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,...

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David Davidson is coming to Knysna.

Posted by on August 6, 2017 in Events | 0 comments

David Davidson is coming to Knysna.

NOT TO BE MISSED: Talk by David Davidson, of Chelsea Flower Show fame. The Topic is Biodiversity. Date: Sunday 3rd Sept, Time: 2.30. The Venue: Ambleridge Clubhouse  The Cost of the Tickets: R100, including tea, and the seats are unreserved. The Event starts with a scrumptious cream tea, and the talk will start at 3.15 and will probably be for about 2 hours. The tickets are available at Knysna Hospice, Bond House, Wilson Street, Hunters Home, Knysna. If preferred, phone Kathy Michaelides on 0823208302 and she  will arrange the ticket for those who cannot get to Bond House. They would prefer it if people could buy their tickets in advance of the event. David Davidson and Raymond Hudson have been responsible for designing and creating the Kirstenbosch-South Africa exhibit for the RHS Chelsea Flower Show for 23 consecutive years, together with a small core team and an enthusiastic crew of volunteers.   During this time, the exhibit has garnered 16 RHS Gold Medals (bringing the total since 1976 to 34), as well as the Anthony Huxley Trophy (1995) and the Lawrence Medal for the best floral exhibit shown to the RHS in 2006. The exhibit was also the first recipient of the RHS President’s Most Creative Award, introduced at Chelsea in 2008. In 2015 the exhibit was awarded Silver Gilt. Plants and art have always been David’s greatest passion, although he began his professional career in psychology and clinical social work. He later headed the Graphic Services Unit at the National Biodiversity Institute (Kirstenbosch) for 18 years – a role that included show design. His current full-time occupation is as a graphic designer and scenic artist. He has also created floral exhibits in other parts of the world including Palmengarten, Germany; the Royal Flora Expo in Thailand; the Singapore Garden Festival and the Gardening World Cup in Nagasaki, Japan. Raymond obtained a Diploma in Horticulture and gained his comprehensive practical training and work experience with the Durban Botanic Garden. He subsequently obtained a Diploma in Parks Administration at the John Brooks School of Landscape Design (1984). Ray’s career in landscaping includes the design and management of numerous large estates and landscaping projects for Keith Kirsten Horticulture International such as the spectacular Cape wine estates of Lourensford and Delaire, as well as the Cavalli equestrian centre, whilst his speciality is domestic and small garden design Share this:Click to email this to a friend (Opens in new window)Click to print (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Reddit (Opens in new...

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Brenton Blue Butterfly

Posted by on August 5, 2017 in Events | 0 comments

Brenton Blue Butterfly

BRENTON BLUE NEWS – JUNE 2017 To all friends and neighbours of the Brenton Blue butterfly – welcome to your latest newsletter! You can obtain more detailedinformation about the Brenton Blue butterfly itself on the website www.brentonblue.org.za, or about the Brenton Blue Trust at www.brentonbluetrust.co.za.  The management committee (MC)for the Brenton Blue includes representatives from CapeNature, WESSA, EWT, LepSoc Africa, the Knysna Municipality (KM)and local residents.   Annual General Meeting (AGM) The 2017 AGM of the Brenton Blue Trust (BBT) was held on the 27th May 2017. New trustee representatives Jeremy Dobson and Mark Williams attended for the first time. Activities of the BBT were reviewed, and included annual reports of current projects such as the COREL (Custodians of Rare and Endangered Lepidoptera) programme, the SALCA (South African Lepidoptera Conservation Assessment) project, and the Karoo BioGaps project. Notable achievements during the year under review included:   Finalisation of the terms of a contract nature reserve agreement with the KM to expand the Brenton Blue Butterfly Reserve (BBBR) from its original 1.6 ha to and expanded area of 15 ha. Agreement in principle with Stellenbosch University to create a 1200 ha contract nature reserve near Witsand to conserve Dickson’s Strandveld Opal (Chrysoritis dicksoni). Completion of the research into the ecology of Barber’s False Bay Ranger (Kedestes barberae bunta) at Strandfontein on the Cape Flats. The financial position of the BBT was currently robust enough to support all foreseen activities for the next two years.   The Knysna fire of 7th June 2017 The Knysna fire of 7th June 2017 also raged along the Brenton Peninsula, destroying dozens of homes, many in Brenton-on-Sea, location of the famous BBBR. The 15 ha expanded BBBR (see above) was severely burnt, leaving only very hardy trees such as candlewoods still standing, although badly scorched. After the fire there was no sign of the butterfly’s larval host plant, Indigofera erecta – not unusual because it is currently in its dormant winter state with underground rootstocks.   Dr Dave Edge, who received his PhD in 2005 for his work done on the ecology of the butterfly, says that the intensity and extent of this fire was completely unprecedented in living memory, as far back as when Brenton-on-Sea was founded in the mid-1960s. Several factors coincided to produce such a fire. Firstly Brenton (and indeed the whole Garden Route) had over the past nine months experienced a very severe drought, with rainfall less than 25% of the norm experienced since weather records have been kept for the Knysna area, and this had dried out the vegetation. Secondly, a proliferation of alien vegetation had increased the fuel load, and many of these alien trees were actually dying because of the drought. Thirdly, the closure of the Brenton-on-Sea garden waste disposal site had meant that residents were deterred from cutting woody plants on their plots. Fourthly, peak daytime temperatures had been up in the mid-thirties for a few days before the fire, as a result of a strong berg wind (from the north). And finally an incredibly strong westerly gale gusting at up to 100 km/hr rapidly brought a fire which had ignited in the Karatara area to the Brenton peninsula, where firefighters became helpless to stop it as it was able to jump fire breaks and wide roads....

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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...

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