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Pterocarpus angolensis, a leguminous tree native to the dry woodlands of Southern Africa, provides valuable timber, but is threatened by land conversion and overharvesting while showing limited natural regeneration. Nitrogen-fixing root nodule symbionts that could improve establishment of young seedlings have not yet been described. Therefore, we investigated the ability of P. angolensis to form nodules with a diverse range of rhizobia. In drought-prone areas under climate change with higher temperatures, inoculants that are heat-tolerant and adapted to these conditions are likely to be of advantage. Sources of bacterial isolates were roots of P. angolensis from nurseries in the Kavango region, other shrubs from this area growing near Pterocarpus such as Indigofera rautanenii, Desmodium barbatum, Chamaecrista sp., or shrubs from drought-prone areas in Namaqualand (Wiborgia monoptera, Leobordea digitata) or Kalahari (Indigofera alternans). Only slight protrusions were observed on P. angolensis roots, from which a non-nodulating Microbacterium sp. was isolated. Rhizobia that were isolated from nodules of other shrubs were affiliated to Bradyrhizobium ripae WR4T, Bradyrhizobium spp. (WR23/WR74/WR93/WR96), or Ensifer/Mesorhizobium (WR41/WR52). As many plant growth-promoting rhizobacteria (PGPR), nodule isolates produced siderophores and solubilized phosphate. Among them, only the Bradyrhizobium strains nodulated P. angolensis under controlled conditions in the laboratory. Isolates were further characterized by multilocus sequence analysis and were found to be distant from known Bradyrhizobium species. Among additional reference species tested for nodulation on P. angolensis, Bradyrhizobium vignae 7-2T and Bradyrhizobium namibiense 5-10T from the Kavango region of Namibia as well as Bradyrhizobium elkanii LMG6234T and Bradyrhizobium yuanmingense LMG21728T induced nitrogen-fixing nodules, while Bradyrhizobium diazoefficiens USDA110T and Bradyrhizobium tropiciagri SEMIA6148T did not. This suggests a broad microsymbiont range from Bradyrhizobium japonicum and B. elkanii lineages. Phylogenetic analysis of nodC genes indicated that nodulating bradyrhizobia did not belong to a specific symbiovar. Also, for I. rautanenii and Wiborgia, nodule isolates B. ripae WR4T or Mesorhizobium sp. WR52, respectively, were authenticated. Characterization of symbionts inducing effective root nodules in P. angolensis and other shrubs from Subsahara Africa (SSA) give insights in their symbiotic partners for the first time and might help in future to develop bioinoculants for young seedlings in nurseries, and for reforestation efforts in Southern Africa.

Pterocarpus angolensis , a leguminous tree native to the dry woodlands of Southern Africa, provides valuable timber, but is threatened by land conversion and overharvesting while showing limited natural regeneration. Nitrogen-fixing root nodule symbionts that could improve establishment of young seedlings have not yet been described. Therefore, we investigated the ability of P. angolensis to form nodules with a diverse range of rhizobia. In drought-prone areas under climate change with higher temperatures, inoculants that are heat-tolerant and adapted to these conditions are likely to be of advantage. Sources of bacterial isolates were roots of P. angolensis from nurseries in the Kavango region, other shrubs from this area growing near Pterocarpus such as Indigofera rautanenii , Desmodium barbatum , Chamaecrista sp., or shrubs from drought-prone areas in Namaqualand (Wiborgia monoptera , Leobordea digitata) or Kalahari (Indigofera alternans). Only slight protrusions were observed on P. angolensis roots, from which a non-nodulating Microbacterium sp. was isolated. Rhizobia that were isolated from nodules of other shrubs were affiliated to Bradyrhizobium ripae WR4T, Bradyrhizobium spp. (WR23/WR74/WR93/WR96), or Ensifer/Mesorhizobium (WR41/WR52). As many plant growth-promoting rhizobacteria (PGPR), nodule isolates produced siderophores and solubilized phosphate. Among them, only the Bradyrhizobium strains nodulated P. angolensis under controlled conditions in the laboratory. Isolates were further characterized by multilocus sequence analysis and were found to be distant from known Bradyrhizobium species. Among additional reference species tested for nodulation on P. angolensis , Bradyrhizobium vignae 7-2T and Bradyrhizobium namibiense 5-10T from the Kavango region of Namibia as well as Bradyrhizobium elkanii LMG6234T and Bradyrhizobium yuanmingense LMG21728T induced nitrogen-fixing nodules, while Bradyrhizobium diazoefficiens USDA110T and Bradyrhizobium tropiciagri SEMIA6148T did not. This suggests a broad microsymbiont range from Bradyrhizobium japonicum and B. elkanii lineages. Phylogenetic analysis of nodC genes indicated that nodulating bradyrhizobia did not belong to a specific symbiovar. Also, for I. rautanenii and Wiborgia , nodule isolates B. ripae WR4T or Mesorhizobium sp. WR52, respectively, were authenticated. Characterization of symbionts inducing effective root nodules in P. angolensis and other shrubs from Subsahara Africa (SSA) give insights in their symbiotic partners for the first time and might help in future to develop bioinoculants for young seedlings in nurseries, and for reforestation efforts in Southern Africa. [ABSTRACT FROM AUTHOR]

Julbernardia paniculata and Pterocarpus angolensis are two plant species with important application in African traditional medicine, particularly in Angola, in the treatment of several diseases. However, scientific studies concerning these species are scarce. The goal of this work was to know better which medicinal approaches are used by the Huíla population in Angola by means of ethnobotanical surveys. Furthermore, extracts of both plants were phytochemically characterized. Antioxidant, anti-inflammatory, wound-healing activities, and potential cytotoxicity were also studied. With this study it was possible to verify that 67% of the individuals that use medicinal plants are women, and their main therapeutic uses are the treatment of problems of the digestive system and skin disorders. Barks of J. paniculata and leaves of P. angolensis are the most often used plant parts. Through high-performance liquid chromatography coupled to diode-array detector (HPLC-DAD) and GC-MS it was possible to characterize the chemical composition of the two species, which are rich in phenolic compounds, terpenes, terpenoids, sesquiterpenoids and fatty acids. Both plants showed to possess antioxidant, anti-inflammatory proprieties, and wound-healing activity. To the best of our knowledge, this is the most comprehensive study of these two species and the first ethnobotanical and ethnopharmacological study of medicinal plants from this region of Angola.

To increase understanding of breakdown strategies for Mozambican timber, simulations were carried out using different sawing patterns that can be alternatives to the low degree of refinement performed for export today. For the simulations, 3D models of 10 Jambirre and 5 Umbila logs were used. The log shape was described as a point cloud and was acquired by 3D-laser scanning of real logs. Three sawing patterns (cant-sawing, through-and-through sawing, and square-sawing) were studied in combination with the log positioning variables skew and rotation. The results showed that both positioning and choice of sawing pattern had a great influence on the volume yield. The results also showed that the log grade had an impact on the sawing pattern that should be used for a high volume yield. The volume yield could be increased by 3 percentage points by choosing alternative sawing patterns for fairly straight logs and by 6 percentage points for crooked logs, compared to the worst choice of sawing pattern.

A native lectin (nPELa), purified from seeds of the species Platypodium elegans , Dalbergieae tribe, was crystallized and structurally characterized by X-ray diffraction crystallography and bioinformatics tools. The obtained crystals diffracted to 1.6 Å resolution, and nPELa structure were solved through molecular substitution. In addition, nPELa has a metal binding site and a conserved carbohydrate recognition domain (CRD) similar to other Dalbergieae tribe lectins, such as PAL ( Pterocarpus angolensis ) and CTL ( Centrolobium tomentosum ). Molecular docking analysis indicated high affinity of this lectin for different mannosides, mainly trimannosides, formed by α-1,3 or α-1,6 glycosidic bond, as evidenced by the obtained scores. In addition, molecular dynamics simulations were performed to demonstrate the structural behavior of nPELa in aqueous solution. In solution, nPELa was highly stable, and structural modifications in its carbohydrate recognition site allowed interaction between the lectin and the different ligands. Different modifications were observed during simulations for each one of the glycans, which included different hydrogen bonds and hydrophobic interactions through changes in the relevant residues. In addition, nPELa was evaluated for its nociceptive activity in mice and was reported to be the first lectin of the Dalbergieae tribe to show CRD-dependent hypernociceptive activity. [ABSTRACT FROM AUTHOR]

The study was carried out on August 31, 2013, at the nursery, Faculty of Agronomy and Forestry, Zambeze University, located on the grounds of the same institution with the objective of evaluating the effect of natural auxin (IAA) produced by the seed corn germination the vegetative propagation of Pterocarpus angolensis in order to develop a procedure for their regeneration through vegetative propagation by cuttings. Cuttings of Pterocarpus angolensis were standardized to a length of 15 cm and sharp-based bissel, were treated with four doses of corn seeds germinating. Corn seeds were placed to germinate in petri dishes for 96 hours, then placed in containers containing 500 ml of water, then the cuttings were placed for 48 hours, the following treatments were considered quantities of seed of maize T1 - 400 seeds, T2 - 300 seeds, T3 - 250 seeds and T4- 0 seed (control). Analysis of variance (ANOVA) showed a significant difference at 5 % probability (0.01 = < p < 0.05), for the different doses of the natural auxin concentration in relation to the average number of sprouting and the number of new shoots whereas lower dose (T3 - 250 seeds), achieved a better performance in all parameters evaluated. No rooting was observed, and all cuttings did not survive the conditions in which the study was conducted, reaching 100% mortality, 55 days after establishment.

Some imported guitars and others made in Zambia exhibit poor sound quality and properties. Zambia grown timbers were evaluated for their suitability as tonewoods. Pinus kesiya was suitable for soundboard as it had brighter appearance and best radiation coefficient 7.3 m4 s-1 kg. Its lower impedance 2733 Nmm2 s m3 gives better sustain. Pterocarpus angolensis was used for the back and sides as it was very stable, volumetric shrinkage 5.4%, and low impedance, 2,298 Nmm2 s m3 which reduced loudness. This species was also used for the neck. Baikiaea plurijuga was employed in fretboard and bridge construction as it was appreciably hard with Brinell hardness rating of 6.05 kN. A guitar made using the selected timbers was tested qualitatively. The Reference and the Experimental guitar attained the same score demonstrating improvements attributable to systematic wood selection. The study established that the quality of locally made guitars could be improved significantly if luthiers adopt appropriate wood selection criteria. [ABSTRACT FROM AUTHOR]

Pterocarpus angolensisis an important timber tree of the miombo woodlands of sub-Saharan Africa. The species only grows in natural mixed forests and little is known about is productivity potential. This study aimed at investigating productivity ofP. angolensison a local scale in Namibia and Angola and on a regional scale in southern Africa. The most commonly accepted productivity indicator is stem diameter increment and this was used to study productivity at a regional scale. Indicators of productivity used at the local scale were basal area, proportional basal area and site form, which were derived from 217 forest inventory plots in Namibia and Angola. The productivity measures were modelled with abiotic site factors; biotic factors were added for the local scale. Results indicated that the most consistent site factors at local and regional scale were not related to climate but to forest cover, with the species having a competitive advantage in more open forests. Mean annual diameter increment in the open forests of Namibia was 0.51 cm after 50 years. Boosted regression tree models at a local scale showed that species presence can be modelled more successfully than species basal area, proportional basal area (correlation of 0.72 vs 0.56 and 0.45, respectively) and site form. The sites with the highest productivity ofP. angolensisat the local scale had a temperature seasonality below 34.5 °C, a slope of less than 1.5°, tree cover less than 20% and stand basal area higher than 9 m2ha−1. The results can assist in establishing a site-dependent growth model for the species and direct forest and fire management towards the most productive areas. [ABSTRACT FROM PUBLISHER]

Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function. [ABSTRACT FROM AUTHOR]

The sawmill industry is a very important link in the Mozambique forest products value chain, but the industry is characterized by undeveloped processing technology and high-volume export of almost unrefined logs. The low volume yield of sawn timber has been identified as a critical gap in the technological development of the industry. To improve the profitability of the industry, there is thus a need to develop methods and techniques that improve the yield. In this paper, different positioning of logs prior to sawing and the possibility of increasing the volume yield of crooked logs by bucking the logs before sawing have been studied. A computer simulation was used to study the cant-sawing and through-and-through sawing of the logs to determine the volume yield of sawn timber from the jambirre (Millettia stuhlmannii Taub.) and umbila (Pterocarpus angolensis DC.) species. The optimal position, i.e. the position of the log before sawing that gives the highest volume yield of sawn timber for a given sawing pattern when the positioning parameters, offset, skew and rotation, are considered gave a considerable higher volume yield than the horns-down position. By bucking very crooked logs and using the horns-down positioning before sawing, the volume yield can be of the same magnitude as that obtained by optimal positioning on full-length (un-bucked) logs. The bucking reduces the crook of the logs and hence increases the volume yield of sawn timber. [ABSTRACT FROM AUTHOR]

Background Tropical dry forests cover less than 13 % of the world’s tropical forests and their area and biodiversity are declining. In southern Africa, the major threat is increasing population pressure, while drought caused by climate change is a potential threat in the drier transition zones to shrub land. Monitoring climate change impacts in these transition zones is difficult as there is inadequate information on forest composition to allow disentanglement from other environmental drivers. Meth ods This study combined historical and modern forest inventories covering an area of 21,000 km2 in a transition zone in Namibia and Angola to distinguish late succession tree communities, to understand their dependence on site factors, and to detect trends in the forest composition over the last 40 years. Results The woodlands were dominated by six tree species that represented 84 % of the total basal area and can be referred to as Baikiaea - Pterocarpus woodlands. A boosted regression tree analysis revealed that late succession tree communities are primarily determined by climate and topography. The Schinziophyton rautanenii and Baikiaea plurijuga communities are common on slightly inclined dune or valley slopes and had the highest basal area (5.5 – 6.2 m2 ha−1). The Burkea africana - Guibourtia coleosperma and Pterocarpus angolensis – Dialium englerianum communities are typical for the sandy plateaux and have a higher proportion of smaller stems caused by a higher fire frequency. A decrease in overall basal area or a trend of increasing domination by the more drought and cold resilient B. africana community was not confirmed by the historical data, but there were significant decreases in basal area for Ochna pulchra and the valuable fruit tree D. englerianum. Conclusions The slope communities are more sheltered from fire, frost and drought but are more susceptible to human expansion. The community with the important timber tree P. angolensis can best withstand high fire frequency but shows signs of a higher vulnerability to climate change. Conservation and climate adaptation strategies should include protection of the slope communities through refuges. Follow-up studies are needed on short term dynamics, especially near the edges of the transition zone towards shrub land.

Em um boletim técnico idealizado pela Organização das Nações Unidas para Alimentação e Agricultura foi ressaltada a importância de estudos em Moçambique para auxiliar as tomadas de decisões técnicas que visem à melhoria dos rendimentos nas serrarias do país. Em virtude das espécies utilizadas, bem como do baixo nível tecnológico do setor, desenvolveu-se este trabalho com o objetivo de avaliar o rendimento em madeira serrada de duas espécies tropicais, em uma serraria localizada na Província de Manica, cidade de Chimoio na região central de Moçambique. Para tanto, foram utilizadas árvores de Combretum imberbe (mondzo) e Pterocarpus angolensis (umbila), sendo selecionadas 12 toras para cada espécie. As toras de cada espécie foram classificadas em três classes diamétricas (quatro toras em cada classe). O desdobro das toras foi efetuado com serra fita, em modelo de desdobro tangencial sucessivo. O rendimento em madeira serrada, para as duas espécies avaliadas, aumentou em função da classe diamétrica, tendo diferenças estatísticas no rendimento em madeira serrada entre as duas espécies nas três classes diamétricas. C. imberbe apresentou maior rendimento em comparação a P. angolensis, sendo que os resultados considerados satisfatórios para o desdobro destas duas espécies de madeira nativas de Moçambique.

Background: Tropical dry forests cover less than 13 % of the world's tropical forests and their area and biodiversity are declining. In southern Africa, the major threat is increasing population pressure, while drought caused by climate change is a potential threat in the drier transition zones to shrub land. Monitoring climate change impacts in these transition zones is difficult as there is inadequate information on forest composition to allow disentanglement from other environmental drivers. Methods: This study combined historical and modern forest inventories covering an area of 21,000 km in a transition zone in Namibia and Angola to distinguish late succession tree communities, to understand their dependence on site factors, and to detect trends in the forest composition over the last 40 years. Results: The woodlands were dominated by six tree species that represented 84 % of the total basal area and can be referred to as Baikiaea - Pterocarpus woodlands. A boosted regression tree analysis revealed that late succession tree communities are primarily determined by climate and topography. The Schinziophyton rautanenii and Baikiaea plurijuga communities are common on slightly inclined dune or valley slopes and had the highest basal area (5.5 - 6.2 m ha). The Burkea africana - Guibourtia coleosperma and Pterocarpus angolensis - Dialium englerianum communities are typical for the sandy plateaux and have a higher proportion of smaller stems caused by a higher fire frequency. A decrease in overall basal area or a trend of increasing domination by the more drought and cold resilient B. africana community was not confirmed by the historical data, but there were significant decreases in basal area for Ochna pulchra and the valuable fruit tree D. englerianum. Conclusions: The slope communities are more sheltered from fire, frost and drought but are more susceptible to human expansion. The community with the important timber tree P. angolensis can best withstand high fire frequency but shows signs of a higher vulnerability to climate change. Conservation and climate adaptation strategies should include protection of the slope communities through refuges. Follow-up studies are needed on short term dynamics, especially near the edges of the transition zone towards shrub land. [ABSTRACT FROM AUTHOR]

Pterocarpus angolensis DC. (Kiaat) is one of the most preferred timber species that occurs in most southern African countries, including Namibia. In Namibia, the species mainly occurs across the five regions in the north-eastern part of the country where commercial timber harvesting has taken place since the 1940s. Information about the growth rates of the species is currently lacking, yet this information is required to determine a sustainable harvesting regime in Namibia. Therefore, more data about diameter increment is needed. This study aims to (1) determine annual diameter increment of P. angolensis in order to assist in planning for sustainable harvesting levels in the northern regions of Namibia, (2) compare growth of P. angolensis with other woodland species ( Burkea africana , Baikiaea plurijuga , Terminalia sericea and Schinziophyton rautanenii ) and (3) compare P. angolensis growth rates found in northern Namibia with those found in other countries within its distribution range. A total of 111 increment cores and 73 stem discs were collected for tree-ring analysis. The results showed that the average diameter increment of P. angolensis was higher in the Kavango regions (0.71–0.80 cm yr −1 ) than in neighbouring regions (0.35–0.41 cm yr −1 ). The northern Namibian growth rate is estimated as 0.50 cm yr −1 and lies within the growth range reported for southern Africa. Growth rates of P. angolensis were more than 0.10 cm yr −1 lower than rates of T. sericea and S . rautanenii , but 0.10 cm yr −1 higher than B. africana and B. plurijuga . Age–diameter relationships of P. angolensis may be a good indicator of tree age if a sufficient number of samples are obtained. Our results revealed a rotation cycle of 95–100 years to reach the minimum harvesting diameter of 45 cm in the Kavango regions. This rotation cycle should be a good guideline for sustainable management of this species. This study suggests that simple ring counting on increment cores and stem discs with additional diameter data can provide valuable information on growth rates and rotation cycles. Additional data and work on older trees (>100 years) is required to complete the age–diameter framework. [ABSTRACT FROM AUTHOR]

Agriculture is expanding rapidly in the miombo woodlands of sub-Saharan Africa. Clear felling results in the loss of species and ecosystem services. The remaining woodland is used as a vital support system for the farming communities, and the impact of this utilisation on biodiversity and ecosystem service provision is not clear. Understanding these effects will aid the development of effective, sustainable land management strategies for multiple outcomes, including biodiversity conservation and resource utilisation. This study provides new data on miombo woodland tree species diversity, structure and carbon storage from a 8766 km 2 landscape in south-western Tanzania, which is undergoing rapid conversion to tobacco cultivation. Human utilisation of the woodland was classified by ground surveys which recorded evidence of use (e.g. cut poles and timber, removal of bark and roots, access routes). Nine sites were surveyed and categorised into three groups: high, medium and low utilisation. To determine the effect of utilisation on the tree community stem density, diameter at breast height, tree species richness and carbon storage were recorded. In the low utilisation sites carbon storage was similar to that found in other miombo woodlands (28 t Ha −1 ), and the Shannon Wiener diversity score for tree species diversity was 3.44. However, in the high utilisation sites, tree species diversity (2.86) and carbon storage declined (14.6 t Ha −1 ). In areas of moderate utilisation diversity and carbon storage were maintained, but the structure of the woodland was affected, with a reduction of Class 1 (Diameter at Breast Height (DBH) < 10 cm) stems, demonstrating low recruitment which leads to a reduction in sustainability. Tree species richness and abundance demonstrated an intermediate disturbance effect in relation to utilisation, with highest levels at medium utilisation sites. Key miombo woodland species from the subfamily Caesalpinioideae in the two genera Brachystegia and Julbernardia were present in all sites, but the frequency of Brachystegia species declined by 60% from low to high utilisation. The IUCN near-threatened timber species Pterocarpus angolensis , highly protected in Tanzania, was harvested throughout the study site, and the majority of trees recorded were immature (DBH ⩽ 20 cm), suggesting that it is commercially extinct for the foreseeable future. These findings illustrate that in miombo woodlands with low to medium utilisation levels key miombo species are retained, and tree species diversity and carbon storage remains optimal. Sustainable land management plans need to regulate utilisation within miombo landscapes and retain areas of woodland. This will ensure their long term viability, and continue to support the 100 million people who are reliant on miombo woodlands for their goods and services. [ABSTRACT FROM AUTHOR]

Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function.

To increase understanding of breakdown strategies for Mozambican timber, simulations were carried out using different sawing patterns that can be alternatives to the low degree of refinement performed for export today. For the simulations, 3D models of 10 Jambirre and 5 Umbila logs were used. The log shape was described as a point cloud and was acquired by 3D-laser scanning of real logs. Three sawing patterns (cantsawing, through-and-through sawing, and square-sawing) were studied in combination with the log positioning variables skew and rotation. The results showed that both positioning and choice of sawing pattern had a great influence on the volume yield. The results also showed that the log grade had an impact on the sawing pattern that should be used for a high volume yield. The volume yield could be increased by 3 percentage points by choosing alternative sawing patterns for fairly straight logs and by 6 percentage points for crooked logs, compared to the worst choice of sawing pattern. [ABSTRACT FROM AUTHOR]

Development of stem volume for umbrella-shaped crown trees remains a big challenge for efficient use of forest resources in Mozambique. In this study, species-specific stem volume equations were developed for the first time for three of the most important timber species in Mozambique:Afzelia quanzensisWelw. (Chanfuta),Millettia stuhlmanniiTaub. (Jambire), andPterocarpus angolensisD.C. (Umbila). The study was carried out at three locations in Mozambique: Inhaminga, Mavume, and Tome covering 58 trees from which, 24 of Chanfuta, 15 of Jambire, and 19 of Umbila. The volume of the sampled stem sections (logs) was calculated using Smalian’s formula, where stem volume total was obtained through the sum of the respective defined sections. Using a nonlinear procedure, different volume models were tested for each tree species independently. The coefficient of the determination of the tested equations in the tree species ranged from .90 to .95, making the equations potential candidate models for the stem volume equations object of the study. Based on statistical parameters analysis, the best fit nonliner power equation was Equation 2 with the lowest AICc and lowest average absolute bias. The stem volume for the studied species is better explained by models including both diameter and height as explanatory variables. [ABSTRACT FROM AUTHOR]

In a technical bulletin designed by the Food and Agriculture Organization, the importance of studies in Mozambique to assist in decision-making techniques that aim to improve incomes of sawmills in the country was emphasized. Because of the species used and the industry's low technological level, this study was carried out in order to assess the lumber yield of two tropical species, in a sawmill in Chimoio, Manica Province, in the central region of Mozambique. We used trees of Combretum imberbe (mondzo) and Pterocarpus angolensis (umbila), selecting 12 logs from each species. The logs were divided into three diameter classes (four logs in each class). Logs were sawed with band saw, in successive tangential unfolding model. Lumber yielding for both species increased depending on the diameter class, with statistical differences of lumber yielding between the two species and in the three diameter classes. C. imberbe had higher yield compared to P. angolensis, with results considered satisfactory for wood unfold of both native species from Mozambique. [ABSTRACT FROM AUTHOR]

This article describes the investigation of white efflorescence on eight wooden African objects from Malawi and Zambia and the treatment of the objects to remove the deposits. The source of the efflorescence on these objects was determined to be the heartwood from which they were carved. Using gas chromatography-mass spectrometry and Fourier transform infrared spectrometry, the crystalline efflorescence was found to consist of homopterocarpin and pterocarpin, two isoflavonoid compounds found in woods and shrubs belonging to the genus Pterocarpus, and African Baphida nitida. The crystal growth appeared to be heaviest on areas of the objects that were more deeply carved as well as on those objects without a surface finish. The storage conditions of the collection were studied and found to have likely accelerated the rate and extent of the natural movement of the pterocarpan compounds from the interior of the heartwood to the outer surfaces. [ABSTRACT FROM AUTHOR]

Highlights: [•] Distribution map with good discrimination of Pterocarpus angolensis (AUC 0.83). [•] Summer rainfall, minimum temperature and temperature seasonality are limiting factors. [•] Potential and realised distributions are very similar with Madagascar as exception. [•] P. angolensis is mainly found in areas with annual fire frequency below 45%. [•] Climate change can decrease the species’ distribution area, especially in the west. [ABSTRACT FROM AUTHOR]

Chanfuta (Afzelia quanzensis Welw.), Jambire (Millettia stuhlmannii Taub.) and Umbila (Pterocarpus angolensis D.C.) are, among others, three of the main tropical tree species producing commercial timber in Mozambique. The present study employed destructive biomass estimation methods at three localities in Mozambique (Inhaminga, Mavume, and Tome) to acquire data on the mean diameter at breast height (DBH), and height of trees sampled in 21 stands each of Chanfuta and Jambire, and 15 stands of Umbila. Mean diameter at breast height (DBH) (ob) for Chanfuta, Jambire, and Umbila was: 33.8 ± 12.6 (range 13.5-61.1), 33.4 ± 7.4 (range 21.0-52.2), and 27.0 ± 9.5 (range 14.0-46.5) cm. The mean total values for biomass (kg) of trees of Chanfuta, Jambire, and Umbila trees were 864, 1016, and 321 respectively. The mean percentages of total tree biomass as stem, branch and leaf respectively were 54, 43, and 3 for Chanfuta; 77, 22, and 1 for Jambire; and 46, 51, and 3 for Umbila. The best fit species-specific equation for estimating total above ground biomass (AGB) was the power equation with only DBH considered as independent variable yielding coefficient of determination (R2) ranging from 0.89 to 0.97. At stand level, a total mean of 27.3 tons ha-1 biomass was determined of which studied species represented 94.6%. At plot level, total mean biomass for Jambire was 11.8 tons ha-1, Chanfuta and Umbila 9.9 and 4.1 tons ha-1 respectively. The developed power equation fitted total and stem biomass data well and could be used for biomass prediction of the studied species in Mozambique. [ABSTRACT FROM AUTHOR]

Lectin activity with specificity for mannose and glucose has been detected in the seed of Platypodium elegans, a legume plant from the Dalbergieae tribe. The gene of Platypodium elegans lectin A has been cloned, and the resulting 261-amino acid protein belongs to the legume lectin family with similarity with Pterocarpus angolensis agglutinin from the same tribe. The recombinant lectin has been expressed in Escherichia coli and refolded from inclusion bodies. Analysis of specificity by glycan array evidenced a very unusual preference for complex type N-glycans with asymmetrical branches. A short branch consisting of one mannose residue is preferred on the 6-arm of the N-glycan, whereas extensions by GlcNAc, Gal, and NeuAc are favorable on the 3-arm. Affinities have been obtained by microcalorimetry using symmetrical and asymmetrical Asn-linked heptasaccharides prepared by the semisynthetic method. Strong affinity with Kd of 4.5 _M was obtained for both ligands. Crystal structures of Platypodium elegans lectinA complexed with branched trimannose and symmetrical complextype Asn- linked heptasaccharide have been solved at 2.1 and 1.65Å resolution, respectively. The lectin adopts the canonical dimeric organization of legume lectins. The trimannose bridges the binding sites of two neighboring dimers, resulting in the formation of infinite chains in the crystal. The Asn-linked heptasaccharide binds with the 6-arm in the primary binding site with extensive additional contacts on both arms. The GlcNAc on the 6-arm is bound in a constrained conformation that may rationalize the higher affinity observed on the glycan array for N-glycans with only a mannose on the 6-arm. [ABSTRACT FROM AUTHOR]

There have been several recent reports of Pterocarpus angolensis (kiaat) trees dying in South Africa, Zambia and Zimbabwe, where this tree is used in traditional medicine and is a valuable source of timber for woodcarving and furniture. A survey of material from diseased P. angolensis trees in South Africa yielded isolates of the Botryosphaeriaceae, an important fungal family known to cause a number of tree diseases. The aim of this study was to identify these Botryosphaeriaceae and to determine their pathogenicity to P. angolensis with branch inoculations. Seven species of the Botryosphaeriaceae were identified based on a combination of morphological characteristics and sequences from the ITS and EF-1α gene regions. Four of these represent undescribed taxa for which the names Pseudofusicoccum violaceum, P. olivaceum, Diplodia alatafructa and Fusicoccum atrovirens are provided. The remaining three species collected include Lasiodiplodia theobromae, L. pseudotheobromae and L. crassispora. Inoculation trials on tree branches showed that L. pseudotheobromae and one isolate of D. alatafructa differed significantly from control inoculations. The high levels of virulence and common occurrence of L. pseudotheobromae suggest that this species could play a role in tree dieback and death. [ABSTRACT FROM AUTHOR]

Pterocarpus angolensis (kiaat) is a well-known southern African tree species of commercial importance that occurs in several vegetation types in the Zambezian regional centre of endemism. The most prominent of these vegetation types are the Zambezian miombo woodland and undifferentiated woodland. A diverse range of ecosystems within these vegetation types necessitate adaptation by tree species to survive extremes of drought, temperature, altitude, soil nutrition and tolerate fire in order to compete with other plant species. There are several reports of a die-back disease of P. angolensis in Zambia, Zimbabwe and South Africa, but very little is known regarding the cause or significance of this problem. In this review, we provide details regarding the history of the disease and consider its possible causal agents. A pathology study conducted at three locations in South Africa on diseased and dying trees resulted in the collection of 199 fungal isolates; comprising saprophytic species such as Candida, Penicillium and Humicola, and potentially pathogenic species such as Lasiodiplodia theobromae, Cytospora spp. and Fusarium spp. Drought, during several years preceding disease, along with a lack of fire management may have contributed to both the present and past reports of tree die-back and death. Finally, an analysis is made of the importance of the problem and actions that might be taken to alleviate it. [ABSTRACT FROM AUTHOR]

Gloeophyllum trabeum and Pycnoporus sanguineus. Antifungal activities of 33 methanol extracts obtained from the bark, sapwood and heartwood of 11 Malaysian timbers, Dipterocarpus apterus, Shorea curtisii, Hopea odorata, Calophyllum rubiginosum, Calophyllum symingtonianum, Cynometra inaequifolia, Swintonia schwenkii, Dyera costulata, Sandoricum koetjape, Pimeleodendron griffithianum and Pterocarpus indicus were evaluated against the brown-rot fungus Gloeophyllum trabeum and the white-rot fungus Pycnoporus sanguineus using a medium in which homogenised hyphae were dispersed. The heartwood of C. symingtonianum and the outer wood of S. schwenkii showed high antifungal activities against G. trabeum while the heartwoods of P. indicus and C. symingtonianum, the bark and sapwood of P. griffithianum, and the sapwood of C. rubiginosum showed high antifungal activities against P. sanguineus. The activities of methanol extracts from selected parts of these wood species were higher than that of the positive control, glycyrrhizic acid dipotassium salt, and results suggest the potential of these extracts as fungistats. [ABSTRACT FROM AUTHOR]

The feasibility of utilising morphological markers for determining existing provenance variation in the African savanna tree Pterocarpus angolensis was assessed. Five provenances were used: Mtao, Gokwe, Nyazura, Chesa (Zimbabwe) and Kapirimposhi (Zambia). Two weeks after germination, seedlings were inoculated with mycorrhizal inoculum and raised in a glasshouse. Height and collar diameter were measured at one, three and five months of age (before stem dieback), and at 14 months (after stem dieback). At the time of dieback, percentage of seedlings losing leaves, stem dieback and mortality were recorded; numbers of new shoots produced in the recovery period were also determined. To further assess growth, leaf, stem and root dry biomass were measured after stem dieback at 14 months. At one month, Chesa seedlings were the tallest and Kapirimposhi seedlings were significantly shorter (p < 0.05) than the rest of the provenances. However, at three and five months of height growth no significant differences were observed. At one month, diameter growth was significantly different with the Kapirimposhi provenance having the smallest diameter (p < 0.05). At three and five months of seedling growth only the Gokwe provenance was significantly different from the rest of the provenances. By seven months of age, stem dieback was observed and foliage loss was over 60% in each of the five provenances. At 14 months of seedling growth after stem dieback the Nyazura and Kapirimposhi provenances were significantly shorter, whereas there were no significant differences in diameter growth and dry biomass from root, stem, leaf or root:shoot dry biomass ratio. Fourteen months after germination new shoots emerged from various axillary bud positions depending on the extent of dieback. [ABSTRACT FROM AUTHOR]

Understanding the availability, extent and apportionment of genetic variability in natural populations of the southern African savanna tree Pterocarpus angolensis can provide reliable information on the evolutionary history and phylogenetic relationships of P. angolensis populations. This information will aid strategies for successful domestication, conservation and sustainable exploitation of the species. In this study random amplified polymorphic DNA (RAPD) analysis was employed to assess genetic diversity of P. angolensis, characterising 60 genotypes originating from four Zimbabwean and two Zambian provenances. Four RAPD primers each generated 11 to 15 scorable bands, with a total of 50 reproducible bands of which 88% were polymorphic. Analysis of molecular variance partitioned the greatest proportion of variability to within population (80.82%). Euclidean distance gave a phiST value of 0.192, indicating a moderately high level of population differentiation. The degree of population diversity found in this study, with two clear strong population structures for most genotypes from Nyazura and Gokwe and the rest of the populations with slight weak structures, suggests that all provenances tested could be beneficially utilised in a domestication programme for P. angolensis. [ABSTRACT FROM AUTHOR]

The experiment was conducted to ascertain narrow-sense heritability (h²) and the family-within-provenance variation in shoot die-back, taproot length and root biomass of half-sib Pterocarpus angolensis families from Malawi, Namibia and Zambia. Provenances differed significantly in shoot die-back for both shoot die-back seasons. A within provenance family effect was not significant in the first shoot die-back season but was significant in the second shoot die-back season. An increase in proportion of seedlings dying back, to 91%, for a Malawi family was observed in the second shoot die-back season. Provenance and within provenance family effects may be due to latitudinal differences between the provenances. The h 2 of shoot die-back was 0.07 (SE = 0.07) in the first shoot die-back season and 0.42 (SE = 0.27) in the second shoot die-back season. Narrow-sense heritability for root biomass was 0.81 (SE = 0.45). The h² for the second die-back season and root biomass suggest the traits are heritable. Random selection of individual families for assessing shoot die-back is important since this trait is only restricted to seedlings and saplings and not mature trees. Within provenance family effects for root biomass were significant, indicating differences between families. Two families from the most northerly provenances of Phalombe and Skull Rock in Malawi were significantly different from other southern families. Non-significant phenotypic correlation between shoot die-back and root biomass shows that shoot die-back is not likely to be determined by root size nor taproot depth. Although a non-significant negative phenotypic correlation (-0.15) between the second shoot die-back season and root biomass was obtained, a family from Malawi that had the highest mean shoot die-back in the second shoot die-back season had the smallest root biomass. Half-sib families with post shoot die-back growth potential, in the first shoot die-back season, are likely to have a better chance of post shoot die-back growth later. [ABSTRACT FROM AUTHOR]

Abstract  Mozambique is a country with vast forestry resources that include native wood species with high commercial value. Thus, the trade of timber as raw material, as well as wooden finished products are commercial options of considerable valuable for the country. This work presents information about anatomical characteristics, physical and mechanical properties and use of some native wood species from Mozambique, namely, Afzelia quanzensis, Androstachys johnsonii, Erytrophleoum suaveolens, Khaya nyasica, Pterocarpus angolensis, Milletia stuhlmannii and the emerging lesser-known species Pericopsis angolensis, Sterculia appendiculata and Sterculia quinqueloba. The study concludes that these Mozambican wood species are similar in several aspects. They are generally described as very hard, dense, having high mechanical strength and durable. The study also concludes that although the lesser-known wood species, S. quinqueloba, has similar properties to the traditionally used one, A. quanzensis, it is less used because of its poorly known properties and potential uses. Thus, further research to determine the properties and suitable end uses of other lesser know species is likely to be beneficial to the country. [ABSTRACT FROM AUTHOR]

Abstract: Pterocarpus angolensis D.C. is a highly valuable and sought after timber species across much of its range in southern Africa. Attempts at plantation cultivation of this species have not been successful, suggesting that sustainable management of natural populations is necessary for the continued utilization of this resource. Such management will require reliable age and long-term growth data. Despite the value of P. angolensis, few long-term studies of the species’ growth rate have been conducted, and some of these studies indicate that current harvest schemes may be inappropriate. This paper presents results of tree-ring analyses of P. angolensis from nine locations across southern Africa. The analyses include estimates of: (1) tree age, (2) diameter increment, (3) the relationship between tree diameter and the percentage of heartwood, and (4) the relationship between mean diameter increment and local rainfall. The mean annual diameter increment averaged over all nine sites was generally lower than other published values, though the range of values was within that of published figures. Cumulative diameter as a function of age indicates that radial growth can be quite variable, both within and among stands. These variable age–diameter relationships within and across the nine sites suggest that diameter may be a reasonable indicator of tree age at the stand level but not across the species’ range. The relationship between stem diameter and percentage heartwood is significantly positive, suggesting that optimal harvesting diameters may be reliably determined. Average annual diameter increment is significantly positively correlated with mean seasonal rainfall, which explains about half of the variance in mean diameter increment. These findings should be helpful for the sustainable management of this important species. [Copyright &y& Elsevier]

Abstract: Tree vegetation and size structure was sampled in a miombo woodland area in E Tanzania and related to environmental factors, particularly soil and disturbance history. A total of 86 tree species was found. Four plant communities were distinguished through multivariate classification. Community 1 was dominated by Brachystegia boehmii, Brachystegia bussei and Julbernardia globiflora, and community 2 by B. boehmii and Brachystegia spiciformis. Community 1 was found on grey, eroded soil and community 2 on red, residual soil, a fact that opens up possibilities to use soil signals of satellite data for vegetation mapping. Community 3 is heavily disturbed miombo woodland near villages and community 4 was found on more clayey soil where miombo woodland is not expected. At our 42 sampled sites, density ranged from 74 to 1041 individualsha−1 and basal area from 3.9 to 16.7m2 ha−1. Regeneration is generally good but large sized trees are less prominent in communities 3 and 4 due to harvesting. With reduced disturbance miombo species may rapidly resume dominance in community 3. A higher than expected representation by the size class 30–40 (−50)cmdbh in community 2 is probably related to disturbance history. Prevalence of certain species (Pseudolachnostylis maprouneifolia, Pterocarpus angolensis and Diplorhynchos condylocarpon) may be related to frequent fires. Selective logging will soon cause extinction of Dalbergia melanoxylon, whereas Pterocarpus angolensis still has good regeneration, possibly because individuals below logging size have a good seed set. A way to get an easy overview of size classes in all species in an area using PCA is discussed. [Copyright &y& Elsevier]

The crystal structure of Pterocarpus angolensis lectin is determined in its ligand-free state, in complex with the fucosylated biantennary complex type decasaccharide NA2F, and in complex with a series of smaller oligosaccharide constituents of NA2F. These results together with thermodynamic binding data indicate that the complete oligosaccharide binding site of the lectin consists of five subsites allowing the specific recognition of the pentasaccharide GlcNAcβ(1–2)Manα(1–3)[GlcNAcβ(1–2)Manα(1–6)]Man. The mannose on the 1–6 arm occupies the monosaccharide binding site while the GlcNAc residue on this arm occupies a subsite that is almost identical to that of concanavalin A (con A). The core mannose and the GlcNAcβ(1–2)Man moiety on the 1–3 arm on the other hand occupy a series of subsites distinct from those of con A. [ABSTRACT FROM AUTHOR]

Abstract: Pterocarpus angolensis is a hardwood species subject to heavy exploitation throughout miombo woodlands of south-central Africa. Rates of natural recruitment measured in western Tanzania were found to be low, with only a third of parent trees generating any seedlings despite considerable seed production. Although heavily protected areas supported large parent trees, these adults had very few seedlings of >5cm DBH nearby, possibly suggesting mortality caused by high densities of browsing ungulates. Outside these well protected areas, cutting has removed most large trees and remaining adults are small producing relatively few seeds. Factors affecting recruitment include location and elevation perhaps indicative of higher precipitation, whereas short grass and reduced parent canopy cover are associated with more seedlings suggesting competition for light. Given these recruitment rates, the prognosis for sustainable exploitation of P. angolensis looks bleak. [Copyright &y& Elsevier]

The Man/Glc-specific legume lectin from the seeds of the African bloodwood tree (Pterocarpus angolensis) was crystallized in the presence of the disaccharide ligand Man(α1–3)ManMe. Small crystals initially appeared from a preliminary screen, but proved difficult to reproduce. The initial crystals were used to prepare microseeds, leading to a reproducible crystallization protocol. All attempts to obtain crystals directly of the ligand-free protein or of other carbohydrate complexes failed. However, the Man(α1–3)ManMe co-crystals withstand soaking with ten other carbohydrates known to bind to the lectin. Soaking for 15 min in 100 mM carbohydrate typically resulted in complete replacement of Man(α1–3)ManMe by the desired carbohydrate despite the involvement of lattice contacts at the binding site. Transferring the crystals for two weeks in carbohydrate-free artificial mother liquor resulted in the complete removal of the sugar from one of the two monomers in the asymmetric unit. Additional treatment of these crystals with 100 mM EDTA for two weeks resulted in removal of the structural calcium and manganese ions, which is accompanied by significant structural rearrangements of the loops that constitute the carbohydrate-binding site. [ABSTRACT FROM AUTHOR]

Estimation of biomass or volume of trees and shrubs is important in many contexts. Foresters and other natural resource managers in east and southern Africa have been faced with a double challenge in this respect: their forest research institutions have been small and young, and their trees and shrubs are difficult to measure. A number of studies have been made in order to estimate biomass or volume of trees in this part of Africa. This review tries to bring together some of the findings of such studies in order to synthesize a few common principles and to make reliable functions more easily accessible to researchers and resource managers. A general conclusion appears to be that typical miombo trees have larger volumes for equal diameters than species typical in file drier southern woodlands. It is also noted that Pterocarpus angolensis takes an intermediary position. Inclusion of height in addition to diameter as independent variable does not increase the coefficient of determination very much. In some cases dbh alone gives an R2 of more than 0.95. This is due to the correlation between diameter and height. In practical inventories of volume or biomass where high precision is not required, economic considerations may, therefore, lead to the conclusion that measurement of height is unnecessary. One study suggests that diameter and crown width is a better pair of independent variables for total biomass of single trees than the traditionally used diameter and height. [ABSTRACT FROM AUTHOR]

Soils and vegetation of a woodland in South Eastern Tanzania were studied in support of a project fostering community participation in the management of a proposed forest reserve. In nine sites within an area of 500 km2, soils were characterized, frequency of occurrence of woody species was assessed and diameter at breast height of timber species recorded. Villagers identified 133 species of which only 56% were scientifically identified. However, as ordination axes derived from the complete data set were highly correlated with those derived from the restricted data set, the latter could be used. On the undulating plains, deep, sandy soils (Hypoluvic Arenosols, Profondic and Arenic Luvisols) occurred low in organic carbon, exchangeable bases and extractable aluminium content. Most common canopy species wereBrachystegia spiciformis/B. boehmiiandPterocarpus angolensis. On the dissected plains on shallow, clayey soils (Leptic Cambisols) with higher organic carbon, exchangeable bases and extractable aluminium content,Acacia nigrescensandMarkhamiaspp. were the most common tree species. On deeper, fertile clayey soils (Profondic Lixisols and Chromic Phaeozems) vegetation consisted of species found in the two vegetation groups.Pterocarpus angolensisandPericopsis angolensiswere the only valuable timber species commonly found, most frequently on the undulating plains. As soils of this area are unfavourable for agriculture, it seems sensible to set this area aside as a forest reserve. [ABSTRACT FROM AUTHOR]

The crystal structure of a Man/Glc-specific lectin from the seeds of the bloodwood tree (Pterocarpus angolensis), a leguminous plant from central Africa, has been determined in complex with mannose and five manno-oligosaccharides. The lectin contains a classical mannose-specificity loop, but its metal-binding loop resembles that of lectins of unrelated specificity from Ulex europaeus and Maackia amurensis. As a consequence, the interactions with mannose in the primary binding site are conserved, but details of carbohydrate-binding outside the primary binding site differ from those seen in the equivalent carbohydrate complexes of concanavalin A. These observations explain the differences in their respective fine specificity profiles for oligomannoses. While Man(α1-3)Man and Man(α1-3)[Man(α1-6)]Man bind to PAL in low-energy conformations identical with that of ConA, Man(α1-6)Man is required to adopt a different conformation. Man(α1-2)Man can bind only in a single binding mode, in sharp contrast to ConA, which creates a higher affinity for this disaccharide by allowing two binding modes. [Copyright &y& Elsevier]