Sunday afternoon service at the Church of the Double Bladed Paddle

7 degrees at daybreak and good company the evening before: no chance of making it out for dawn this weekend.  So it was the afternoon service for me in the Church of the Double-Bladed Paddle.  Down the end of our street, the Hawkesbury in the golden hour.

Beautiful cirrus sky and skyline

Golden bubble water crop horizontal

A seaplane was parked out front of the ritzy Berowra Waters Restaurant, a few devotees of fine dining lingering over white linen, but otherwise the river was quiet.  Weekenders emptied of their winter visitors, off home to find socks and check homework.  Some stirrings in the sandy creek bed – stingrays? – but no fishermen and hardly a fish.

Some sun worshippers were receiving the blessing of the last rays on the southern shores of Calabash Bay.

And then, a true glimpse of the sacred.  The sacred kingfisher, that is.  I’d suspected they might be found around here, even in the winter.  There was that green flash out of the corner of my eye as I scrambled over the rocks onto Bar Island, and the briefest of glimpses, framed by mangrove leaves, my camera hopelessly buried, one morning in Bujwa Bay.

But this glorious creature showed no inclination to move from his place in the sun, calmly accepting the adoration of passing paddlers.

Sacred kingfisher facing slightly away horizontal crop tighter square

Sacred kingfisher

But even a sacred kingfisher can be profane.  I’m reverently gazing, barely taking a breath, and the big guy takes the opportunity to have a lightning fast chunder.  There’s a  familiar doggo look on his face as he sits there on his sunlit stick recovering.

But you expect veneration anyway, right, mate?  And you’ll get it too.

Sacred kingfisher other side 2 wide tighter

Last winter in Calabash Bay…

Burn-off at Bujwa Bay

The only trouble with living in paradise (apart from the long commute) is combustibility.  Our gorgeous view – mile after mile of incendiary eucalypts.  So the still, dry days and nights of autumn were thick with smoke, not from the big bad one we’re dreading, but hazard reduction burns in the bush all round the town.

Last time I went down to Bujwa Bay, it was the kind of cool and breathless day that must make the Rural Fire Service very very happy.   Mist hovered over the water in a bright line of morning light.  Forty minutes of silent paddling past the sleeping celebrities of Berowra Waters and I was round Oaky Corner and into the sunshine.

In the quiet there was a cryptic crunching noise.   Eventually, I spotted the pair of glossy black-cockatoos hidden amongst at the shore-line casuarinas.  My sense of being some kind of bird whisperer evaporated when, after fifteen minutes fooling around trying to get a decent shot of the cockies, I looked up to meet the eye of a bloody great big white-bellied sea eagle sitting directly above me.  And then, just round the corner, his pal taking in the rays.  They’re not stupid these birds, parked in the sunniest spot on the bay.

Having bonded with the local bird-life, when I heard about the burn-off, I was worried.   What happens to it all when the bush goes up in smoke?

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Egg the kayak entering Bujwa Bay after the burn-off

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Back-burnt grasstrees at Bujwa Bay

It’s not all bad news.

Harry Rechter describes  birds enjoying a feast during a controlled burn in Brisbane Waters National Park, not so far from here.
“Although fuel loads in the… heath and woodland were high, and flames soared above the tallest trees and shrubs, birds moved easily in front of and above the fire to appear minutes later on the blackened vegetation to feed on less fortunate insects and small lizards”.
I missed the raptors and the insectivores that no doubt turned up at Bujwa Bay at the first sign of smoke, looking for Cajun-style chow. But chances are these blackened grasstrees will be bursting into flower next time I paddle by.  I might see lyrebirds too, raking newly formed clearings.  Ground-feeders and grain-eaters – corellas for instance – return in force after fires have passed.  The little insectivores – thornbills, wrens and robins – that build nests close to the ground don’t miss the scorched canopy, and enjoy the bugs that flourish on the flush of new growth.  The carbonised shrubbery might even give me the chance of catching a blurry LBB or two on film.
Burnt crown and cliff

After the burn-off: partly scorched eucalypts

It’s a nice idea to think that the burn-offs that protect the town are a boon for the local plants and animals too.   And there’s a euphonious catchphrase that goes with that idea: “pyrodiversity begets biodiversity”. Fire incinerates the garden escapes and wakes the soilbank’s astounding store of dormant seeds. If we burn little and often, it’s been thought, we make a mosaic of habitats: patches of open space and newly germinating seeds; places burnt a few years back; and refuges long unburnt, full of craggy trees, hollow logs and dense undergrowth.

Pyrodiversity is popular amongst land management folks, and there’s some evidence that it works, at least in some places.  But not everyone buys the story that the frequent fires that protect people and property suit other critters too. Out in the mallee, near where I grew up, a fire and biodiversity project run by Deakin and LaTrobe universities has been laboriously checking the idea out.

For all the mallee’s underground lignotubers, ready to reshoot after fire, other parts of the ecosystem – large stretches of spinifex grass, for one, that shelter dragons and legless lizards – can take fifty or more years to return after a burn.  All of which makes me feel tremendously guilty about the swiftly abandoned spinifex-covered cubbies that my brother and sister and I used to make in the mallee scrub out the back of our house.  We will never know how many now-extinct species we displaced.

Away from regrets about the trail of ecological devastation I left in childhood and back to burn-off related angst. The research in these arid areas suggests it’s not pyrodiversity that’s important for a species-rich environment but having enough country that’s reached the right stage of maturity since the last fire.  As a person in mid-life, it pleases me to say that older vegetation often seems to sustain more species of birds, mammals and reptiles, including the rare ones. Even birds that like paddocks and open plains prefer unburnt land.  Some reptiles favour recently fired landscapes, but plant communities that haven’t been burnt for a decade or two harbor the richest variety of lizards and snakes.

I tried and failed to find the experts on biodiversity and fire on Hawkesbury sandstone.  But researchers studying both subtropical Queensland and foothill forests in Victoria said similar things.  A varied landscape is important, but

the richness of frugivore, insectivore and canopy forager assemblages is driven by the presence of structurally complex vegetation and old-growth canopy trees, which are more likely to be present in areas that have not experienced fire for a prolonged period of time (Burgess 2016)

Paston and colleagues put their conclusion bluntly: “prescribed fire is of little utility for the broadscale conservation of biodiversity” (2011, 3238).

And it seems, for birds at least, smaller patches of unburnt country won’t really do – it’s larger areas that haven’t seen fire for a while that are rich in species.  One bunch of researchers found that little islands of older habitat surrounded by new growth was grabbed by one or two aggressive predatory or colonial birds, rather than harbouring lots of different critters.  One recent paper, written about arid areas, sum it up:

Our results suggest a shift in current fire management thinking… is needed, away from a focus on creating small, unburnt patches towards preserving large, intact, unburnt areas (Berry 2015 493)

Burnt crown and dark silhouette from distance

What does all this mean for Bujwa Bay?

There was nothing moving in the incinerated trees on the ridgeline as I made my way up the creek at high tide, but then, it was early and damn chilly.  Even the herons had given up on fishing and were huddled in the trees, keeping their feet dry.

But the damp fringes of the mangroves were alive with silvereyes and yellow-faced honeyeaters, and I heard the plunk of a sacred kingfisher diving for breakfast.  Gullies are especially valuable habitats for birds at the best of times.  If they’re protected from fire by burning on the slopes nearby they can be an even better retreat when that big one comes.  The top of the creek was lush and green. I can only guess that the rangers and RFS know what they’re doing.

White faced heron in tree 2 square

Chilly looking white-faced heron

In the light of recent research, Taylor and his colleagues comment dryly “current fire management for avifaunal conservation may require substantial refinement” (Taylor, 2012, 525).

But let’s not fool ourselves.  Around here at least, fire management is not for the avifauna.  It’s for me, and people like me, who choose to live high on a hill, surrounded by the beautiful, burnable bush.

Additional references.  Because the whole thing is really is quite complicated and you might want to check I didn’t get it totally wrong.

Berry, L. Lindenmeyer, D, Driscoll, D. (2015) “Large unburnt areas, not small unburnt patches, are needed to conserve avian diversity in fire-prone landscapes” Journal ofApplied Ecology Vol 52 Issue 2

Burgess, Emma, and Maron, Martine (2016) “Does the response of bird assemblages to fire mosaic properties vary among spatial scales and foraging guilds?” Landscape Ecology March 2016, Volume 31, Issue 3,pp 687–699

Doty, A., Stawski, C, Nowack, J., Bondarenco, A. (2015) “Increased lyrebird presence in a post-fire landscape” Australian Journal of Zoology 63,9–11

Hope Ben (2012) “Short-term response of the long-nosed bandicoot, Perameles nasuta, and the southern brown bandicoot, Isoodon obesulus obesulus, to low-intensity prescribed fire in heathland vegetation” Wildlife Research 39(8) 731-744

Korczynskyj, Luke and Byron B. Lamont (2005) “Grasstree (Xanthorrhoea preissii) recovery after fire in two seasons and habitats” Australian Journal of Botany, 53 509-515

Kelly, Luke T. Andrew F. Bennett, Michael F. Clarke, and Michael A. McCarthy (2015) “Optimal fire histories for biodiversity conservationConservation Biology, Volume 29, No. 2, 473–485

Lindenmayer, David B., Wade Blanchard, Lachlan McBurney, David Blair, Sam C. Banks, Don A. Driscoll, Annabel L. Smith and A. M. Gill (2014) “Complex responses of birds to landscape-level fire extent, fire severity and environmental driversDiversity and Distributions 20, 467–477

Nimmo, D, Kelly, L., Spence-Bailey, L, Watson, S.J. Taylor, R.S., Clarke, M.F and Bennett, A.F. (2012) “Fire Mosaics and Reptile Conservation in a Fire-Prone Region” Conservation Biology 27 (12)

Pastro, Louise L., Christopher R. Dickman and Mike Letnic (2011) “Burning for biodiversity or burning biodiversity? Prescribed burn vs. wildfire impacts on plants, lizards and mammals”  Ecological Applications Vol. 21, No. 8, pp. 3

Robinson, Natasha, Leonard, Steven, Bennett, Andrew, Clarke, Michael (2016) “Are forest gullies refuges for birds when burnt? The value of topographical heterogeneity to avian diversity in a fire-prone landscape” Biological Conservation 200, pp.1-7

Sitters, Holly , Di Stefano, Julian, Christie, Fiona, Swan, Matthew, York, Alan (2016) “Bird functional diversity decreases with time since disturbance” Ecological Applications, 26(1), pp. 115–127

Smith, Annabel, C.Michael Bull, Don Driscoll (2013) “Successional specialization in a reptile community cautions against widespread planned burning and complete fire suppression”Journal of Applied Ecology 2013, 50, 1178–118

A flash of gold and a stash of blue

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Season of mists and mellow tinnies: the Hawkesbury in fall

Autumn lasted for aroundabout a fortnight this year.  The endless summer of an apocalyptic El Nino wrapped up in mid-May, giving the deciduous trees an extremely tight schedule to dispense with their leaves before this weekend’s torrential rain.

We’ve had autumnal glory in the kitchen as well.  When Keats talked about the “season of mists and mellow fruitfulness”, I’m not sure he was thinking about bananas.  In theory our crop of tiny fragrant fruits should have been perfect for lunchboxes, but I made the mistake of describing the first-ripened one as “Geoffrey”.   After this, not only Geoffrey but all his brothers were deemed “too cute” to be eaten.

As well as the gold in the fruitbowl, there’s been plenty of gold in the trees.  The yellow-tailed black cockatoos are back in force, mewling and crunching in the radiata pines.

Yellow tail and autumn leaves horizontal

Fly by from a yellow tailed black cockatoo

And for the first time this year, I’ve noticed the migrating yellow-faced honeyeaters.  Thousands of them pass through the Blue Mountains most autumns, it seems, but this year they’ve been funnelled between the mountains and the coast, through the Hunter Valley.  I first spotted them darting through the riverside casuarinas at Karuah National Park, on our trip north, but since we’ve been back, I’ve seen flocks of them with their travelling companions, the noisy friarbirds, pouring up the Hawkesbury.  I’ve even seen them on the way to work, taking a moment out on their journey to watch the commuters boarding the morning train at Berowra Station.

But not all the autumnal excitement has been touched with gold.  Last weekend, halfway through detaining my broad beans (fencing, netting and a mulch of lavender and liquidambar – doubtless all in vain) I spotted a little collation of royal blue underneath the pomegranate tree. Nerf gun ammunition, the lid of a milk container, a peg.  Signs that we need to tidy up the yard, and a hint that randy bowerbirds might just do it for us.

 

More autumnal reflections from our backyard:

Let them eat light!

Autumn in terminal decline?

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Backyard gold

Encounters with eagles

May I present this week’s sea eagle?

As yet on my estuarine adventures, I haven’t seen a score of sea-eagles on a single morning (although I can imagine a battalion of them, flying in formation), but an encounter with an eagle has become as much a regular feature of my kayaking expeditions as the ubiquitous white-faced heron. Those cryptic little passerines in the riverside scrub are hard to spot even if you’re not short sighted and half deaf.  So three cheers for the white-bellied sea eagle “large and conspicuous” “easily sighted when… soaring… in search of prey“.  Haliaeetus leucogaster, you are the middle aged canoeist’s friend.

There was the eagle we saw battling it out with a pair of whistling kites over fishing rights on a fabulous family excursion across the Hawkesbury from Brooklyn, across the surf-line and up the Patonga River.  According to Wikipedia, sea eagles harass smaller raptors like kites in hopes of stealing their prey.  Not today, Josephine.  This eagle was bested by the lowly kite, unwilling to relinquish a top notch fishing spot.  I need to listen to my own advice to my students – don’t believe Wikipedia!

An eagle even made a guest appearance on a modest little paddle down the end of our street.  This was one mellow raptor, its apparent indifference to poorly coordinated amateur photographers splashing around trying to get a good shot belying its rep as a “shy and easily disturbed species“.  Ruth, my companion on the water that day, had seen a sea eagle, earlier, on the very same bare branch, while bushwalking along the ridge above. Same bird or just a popular perch?

Since the rule for my stolen Saturday morning paddles is no more than half an hour in the car, I’ve frequently had this very thought as I spot yet another sea eagle.  Same bird?  Am I being stalked by just one glorious if persistent raptor who’s somehow taken a fancy to my little craft, charmed perhaps by its avian-friendly name?  Or is the Hawkesbury awash with sea eagles?

Even the Department of Environment in its definitive run down on Haliaeetus leucogaster doesn’t seem super sure. Their guesstimate of 500 pairs across the whole country is based on a one for every 40 kilometre of Australian coastline would pretty much mean that all the eagles in my photos are the same dude (or dudette – the females are larger but I find it’s kind of hard to tell if a bird is small or if it’s just far away).

Either way, I’m 100% sure this week’s eagle is a new one, since I saw it at the start of a paddle down Wallarah Creek, seventy ks north of here.  The creek wends its quiet way through bushland past the Wyong North sewage treatment plant to Budgewoi Lake.  What with my burgeoning interest in taking blurry pictures of distant bird-life, it seems I will be spending more and more time hanging around sewage farms – they seem to be the go-to venue for the would-be twitcher.

The Budgewoi eagles seem a bit more coy than the Berowra locals, as you can tell from this dodgy pic on my maxed out zoom.  Or maybe it’s just that this sea-eagle didn’t want to share her supersized snack.

Which, after observing the consequences of fraternisation with humans for other birds I saw on my way up Wallarah Creek, is probably a good thing.

Up until recently, it was thought that carelessly discarded bait, hooks and line were the big killers of waterbirds, and there have been some efforts made to make sure fisherfolk dispose of their scraps in the rubbish rather than leaving them lying around – not such a big ask really.  Some have even argued for the use of biodegradable line and hooks that will rust away (eventually).

But efforts to get fishermen to clean up their act have had surprisingly little impact on the number of waterbirds being injured or killed by fishing tackle.   In fact, research by academics and wildlife rescue organisations in South Australia and New South Wales suggest that the vast majority of birds that get entangled or hooked – often pelicans, but also plovers, gulls and stilts – get caught up when they are close to people actually fishing.

After my trip up Wallarah Creek I can see why.  As I passed riverfront houses with their landing slips and jetties I saw pelicans lounging on back lawns and an excited egret being thrown small fry by a local.  Even the striated heron, normally shy, flew off in the direction of human habitation, not the other way.  The birds around here are familiar with humans, their tinnies, their by-catch and, unfortunately, their fishing lines.

Rest day on the Tour de Hawkesbury

Plunging down the switchbacks of Berowra Waters Road with a canoe strapped on top as a weekend dawn breaks is a hair raising experience, for a newbie driver like me anyway.  At any moment, heavy breathing MAMILs (Middle Aged Males In Lycra according to our friend Bruce Ashley, author of Bike It! Sydney and Cycling around Canberra) might suddenly loom out of the fog in the middle of the not-quite-two-lane road.

They’ve swooped down through Galston Gorge, across the only bridge, passed swiftly through Arcadian horsey country, and after a moment of quietly gazing out at the marina as they cross the ferry, they’re battling the steep 200 metres ascent up to the ridge.  It would seem rather cruel if, after all that effort, my kayak shot off the roof in an emergency stop and impaled them before they got that well-earned coffee.

Scary as this drive is, it’s not quite as nerveracking as coming back from the Hawkesbury up the Old Pacific Highway on a misty morning – a journey that is begging to be made into a terrifying but addictive computer game called something like “Drive of Doom” or “Death Dodgems”.

Peering through the billowing mist round the hairpin bends, you hope you’ll spot the scattered packs of labouring MAMILs in time to slide right, all the while praying that a mob of motorbikes doesn’t choose that moment to come roaring up from behind to wipe themselves out on your rear window.  Or that an oncoming vehicle doesn’t take the next tight corner wide and smash into you headlong.  The reward if you win a game is obvious: a triumphant stop high above the clouds at “Pie in the Sky“, a place where the lambs lie down with the lions, or at least, the road cyclists eat pies with the bikies.

But not this weekend.  Not a single specimen of the MAMIL, keystone species in our local ecosystem, to be seen.  What’s going on around here?

Eventually, as I hauled the kayak off the car and wrestled it into the water, I worked it out.  The MAMILs have been up all night watching the Tour de France.  At two o’clock in the morning they were gripped as Mark “The Manx Missile” Cavendish floated past Andre “The Gorilla” Greipel to claim his first stage win in two years, his twenty sixth stage in the Tour.  And they’re still curled up in bed, knees bent under the covers, dreaming they’re Australia’s next Cadell Evans.  Middle aged, but still contenders.

The river was very very quiet too.  In February this year, I ventured for the first time into the brackish winding creeks that feed Calabash Bay.  It was fish paradise.  Despite my complete indifference to fish as a meal, pet or leisure pursuit, the sheer numbers of tiny transparent spratlings leaping from the water and darting between the mangrove roots was eye opening.

Even nearly twenty years ago, just after the high point of algae blooms and floating maritime corpses in Berowra Creek, research into estuary processes discovered twenty nine species of fish up and down the water.  Marra Marra Creek, in the lower reaches, with its saltmarshes and long stretch of mangroves, was the richest, but even upstream there were flathead and flounder, gobies and mullet and perchlets, silver biddies and pacific blue eye.

But this weekend, nothing.  I went to see the fish and it was out.

One azure kingfisher was so weak with hunger it sat exhausted on a waterside twig in full view long enough for me to take a numerous terrible blurry photographs.  If I keep going out in these lean times, I may finally get the chance to take a sharp, closeup shot of an emaciated glinting blue bird spiralling slowly downriver on its back.

Despite my glass-half-empty-and-probably-tainted-with-nuclear-fallout tendencies, I’m pretty sure the lack of visible fish is a natural thing, part of the cycle of life.  Most of the inhabitants of the creek spawn in spring and summer, so the tiddlers of the summertime shallows are no doubt happily traversing deeper waters now, invisible and unknowable to those who drift involuntarily into unconsciousness at the mere mention of rod, bait or tackle.

There must have been a few fish around, I guess, along with the amphipods, the isopods, the molluscs and the worms. I saw a few blokes slumped gloomily in tinnies, a handful of great cormorants and the contractual obligation pair of white faced heron in every cove and mudflat.

My ship building neighbour rates his sequence of ancient clapped out Mercedes according to the number of cows featured in the interior trim (“a two cow Merc”, “a four cow Merc” etc).  I’m thinking I should start rating my canoeing trips similarly, according to the number of white-faced herons I see during the day.  This Saturday was, by my calculation, at least a nine-heron day, and that’s not giving myself extra points for seeing the birds in pairs, hedgehog like in their full breeding regalia.

But all in all, there still plenty of solitude to be found out there in the mist.  I’m not sure, but I may have discovered a new form of white-water canoeing.  It may not be high-octane, but it’s got to be higher energy than watching Gabriel Gate on late night TV.  I think I like it.

What’s at the bottom of the garden?

Where does our backyard end?  The unwary burglar or, more plausibly, brush turkey fetishist leaping over the back fence and finding themselves falling off the small but perfectly formed cliff between our place and our downhill neighbours might think the answer obvious.  But clearly, property boundaries don’t mean a lot to the brush turkeys or the bowerbirds.  As far as they’re concerned, our backyard is just a part of Berowra Valley National Park with better snacks.

And since our yard is, in essence, a part-time storm drain, you could say that this is where our backyard ends:

Sometimes the view from the deck seems like a theatre backdrop, an artful two dimensional screen behind our suburban dramas.   Every evening, the cockies, wheeling and screeching, burst through the scenic backcloth.  Last weekend, a bit more quietly (bar the kayak-onto-roofrack related cursing) I did the same, plunging into the dawn mist towards the very bottom of the garden, the watery end point of our backyard.

In the 1990s, Berowra Creek was not a good place to be a fish. Sewage outflows from waterside communities at Dusty Hole and Berowra Waters and the landlubber suburbs to the south meant algal blooms, brick red water and floating fish.  As the cheery Hornsby Shire Biodiversity Plan ten years back noted “Some parts of the tributary creeks in the Berowra Creek catchment feature weed invasion, garden plants and waste, streambed siltation, rubbish and gross pollutants from stormwater drains, bank erosion, undercutting, tree death and poor water quality” (2006, 28).  It’s enough to make a gardener think long and hard about what might wash down the hill in the next heavy rain.

Thankfully there’s a whole lot less nitrogen going into the creek these days largely thanks to better poo processing.  I don’t have a lot of interest in fish. I don’t eat them, they make rubbish cuddly pets and they lay very tiny eggs far too infrequently.  But even to my disinterested eye, the backwaters and mangrove flats of the estuary look like fish paradise.  Okay, fish paradise probably doesn’t feature stingrays, cormorants or osprey, but you get my point.

Fishermen get up earlier than kingfishers, it seems.  People who say they’re “up with the birds” or even, in that eloquent Australianism “up before sparrow fart”, are clearly lying through their teeth.  The welcome swallows were barely out of the fluffy slippers and the ducks were still brushing their hair and cleaning their teeth, but the fishermen of the Hawkesbury were already out on the water, lurking in quiet bays or drifting mid-channel like tinny Mary Celestes.

The feathered fisherfolk only seemed to appear after the mist began to rise.  I’m not sure whether I can attribute that to poor avian night vision or my water spattered multifocals.  You’ve got to assume the rufous night heron can see in the dark, but I only saw it scoop up a take-away in a kind of disgruntled way, after some annoying canoeist with an inadequate zoom lens made a nap in the mangroves untenable, and that was long after sunrise.

For all the wildlife in these parts, that sharp edged snap of an azure kingfisher sparkling in flight is as much beyond me as a decent crop of salad potatoes, it seems.  But I’m not going to complain.  Over the last few weeks I’ve seen plenty of boats with girls’ names, but I haven’t seen too many Rubys, Calistas or Beverleys actually messing about in boats.  There may be fairies at the bottom of the garden and there are certainly plenty of fish, but there don’t seem to be quite as many fishwives.  Seems like it’s a rare privilege to be Her Outdoors.

Happy International Year of Soils!

I’m not kidding.  The UN has declared 2015 the International Year of Soils.  And not before time.  Everyone should be preoccupied with dirt.  I know I am.  What is going in down there, under the ground? Are my veggies growing in podzol or mycelium? Hang on, that’s soil profiles in Minecraft, not in Berowra.

The CSIRO’s recently released Soil and Landscape Grid with its 3 dimensional digital soil attribute maps could resolve most Australian gardeners’ soil questions. In case you were wondering how these maps were developed, let me put you out of your misery:

“The spatial modeling was performed using decision trees with piecewise linear models and kriging of residuals. Fifty environmental covariates that represent climate, biota, terrain, and soil and parent material were used in the modeling. Uncertainty was derived using a bootstrap (Monte Carlo-type) approach to derive for each pixel a probability density function (pdf), from which we derived 90% confidence limits”

More kriging of residuals, I say!

Gags aside, this free online resource shows why Australia needs publicly funded science and why sacking researchers in the CSIRO to bankroll Gina Rinehart’s tax breaks is a major error (if you need more persuading, CSIRO scientists also invented WiFi, Aerogard, the permanent pleat, and the word petrichor, which describes the lovely smell of damp earth after rain).

After reading about the rocks in our neck of the woods, however, I’m not sure we are best placed to fully exploit the sophisticated visualising technologies of the Soil and Landscape Grid.  The geology around here is pretty danged boring. Other than the odd lens of shale, mostly on the ridge-tops (that is, under roads and houses) it’s Hawkesbury sandstone all the way down, 40 million years and 270 metres of it.  Or at least, all the way down to Berowra Creek where there’s an outcrop of more fertile Narrabeen Group of shales, sandstone and clays here and there.

Of course, we’re not alone in our preposterously deep beds of sandstone.  They’re on display in the Blue Mountains too, though with a few more layers clay and basalt intrusions to break up the tedium.

The humungous quantities of sandstone across a swathe of the Sydney Basin makes my sentimentality about the disappearing rock faces along the new railway cuttings of the Northern Line even more absurd.  After reading about the good exposures of Ashfield Shale between Hornsbury and Beecroft,  I’ve become a tiny bit obsessed with capturing the freshly exposed slices of Sydney Basin geology as they are revealed by the diggers and before they’re covered with nasty grey concrete.  Wordsworth was mortified by the ugliness of railway cuttings slashing their way through the nineteenth century British countryside.  Here am I mourning for disappearing railway cuttings, a slice of geological time revealed and then lost again.

Perhaps I should stop grieving the lost glories of the Pennant Hills trackwork and spend more time worrying about what my garden might be doing to the “quartz rich, nutrient poor” soils of Berowra.

My snake beans are kinda sallow – I reckon they need a side serve of well-rotted chicken manure.  But even as I contemplate emptying the compost tumbler, I can’t help but fret about where my vegetable garden sits, perched above the national park with its “rich and distinctive assemblage of species that thrive on poor soils” , “60-80 different plant species growing together on an area half the size of an average house block” (Benson, Howell, McDougall, 1996, 24-5).  Benson and Howell in their fascinating Taken for Granted: the bushland of Sydney and its suburbs (Kangaroo Press/Royal Botanic Gardens, 1990) mourn:

 “much of Hornsby’s rugged sandstone terrain remained undisturbed until after World War III when the increasing availability of the car and improved building technology made steeper, more remote sites available for housing.  As a result, bushland on ridge-tops and upper slopes has been totally destroyed, the bush remaining only where it is virtually impossible to built, and along steep gullies which have become drainage lines.  Virtually very catchment system includes some suburban development, stormwater run-off from which contains silt and nutrients.  These promote weed invasion of sandstone gullies… in newer areas such at Mt Colah and Berowra [the] invasion is beginning, and the consequences appear inevitable” (108)

And that’s us, in our mid-century twentieth century house, teetering on a steep slope in a fold of the hillside you might otherwise call a creek bed.  My painstakingly-made hot compost, my organic sugarcane mulch, the poo from my beloved chickens, all building nitrogen, carbon, phosphorus rich earth – garden alchemy.  I’m creating an anthroposol – a human made soil – and I’m not entirely sure that’s a good thing.

As a homage to the UN’s declaration, I’ve stared in a  incomprehending way at a schematic cross-section of Hawkesbury soils, I’ve thought long and hard about our B horizon (by staring even longer at this quite marvellous online introduction to soil classification – thanks again, CSIRO) and I’ve double-checked Minecraft’s definition of “podzolic” with the kids but I’m not sure how far it’s got me.

Maybe this is the chthonic thinking – thinking about the soil and the communities, plant and animal that grow from it – that my friend Kate urges us all to do in her fab blog about the Armidale Community Garden, but it’s not so much grounded me as taken me directly to Hades via the Field of Punishment.  This is a special special place of suffering for people who long to understand rocks and dirt but can never remember whether the Devonian comes before or after the Carboniferous, no matter how many times they read David Johnson’s splendid Geology of Australia.  And that’s without wrestling with the geopolitics of topsoil loss or the impact of international agribusiness on pesticide residues or the links between soil, country and indigenous chlthonic law

The only solution to this torment, I feel, is another variant of subterranean thinking: that sense of mindfulness I get sitting in a darkened vehicle with a swag of empty shopping bags, gazing tranquilly at the carefully preserved, sandstone rock exposures in the underground car park of Berowra Coles.

Happy International Year of Soils everyone!