I imagine that a certain 19th century Irish hydrographer would be a little surprised to have his name regularly invoked by a couple of 21st century Tasmanian land lubbers. Francis Beaufort, later Rear Admiral Sir Francis Beaufort, of the Royal Navy, was the inventor of the Beaufort scale. This empirical measure related wind speed to observed conditions at sea and, later, on land.
Its full name is the Beaufort wind force scale, and I first came across it as a climatology student in the 1970s. What was, and is, useful about the Beaufort scale is that it has standardised the observable effects of wind on both sea and land. So, for instance, a force 8 gale on land, measuring up to 74km/h, will see twigs break off trees, and will impede the progress of a pedestrian.
On our daily walks through The Patch, we aforementioned land lubbers occasionally meet such conditions. “A bit of a Beaufort day,” we might call, as we lean hard into the Roaring Forties winds that leave a trail of torn foliage along our track. Sometimes, and particularly around the spring equinox, or during summer cold fronts, The Patch will experience force 9 or 10 gales, with winds in excess of 100km/h. According to the scale, such winds will lead to the uprooting of trees, and considerable structural damage to buildings.
Beaufort’s comfort was that such gales were “seldom experienced inland”. He clearly didn’t live in 21st century Tasmania. We experience that kind of wind a couple of times a year, though we should add that even if Beaufort had lived here, wind patterns have altered markedly since his day. According to the Bureau of Meteorology, average wind speeds in Hobart have increased from 11.3 km/h at the start of the 20th century, to 16.8 km/h in the early years of the 21st century. That’s an approximate 5 per cent increase per decade for a century. It’s been accompanied by an increased occurrence of what the Bureau of Meteorology calls “severe wind events” (Force 9 and above).
This is global climate change as it’s experienced in one local place. As if to underline this, in one severe wind event three years ago, neighbours had their entire roof relocated more than 50 metres away. Eventually the whole house was pulled down, and replaced by multiple new dwellings. The old proverb “it’s an ill wind that blows nobody any good” holds true at least for those who will get new homes out of that storm.
The same paradox works for some of the creatures that call The Patch home. We venture out to observe the results of one particularly fierce gale. After the scouring exhale of the storm comes a softer inhale, the air now still, swept clean. On the ground it’s a different story. Broken limbs, twisted tree trunks, tattered and torn foliage, speak only of destruction. But as we watch and listen to the birds, another story begins to emerge. Most have had a hard night, with nests blown out of trees, nestlings scattered, even wings torn by the ferocity of the gale. Yet many are noisily active, especially the scavenging ravens and currawongs. They loudly tell each other the night’s story, as well as tales of food and opportunity.
Those avian hoons, the sulphur-crested cockatoos, scratch the air with their unmelodious squawks as they wheel intently around the carnage. Being hollow-nesters, they are always on the lookout for new nest sites. They will line these hollows with debris, which is now plentiful. What to us looks like a broken tree, could to these creatures be a new home, as long as they can out-scavenge other hollow-nesters such as brushtail possums, owls and parrots.
For many other creatures, the mess itself is a windfall. Jack jumper ants (Myrmecia pilosula) gather leaves, twigs and other plant fragments to use in disguising their nests. These notoriously aggressive ants have a very painful sting, rating up to 3 out of a maximum 4 on the Starr Sting Pain Scale (yes, there’s a scale for that too). Despite their sergeant-major belligerence, jack jumpers have a sweet tooth, living on nectar and similar plant sugars rather than eating other invertebrates. But any sweetness ends there, as they will strongly compete with any other species in their patch. With the social huntsman spider (Delena cancerides), for instance, they will take over their nests by filling them with leaf litter and other debris, which renders them unusable by the spiders.
Huntsman spiders might also be made homeless when the bark under which they nest is torn off by strong winds. Under those circumstances it’s understandable, if not entirely welcome, that they seek out other hidey-holes, such as beneath car sun visors and behind curtains. We exercise firm sympathy when a huntsman tries to share our space, catching and relocating them using a large see-through container and an oversized piece of cardboard.
On the way back from our post-gale walk, we find the neighbour’s children taking full advantage of the ill wind. Against the trunk of a large stringybark, they’re constructing a rough lean-to. They’ve gathered broken branches and long strips of wind-torn bark to use as building materials. No doubt a Beaufort day will redistribute the cubby over a year or two. But not before some childhood memories have been made.
Peter Grant lives in the foothills of kunanyi with his wife. He worked with the Tasmania Parks and Wildlife Service for 24 years as manager of interpretation and education. His passion for the natural world led him to write Habitat Garden (ABC Books) and found the Wildcare Tasmania Nature Writing Prize. More of his writing can be seen at naturescribe.com.
