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- Volume 2002, Issue 195, 2002
Southern African Forestry Journal - Volume 2002, Issue 195, 2002
Volume 2002, Issue 195, 2002
Author D.L. OwenSource: Southern African Forestry Journal 2002, pp 1 –2 (2002)More Less
Extracted from text ... Southern African Forestry Journal - No. 195, October 2002 1 Foreword The contributions included in this Dedicated Edition of the Southern African Forestry Journal are all papers presented at Concurrent Conference No 2 at Wood for Africa 2002 "Creating, growing trees through innovation and technology" held in Hilton, near Pietermaritzburg, RSA from 2 to 4 July 2002. Against the Wood for 2002 theme of "The future explored" I want to draw readers attention to the editorial message by Mike Edwards, that leads us to the Guest Editorial - the plenary session paper - by ..
Author M.B.P. EdwardsSource: Southern African Forestry Journal 2002, pp 3 –4 (2002)More Less
Extracted from text ... Southern African Forestry Journal - No. 195, October 2002 3 Dedicated Edition Sponsor's Editorial Comment "When you have nothing to show or to be proud of, it is best to keep quiet. When however you have lots to show and to be proud of, then let the World know about it." This statement is the basis on which the Forestry Industry in South Africa was confidently able to go ahead and organise the Wood for Africa 2002 Conference and Exhibition. The interest, attendance and business conducted at Wood for fully justified the Industry's confidence as ..
Southern Africa : woodbasket of the future : guest editorial : "Plenary session address at Wood for 2002"Author John L. JobSource: Southern African Forestry Journal 2002, pp 5 –10 (2002)More Less
With increasing political and economic stability in prospect, the region's potential as a grower of plantations is explored. Along with the potential afforestation, the region's ability to exploit the resources so generated is considered across a variety of manufacturing industries. The need for political alignment, as well as stability, as prerequisites for success are discussed. Concerted efforts within the region are needed to create the potential and much-needed wealth.
Deployment strategies to maximise value recovery from tree improvement : the experience of two South African companies : operational deployment of technologySource: Southern African Forestry Journal 2002, pp 11 –22 (2002)More Less
Current strategies for deployment of improved material from the tree breeding programmes of two South African forestry companies are reviewed for all commercial species, including both hardwoods and softwoods. How high site variability and propagation constraints restrict this are examined and illustrated with examples. The multiplication techniques are viewed not just as a means of amplifying improved material, but also from a plant quality perspective and the effect this can have on the establishment of the crop. Lastly, two important questions are posed. Is enough known about the sexual reproduction of the commercial species in South African forestry? What developments in vegetative propagation techniques are necessary to allow the exploitation of the gains being offered from advanced generation breeding in the tree improvement programmes within the two companies?
Some issues associated with the commercial implementation of weed management recommendations : operational deployment of technologySource: Southern African Forestry Journal 2002, pp 23 –32 (2002)More Less
The Institute for Commercial Forestry Research (ICFR) is owned by the South African forestry industry and undertakes research on applied aspects of commercial timber growing. The type of research conducted depends, to a large extent, on a combination of our areas of expertise and the needs as determined by our sponsors. By way of a case study (one single trial) in the field of weed management research, an attempt is made to show the processes of research and development and how these lead to knowledge that is transferred to the end user. From this single trial with clear objectives, a number of tentative recommendations were made based upon early results. The commercial implementation of these results was only partially successful, with questions being raised that could only be addressed through additional trial work. Even though subsequent research efforts can be considered a success from a research perspective, in that they provided solutions to the questions asked, few have been applied commercially. This raises concerns, especially as to what the issues are that prevent the implementation of weed management recommendations. Some of the issues discussed include: researcher competence, whether the industry knows what it wants, robustness of research findings, how technology is transferred, complexity of weed growth information, institutionalisation of systems and economic and political constraints. By way of discussing the mixed successes in technology transfer, a hypothesis is developed as to where the barriers to effective technology transfer are and how these can be overcome. We believe that the most effective way of overcoming this is through the establishment and strengthening of the research-consumer interface. This needs to be included as a research activity, and to be enabled and resourced by end-users.
Source: Southern African Forestry Journal 2002, pp 33 –38 (2002)More Less
The southern African forestry and forest products industry contributes two percent of the countries gross domestic product, yet is one of the most globalised industrial sectors. Forest product exports make up eight percent of the countries total exports and produce an annual net trade surplus of R5 billion. To remain globally competitive, the southern African forestry industry must continue to produce low cost wood of the required quality for processors. Increasing yield per hectare is a significant means to achieving this aim and is actively pursued by industry players, particularly through genetic improvement of planting stock. <br> To maximise future productivity from plantations, it is important to consider and measure a number of components within the deployment process. The concept of operational gain is more than the weighted average of the genetic quality of planted hectares, and encompasses tree breeding efficiencies, propagation efficiencies, matching of species and genotype to site, plant use efficiency and early measures of stand density and growth.<br> To test the operational gain concept, trials have been planted to eucalypts in the Kwa-Zulu Natal midlands. Two and a half year volume measurements from two of these trials are presented. The trials test a factorial combination of species, genetic level, stand density and level of silvicultural input. Results at two and a half years demonstrate the additive nature of yield gains associated with each of these factors. The results confirm the need to measure efficiencies in all the components of the deployment process in order to maximise productivity. It is suggested that the measurement of operational gain, should include the measure of genetic gain against established benchmarks, conformance to site/species matching best practice, plant use efficiency and the assessment of stand density and variation in height at one year, for eucalypt pulpwood crops.
Management of insect pests : have the goalposts changed with certification? : operational deployment of technologyAuthor Prem GovenderSource: Southern African Forestry Journal 2002, pp 39 –46 (2002)More Less
The certification of commercial forestry according to the Forest Stewardship Council specifications has successfully occurred in many South African plantations and this trend is set to increase in the future. Various principles and criteria govern the management of insect pests in certified forests, which differ from traditional control measures. Regulations on the use of insecticides, biocontrol agents, monitoring, assessment and management of insect pests have become more specific. World Health Organisation type 1a and 1b, chlorinated hydrocarbons and persistent, toxic and bioaccumulative insecticides are prohibited. Only <i>Bacillus thuringiensis</i> is acceptable from the about twelve insecticides used in forestry. The use of biological control agents need to be documented, minimised and monitored. Flora and fauna in general and insect pest species must be regularly monitored and the results incorporated into an ongoing management plan. A summary of monitoring indicators should be made available to the public. An integrated pest management approach for the control of insect pests is advocated but with restrictions on the use of insecticides and biological control. Although the FSC management plan for the control of insect pests would certainly contribute to the sustainability of commercial plantations in the future, it poses many challenges in the short term.
Growth and yield as an indication of sustainable forest management in industrial plantations : evidence for sustainable plantation forestrySource: Southern African Forestry Journal 2002, pp 47 –56 (2002)More Less
Evidence from growth and yield measurements of successive rotations of industrial plantations is reviewed. The objectives, methodologies and limitations of the evidence is discussed and suggestions made concerning appropriate aims and methods for such work. Reported comparisons of forest productivity between successive rotations of <i>Pinus radiata</i>, <i>P. patula</i>, <i>P. taeda</i> and <i>P. elliottii</i> demonstrate that yield declines can occur when inappropriate forestry practices are applied to specific sites. Identification and understanding of these effects appear to have been initiated by data from simple growth comparisons between rotations. In these studies the observation of decline in successive rotations was followed by empirical and process studies to establish a cause. This in turn leads to modification of forestry practice to correct the decline. These experiences suggest two important objectives for monitoring of growth and yield in successive rotations; firstly, as a physical check that the actual trend in yield between rotations is consistent with expectation and secondly, as a tool to elucidate the cause of observed change in productivity between rotations. The chosen methodology must relate to the specific objective of the study. The lack of comparative data from successive rotations of fast-grown <i>Eucalyptus</i> plantations is highlighted.
Biological processes as indicators of sustainable plantation forestry : evidence for sustainable plantation forestryAuthor Mary C. ScholesSource: Southern African Forestry Journal 2002, pp 57 –62 (2002)More Less
This paper discusses the use of an ecosystems approach in the management of plantations and the concept of plantations in providing goods and services. Ecological indicators are compared for the CIFOR and South African systems. The CIFOR system focuses on three criteria, which involve the maintenance of a) biodiversity, b) ecosystem function and c) genetic variation. The South African system has chosen six criteria : a) the protection of natural forests, b) conservation of biodiversity, c) conservation of ecosystem structures and processes, d) protection of forests from fire, pests, diseases and alien plants, d) maintenance of production potential and e) the conservation of soil and water resources. Ideas are presented on indicators and measures, which may be useful in the sustainable management of nutrient cycling, yield production, pest outbreaks and water use and quality. Indices of nitrogen mineralization rates, soil carbon stocks and ongoing mensuration of biomass are key measurements. Under global change conditions it is predicted that the outbreaks of pests will be more severe and the industry must be prepared to invest in appropriate monitoring and technologies. It is emphasized that a framework needs to be provided into which the indicator measures can be placed. This would best be accomplished by the simultaneous development of a number of relatively simple ecosystem and plant-physiological based models.
Nutritional sustainability of Eucalyptus plantations : a case study at Karkloof, South Africa : evidence for sustainable plantation forestrySource: Southern African Forestry Journal 2002, pp 63 –72 (2002)More Less
The nutritional sustainability of a short-rotation <i>Eucalyptus grandis</i> plantation system was evaluated in a trial located at Karkloof, KwaZulu-Natal, South Africa, by determining nutrient pools and fluxes. Nutrient pools in the forest floor and biomass (above- and below-ground) were assessed by destructive sampling. The size of nutrient pools in the soil that approximate to readily available and potentially available fractions was estimated from chemical extractions. An approximate nutrient input-output budget was constructed.<br> The study has shown that large nutrient pools occur in the forest floor and below-ground biomass when compared to most short-rotation eucalypt cropping systems overseas. The readily available soil pools are moderately large (100 to 800 kg ha<sup>-1</sup>) when compared to similar systems in the tropics (Brazil & Congo). The potentially available nutrient pools are particularly rich in potassium (2.5) and magnesium (1.1 t ha<sup>-1</sup>). This indicates that the system is well buffered against nutrient depletion in the short and long term.<br> Estimates of nutrient fluxes revealed that fertilization and mineral weathering constitute small inputs, while atmospheric deposition makes a major contribution to the system (95% of total N inputs, 92% of total Ca and Mg and 82% of total K inputs). Sizeable nutrient losses were caused by slash burning (N), leaching (Ca & Mg), and both wood harvesting and firewood collection (N, K & Ca). The management regime and intensity of operations both have a pronounced effect on nutrient fluxes to and from the system, and hence, the net balance of the budget was calculated for different management regimes at representative intensities. Net fluxes were positive or near zero for most elements in the absence of firewood collection or slash burning and changed to losses of between ca. 5 to 10 kg ha<sup>-1</sup> a<sup>-1</sup> per individual nutrient when slash burning was incorporated in the regime. Despite the increases in nutrient loss with more intensive management, the indices of nutritional sustainability for all regimes tested still indicated a stable system with respect to nutrition.<br> Nutritional sustainability has been gauged by other researchers using the ratio (nutrient export in harvesting) / (available nutrient pool size). An index of nutritional stability (pINS) is proposed, based on the negative logarithm of the ratio (net nutrient loss) / (nutrient pool) where the nutrient pool can be readily available soil pools or (long term) potentially available system pools. Although this index has intensive data requirements, it evaluates management intensity effects as well as the "buffer capacity" of the system more rigorously than previously proposed indices.
Water use efficiency : what are the implications for plantation forestry? : evidence for sustainable plantation forestryAuthor N.W. PammenterSource: Southern African Forestry Journal 2002, pp 73 –78 (2002)More Less
Water use efficiency (WUE) is the ratio of some measure of growth or carbon assimilation to water utilization. It can be considered at the level of the leaf, whole plant or stand, and can be expressed in terms of total plant biomass or that of harvestable stems. It is a ratio and will be influenced by changes in either or both of the components. WUE is extremely variable with climatic and local weather conditions, soil type and plant age. Increases in yield of harvestable stem would increase WUE, but breeding practices have probably already maximised stem yield. Reductions in transpiration are considered unlikely to be achievable in plants growing in well-watered soils, and any such reductions would probably also bring about reductions in productivity. 'Water conservation' strategies are also unlikely in plants in water-limited soils, as competing neighbours would utilise the conserved water. It is not known whether there are differences among genotypes in intrinsic WUE, but if there are, these are more likely to become apparent under conditions of low, rather than high water availability. However, high WUE may not be a good selection criterion for plants suitable for water-limited conditions; the ability to acquire water and the ability to survive periods without water may be more important than the efficiency with which water is utilised.
The future of exotic plantation forestry in the tropics and southern hemisphere : lessons from pitch canker : evidence for sustainable plantation forestrySource: Southern African Forestry Journal 2002, pp 79 –82 (2002)More Less
Exotic plantation forestry, particularly with <i>Pinus</i> and <i>Eucalyptus</i> species in the tropics and southern Hemisphere, has expanded dramatically during the course of the last Century. Success of these intensively managed plantations is largely attributed to the fact that trees have been separated from their natural enemies. Due to increasing rates of introduction of pests and pathogens, this is a situation that is changing relatively rapidly. There is also growing evidence that unexpected native pests and pathogens are developing the capacity to infect exotic plantation trees. Clearly, highly productive, and intensively managed fibre farms are threatened and their future is likely to be more complicated than it has been in the past. The appearance of the pitch canker pathogen, <i>Fusarium circinatum</i> in South Africa, provides a contemporary example of new problems relating to a pathogen, previously absent from a country. This pathogen was first found in a single nursery and it has rapidly spread to all South African pine nurseries. It has significantly complicated pine propagation and is resulting in substantial losses in plantation establishment. Whether the fungus will manifest itself as a pathogen of adult trees as is the case elsewhere, is unknown. But this prospect is a matter of serious concern. Research aimed at a better understanding of the biology of <i>F. circinatum</i> in South Africa is essential. Furthermore, development of disease tolerant planting stock, in advance of a potentially deteriorating situation, would appear to be crucially important.
Author S.D. VerrynSource: Southern African Forestry Journal 2002, pp 83 –88 (2002)More Less
Tree breeding has had significant impacts on the success of the South Africa forest industry. Examples are cited for tree growth rate, where for instance, a mean genetic improvement of 39% has been measured in F2 <i>E.grandis</i> over unimproved controls over various sites. The mean improvement of F1 over P0 was recorded as 15% in the genetic gains trials, which compares with the realised reduction of rotation length by 10-15% in sawtimber crops. In <i>E.grandis</i> sawtimber, the impact of wood splitting has been reduced by approximately 29%. Similarly, substantial progress has been made in stem form, and species selection against pest and diseases. Selection of species with suitable properties for pulp yield is currently gaining momentum, with the increasing use of <i>E.smithii</i>, and the initiation of Project Pulp. Tree breeding will have to harness increasingly sophisticated technologies to make advances in the traits which have already undergone some improvement, such as tree growth. This is due to the gradual fixing of the genes which are easily captured, leaving the more challenging inheritance for advanced breeding techniques. There is a constant change in the market needs from trees (and tree breeders), as technologies change, markets change, and the environment changes. Tree breeding will continue to be a critical tool in maintaining a healthy forestry industry.
Author Eric KietzkaSource: Southern African Forestry Journal 2002, pp 89 –92 (2002)More Less
Many tree breeding programs are moving into advanced generation breeding, and breeders need to ensure continued gains from these programs. The potential of infusing genetic material into existing breeding programs, the introduction of "new" species, and hybridisation are discussed as options available to the tree breeder to increase variability and gain.<br> <i>Pinus patula</i> is the most important pine species in South Africa. The provenance origin of the first introductions of <i>P. patula</i> seed is unknown. The results of a series of <i>P. patula</i> provenance / progeny trials established from wide range collections made by CAMCORE indicate that the original importations did not come from the best sources. Infusion of this new material into local breeding populations will result in generating new variation in the base populations and resultant added gains.<br> Mondi Forests main processor requirements are for pulp and paper and <i>P. patula</i> is the preferred species. Recent expansions in afforestation have tended towards marginal land with regard to rainfall, temperature and soils. Results from a series of CAMCORE <i>P. greggii</i> trials established on these site types indicate that <i>P. greggii</i> shows potential as an alternative to <i>P. patula</i>.<br> Species hybridisation is another option for breeders to generate new variability, to take advantage of hybrid vigour or to combine specific traits from different species. Hybrid work in South Africa was initiated by SAFRI in 1968 and the <i>P. elliottii x P. caribaea</i> hybrid showed excellent growth potential. Mondi has concentrated its efforts on the <i>P. greggii x P. patula</i> hybrid and results of the first trial established with this hybrid has shown it to have potential.
Somatic embryogenesis as a tool to capture genetic gain from tree breeding strategies : risks and benefits : creating new germplasmAuthor Nicky JonesSource: Southern African Forestry Journal 2002, pp 93 –101 (2002)More Less
For clonal testing and ultimate commercialization of selected clonal lines, breeding programmes are reliant on vegetative propagation techniques. Somatic embryogenesis is a propagation technique that has the potential to assist with the deployment of pine clones. By virtue of its amenability to cryopreservation, it offers the opportunity to overcome the constraints associated with conventional vegetative propagation (hedge maturation), which hamper the advancement of clonal forestry in woody tree species. The limitations of somatic embyogenesis in pines include poor induction and maturation frequencies and the potential for somaclonal variation. These restrict the number of families or genotypes that can be processed. Methods of overcoming these restrictions are discussed together with the associated long-term potential of somatic embryogenesis, including genetic engineering and synthetic seed production.