SYNOPSIS Test done by the author and others have shown that the strength of laminated beams is usually governed by the strength of the finger joints in the extreme tension laminate. The author illustrates how the influence of the number of finger joints in a laminate can be quantified. He also points out that the variability of the finger joint strength can have a big influence on the strength, especially at the lower end of the strength distribution.
SYNOPSIS Clonal identities in a tree breeding and clonal development programme in Portugal consisted of two letters followed by a number of up to three digits. In Eucalpytus globulus clones the letters encoded pedigree information (and the year of induction into the clonal programme), while in interspecific hybrid clones they signified the parent species. Within the pedigree or hybrid, blocks of clonal numbers conveyed additional information including the family, while the individual numbers within the blocks were unique to each clone. The standard form of the identity minimised the risk of mistranscription and was easy to remember.
SYNOPSIS Defined as the use of available resources other than the planted trees on Mondi's landholdings, the development of various MRU projects is described from 1975 onwards. Projects are differentiated into those that are directly dependant on the presence of planted trees, such as Boletus mushrooms and honey production, and those that are not, such as aquaculture, ecotourism, livestock grazing, recreational hunting and angling, and the recreational use of available accommodation. The theme of “use it or lose it” is emphasised, as is the potential of MRU projects to contribute to RDP.
SYNOPSIS Narrow sense individual (h2), family (h2 f) and within family (h2 w) heritability values for Pinus patula from three CAMCORE trials in Colombia were calculated for height, diameter at breast height and volume per tree at eight years of age. Heritabilities ranged from low (0,12) to high (0,89), depending on the trait. For volume per tree, the expected genetic gains were 59%, 25% and 79% for three trials measured at eight years of age. The realised genetic gains for volume per tree were 16%, 15% and 31%. These gains are for plantations at eight years of age and in similar environments to the trial sites. In an effort to expand the genetic base, further CAMCORE trials of P. patula are being planted by Smurfit Cartón-de Colombia.
SYNOPSIS Forestry is an important user of water. It is also, in the eyes of some, an efficient user—and it is undoubtedly a nationally important industry. As pressures for the water resources increase, the forest industry finds itself ranged more and more frequently against both accustomed and previously less recognised users. Industrial and agricultural demands are growing, the needs of the environment are no longer ignored, and rural communities dependent on local water sources have at last found a champion. The consequence has been confusion as much as conflict, with understanding perhaps a bigger problem than knowledge. Far reaching modifications in the exercise of control over new afforestation were imposed early in 1995, and these are shaking out as government moves towards a broadly based national forestry policy. It would seem to be policy in practice that research is no longer needed to prove that trees use water (vide the demise of catchment research experiments), and efforts are now being aimed at the search for solutions. A number of approaches present themselves immediately. The country's goal with regard to timber production must be clearly and honestly spelt out, and must be reconciled with its need for water. Strategic planning must be integrated! So too should regions be assessed on a strategic basis, with decisions driven at national, regional and even quaternary catchment level. There is little doubt that regulation will continue, and become even more fierce—but fairness demands that attention be paid to all users and to all the costs and benefits along the production and value addition chain. The introduction of Integrated Environmental Management Planning, or at least Environmental Impact Assessments, should be imposed as something fresh, and not an add-on to an existing set of rules and regulations. This will allow for innovation in the planning of new forestry developments, and will create the space for new approaches in the management of existing plantations. Environmental management can do much to offset the conflict between industry, conservation, and other water users—recognition of this can drive people, forest companies, and national policy toward win-win solutions. So, too, must community needs be prioritised; but these are for both water and for employment—the opportunities are there!
(1996). The quest for natural forest management in Ghana, Cote d'Ivore and Liberia. South African Forestry Journal: Vol. 175, No. 1, pp. 59-59.
SYNOPSIS Young, small shoot explants of E. grandis were multiplied in the presence of 0,5 and 1 g/ℓ benomyl, 0,25 and 0,5 g/ℓ chlorothalonil, 0,36 and 0,72 g/ℓ propamocarb hydrochloride and 0,002 5 g/ℓ Amphotericin B. The multiplied shoots were then regenerated into plantlets in fungicide-free medium and hardened-off. At the concentrations tested, benomyl and chlorothalonil significantly inhibited survival, multiplication and growth, and the phytotoxic effects persisted after transfer to soil. At 0,36 g/ℓ, propamocarb hydrochloride did not significantly affect the total yield and development of plants, and Amphotericin B exhibited an hormone-like positive effect on growth. On the basis of these results and on the broad range anti-fungal activity of propamocarb hydrochloride, this fungicide appears to be a good agent for the eradication of fungal infections in eucalyptus cultures.
SYNOPSIS The effect of environment on growth-stress splitting, wood density, fibre length, shrinkage and heartwood content was studied using 31 five-year-old eucalypt clones, mostly Eucalyptus grandis and E. grandis-based hybrids, grown in replicated trials at 26 sites. An analysis of variance was carried out for each wood property to test the interaction between site and clone. For each clone a linear regression of the individual property value on the mean of all clones for each site was computed as a further measure of clone-by-site interaction. Both analyses indicated that genotype-by-environment interaction does exist for some clones and that it is applicable to all the wood properties considered except fibre length. However, clones showing sensitivity to changes in the environment for a particular wood property did not necessarily show sensitivity in the case of other wood properties. In other words, no clone could be singled out for showing sensitivity towards changes in the environment for all its wood properties. Although the trial was young at the time of sampling, the results indicated some important trends. Information of this kind is of fundamental importance for tree breeding programmes as it would form a useful basis for correct choice of clones if GEI of significant nature and magnitude is detected.
(1996). Vegetation management in Pinus radiata: A literature review. South African Forestry Journal: Vol. 177, No. 1, pp. 41-50.
SYNOPSIS During a survey of plant-parasitic nematodes in the Bergplaas Plantation, Western Cape Province, one Acacia melanoxylon compartment, seven Pinus compartments and twenty-two pockets of indigenous forest and virgin veld were sampled. Criconema, Rotylenchus and Scutellonema species were found at most of the localities whereas Helicotylenchus, Hemicycliophora, Meloidogyne, Ogma, Paralongidorus, Paratylenchus, Rotylenchulus, Trichodorus and Xiphinema species were found at fewer localities. The genera Criconemella, Meloinema, Mesocriconema, Paratrichodorus and Pratylenchus were found at single localities only. Criconema simplex sp. n., collected around natural vegetation is described. The females are characterised by 54 to 59 smooth, retrorse body annuli; the first annulus with a smaller diameter than the second annulus and sometimes with one or two lateral clefts, no submedian lobes or labial plates, a rounded tail tip, a straight vagina and a 39 to 44 μm-long stylet. Hemicycliophora nullinca Van den Berg, 1987, and Mesocriconema neli Van den Berg, 1984, are briefly discussed.
SYNOPSIS The effect of two formulations of hexazinone at two rates with two application methods (1,5 m wide strip and total area) on fynbos were tested in a one-year-old Pinus radiata stand. Total manual weeding and mechanical ring weeding of one metre radius were added as experiment treatments to obtain 10 treatments. Tree height and diameter growth were monitored to determine the effect of weed control. After 13 months the liquid formulation of hexazinone was significantly better than the powder formulation. There were no significant differences between the two application methods. The higher herbicide rates showed better weed suppression than the lower rates although non-significantly so. Floristic surveys conducted over a three-year period indicated satisfactory weed suppression. Plant moisture stress measurements in the first three summers (dry season) after application indicated that the trees were not under water stress.
The tropical rainforest ecosystem rainforest use - wisdom, folly, ambivalence sustainable forestry in rainforests principles and strategies of sustainability Sarawak forestry - torturous road towards sustainability naturalistic natural rainforest management in Sarawak restoration of degraded ecosystems short-rotation tree plantations forest management guidelines timber certification, trademarking and monitoring failures, major obstacles, trends and needs.
SYNOPSIS This paper details the latest results of site preparation and tending experiments in Pinus radiata on regenerated sites, on both Kruisfontein Plantation in the Southern Cape District of the Western Cape Forest Region and Blueliliesbush Plantation in the Tsitsikamma Forest Region. In the Kruisfontein experiment, significant differences in height and root collar diameter were observed for both the soil cultivation and phosphogypsum treatments. The soil cultivation treatments also showed significant differences in tree survival. The Blueliliesbush experiment showed significant differences in height and root collar diameter for the weed control treatments, as well as for the seedling size treatments, but not for the soil cultivation treatments. The seedling size treatments also showed significant differences in tree survival.
SYNOPSIS The relative susceptibilities of half-sib progenies of Pinus radiata obtained from seed parents selected for apparent resistance to the pine pathogen Sphaeropsis sapinea in plantations in the Western Cape and Chile were assessed in two separate trials. In each trial, artificial inoculations with the pathogen were performed on the stems of 20 one-year-old potted seedlings. Cambial lesions which resulted on stems were measured 14 days after inoculation and the mean lesion length for each selection was evaluated as a trait indicative of the degree of field resistance of the respective parents. Substantial differences in mean lesion lengths were observed among the different progenies in both trials. There were significant differences (P<0,05) between minimum and maximum progeny means as well as among intermediate progeny means for each of the two trials. The results of this preliminary study suggest that indirect selection of P. radiata for resistance to S. sapinea from within a general breeding population has considerable potential which should be investigated more intensively.
SYNOPSIS The invasion status of Australian blackwood, Acacia melanoxylon, is assessed against its value as a commercial tree in the southern Cape forests. The species was introduced from Australian rain forests and planted extensively in the southern Cape forests since 1909. It has since become well established in the forests, and invaded open areas outside the forest. However, it is also a useful and valuable timber tree which contributes more than 60% of both the timber volume and revenue obtained from the forest. A Blackwood Group System was established in the forest since 1968 in which the tree was planted in pure stands in the forest gaps caused by the felling of large trees. This study comprised various investigations to assess the invasion status of the species in the forests and to determine under what conditions it poses a threat to the forest. The results show that A. melanoxylon occurs in all the main forests throughout the southern Cape. It has the characteristics of an aggressive invader plant, but it does not aggressively invade closed, evergreen forest. In dosed forest its population diameter distribution is bell-shaped, a curve typical of pioneering populations in maturing vegetation. Outside the forest it is a serious invader of open and disturbed sites, as is shown by its negatively exponential diameter distribution along rivers and forest margins, i.e. a curve typical of expanding populations. In the forest it requires large gaps to grow fast. In the larger logging gaps (but generally small gaps) mean diameter growth was 0,9 cm/a over 22 years. In the larger gaps (l 200 to 1 500 m2) of the Blackwood Group System, diameter growth averaged 1,6 to 1,9 cm and the largest tree of 58 cm averaged 2,6 cm/a diameter growth over 22 years. Volume growth was 10,5 to 13,4 m3/ha per annum. The surrounding forest had a suppressive effect on the diameter and height growth of A. melanoxylon trees on the gap margin. A wide range of indigenous forest canopy tree species, including the commercially valuable Ocotea bullata, Podocarpus falcatus and P. latifolius, regenerated and became established in the understorey of A. melanoxylon in the Blackwood Groups. Crown volume is significantly related to DBH and total tree height. The large emergent crown and very shallow root system make the large trees very susceptible to strong gusty winds. It is concluded that the ecological characteristics and requirements of the shade-intolerant blackwood should be considered in relation to the ecological processes of disturbance and recovery of the forest to reconcile its production from the forest as timber tree with control of its invasion potential. Recommendations are made to consider the species as a useful, fast-growing, shade-intolerant pioneer tree which requires large gaps for optimum timber production, but whose spread can be controlled by keeping canopy gaps to a minimum.
SYNOPSIS Some areas of forestry estates, including unplantable ones, may be zoned and managed for nature conservation. This paper is an analysis of the results of studies of plants, birds and small mammals at Jonkershoek, Stellenbosch, to determine whether pine plantations are “inhospitable” to ecological and demographic processes required for the persistence of these biota in native habitat “islands” within forestry areas. The present study indicates that pine plantations are not unqualified “inhospitable seas”. However, the human-assisted dominance of the pines over the indigenous vegetation eliminates many species of the original habitat and reduces the numbers, or the frequency of occurrence, of the remaining species. There were significantly fewer vertebrate-pollinated, indigenous, plant species in the plantation sample than in the mountain fynbos one, and significantly more vertebrate-dispersed, native, plant species. Vertebrate pollinators were infrequently recorded in, or absent from, mature pine plantations. These factors are likely to affect some ecological and demographic processes in the pine plantations, such as vertebrate-mediated pollination, and perhaps the continuity of these processes between large areas of original habitat and indigenous habitat patches in the forestry area. Therefore we suggest that areas of fynbos and riparian forest surrounded by plantations should be considered as “islands” in an “inhospitable sea” when considering the zonation and management of indigenous habitat for conservation on forestry estates.
SYNOPSIS SYNOPSIS The paired catchment method was used to measure the effects of riparian zone clearing and clearfelling on streamflow, stormflows and water quality. The forested riparian zone of a 39,6 ha, humid Northern Province catchment, amounting to 10 % of the catchment area, was cleared and kept clear of vegetation. Two years later the entire catchment was cleared by bulldozing and burning its cover of indigenous evergreen forest and scrub forest, and replanted to Eucalyptus grandis seedlings. The riparian clearing resulted in a small 55 mm (9 %) increase in streamflow in the first year, and mean increases per storm in quickflow volume of 2,32 mm (71 %), in stormflow volume of 4,60 mm (76 %) and in storm response ratio by 2,37 % (a 50 % increase). By the second year these effects were diminished, and total flow was reduced by 56 mm (19 %) below expected flow. Clearfelling and replanting of the catchment had similarly small effects on streamflow and stormflows. This could be ascribed partly to a serious drought at the time of the treatment. Only the total streamflow could be shown to have changed significantly after the clearfelling. In the first year after clearing total flow increased by 27 mm (35 %), but by the second year the rapid establishment of the eucalypt crop and a dense cover of weeds had resulted in a small decrease in total flow of 12 mm (6 %). There was no significant response in total suspended sediment (TSS) concentrations to the riparian clearing. In total the sediment loss from the catchment was 0,186 t/ha in the first and 0,046 t/ha in the second year after the riparian treatment. In the first year after the clearfelling and afforestation of the whole catchment, the only water quality variables to change significantly were K+, NO3-N, PO4 3,-P and Si. In the second year after clearfelling there were changes in TSS, K+, TP, Si, NO3-N, and PO4 3,-P. Sediment losses amounted to only 0,022 and 0,028 t/ha in the first and second years respectively. None of the concentrations in stormflow showed significant changes. Most concentration levels, and especially that of sediment, were lower during the period of the drought. We conclude that: 1. indigenous evergreen forest is a relatively conservative user of water and that the quality of water from such catchments is high; 2, clearing of riparian and other indigenous forest and scrub vegetation is not a practical means of augmenting streamflow in this region; 3. the apparently extreme treatments applied did not disturb the soil mantle enough, or for long enough, to change the mode of streamflow generation in this catchment; 4. although the extreme clearfelling treatment had a statistically significant effect on a few water quality variables, concentrations never exceeded levels acceptable for aquatic life in river water; and 5. the minimal effects of the treatments may in part be due to the below average rainfall experienced during the experiment.
SYNOPSIS Eucalyptus nitens (Deane & Maiden) Maiden is an economically important Eucalyptus species with a broad natural range in Australia and has been identified as a priority fuelwood plantation species in Lesotho. Unlike most eucalypts, E. nitens is a shy seed bearer. This study was aimed at propagating Eucalyptus nitens using stem cuttings. These were taken seasonally from an 11-year-old E. nitens stand and three-year-old stock plants. Cuttings were prepared in a factorial combination of four types of media (viz. peat, sand, vermiculite and a 1:1:1 mixture of the three) and two hormone dipping treatments (viz. no dipping and dipping in Seradix No. 3 rooting powder containing 0,8% IBA). In the last experiment, 0,2% IBA was used. Rooting performance was evaluated under glasshouse conditions using a warm bench propagation unit. Adventitious root formation on cuttings of E. nitens was not effectively influenced by the application of IBA. Rooting of cuttings obtained from 11-year-old E. nitens decreased from 7% in February to 0% in November. Cuttings taken from three-year-old stock plants rooted better regardless of season, 30% and 56% rooting for March and September respectively. When the rooting media were assessed, no major differences were found for the cuttings from the 11-year-old stand. However, with the juvenile material the vermiculite-containing media, combined with the no dipping treatment, performed significantly better than the others.
SYNOPSIS In South African Forestry the planting of poplar trees for matchwood is a niche industry for a niche market. However, clouds are appearing over the horizon, in the form of a reduction in area being managed for this purpose and, lately, in a reduction in volume produced. Reasons for the apparent decline are investigated, while proposals are offered to maintain, for the nation's benefit, a minimum area of poplar groves under responsible conservation management.
