The perfect fire.

Posted by on August 6, 2017 in Our Environment | 0 comments

The perfect fire.

At our meeting on Friday we had numerous request for the article written by Dr. Guy Preston.   Knysna Fires : Five factors that produced the Perfect Inferno Dr Guy Preston, PhD (Environmental Science) Deputy Director-General: Environmental Programmes, Department of Environmental Affairs. June 2017 will be remembered by South Africans for decades to come.  A historical moment when Mother Nature showed her true power and the only option was to get out of her path and watch in awe. For a week preceding the fire, extreme weather warnings had been issued with predictions of flooding in drought stricken Cape Town and surrounds and rain and strong winds in the Garden Route. Waking up on the 7 June, little did anyone know that within 72 hours 10,000 hectares and in excess of 500 structures in the Garden Route would be burnt, some houses simply reduced to a heap of rubble and vast swathes of pine plantations burnt. While fires aren’t uncommon in the Garden Route, this fire had all the conditions to make the ‘Perfect Fire’, something that thankfully occurs only every 100 years. With hindsight being a perfect science, understanding the fire has produced insight into the elements that created this inferno. There were five core conditions that made this fire so unique, namely : 1. The regional drought conditions, 2. The fuel load in the environment and suburbs, 3. Topography of the area, 4. Hot ambient air conditions, 5. The speed of the wind. Each of these conditions would contribute to a fire, indeed the combination of two or three conditions would generate a formidable fire, but the combination of all five factors produced a historical fire. Looking at each factor and how it contributed to the perfect conditions will assist in understanding the mechanisms and how to plan to mitigate escalated damage in the future. Drought Conditions : The Garden Route, along with the rest of the Western Cape has been in the grips of a severe drought for 12 months. While Cape Town exhibits an established winter rainfall, the Garden Route between Mossel Bay and Storms River don’t. Contrary to popular belief, the Garden Route doesn’t have a rainfall season. The impact of the current drought on vegetation and the resultant increase of fuel for a fire has been substantial. One drought survival mechanism of plants is to reduce the surface area of trans- evaporation, or simply put, to defoliate and drop leaves. The defoliation can represent up to 40% of the trees leaf mass. With the accumulation of extra leaf mass, the usual systems of decomposition by both chemical (fungal) and mechanical (earthworms, crickets, Pill Millipedes etc) means is retarded and thicker layers build up. This build up in areas can result in the formation of natural compost heaps. Normal composting is an exothermic process reaching internal temperatures between 45 and 77°C. Under certain conditions a compost heap can spontaneously combust. Alone, the additional leaf litter and potential compost heaps has a potential for starting a small fire, or series of fires. Accumulation of Fuel : It is important to understand the different vegetation types in the Garden Route to appreciate the contribution to the build-up of flammable material for fires. Everyone speaks of the Knysna Forest and the Fynbos in the Garden Route. However,...

read more

What the humble (but mighty) ant can teach us humans

Posted by on August 5, 2017 in Our Environment | 0 comments

What the humble (but mighty) ant can teach us humans

Not just about weight-lifting, but everything from health to traffic jams Ants can teach humans in areas as diverse as health care, defence, and transport Size for size, they are much stronger than us and can lift 5,000 times its weight The tiny insects make up a quarter of all the animals on earth, at ten quadrillion   By John Naish for the Daily Mail PUBLISHED: 01:49 BST, 24 July 2017 | UPDATED: 02:02 BST, 24 July 2017 Humans may think we rule the world — but the tiny ant can tell us how to do it better. Ants make up around a quarter of the Earth’s animal numbers, with about ten quadrillion of them — that’s 10,000,000,000,000,000 (more than a million ants to every human). And, size for size, they’re mind-bogglingly much stronger than us, as a stunning picture, first seen in last week’s Mail, of a weaver ant in Indonesia lifting a bee 40 times its own weight, confirmed. Here, we reveal what ants could teach us in areas as diverse as health care, defence, transport and creating empires . . . Mini Olympians +13  Inside their exoskeletons, ants’ muscles don’t have to provide much support holding up the body, so they can use their strength to lift other objects One record belongs to the common American field ant, which can bear up to 5,000 times its own weight (the equivalent of a 10 st person carrying more than 300 tons) No amount of training or performance-enhancing drugs will enable humans to emulate the physical feats of ants. One record belongs to the common American field ant, which can bear up to 5,000 times its own weight (the equivalent of a 10 st person carrying more than 300 tons). Thanks to its sticky feet, the Asian weaver ant can carry more than 100 times its own bodyweight — while hanging upside down from a sheet of glass. Ants are so strong because their bodies are so light. Inside their exoskeletons, their muscles don’t have to provide much support holding up the body, so they can use their strength to lift other objects. Human bodies are vastly heavier, so we have to expend a lot of our own muscle power just holding ourselves up. Empire builders No amount of training or performance-enhancing drugs will enable humans to emulate the physical feats of ants The largest ant colony found is more than 3,750 miles wide, created by Argentinian ants on the Mediterranean coast. They’re thought to have gone there in cargo ships. This super-colony is estimated to comprise more than a billion ants in nests that border each other like nation states. The EU contains half as many people, and they clearly can’t co-operate so effectively. By generally working in concert, ant brains combine to create one huge super-brain, which, arguably, makes the insects collectively the most intelligent in the animal kingdom. An ant’s brain contains only 250,000 cells, compared with a honey bee’s 960,000 and up to 100 billion in the human brain. But collectively, they create a highly developed social system where millions of individuals operate in perfect synchronicity, with queens to lay eggs, drones to fertilise the queens and sterile wingless females as workers and soldiers. Ants hold the record for sexual restraint and abundant fertility. Queens have one sexual encounter, storing...

read more

Tony Rebello comments on Fynbos and Fire

Posted by on July 17, 2017 in Our Environment | 0 comments

Tony Rebello comments on Fynbos and Fire

Dr Tony Rebelo of South African National Biodiversity Institute, Pretoria with expertise in Botany, is also the Scientific Officer for the Protea Atlas Project. He obtained his PhD in Zoology at UCT in 1992 on the topic of the Preservation of the Cape Flora. He has co-authored books on Pollination Ecology, Proteas and Vegetation types of South Africa, as well as numerous scientific publications on these topics. His special interests are conservation planning, protea ecology and encouraging amateurs to get involved in scientific research. To this end he has championed the design of user-friendly field guides, the use of common names for plants and also the Protea Atlas Project. Tony’s comments: ‘Leave the Fynbos alone.  It is 100% adapted to fire and anything you do will be negative.  Forget about any restoration: if Fynbos cannot restore itself then there is nothing you can do about it. Your problem is primarily one of alien control.    Where the veld is pasture or plantation or garden, the goals will be obvious: restore the system to its desired goal by any means acceptable.   For invaded areas of Fynbos, your aim should be to remove the aliens without compromising the Fynbos restoration.  This means: ·         Get in early, before the aliens take over ·         Target areas of low infestation Fynbos for priority rapid and manual alien removal.  Under no circumstances any chemicals or vehicular methods.  All that is required here is that the aliens are managed.  Every attempt by engineers to want to prevent erosion or any other perceived threat should be totally prevented.  Natural ecosystems are capable of looking after themselves. ·         Target areas of high infestation but good quality fynbos for urgent manual alien removal.  Included here should be areas degraded that contain highly threatened species, and ex-plantations with good restoration potential.    If at all possible, no chemicals and no vehicular methods should be used.  Here the concern is damage done by clearing and possible subsequent effects.  Careful contour stacking and access should eliminate erosion issues.  Getting in early will keep waste fuel loads (stacks) low, allow easy access,  and allow optimal fynbos recovery.  Where chemicals are needed, the teams dealing with species requiring mechanical control should complete the site before the chemical teams enter and careful supervision of winds, application and methods is required.  The Emergency here is NOT erosion or restoration but the Emergency IS getting aliens out over as large an area as fast as possible with minimal  damage to the natural Fynbos recovery. From Tokai, the problem is that the alien control teams ignore the priority setting by ecologists and SANParks and do their own thing.  At Tokai SANParks had to send in special teams for the priority areas because W4W were not interested in any triage or priority sites identified by other agencies.  This issues will need urgent attention. Provided aliens are quickly controlled Fynbos regeneration can be largely passive: very little restoration is needed.  For plantations some overstorey serotinous guilds need to be restored, but little else.  By the time the aliens are removed (2-3 years) it is too late to do active restoration, except in a few, localized, heavily-damaged areas where the ground is still totally bare one season after alien removal. ·     ...

read more

Knysna’s Great Fire of 2017

Posted by on July 7, 2017 in Our Environment | 0 comments

Knysna’s Great Fire of 2017

A month has elapsed since the event, I can hardly recall where the weeks went.  Many suffered loss or damage,  were traumatised , and are now  uncertain about  a future in Knysna. My apologies for not keeping the site up to date – but it took a while to get the electricity, water and connectivity sorted out. We take all these services for granted, never giving any thought how we can function without it. With each service being restored, we had a celebration.  We give thanks to the  many angels and saints in Knysna, you will forever be our heroes. Esther PS The article below is the only informative publication – worth a read.   July 3, 2017 SA Forestry on Line. MTO’s Kruisfontein plantation with staff houses in the centre. In the background is the Harkerville indigenous forest that did not burn except on the edges. (With apology to ‘The Great Fire of 1869’) by Theo Stehle On the fateful day of 7th June 2017 a set of circumstances triggered a disastrous wildfire of unprecedented proportions in the Sedgefield-Knysna-Plettenberg bay area. Not only were vast areas of commercial plantations consumed, but lives were lost, and damage of billions of rands caused to properties and infrastructure. It was probably the biggest fire disaster in South Africa in modern times, with over 1 000 fire fighting personnel from all over the country deployed to combat it. Forestry fires also raged in the Tsitsikamma and further east in the Sarah Baartman District Municipality, viz. in the MTO Forestry plantations Witelsbosch and Longmore. The MTO Longmore sawmill burnt down in the fire. Fires also created havoc in the Nelson Mandela Bay metropolitan area. The extent and intensity of this fire reminds one of the 1869 ‘Great Fire’ which raged out of control between Riversdale and Uitenhage for weeks, also after a prolonged serious drought and under similar extreme fire danger conditions. However, there the similarity ends, for those fires were bergwind driven, and the area was sparsely populated, having largely consisted of natural vegetation with little human development. Alien invasive species and exotic plantations were unknown. With the writing of this news report, a week after the event and with most of the detail information still outstanding, mopping up operations are continuing over a large area and Tsitsikamma fires are still burning. The event of 7th June was something local foresters greatly feared for weeks before the disaster – it was a time bomb waiting for the fuse to be lit. It was preceded by a few weeks of extremely dry and warm weather conditions, with the past months having experienced rainfall far below the average. Soil moisture was all but depleted and vegetation was suffering from drought. In the early morning hours a gusty, gale force north westerly wind such as had not been experienced in living memory, and which during the course of the day reached speeds of up to 90 km/h, hit the area. A set of weather conditions known as a ‘cut-off low’ with exceptionally strong winds had been forecast a week before, and all schools in the Western Cape closed for that day. Two main fires, followed by a number of smaller fires, started from the Elandskraal area north east of Sedgefield and in the MTO Kruisfontein...

read more