Deforestation and Biomass Production in Miombo Forest in Huambo (Angola): A Balance between Local and Global Needs

Miombo is one of the most widely distributed ecosystems in Angola, with a great social and environmental value. Thus, the rural population uses the biomass as fuel and miombo provides important ecosystem services, such as its carbon sequestration capacity. The objectives of this work were (i) to assess deforestation in miombo forest in Huambo province (Angola) during the last 20 years, (ii) to evaluate carbon storage capacity of miombo, and (iii) to calculate the charcoal productive capacity of those forests. From 2000 to 2019, 359,130 ha (12.96%) were deforested in Huambo province. Thirty-six woody species were identified as major components of miombo forest, the most frequent being Albizia anthunesiana, Brachystegia spiciformis, Julbernardia paniculata, Monote spp., Brachystegia boemii, Isoberlinea angolensis, Anisophyllea boehmii, Syzygium guineense, and Erythrophleum africanum. The total biomass estimated in miombo forest was 195.05 Mg ha−1 (55.02 Mg ha−1 radical and 140.04 Mg ha−1 area), with a total wood volume of 78.57 m3 ha−1. This represents values of 91.67 Mg ha−1 of accumulated carbon and 336.13 Mg ha−1 of CO2 equivalent. The potential charcoal productivity was 15,359.9 kg ha−1, corresponding to 24.78 trees ha−1. The Annual Allowable Cutting Volume was 10.77 m3 ha−1 year−1, 14.13 m3 ha−1 year−1, 21.17 m3 ha−1, and 32.85 m3 ha−1 year−1 for rotation lengths of 55, 40, 25, and 15 years, respectively, corresponding to a potential annual charcoal productivity of 2107.08 Kg ha−1 year−1, 2762.96 Kg ha−1 year−1, 4139.21 Kg ha−1, and 422.56 Kg ha−1 year−1. However, deforestation rates in the last 19 years and low charcoal productive capacity could compromise the sustainability of the Miombo ecosystem and its value as an ecosystem service provider in the province if appropriate management strategies are not developed.

Machining Operations on Messassa Wood

This study aimed to evaluate the effect of machining operations on the surface quality of the messassa wood (Brachystegia spiciformis and Julbernadia globiflora) for use in the furniture industry. The wood cames from Mozambican Miombo Woodland. The following machining operations were performed: planing, shaping, milling, tearing and boring based on technical standard. The wood had a surface quality approval rating above 70% in all tested machining operations. A perfect surface quality was obtained with a feed speed of 6 m.min-1 in planing. Brachystegia spiciformis had easy workability and extremely well performance compared to Julbernadia globiflora. Nevertheless, both wood species have great potential for use in higher value-added products such as furniture and frame production.

Forage preference identification of wild Gynanisa maja (Klug, 1836) and perspectives for improved livelihoods in Zambia

Gynanisa maja (Klung, 1836) is the wild edible caterpillar of a speckled emperor moth belonging to the order Lepidoptera and the family Saturniidae. It is a species of nutritional and economic importance and provides food security at household level during its harvesting season. Despite the significant value this caterpillar has, it is harvested seasonally and harvested in unsustainable ways such as cutting down of its food plants resulting in habitat destruction likely to lead into species extinction consequently, threatening food security. Therefore, this study aimed at identifying the preferred food plants of wild G. maja that will help in the definition of the actions needed for conservation of the G. maja moth consequently contribute positively towards combating food and nutrition insecurity. The household survey was carried out in 61 villages from five clusters of Luampa district to determine the knowledge of people on the food plants of G. maja and the structured questionnaire was used to collect data via face to face interview. A total of 400 respondents participated and five food plants belonging to the family Fabaceae were mentioned which include; Julbernadia paniculata (Benth.) Troupin, Erythrophleum africanum (Welw. ex Benth.) Harms, Brachystegia longifolia Benth, Albizia antunesiana Harms and Brachystegia spiciformis Benth. All (100% of respondents) mentioned J. paniculata (Benth.) Troupin as the primary preferred food plant of G. maja while others indicated the other four food plants as secondary or alternatives. Based on these findings, the food plant like J. paniculata can be utilised for embarking on farming G. maja which will result in the conservation of G. maja and its food plant.

VALORACIÓN ECOLÓGICA Y ESTRUCTURAL DEL BOSQUE DE MIOMBO AFECTADO POR DISTURBIOS ANTRÓPICOS

La investigación se realizó dejunio a noviembre de 2019; con el objetivo de realizar la valoración ecológica de la estructura del bosque de Miombo afectado por disturbios antrópicos, levantando 30 parcelas de 500 m2 con muestreosistemático,inventariando los individuos con d1.30≥ a 5 cm, evaluando la composición florística, y los valores estructurales. Seobtuvieron 1290 individuos, 27 especies, 23 géneros y 10 familias con predominio de la familia Fabaceae. Se observó una comunidad con detrimento en ladominancia, y los valores de importanciaecológica, Brachystegia spiciformis, Monotes sp., Brachystegia boehmii y Syzygium guineense ocuparon las cuatro primeras posiciones acumulando de conjunto 40 % de la flora encontrada. Como reflejo de la bajadominancia ecológica, el valor del índice de diversidad de Shannon (H’ = 0,75 nats.ind-1) fue bajo, caracterizando la comunidad de poca diversa. La estructura vertical está determinada por dos estratos arbóreos: un inferior con altura de 3,14 m; el medio que va de 3,14 hasta 4,50 m caracterizando al bosque de porte bajo. La distribución diamétrica se caracterizó por la concentración de individuos en las primeras clases diamétricas, asemejándose a la forma típica de J invertida, representada de un bosque natural heterogéneo y disetáneo con tendencia a la heterogeneidad. Los disturbios antrópicos que afectan la estructura son: distancia a la carretera, distancia a calveros, las especies, distancia a caminos, distancia a cultivos agrícolas, además de los incendios forestales.

Effects of thermal modification on physical and mechanical properties of Mozambican Brachystegia spiciformis and Julbernardia globiflora wood

Mozambique’s large pool of tropical hardwoods is hampered by the prevalence of low-grade tree species along with a lack of cost-effective processing technologies to improve timber properties. Brachystegia spiciformis and Julbernadia globiflora are the most abundant tree species in terms of volume in the country, but with limited use due to their low timber quality. In this study, thermal modification at three different temperatures (215 °C; 230 °C; 245 °C) was applied for 2 h to the timber of both species, followed by measurement of a set of physical and mechanical wood properties. The results show that the originally light-coloured sapwood of both tree species darkened gradually as the intensity of thermal modification increased. Additionally, from untreated samples to the highest thermal treatment level, timber of B. spiciformis incurred a maximum mass loss of 27%, while oven-dry density was reduced from 0.65 to 0.56 g/cm3 and equilibrium moisture content (EMC) changed from 7 to 3%. Timber of J. globiflora had a mass loss of 23% after the highest treatment level, an oven-dry density reduction of 0.81 to 0.74 g/cm3 and an EMC decrease from 8 to 3%. The changes in mechanical properties from reference samples to the highest thermal treatment level were also significant. For B. spiciformis, MOE decreased by 10.2%, MOR by 50.8%, compression strength parallel to the grain by 29.2% and Brinell hardness by 23.5%. Timber of J. globiflora followed the same trend with an MOE decrease by 6.9%, an MOR decrease by 53.2% and a decrease in compression strength parallel to the grain by 21.9%. All tested wood properties showed significant responses to thermal modification after the most intensive treatment level had been applied. Despite the degradation of mechanical properties in both species, an optimal combination of temperature and treatment time could be achieved. The recorded changes of the tested wood properties in both species could increase the range of applications; the new colour resembled that of highly sought-after tropical hardwoods.

Evaluation of the quality of surface finish of messassa wood for three types of varnishes.

The aim of this study was to evaluate the performance of the messassa wood Brachystegia spiciformis and Julbernardia globiflora for three types of finishing products for use in the furniture and frames industries. Coating performance was assessed by adhesion strength, impact deformation resistance, abrasiveness, gloss and overall color variation tests based on technical standards. Copal painting application was higher for gloss, adhesion and lower abrasiveness compared to water based and polyurethane. The impact deformation was higher for polyurethane than water-based and copal for both species. The darkening of wood for Brachystegia spiciformis and a slight lightening of wood by Julbernardia globiflora characterize the overall color variation after application of the coating products. According to these results, the varnishes can be used to add value to the messassa wood as a finish in solid wood furniture and frames.

Composição florística e estrutura da vegetação da savana de Miombo em dois ambientes distintos no Distrito de Sanga, Norte de Moçambique

O presente estudo teve como objetivo avaliar a composição e a estrutura da vegetação em dois ambientes de Miombo, sendo o primeiro denominado de Ambiente I (trecho de mata de Miombo), o segundo de Ambiente II (área abandonada após agricultura). Foram estabelecidas quinze parcelas de 20 m x 50 m em cada ambiente. Todos os indivíduos lenhosos e em regeneração com DAP> = 5cm foram medidos e identificados. A suficiência amostral foi avaliada com base nas curvas de rarefação. O padrão de variação florístico entre os ambientes avaliado através do Escalonamento Multidimensional não Métrico (NMDS). No Ambiente I, 40 espécies distribuídas em 21 famílias foram registradas enquanto que no ambiente II constatou-se a ocorrência de 19 espécies pertencentes a 10 famílias. Os parâmetros florísticos e fitossociológicos avaliados foram densidade, dominância, frequência e índice de valor de importância (IVI). Em ordem decrescente, Brachystegia spiciformis e Julbernardia globiflora apresentaram maiores IVI no Ambiente I. Uapaca kirkiana e Diplorhynchus condylocarpon detiveram os maiores valores para tal índice no Ambiente II. As espécies dominantes no Ambiente II são as comumente encontradas nesses ambientes e são capazes de crescer em áreas antropizadas e mostram uma capacidade de recuperação da vegetação do Miombo contra distúrbios antrópicos.