we can do about – so why aren’t we?

Cities and towns heat up faster because of their concrete, bitumen, and dark roofs. So much research has been done on this it even has its own name – the urban heat island effect.

The rapid urban sprawl we are have in West Gippsland is amplifying the urban heat we are experiencing. From the Baw Baw Shire forecast idcommunity demographicresources page - “The Baw Baw Shire population forecast for 2026 is 65,168, and is forecast to grow to 93,737 by 2046.” – so it ain’t going to get better very quickly.

The BBSC website climate change page makes interesting, if brief, reading.

Canopy is cool!

Our developments need more shade, starting with wider nature strips and bigger back yards that can take trees with a canopy. Planning could include the provision of urban shade forests or tiny forests accessible to the population. Green roofs (living plants) and green walls (vertical gardens) provide insulation, lower the ambient temperature and reduce runoff. Urban gardens and nature strips can be designed with water retention infrastructure – permeable footpaths, rain gardens, runoff swales, etc.

Time to get real about this stuff!

 

Bad hair day

Bad hair day

We’ve all had one. I recently came across this Eastern Yellow Robin whose bad hair day didn’t seem to trouble him too much as he continued to dive onto unsuspecting prey in the leaf litter around his tree.

Recently fledged Eastern Yellow Robin

As their feathers grow old, birds will undergo periodic shedding of the dead feathers and replace with new (pin) feathers. The process can be energy-draining for some birds, sometimes rendering them flightless for a short period.

Almost there

Nestlings and fledglings also undergo a moult as they rapidly grow. Often their plumage changes dramatically as the go from fluffy, insulating or camouflaged appearance to the final adult bird.

Finally not a hair out of place

Trees and wind

The effects of strong winds on trees is a much-researched topic. International conferences have been conducted on the issue.

Trees bend and sway in strong winds to dissipate energy and help them withstand the onslaught without failing. Young trees that are exposed to persistent one-direction winds develop stronger root systems to resist wind loads.

The Bureau of Meteorology states, “The predominant wind stream over Victoria is of general westerly origin, although it may arrive over the State from the northwest or from the southwest. There are wide variations from this general description, however, and many northerlies or southerlies are experienced. Furthermore, the hot northerlies which bring heatwave conditions from the interior are well known, whilst in winter and spring exceptionally cold weather may accompany a southerly wind stream.”

The recent strong easterly wind Gippsland experienced was caused by the combination of a low-pressure system off the southern NSW coast and a slow-moving high-pressure system south of Tasmania. Winds travel clockwise around lows and anticlockwise around highs.

As a result of the developing pressure system, the BoM published forecasts of strong easterly winds for much of Victoria for several days in a row.

Some easterly gusts were quite strong and placed trees in this district under conditions they are not acclimatised to.

Street trees or stand-alone trees, without the protection of other nearby trees, are more exposed to wind loads. Urban trees will often have root zones that are restricted by building foundations, roads and footpaths, etc. Urban trees will often be exposed to environmental stresses that cause them to exhibit ‘old age’ characteristics years before their wild-growing relatives. Urban and stand-alone trees may not have the support of a root system entwined with other nearby trees.

Urban and stand-alone trees are often more susceptible to failure by windthrow. Trees compromised by decay or previous damage are at higher risk of wind damage.

Climate change is intensifying the strength and frequency of strong wind events by increasing atmospheric heat and moisture, leading to more violent thunderstorms, faster-intensifying cyclones, and stronger gusts.