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- Volume 2002, Issue 194, 2002
Southern African Forestry Journal - Volume 2002, Issue 194, 2002
Volume 2002, Issue 194, 2002
Author Graham JewittSource: Southern African Forestry Journal 2002, pp 1 –6 (2002)More Less
Extracted from text ... Southern African Forestry Journal - No. 194, July 2002 1 Guest Editorial The 8%-4% debate: Commercial afforestation and water use in South Africa INTRODUCTION An estimate that commercial afforestation uses 8% of the country's water supplies has been quoted so often that it is has become a basis for discussions about commercial forestry and water use. Although disputed by many stakeholders in the forestry industry, the figure of 8% has been bandied around, by both protagonists and antagonists of commercial afforestation so often, that like the long held belief that 8000 elephants is the optimum number for the Kruger National ..
Early performance of Casuarina junghuhniana provenances / land races at Lushoto, Tanzania : scientific paperSource: Southern African Forestry Journal 2002, pp 7 –14 (2002)More Less
A trial involving 21 provenances form Indonesia and 7 "local" seed sources of <i>Casuarina junghuhniana</i> was established at Lushoto, Tanzania in March 1997. At 22 and 48 months of age, the following characteristics were assessed: survival, root collar diameter (RCD), breast height diameter (DBH) and height. The following were only assessed at 48 months of age: stem volume, biomass production and foliar nitrogen (N) and phosphorus (P) nutrient concentration and content. At all assessment occasions except for height (22 months of age), N and P concentration and P content (48 months of age), significant provenance/land race variation was observed for the rest of the characteristics studied. At 48 months of age, the four best performing seed sources were: Mt. Bromo, East Java; Mt. Pohen, Bali; KARI, Muguga, Kenya and Mt. Brumo, East Java while the four worst performing ones were: Kapan, Kumpang, Timor; 25 km S.W.Soe, Timor; Noelmina River, Timor and Buat, Soe, Timor. Although these results are based on early performance of the seed sources, the promising seed sources are recommended for pilot planting at Lushoto and similar sites. Further evaluation is however, necessary to confirm the best provenances/land races.
Evaluation of 19 provenances of Calliandra calothyrsus at Gairo and SUA Farm, Morogoro, Tanzania : scientific paperSource: Southern African Forestry Journal 2002, pp 15 –26 (2002)More Less
Performance evaluation was conducted among nineteen provenances of <i>Calliandra calothyrsus</i> from meso-America, Indonesia and Tanzania. Two trials were established in February and March, 1996 at Gairo (8 provenances) and Sokoine University of Agriculture (SUA) Farm (17 provenances) in Morogoro, Tanzania. Assessment was carried out at 3, 6, 14, 27, and 41 months for survival, root collar diameter and height. Biomass production was assessed during the last assessment occasion at SUA Farm (27 months after planting) and for Gairo at 27 and 41 months after planting respectively. At 27 months, when final assessment was done at SUA Farm, survival ranged from 33.3% (Lushoto Arboretum and Babati provenances) to 91.7% (Gracie Rock provenance). Above ground biomass production ranged from 4.81 to 17.26 t/ha for provenances Lushoto Arboretum and San Ramon respectively. When final assessment was done at Gairo site 41 months after planting, survival ranged from 50% for Apic Apac provenance to 75.0% for Fortuna and Cofradia provenances. Above ground biomass production ranged from 12.60 to 22.35 t/ ha for Apic Apac and Fortuna provenances respectively. Analysis of leaf samples showed low variation in N and P leaf contents for the provenances studied (ranges 1.35-2.50 N% and 0.09-0.18 P%). Based on the findings from this study, provenances Union Juarez, San Ramon, Bandug, Bombana and Flores are recommended for the SUA farm site and Fortuna, Cofradia, Bandung and San Miguel for the Gairo site.
Knowledge on Sclerocarya birrea subsp. caffra with emphasis on its importance as a non-timber forest product in South and southern Africa : a summary : Part 1 : Taxonomy, ecology and role in rural livelihoods : review paperSource: Southern African Forestry Journal 2002, pp 27 –42 (2002)More Less
<i>Sclerocarya birrea</i> (marula) is a widespread species throughout the semi-arid, deciduous savannas of much of sub-Saharan Africa. It is widely used by rural populations in most countries in which it is found. It has multiple uses, including the fruits, kernels, oil, bark, wood and leaves. Because of these multiple uses, and its significance in the landscape, several African cultures have specific beliefs and ceremonies associated with this species, and it is often maintained in homestead and arable plots. Because of the widespread occurrence, potentially high fruit production and use of <i>S. birrea</i> it has frequently been identified as a key species to support the development of rural enterprises based on the fruit, beer, oil or nuts and therefore as a species for potential domestication. Localised breeding and cultivation initiatives commenced in the 1970s and some continue. Interest in this species was renewed after the development of a highly successful liqueur using extracts from the fruit. This has developed further in southern Africa over the last 3 to 5 years, especially commercialisation initiatives orientated towards befitting the rural poor. Recently, the UK Department for International Development (DFID) initiated a project to examine the impacts of commercialisation of non-timber forest products, such as marula, on the livelihood capital of the rural poor. As a first phase, the research team compiled a comprehensive literature review of <i>S. birrea</i> , with emphasis on possible commercialisation. This is to be published in two parts. The first part deals with the taxonomy, ecology and its subsistence use and cultural value to rural households. The second part of the review will focus on issues relating to specific properties of the marula, management, intellectual property and its potential commercialisation.
Abnormal compression wood in Pinus taeda : a review of current knowledge and proposed future strategy : review paperSource: Southern African Forestry Journal 2002, pp 43 –52 (2002)More Less
Abnormal compression wood in <i>P. taeda</i> stands was first discovered in the early 1980s. Since then several research projects and surveys have been carried out in order to develop a better understanding of the problem and to try to find a solution. Currently a large proportion of the sawmill intake of logs in the Mpumalanga and Northern Province forest regions consists of this species, of which a reasonable proportion is affected by abnormal compression wood to varying degrees. This paper summarises the existing knowledge on the problem and current ways of dealing with it. Conclusions are that, since on average about 95% of the trees are either free from abnormal compression wood or manifest only a very slight presence of the phenomenon, the impact of the problem may not be as severe as generally thought, provided that a number of precautions are adhered to. Procedures such as leaving the worst affected logs in the plantations or labelling such logs as unsuitable for the production of veneer or boards for value-adding applications, may help considerably in reducing the impact of the problem. Graders at sawmills should be trained to assess the severity of abnormal compression wood present in sawn boards by inspecting the cross-cut ends of the boards where the phenomenon is usually best observed. Such boards should be labelled as not suitable for value-adding purposes or for further processing, except for cross-cutting them into particular lengths, should that be required. <i>P. taeda</i> has proved to be one of the best pine species with respect to growth and wood quality and should not be rejected outright. Further research on the phenomenon in order to extend the existing knowledge on the effects of genetics and silviculture is, therefore, strongly recommended. Tree breeding, in particular, appears to be the most promising approach to return this species to its former prominent position.
Source: Southern African Forestry Journal 2002, pp 53 –58 (2002)More Less
The development of embryonal suspensor mass (ESM) from immature embryos of <i>Pinus radiata</i> on a solidified growth medium containing 0, 5 mgl <sup>-1</sup> benzyladenine, 3, 0 mgl <sup>-1</sup> 2, 4-dichlorophenoxyacetic acid, 500 mgl <sup>-1</sup> casein hydrolysate and 250 mgl <sup>-1</sup> L-glutamine was used as inoculum to establish cell suspension cultures. Regular transplants of the ESM established on the solidified medium onto a hormone-free medium ensured sustainable growth and hence a source of ESM. Conditions for optimal growth in liquid media were investigated. The cell suspension turbidity was measured and used as a growth parameter. Optimal growth and normal embryo development were obtained in a liquid medium containing maltose as the carbohydrate source at a concentration of 3% (m/v) and supplemented with 0, 5 mgl <sup>-1</sup> 2, 4- dichlorophenoxyacetic acid. The results obtained from this study present an opportunity for large-scale propagation of <i>Pinus radiata</i> .
Post fire indicators of fire intensity at indigenous forest margins in the southern Cape, South Africa : research noteSource: Southern African Forestry Journal 2002, pp 59 –64 (2002)More Less
The aim of this study was to identify post fire indicators of fire intensity at indigenous forest margins in the southern Cape. Three sites in the southern Cape were subjectively chosen in recently burnt areas to represent areas of varying fire intensity. Tree mortality outside the forest edge confirmed our subjective classification of the three sample sites into high, medium and low fire intensity sites. Fire intensity was correlated to <i>Virgilia divaricata</i> seedling density, species richness, the width of the <i>Virgilia divaricata</i> strip and the width of the burnt forest margin. These easy to measure parameters could in future be used as practical field indicators of post fire intensity. Fire intensity could then be correlated to changes in forest species composition and structure to further quantify the impacts of fires on the indigenous forest margin.
The estimation of the growing stock of eucalypt plantation forests, based on spectral signatures of satellite imagery, in South Africa : research noteSource: Southern African Forestry Journal 2002, pp 65 –70 (2002)More Less
The present study deals with the application of spectral signatures, obtained from multispectral satellite images, in order to obtain regression estimates for the timber volume per unit area. The studies were carried out in South African <i>Eucalyptus</i> plantations. The greyscale values, recovered from sampling points based on 3 x 3 pixels, were satisfactorily closely correlated with the target variable. Cost-efficiency calculations indicated that two-and multiphase sampling with the aid of satellite images are an attractive alternative for traditional terrestric measurements. Further research is required.