Leucaena leucocephala – a tale of ongoing stupidity – or is it dishonesty?

What, you may ask, is Leucaena leucocephala?  And why a blog about it in relation to sustainability in the Lockyer Valley?

Well, first let me admit that this is a bit of a “vent”, as they say.  It is also a reminder that misleading and stupid advice by government agencies is not something that was invented recently.

In the early ’80s I came back from the Northern Marianas Islands, where I’d been working on archaeological surveys to trace the history of the Chamorro people who were suspected of having been on the islands for up to 2000 years.  The Marianas are a group of about 15 islands in the northwest Pacific Ocean, southeast of Japan and about half way between Hawaii and the Philippines.  Only three of the islands are permanently inhabited: Saipan, Tinian and Rota.

Up until the Second World War the Marianas were under Japanese control as part of the South Pacific Mandate granted by the League of Nations.  They’re now a Commonwealth in Political Association with the United States of America, though why anyone would want such an association is beyond me.

What’s this got to do with Leucaena or sustainability?  Well … read on.  The islands of the Marianas were part of the chain of island “stepping stones” utilised by the US on its path to the eventual conquest of the Japanese mainland.  Some of the most violent battles of the World War II were fought there.  Saipan and Tinian were bombed, shelled and fought over until they were, across large areas, bare cratered earth.  The battles were so fierce that when I was there you could pick up about ten bits of shrapnel or actual bullets per square metre on parts of the bare limestone on the coast of Tinian.  There were larger bits of bomb casing sticking out of some of the few remaining trees, and in places bits of war debris, including sometimes aircraft parts, were mixed in with 2000 year old archaeological layers.

When the war finished the nearly denuded islands of Saipan and Tinian were in danger of literally having most of their topsoil washed into the sea in the wet season.  The surviving Chamorro people were at risk of losing the agriculture which was the basis if their existence.  Rota was spared invasion and destruction because it had no strategic value, lacking major Japanese fortifications or areas where airstrips could be built.  The troops stationed there were cut-off and left to starve until they surrendered, so the island was spared the destruction visited on Saipan and Tinian.

So what to do?  The quick, and as it turned out “dirty”, solution was to bomb the islands with huge quantities of the seeds of Leucaena leucocephala, a fast-growing member of the Mimosa family (like our Acacias) that originated in Central America.  They got the seeds from the Philippines where it had become naturalised and was widely distributed.  Leucaena is very well adapted to the tropics and sub-tropics.  It grows in dense stands as a small (up to six metres or so), whip-stick tree which produces seeds prolifically.  The stands are often so dense that nothing else can grow under them.

Leucaena grows in dense stands

Prolific seed production by Leucaena

Having done field work on Rota, Tinian and Saipan I had seen both the original lush, tropical vegetation of Rota, which luckily had not needed post-war soil stabilisation and is rich in species and wildlife, and the widespread, mono-species stands of Leucaena across Tinian and Saipan with very little wildlife.  The farmers on those islands spent a lot of their time in controlling the Leucaena regrowth, often to the point that agriculture became uneconomic, and in the towns it was even a pest in the lawns, growing faster than the grass.  Clearly the species was a mega-weed.

Arriving back in Australia, one of the first things I read in the newspaper was about how the Queensland Department of Primary Industries was promoting the planting of Leucaena as a cattle fodder, ideally adapted to tropical and sub-tropical areas with poor soils and monsoonal rainfall patterns.  Unbelievable!

Very concerned, I phoned the DPI to find out more and to share my observations of what Leucaena can do to the environment.  The agronomist I spoke to heard me out, then said that this might be the case in places where the seed was distributed willy nilly across the landscape, but I had to understand that what DPI was advocating for Queensland was “controlled” use of Leucaena in pasture – where it would never grow to seed-bearing stage because it would be grazed off before that.  Seriously.  Like the cattle were going to be in the paddocks the whole time, never turning their backs in case a plant set seed?

I was under the impression that Leucaena was being introduced into Australia at that time (remember this was before the internet and Google, and I’m not an agronomist), and that perhaps they really didn’t believe that it could become a pest.  But according to the UN Food and Agriculture Organisation (FAO) Leucaena had been introduced into Australia in the late 19th century and it was naturalised in parts of northern Australia by 1920.  So there should have been plenty of evidence that it was a very potent pest species.

Despite this, during the 1970s and early 1980s, Leucaena was being touted around the world as the ‘miracle tree’ because of its worldwide success as a long-lived and highly nutritious forage tree according to FAO, and the Queensland DPI were right there on the bandwagon and not about to listen to any contrary views.

Fast forward to the present:  According to the Biosecurity Queensland Factsheet on Leucaena it is “A very troublesome weed of waterways and roadsides in tropical and sub-tropical regions. It is also found in open woodlands, gardens, parks, waste areas, disturbed sites and on coastal foreshores and offshore islands.” and is “… widely naturalised and relatively common in the coastal and sub-coastal districts of northern and eastern Australia. It is most common in south-eastern, central and northern Queensland and in the northern parts of the Northern Territory. Also present in the coastal districts of northern and central New South Wales, in the coastal districts of Western Australia, on Christmas Island and on the Cocos Islands”.

So we come to the Lockyer Valley.  Try keeping a careful watch on the roadsides in the Valley, as well as between Toowoomba and Brisbane, including along Mt Crosby Road if you take that route into Brisbane – there’s no doubt that Leucaena is well and truly established in Southeast Queensland.

In fact, the Queensland Department of Agriculture, Forestry and Fisheries (DAFF) is now warning that “Unless heavily grazed or otherwise controlled, it is able to rapidly spread to adjacent areas”.

And this wasn’t bleeding obvious in the early 1980s to anyone who wanted to take more than a narrow, rose-coloured view of the species?  Give me a break.  Was I the only person who had noticed that it was a very noxious weed?

The cat, as they say, is now out of the bag – though in this case, given the number of other highly environmentally impacting species that have been introduced or promoted by government agencies across Australia, it might be more appropriate to say that Pandora’s Box is well and truly open.

Has anything changed?  Well, Leucaena is now well recognised as a problem here in Australia.  But is it really?

The Australian Government, through the Australian Centre for International Agricultural Research (ACIAR, which funds and advises on a lot of our foreign aid policy and projects) is running a website called Tropical Forages: An interactive selection tool, in partnership with the CSIRO, the Queensland Government and a number of other organisations.  This website advises that Leucaena “Will not normally spread under grazing as cattle relish young seedlings.  Some thickening up of grazed stands has occurred in eastern Australia where leucaena is left ungrazed during the growing season for provision of autumn feed.”  Is my 1980s agronomist friend now working in Australia’s international aid industry?

This ongoing level of ignorance and stupidity is beyond belief.  I hope to see the day when there will be major legal class actions in Australia against government agencies for the massive damage done to our environment and economy as a result of the lack of proper consideration of plant introductions.

Ghost Snake

I was watering “the grove” the other day – an area with a range of canopy layers between the outdoor toilet and the workshop – when a slithery movement on a grapefruit branch beside my head caught my eye and got my pulse racing.  Seen briefly out of the corner of my eye it was definitely “snakey”.

Well it was “snakey” – the tail of a snake, moving on the branch.  But this was no ordinary snake.  It was pale and translucent and stretched back into the gloom under the dense canopy.

Definitely no ordinary snake. This was a ghost snake.

P1050523_head_webThe complete skin of a Green Tree Snake (Dendrelaphis punctulata)  was stretched along the branch, then up to another branch and along that, with the head at the far end.  As the light breeze moved the branches the tail moved backward and forward on the branch near me, looking at first glance as if it was alive.

It’s a pity I didn’t think to get the camera at the time, but it was getting dark and I still had chores to do.  The next morning we gently gathered the skin from the branches and laid it out on the porch – all 1.75 metres of it (they grow to two metres).  Apart from a small tear in the middle it was undamaged, leaving us wondering how on earth the snake got out of the old skin.

P1050522_full skin_web

This is the longest Green Tree Snake we’ve seen and we’re pretty sure this one is an old friend that has been around here for ten years or more, first making our acquaintance when it took to sunning itself on the kitchen sink on winter mornings.

We see it regularly, most recently when it decided that the top of the “resting” composting toilet bin was a lovely place to soak up some warmth from the composting process going on in the bin.  When we got too close it relocated into the top of the bin – even warmer, and no pesky humans – and no, it doesn’t smell (I’ll do a series of posts on our composting strategies in the near future).

This snake frequently climbs up the toilet vent pipe to the “whirlybird” ventilator on top and then through it and down into the pipe to look for Green Tree Frogs inside.  Usually it’s only the grandfather Tree Frog that has been around nearly as long as this snake, and the snake has no chance of getting its mouth around that massive frog.  That doesn’t stop it trying though, and we are alerted by the frog’s distress calls as the snake struggles to get its jaws open around the frog’s head.  The end result is that the frog gets scratches on its back from the snake’s fangs and the snake is moved on by us.

This is probably the same snake, trying to climb the wall of the house two years ago (you can see the post about that here).

Back to the skin; its a fascinating thing of great beauty.  The scale pattern varies along the body, and from the top to the underside.

P1050525_scale pattern1_web P1050526_scale pattern2_webAnd here’s what the real living Green Tree Snake looks like.  This isn’t our old friend but one that I saw down near the creek a year or so back.

P1020209_crop_head_webThese snakes are harmless, and generally not at all aggressive.  The blue colour between the scales is a threat display and only appears when the snake expands its body make itself look larger and to expose the blue skin between the scales.  This one raised its head to get a better look at me (I was crouching beside it to get a better angle to photograph it) and trying to “smell” me with its tongue.

You can find more about this species on the Queensland Museum website and Wikipedia, and quite a bit about its ecology at Critters of Calamvale Creek.

March wildlife

Pretty quiet month for birds, not necessarily because there weren’t many birds about – just that there wasn’t much time devoted to watching and/or identifying birds.  Seventeen species listed, out of 58 species that we’ve seen in the ten years we have records for March.

We did see two bird species that we hadn’t seen here in March: Golden Whistler and Spotted Quail-thrush.

The Spotted Quail-thrush is a species that we don’t see very often. They are quite shy, spend most of their time on the ground with a preference (here at least) for relatively sparse groundcover in rocky areas, and are likely to walk away quietly when disturbed.

Spotted Quail-thrush. [Copyright Kevin1234 - Creative Commons Attribution-ShareAlike]

Spotted Quail-thrush. [Copyright Kevin1234 – Creative Commons Attribution-ShareAlike]

The one I saw in March flew in straight and low and landed on a heap of Acacia logs just in front of me, with an alert, almost “Road Runner” look, before flying off almost immediately

The Golden Whistler sighting extends our records of this species by one month – previously April to August, now March to August.

Of the 15 other bird species seen, 12 have been seen here in every month of the year, including the Yellow-tailed Black Cockatoos which were very active throughout the month.

Welcome frog sightings were the Graceful Tree-frog (Litoria gracilenta) – under the light outside the front door, instead of its usual very elegant pose along a slender branch with its legs tucked up under its body –  and the Green-thighed Frog (Litoria brevipalmata).

One of our favourite reptiles was common in March. Burton’s Snake-lizard (Lialis burtoni) seemed to be everywhere.  This is how they are often seen:

Lialis burtoni_DSCF4178_webThey often seem to be hoping that their somewhat cryptic colouration will keep them from being seen – though in fact I think they are often sitting in wait for some prey to come along and just choose to ignore the temporary human disturbance.  In fact we had one in March that kept up an “ambush” pose on the ground under the bottom rung of a ladder while we were up and down replacing hot water system tubes for half an hour or more.  Another was seen sunning itself on a railway sleeper on the edge of a garden bed, within less than two metres of us watching from the window, and within two metres of a Red-necked Wallaby and her joey grazing on the garden bed.

Burton’s Snake-lizards are an amazingly adapted lizard.  Their main (only?) prey is other lizards, and they have modified their body shape to be able to get into crevices where skinks and geckoes like to hide.  Their jaws are elongated, to be able to grab and squeeze their prey, and the top jaw hinges where it joins the skull.  I think this is so that they can extend their gape to get an even pressure between the two jaws.

Lialis_burtonii_DSCF0687_proc1_crop2This one was lurking in the grass and I nearly stepped on it.  Just as I saw it, it darted forward to grab this skink.  It’s first grip was across the back, but it quickly flipped the skink up in the air and caught it across the chest, holding it tightly until it suffocated.  You can see the line of the upper-jaw hinge just behind its eye.  Once the skink had ceased struggling the Snake-lizard moved so as to get the skink’s head into its mouth.

Lialis_burtonii_DSCF0693_webWithin five minutes there was only the skink’s tail protruding from the its mouth, and five minutes later it went off, no doubt to find somewhere safe to rest and digest its meal.

Now let’s see what April brings by way of wildlife.

Garlic and green manure

We tried growing garlic last year, with some success, but I had the feeling that if we’d prepared the ground a bit better the bulbs might have been larger, so this year we decided to try adding green manure to the soil a month or so before planting the garlic.  With this in mind we planted the bed up with lemongrass about three months ago.

Before reading further you need to understand that on our place “soil” is mostly a concept.  We live in rugged sandstone country and what passes for natural soil is mostly rocky gravel with sand and (perhaps) some humic material.  If we want good soil we have to make it.

Another source of complexity is that because of the depredations of possums, wallabies and bandicoots we need to grow most of our vegetables behind fences topped off with a strand of electric tape.  It wasn’t always like this.  For the first six or seven years we seemed to have a rock-solid agreement with the wildlife (apart from the parrots) that if we didn’t eat their food, they wouldn’t eat ours.  However over the course of a year, and strangely it was a very wet year when there was plenty of natural food for the wildlife, they suddenly decided that our vegetable were infinitely preferable to bush tucker.

Anyway, this is a long-winded way of getting to the point that there are few things we can grow unprotected, but these include all the onion-garlic group, lemongrass, turmeric, ginger, and citrus.  So, in order to be economical with the fenced area, the garlic gets grown ‘in the open’.  This pretty much means that it goes into a terraced garden bed behind a rock wall, which tends to make the whole thing “well drained”, particularly if there isn’t much humic material in the soil to start with.  Hence one of the attractions of green manuring, and the choice of lemongrass as one of the components of the green manure – nothing was going to graze it off.

The functions of green manure are said to include

  • increasing the percentage of organic matter in the soil, and thereby improving water infiltration and retention, aeration and enhancing other desirable soil characteristics, including soil structure;
  • promoting a more varied and healthy soil biota; and
  • adding nutrient resources that deep-rooted green manure crops bring up from deep in the soil (but lemongrass is shallow-rooted).

Here’s the harvest of lemongrass from what will be the garlic bed.  It was densely planted three months before we cut it in the middle of March.  About half of the crop we gave away to friends in the Indonesian community here – it’s a staple of many Indonesian dishes – which is the material in the buckets and pots on the bank.  The heap in the middle is for the green manure, and the lemongrass still growing on the left of the photo gives an idea of the size of the plants we harvested.  The bed in the foreground is where the green manure, and later the garlic, will go.

Lemongrass garden and harvest_smallP1050476

I also wondered whether the aromatic oils in the lemongrass might have a useful effect in inhibiting soil pests like nematodes, but I couldn’t find anything on this.  In fact I couldn’t find anything at all on lemongrass as a green manure.

We also decided to add the fresh green growth from the pigeon peas.  Pigeon peas (Cajanus cajan) are an evergreen perennial legume shrub that grows to more than two metres in good conditions.  Cath Manuel has an informative short article on pigeon peas over at Soil to Supper, and there’s even more detail on the Tropical Permaculture site.  Both recommend them as a mulch or soil improver, and NSW Agriculture says they are an excellent rotation crop for building up soil nitrogen and breaking weed and disease cycles.  Pigeon pea hosts the VAM fungus which allows the plant to access phosphorous and zinc in the soil, and presumably this is incorporated into the plant, adding to its usefulness as a green manure.

The other ingredient in our green manure mix was mulberry stems and leaves.  We coppice mulberries rather than growing them as trees, for two reasons.  First, the variety we have tends to grow straight up.  No amount of pruning or shaping seems to be able to persuade it to grow as a relatively low spreading tree that one could easily harvest fruit from.  Second, ultimately we will mainly want the leaves as a food supplement for poultry.  We learned from our good friend Thanongsi, who runs a successful demonstration sustainable agriculture farm in central Laos, that he finds he does not have to provide any supplements to goats or poultry that are given mulberry leaves as a component of their fodder.  So presumably these nutritional supplements are going to be incorporated into the green manure.

Here are our green manure ingredients ready for mulching.

Green Manure components_P1050477_smallIn the background is the lemongrass, the heap in the foreground is the pigeon pea, and on the right is the mulberry.  It is important to use only the green and sappy ends of the branches for green manure, to make sure that it breaks down quickly and easily in the soil.  Of course the blades of the lemongrass are typically coarse and hard, but when finely mulched and combined with the other ingredients should break down readily.  One advantage of the mix of ingredients is that when combined it isn’t so “wet” that it will choke up the chipper/mulcher (seen in the background of the photo above).  I’d highly recommend this machine from Greenfields.  It has a very sturdy direct drive from the motor to the chipper blades (rather than a belt-drive which would need regular adjustment) and can chip green branches up to 50mm diameter without even dropping the revs.  We’ve chipped everything less than 50mm in diameter from about ten full-sized trees with this machine, as well as a lot of prunings, and it is still on it’s first set of blades (which can be re-sharpened, but haven’t needed it yet).

Here’s the mulched ingredients on the bed, ready for spreading and digging in, after which it will be watered and covered with a thick barley straw mulch for the next month.  You can see the “shorn” pigeon pea bushes in the background – they hardly look like they’ve been touched.

Green manure before spreading_P1050479_smallI’ll let you know what it looks like when we dig it over to plant the garlic (which was ordered today from GreenHarvest).

Autumn fungi

March was an amazing month for fungi.  The much higher than usual rainfall combined with the unseasonal high temperatures seemed to be perfect for mushrooms.

The Red-staining Polypore – not a particularly romantic name, but referring to the multiple pores on the underside of the cap that turn red when bruised (see photo below) – was one that was much more common than usual.  Its scientific name is Amauroderma rude.

Here’s what the top of the cap of a fairly fresh specimen looks like.

Amauroderma rude_DSCF3603_Evernoteand the underside, “bruised” when I squeezed it a bit while picking it up

Amauroderma rude_DSCF3606_smallThis species grows on a woody stem that starts out looking like an old brown stick standing vertically in the ground, then gets a bit of “white fungus” on the top end, before gradually morphing into a more or less classic mushroom shape.  Here’s a time sequence – three shots, three days apart.

Amauroderma rude SEQUENCELater the cap becomes a dark “tobacco” brown, going through a stage where it has a narrow white margin which is lost on many specimens.  The mature cap, like the stem, is hard and woody.

I’ll post some more shots of our autumn fungi as I find time to process the photos.

Peak oil, fracking and the fate of technological society

Been a while between posts – mostly due to ongoing shoulder problems causing chronic pain and a resultant lack of interest in doing anything that requires focussed concentration.  Now I have discovered that the physical posture associated with sitting meditation takes the pressure off the damaged areas and virtually eliminates the pain – possibly for 12 hours or more, so more blogging may be on the way.

I’ve just been reading a great post by the Archdruid, addressing the apparently increasingly widespread view that coal seam gas and shale oil fracking have solved the world’s fossil fuel dilemma by permanently banishing the spectre of peak oil and, starting with the US, have put us back on the road to endless technological progress and economic growth.  The reality, as he says so eloquently is that:

… technological progress, as well as the sciences that helped to make it possible, are subject to the law of diminishing returns; furthermore, that what has been called progress is in large part a mere side effect of a short-term, self-limiting process of stripping the planet’s easily accessible carbon reserves at an extravagant pace, and will stop in its tracks and shift into reverse as those reserves run short; more broadly, that modern industrial society is in no way exempt from the common fate of civilizations.

Click HERE to read a very well argued presentation of the evidence that the reserves can be produced using fracking and other CSG technologies are within the predicted long tail of fossil fuel reserves that would become accessible once prices were sufficiently high, and make no difference to the arrival of peak oil or the eventual outcome.