Hi Robin Thanks for your comments. Begging your pardon, I would insist that grasslands are the climax vegetation for the region, having evolved over at least 200 million years. You are right in saying that fires play a major role in the formation of grassland; naturally (and ideally) fires should occur at 4-7 year intervals. Many grassland plants have specifically adapted and are dependant on fire for propagation. Thus fire is good for natural grasslands. Fragmented patches of grasslands within plantation areas seldom, if ever get burnt, leading to a loss of fire dependant organisms. Often, 'fire breaks' maintained by the plantation industry gets burnt much to frequently, leading to loss of ground cover and soil erosion. Other factors vital to the formation of grasslands are climate (frost), altitude and grazing by huge herds of animals. Unfortunately, human values have reduced these herds of animals to a fraction of the original numbers, almost all contained in our national parks and few private reserves. Many grassland plans are high in medicinal value, having responded to the grazing animals by forming toxic chemical compounds for protection. These 'muti plants' are in high demand for use by indigenous medicinal practitioners, and seriously exploited in many areas. Grasslands have a high level of biodiversity, with many species of mammals, birds, insects, and plants endemic to the biome. Grasslands perform several functions vital to the health of the integrated natural environment, most notably water retention (acting as a spunge to absorb water during rainfall, releasing it slowly), thus preventing soil erosion and flash-floods. It is often quoted that grassland worldwide has been 80% destroyed, and is indeed the most threatened biome worldwide. This often as result of agriculture. Grasslands produce excellent agricultural soils, and Southern Africa's grasslands are well known for its high yielding crops.
In Mpumalanga province, more than 615 thousand hectares of alien timber plantations have been established. Alien timber species are preferred as they grow straight and fast, with little or no natural competitors or enemies. As much as 60% and more of the raw pulp produced gets exported, to fulfill the lucrative, exorbitant pulp / paper demand in the North. My view is that by exporting pulp, we are in essence exporting soil nutrients and water. But the plantation model does not allow the soil to regain its health. After harvesting, slash gets burnt and new plantings commence. Chemical fertilizers are applied at planting in marginal soils. Herbicides are used to control 'weeds'. As soon as the canopy closes up, not enough light penetrates to sustain indigenous flora and herbicides use become less intensive. I would like to inquire from you what the forest floor of a real forest looks like? Does it contain thick layers of non decomposing debris, as you find within the quiet of these plantations. It seems as if even micro organisms needed for composting dead organic matter is absent. Note that I hesitate to use the word 'forest' in association with these timber plantations. There is no undergrowth, few birds, minimal soil life and no sounds of insect's buzzing around. These industrial mono cultures are heavily dependant on machinery, at the expense of 'man-power'. Timber rotations are at seven to twenty-five year rotations, not very labor intensive. In addition, these timber species use vast quantities of water. Several springs locally have become bone dry since the introduction of plantations. The solution lies in diversifying using indigenous alternatives, eliminating chemicals, re-introducing animals and devoting some land currently under plantations to 'food gardens'. Ultimately of course, all this should be bio-dynamically managed...! My family owns and operates a pre-historic theme park on a tourism route in rural Mpumalanga, South Africa. We have a small, 10ha pecan grove on a otherwise undisturbed 300ha mountainous property. Except for bush encroachment, another serious problem is alien plant infestations, most notably a shrub called lantana. If all goes according to plan, we will be installing and operating a field broadcaster under Hugh Lovell's guidance in 2003, specifically to control lantana. Regards Philip -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Robin Duchesneau Sent: Monday, October 14, 2002 1:35 AM To: [EMAIL PROTECTED] Subject: Re: Industrial Timber Plantations - Sustainable? Dear Philip, Sustainability is a question of values. Which values humans choose to sustain is both subjective and arbitrary. As such, it should be known that is practically impossible to sustain all values as often we face tradeoffs. A conformable compromise is often what we strive for; a balance between economy, ecology, and other spiritual values. Some people believe that we should fragment the landscape an dedicate pieces of land for different values, rather then seeking a balance for every location. I suspect that the grass landscape in your region is maintained by fire, rather then being a true climax. As such, fire disturbance prevents tree seedlings from establishing and growing to maturity. Thus, removing fire is a 'human disturbance' that can be useful for establishing and maintaining a forest cover, but prone to cause long-term ecological unbalances. Such is the case when fire is removed and insect populations rise to epidemic levels. Forest monocultures aren't wrong per say. Nature often functions this way, as some species are better adapted for certain environments than others. Species exclusion, or extreme lethal vegetation competition, is a natural mechanism. What's not so natural is when an alien species is being established in an environment that cannot handle its presence. This might be the case in your region since the plantations are lifeless, and lead to problems such as 'green deserts', 'green cancer' and 'ecological wastelands'. Whether or not the soil will modify itself, due to the presence of trees and removal of fire disturbance, and become a productive medium is questionable. It depends. Yes, you are right in affirming that the soil will have more fungi; basidiomycetes. These forest fungi grow well with wood substrates (see the BDNow discussions on wood chips). The question of biodiversity is difficult. If the forester has good knowledge in site restoration and soil health, then biodiversity might stay the same; lost species will be replaced by new ones. Could it be that your region was once a forest and latter transformed into a grassland because of climate change and human impact? This is the case for many deserts in the world. And... there are now holistic techniques for bringing back 'natural forests' to these areas, if this is the values that people want. Personally, I would first ask myself which tree species could grow naturally in that location, rather then force alien species. I'm sure that if you go for a walk-about and observe the landscape you'll find the answer. Then, I would learn more about the reproductive nature of these tree species. It could well be that they need shrubs and other organisms to help them regenerate properly. Anyway... this is just a reflection of my personal value system. As the visiting scientist if they plan to chemically fertilize the plantation, or if they have a management plan for insect infestations, or how they will prevent fire from burning the forest. Also, why they are not interested in reclaiming the sites with natural tree species. Is it that they have already established a wood market, or that they don't know what the hell they are doing? And finally, what is the set of values that they want to sustain (jobs, $$$,...)? Philip, what do you do in Africa? Are you farming land? ( I'm a forest ecologist in Canada) Cheers, Robin ----- Original Message ----- From: "Philip Owen" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: 13 octobre, 2002 04:05 Subject: Industrial Timber Plantations - Sustainable? > Dear BDNow > > Here in Mpumalanga Escarment, South Africa, most of the original climax > grasslands have been planted to industrial monoculture pine and > eucalyptus plantations. Both these species are alien to the region. > These alien timber plantations are the "mother of all monocultures", > with drastic impacts on biodiversity and vital functions performed by > the original integrated natural environment. > > Conditions in the understory of these plantations are lifeless, leading > to terms such as 'green deserts', 'green cancer' and 'ecological > wastelands' beieng applied. As I understand grasslands are bacterially > dominated, and forests dominated by fungi. As these grasslands locally > are being replaced by 'false forests' the soil landscape is becoming > fungal dominated. > At an upcoming meeting scientists associated with the industry will > argue that this implies the soil will become progressively better for > growing timber, and that soil nutrient quality in timber stands are > actually improving for tree growing...??? > > How can this be true? > > Surely the fact that it is a mono culture with extremely limited > biodiversity and ecological interactions dooms it to medium / long term > soil nutrient depletion? > > Your comments will be much appreciated. > > Philip Owen > www.geasphere.co.za <http://www.geasphere.co.za/> > > >
