TREE LIFE

JUNE 2011

MASHONALAND CALENDAR

Note: There will be no 3rd Sunday outing on 19th June as Society members will be away at La Rochelle.

Saturday, 25 June 2011 Visit to the Kimberleys, Avondale

The only outing this month will be a visit to Mike Kimberley’s garden on Saturday June 25th. Mike has planted many interesting native and exotic trees, and it should be an interesting afternoon. Meet at 2.30 pm.

WHO WILL CHAMPION AFRICA’S ACACIA

Is it time to take this matter to the international Court at The Hague? Will the rightful ‘owners’ of the name Acacia win the day this July 2011 in Melbourne? By all that is right the name Acacia belongs to Africa, Asia and the Americas – not just to Australia. The hijacking of the name in 2007 at the International Botanical Conference (IBC) was the result of some nefarious gerrymandering and shady manoeuvres in the back corridors by a small group of plant taxonomists who are now doing their utmost to discredit those wanting what is rightfully theirs.

At the July 2011 IBC in Melbourne the debate will rage on and whatever the decision, there is going to be ill-feeling.

Acacia abyssinica, flat topped Acacia; Photo Wikipedia

Typically when it comes to acrimonious exchanges those that shout loudest and can muster a majority willy-nilly will win – not necessarily those that are right! It must be said that the Melbourne Congress will be very expensive and will certainly be well attended by a powerful Australian contingent – while the poorer nations will mostly find it impossible to get funding to attend (even our own SANBI contingent will be extremely small because of a lack of funding – and South Africa is much better off than all other African countries when it comes to supporting our National Herbaria).

Since Vienna when Dick Brummitt and a few henchmen succeeded in hijacking the name Acacia for the Australian ‘wattles’ there has been a flurry of email activity, and several papers have been published in Taxon ‘explaining’ how righteous the Vienna decision was or how wrong it was (depending on whose side you are on). The simple truth of the matter is that Brummitt and a small group of Australians decided that it would be much easier on Australia if they kept the name acacia for their 1000-odd species of ‘wattle’, and the rest of the world with their few hundred species of acacia lost the right to use the name. This despite the fact that the International Rules of Botanical Nomenclature clearly state that the oldest name takes precedence, so it has been a case of First World hijacking of Third World rights (again) – with one wealthy country of 20 million people wrenching a name that is clearly not theirs from several billion people in many countries in Asia, Africa and the Americas.

Immediately after I first wrote about this manoeuvre in Veld & Flora there was a flood of responses from readers expressing outrage. There were even suggestions of taking the decision to the International Court in The Hague then. Professor Jan Glawesky from the Law Department at the University of Cape Town encouraged an Honours International Law student to study the facts and he presented their findings at an international gathering at which their paper received excellent reviews and astonishment from those present that such a hijacking had occurred.
Taxonomists are simply the custodians of plant nomenclature and should not have the right to piracy, no matter how justified they try and make it appear. Essentially the rules are that the oldest name for a plant is the embedded name, and only under exceptional circumstances can that name be altered – the Brummitt brigade tried to make this an exceptional case at Vienna, and despite some irregularities in the voting process, won the day because most countries did not even know that such a manoeuvre was on the agenda.

After Melbourne we Africans may no longer be able to use the name Acacia for those flat-topped, iconic tree species that characterize the African Savanna. But instead the Australian wattles will have our name. We need to fight this hijacking in the highest of international courts but more than anything, we need someone with a high profile to become Africa’s champion.

Eugene Moll
[Reprinted in the interests of science from Veld & Flora, Vol. 97(2) June 2011.]

FIRESTORMS IN SAVANNA AND FOREST ECOSYSTEMS

On the morning of 13 September 2008, the undulating landscape of Hluhluwe Game Reserve was a rolling patchwork of green, dense forests and the pale yellows and browns of winter grasses. But over the next 48 hours the hills of Hluhluwe were transformed, and areas dominated by thickets and forests were diminished essentially overnight, opening the landscape for sun-loving grasses to invade. The land singed and black, all bush removed, smouldering. Over a few days, the ashy black was replaced with the stark green of new growth. From forest to grassland: a shocking natural transition brought about by just one event – a fierce firestorm.

Despite the terrible aura of destruction, fire is a necessary and vital driver within savanna ecosystems. Grasses and forests have long coexisted and natural fires have been sweeping through the African landscape for millions of years, fine-tuning the mosaic of these fundamentally incompatible communities. Grasslands depend upon these fires for regeneration, while they are very destructive to forests. But forests usually survive grass fires with only their margins singed. However, the way in which fire patterns the landscape needs be better understood, because everything is changing…

Globally, and in South Africa, the effects of climate change on our ecosystems are quite noticeable. A risky trio of changing rainfall patterns, rising air temperatures and low humidity has resulted in extreme fire weather with widespread increases in forest flammability and subsequent large-scale fire events. Over the past decade extreme fire weather patterns have generally increased in frequency, size and intensity to levels beyond those historically experienced. If this is the case now, what then might the future hold? In the face of climate unpredictability, how do we foresee, prepare for, utilize, and manage these events during the fire season?

A grassland perspective

While it is tempting to focus on the shock of destruction caused by extreme fire events, they can also be recognized as positive agents that can be used to tackle the worrying colonization of grassland systems by advancing indigenous woody vegetation, called ‘bush encroachment’. And bush encroachment is on the rise. In the face of the new climate regime, woody plant cover is promoted as never before in the history of savanna landscapes. Why? Because present carbon dioxide (CO2> levels in the atmosphere are higher now than they have been for at least one million years and C02 acts like a steroid for the growth of woody plants. What results is a shift in the grass-tree balance with woody plants gaining increasingly over savanna grasses, which have evolved under lower C02 conditions. Left unchecked, what we may witness is the loss of our grassland and savanna biomes to advancing scrub forest. Firestorms could be the best way to reverse this.

A forest perspective

Forest ecologists, however, have thrown another spanner into the works. Many have raised concerns about the threat that grass-fuelled fires might pose to forests and the biodiversity they support. Forest-grassland mosaics exist because, though grasslands can burn very frequently, fires do not usually penetrate forests. Typically these fires require a continuous supply of grass fuel for the fires to spread and forests shade out the grasses. But if the ‘rules’ change, and grassland fires begin to enter and burn forests more frequently, then forests may be eliminated.
For the last half century and more in Hluhluwe Game Reserve in KwaZulu-Natal, forests have had the upper hand. Major bush encroachment has engulfed the grasslands, despite frequent fires and the activities of elephants and many other browsers (such as Impala, Nyala, Black Rhino, Kudu, Bushbuck and Giraffe). However decades of scrub forest invasion of grasslands was reversed in a single day. In September 2008 a very severe fire burnt right through the newly formed thickets and a forest section in the park, completely destroying the forest structure. This was a novel situation that challenged what we know. Typically fires do not penetrate beyond the edges of the forest and thicket stands. What was the cause of this firestorm? And, the burning question is how did it happen?

One possible answer was that the reserve had been heavily infested with Chromolaena odorata, an invasive pest in the park that belongs to the sunflower family and hails from North and Central America. The plant is more flammable than the scrub forest species it replaces while piles of dried, felled Chromoleana would provide a ready fuel-bed. However alien clearing teams at Hluhluwe have done a remarkable job in getting rid of Chromolaena and we could find no evidence to show that either old cleared areas, or areas yet to be cleared, burnt any more fiercely than uninvaded areas.

So if not the fuel, then how about the weather preceding the fire? The big fires in California, Greece and Australia in the last few years were preceded by long, hot droughts – ideal conditions for high intensity wildfires that burn down forests. Yet the 2008 Hluhluwe firestorm was preceded by an average rainfall season, not particularly hot, nor dry. Indeed the fire danger index used by plantation foresters showed nothing unusual in the days preceding the fire.

Switched on for fire

In growing frustration, we turned to an idea first suggested by Australian colleagues. Imagine a set of switches. To get a ship or a plane moving, all those switches need to be on. Well, fire, they suggest, is the same – all switches need to be on and then there is nothing stopping the firestorm. If any switch is off, it will be an ‘ordinary’ fire (or no fire at all). So what are the switches for a severe fire event? The Working on Fire teams have come up with a memorable rule—’thirty, thirty, thirty conditions’. This means air temperature greater than 30°C, relative humidity less than 30% and wind speed greater than 30 km/hour. Fires during these conditions cannot be contained. Any sensible person would go swimming. You can imagine the other key switches: there must be enough grass to fuel the fire, the grasses should be dry, and you need a match. Well, there was plenty of grass, it was bone dry at the end of winter, and an arsonist provided the match. And our detailed weather station data showed that 303 conditions continued for hour after hour on the day of the firestorm. All switches were on!

The unnerving thing is that, unlike the big fires of Australia, Greece and the USA, the extreme weather conditions appeared overnight and without any prolonged build-up. Analysis of the climate data from our weather station at Hluhluwe from 2001-2008 showed that the alignment of all three switches to produce 303 weather conditions is very rare. It is even rarer if the fuel switches are included. And then you need the final switch of the fool with the match.
Or is it that foolish? Thicket and forest patches that developed and expanded over decades were changed in composition and structure over 48 hours. Was this event desirable or undesirable? The fire was desirable from the point of view of reducing bush encroachment, but undesirable due to the loss of forest and the biodiversity it supported. This fire created the potential for a system switch, allowing the return of savanna through the spread of savanna grasses into the now open, sunlit landscape.

Should we throw the final switch sometimes?

Preliminary data from this study in Hluhluwe suggests that burning the veld under weather conditions conducive to severe fires, the 303 phenomenon, provides an opportunity for managers to reclaim invaded grasslands by opening up densely wooded areas. There are, of course, major safety issues, such as good fire training, equipment and manpower that need to be taken into account before firestorms can be effectively and safely emulated.
Through understanding the causes of such an extreme fire event as that of Hluhluwe in 2008, managers in the future could either ignite fires under extreme conditions to help savannas recover from bush encroachment, or be under high alert when extreme conditions arise. As far as we know this is the first South African study characterizing the climatic and other conditions causing grass-fuelled firestorms capable of burning into forested areas. The onset of 303 conditions, when a mild fire is already burning, may be very important to understanding the dynamics of these severe fire events. The ability to predict firestorms, and their consequences in the future could be improved by furthering our understanding of the dynamics of flammable connectivity and the relationships between fire switches.
We wonder whether similar extreme weather events might account for the very damaging fires that have occurred in South Africa in the last few years where losses of lives (of both people and livestock) and destruction of infrastructure and property have been devastating. Our interest is ablaze and several burning questions remain unsolved. We are particularly interested to see whether the 303 rule has any wider relevance as a marker of extreme fires. As an early warning signal, it seems essential to identify synoptic conditions that best predict the onset of firestorm weather.
No doubt different land-users will have different attitudes to firestorms. In the Hluhluwe context, we argue that they provide an excellent opportunity to turn back the tide of scrub forest invasion of the grassy biomes. But if firestorms become the norm in our globally warmed future, they would be disastrous for our indigenous forests. Regardless of their ecological effects, these are extremely dangerous phenomena and we salute the Working on Fire teams for identifying the weather conditions and for their skill in managing the fires.

Catherine Browne & William Bond
GET CONNECTED We are in the early stages of understanding fire storms. We don’t know all the answers or even the questions but are open to communication and would be most grateful for any information. The authors can be contacted at catmbrowne@gmail.com.

[Reprinted in the interests of science from Veld & Flora, Vol. 97(2) June 2011.]

CHAIRMAN’S REPORT 2010-11 Presented at the AGM on Sunday 15 May 2011

I have pleasure in presenting the Chairman’s report for the year 1 April 2010 to 31 March 2011.

General

This is my tenth annual report as Chairman. 2010 was the second year in which Zimbabwe operated a multi-currency environment (mainly the US$) and the resulting price stability and the ready supply of goods and fuel made the running of the Society so much easier.

During the year, we managed to organise eleven out of twelve 3rd Sunday outings, the only missing month being September when there was the outing to Aberfoyle. I started again my 4th Saturday walks and these were held in 7 of the 12 months of the period.

In addition to the regular monthly outings, we held a ‘Show and Tell’ afternoon on June 27th 2010 and Bill and Lynn Kinsey hosted a Cinematic Social on 13 March 2011. Both events were well attended and were most interesting and enjoyable.

The outings were as shown in the following table:

April    :    Lanark Game Park –
May :    AGM    Belfast Close MacDonald Park, Harare
June    :    Chedgelow Farm –
July :    Raintree Greystone Park NR
August    :    Gosho Park 167, Enterprise Rd
September :    Aberfoyle Domboshawa
October    :    Mfuti    Haka Game Park
November :    Stone Bushes, Norton –
December : Xmas Social – Val D’Or –
January : Rydal Court, Ruwa –
February : Christon Bank Blue Kerry
March    : Bally Vaughan Fawlty Towers

I am also very pleased to report that Bill Clarke organised a longer outing to Aberfoyle in September, the first such outing since 2006. A further longer trip has been arranged to La Rochelle in June. Many thanks to Bill for undertaking the organization of these outings.

Once again, I am very grateful to Meg Coates-Palgrave and David Hartung for stepping in as leaders when I was unavailable and for JP Félu for writing up some of the outings.

Membership
The current membership, compared to previous years, is as follows:
Membership    2011    2010    2009    2008    2007
Ordinary members    97 105    80    94 114
Associate members    3    7 5 5 5
Honorary members 3    4 5 6 6
TOTAL    103 116    90 105 125

Tree Mapping

Maureen Silva-Jones has recently acquired a new computer and work is actively under way in adding new records. Please send any records you may have to Maureen.

Tree Life
Once again, despite the inevitable and frequent last minute changes to the outings, Bill Kinsey continued to produce Tree Life efficiently during the period. The newsletter appeared in all 12 months.

Finance
The financial position of the Society remains strong. The treasurer, Bill Clarke will be reporting on this later in the meeting.

Website
The website has been kept up to date by Odette Lind and our thanks go to her for her hard work.

Committee
The Committee consisted of Ruth Evans (Secretary), Bill Clarke (Treasurer), Richard Oulton, Mimi Rowe, J-P Félu, Terry Fallon and myself. My sincere thanks go to all of them for their hard work and support on behalf of the Society.
At the previous AGM, we welcomed Bill Clarke who has done a sterling job in putting the accounting and finances on to a firmer footing.

Herbarium fumigation
Fumigations of the National Herbarium were carried out in July 2010 and January 2011. We have almost enough money to do a fourth fumigation in July 2011, after which I think we should organise another appeal.

Cultivated Trees
Traditionally, the Society has interested itself only in native and naturalised species of tree. However, many enquiries from the public and our members in fact relate to planted species and it has been decided that we should acquire more knowledge of these plants. As a start, during the year, work got underway to produce a checklist of cultivated trees.

Farewells
We have to report the sad news of the death of Bob Tanner. Sue and Bob attended the outing to Aberfoyle in September.

In conclusion …
The year saw an increase in our outings and activities, continuing financial soundness, despite some signs of falling membership.

Mark Hyde, Chairman