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.

Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

This study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

Floristic, Structure, and Regeneration of Woody Species in Bola Wanche Forest of Humbo Carbon Project, Wolaita, Ethiopia

BackgroundThe forest resources of the Humbo Carbon Project have ecological and environmental problems such as soil degradation, soil erosion and alteration of natural resources are some of the negative effects resulting from the destruction of forests Our present study was carried out to investigate regeneration status and dynamics of populations of woody species in Bola Wanche forest of Humbo Carbon Project Wolaita zone, Ethiopia. Methods and ResultsThirty-two (20m x 20m) plots were laid at an interval of 100m to collect vegetation data. In each plot, five 1m 2 quadrats were laid to assess regeneration status. DBH (Diameter at Breast Height) of each woody species with DBH ≥2.5cm was measured. Altitude, aspect and slope of each plot were recorded. Among 61 woody species representing 56 genera and 35 families, Syzygium guineense and Dodonaea angustifolia were the most dominant. There was significant difference in the dominance (p < 0.0001) of species between plots. Inverted J-shape and bell-shape population distribution patterns were recognized. The regeneration phase was dominated by D. angustifolia. Only 36% of the species in matured vegetation was represented in seedling phase. Environmental factors considered in this study were not influenced abundance of species and individuals between plots. But when dominant species evaluated separately, altitude had significant influence on abundance of S. guineense and Combretum molle while aspect on C. molle and Terminalia schimperiana. But no factor had influenced abundance of D. angustifolia. ConclusionThe study concluded the abundance and dominance of few families and species, prevalence of small size populations and fair regeneration of forest. This may indicate that the forest is in its early secondary successional stage and need high intention of conservation and management.

Proximate Analyses and Amino Acid Composition of Selected Wild Indigenous Fruits of Southern Africa

A literature survey revealed that several wild indigenous Southern African fruits had previously not been evaluated for their proximate and amino acid composition, as well as the total energy value (caloric value). Fourteen species including Carissa macrocarpa, Carpobrotus edulis, Dovyalis caffra, Halleria lucida, Manilkara mochisia, Pappea capensis, Phoenix reclinata, and Syzygium guineense were analyzed in this study. The nutritional values for several species such as C. edulis, H. lucida, P. reclinata, and M. mochisia are being reported here for the first time. The following fruits had the highest proximate values: C. macrocarpa (ash at 20.42 mg/100 g), S. guineense (fat at 7.75 mg/100 g), P. reclinata (fiber at 29.89 mg/100 g), and H. lucida (protein at 6.98 mg/100 g and carbohydrates at 36.98 mg/100 g). Essential amino acids such as histidine, isoleucine, lysine, methionine, phenylalanine, tryptophan, and valine were reported in all studied indigenous fruits. The high protein content in H. lucida was exhibited by the highest amino acid quantities for histidine. However, the fruits are a poor source of proteins since the content is lower than the recommended daily intake. The jacket-plum (Pappea capensis), on the other hand, meets and exceeds the required daily intake of lysine (0.0003 g/100 g or 13 mg/kg) recommended by the World Health Organization.

Teratogenic Effect of High Dose of Syzygium guineense (Myrtaceae) Leaves on Wistar Albino Rat Embryos and Fetuses

Syzygium guineense is an important medicinal plant effective against hypertension, diabetes mellitus, and cancer but with no evidence of its teratogenicity. This study was planned to investigate the teratogenic potential of S. guineense leaves on rat embryos and fetuses. Five groups of Wistar albino rats, each consisting of ten pregnant rats, were used as experimental animals. Groups I-III rats were treated with 250, 500, and 1000 mg/kg of hydroethanolic extract of S. guineense leaves, and groups IV and V were control and ad libitum control, respectively. Rats were treated during day 6–12 of gestation. Embryos and fetuses were retrieved at day 12 and day 20 of gestation, respectively. The embryos were assessed for developmental delays and growth retardation. The fetuses were examined for gross external, skeletal, and visceral anomalies. In 12-day old rat embryos, crown-rump length, number of somites, and morphological scores were significantly reduced by the treatment of 1000 mg/kg of the extract. The external morphological and visceral examinations of rat fetuses did not reveal any detectable structural malformations in the cranial, nasal, oral cavities, and visceral organs. The ossification centers of fetal skull, vertebrae, hyoid, forelimb, and hindlimb bones were not significantly varied across all groups. However, even if not statistically significant, high-dose treated rat fetuses had a reduced number of ossification centers in the sternum, caudal vertebrae, metatarsal, metacarpal, and phalanges. Treatment with the hydroethanolic extract of S. guineense leaves produced no significant skeletal and soft tissue malformations. The plant extract did not produce significant teratogenic effects on rat embryos/fetuses up to 500 mg/kg doses but retarded the growth of embryos at high dose (1000 mg/kg) as evidenced by decreased crown-rump length, number of somites, and morphological scores. Therefore, it is not advisable to take large doses of the plant during pregnancy.

Quantitative Ethnomedicinal Study of Plants Used by the Population in the Middle Plateaux of Uvira Territory (D. R. of Congo).

BackgroundThis work increases the ethnomedicinal plants information in the Uvira Territory and, in particular, the middle plateau. Till now little is known about ethnomedicinal researches in Uvira Territory and no previous study has surveyed the medicinal uses of plants in the middle plateau of Uvira Territory. MethodsThe plant uses information survey was collected through a direct interview conducted with 25 local healers in 7 villages. The ethnobotanical information for each species, including scientific name, family, local name, morphological type, plant parts used, preparation, disease name, plant habitat was collected. The conservation status of plant species was checked by the International Union for Conservation of Nature. various quantitative indices (Relative frequency of citation Use Value, Informant consensus factor, Family Importance Value, Pearson’s correlation, Jaccard Index) were calculatedResultsInformation on 69 medicinal plants belonging to 61 genera and 34 families was collected. The total number of species per family showed that Fabaceae, Asteraceae, and Myrtaceae were most represented. Most species were herbs. Leave was the most frequently used part and decoction was the principal preparation method. Significantly higher numbers of medicinal plants were used against digestive system disorders and intestinal parasites. Tetradenia riparia, Syzygium guineense, Morella salicifolia and Erythrina abyssinica were the medicinal plants with the highest UV values. The Pearson correlation coefficient between RFC and UV was 0.95 showing a highly positive significant association. A total of 14 species were recorded as vulnerable.ConclusionThis study was able to show that this area, located in middle plateau of Uvira Territory, can provide a considerable medicinal plant diversity with an heterogenous medicinal importance to the community. With the relative high number of vulnerable species, there is a requirement for a sustainable management for these medicinal plants.

Fire Suppression as Well as Seed Dispersal Play Critical Role in the Establishment of Forest Tree Species in Tropical Woodland

This study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in a tropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum seedling (forest tree species) was monitored for 2.5 years in four different microsites in savannah-woodland in Malawi under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), and Uapaca kirkiana (a woodland tree), and in a treeless site. S. guineense ssp. afromontanum seed deposition was also monitored in the four sites, and the natural establishment of forest tree species was observed to confirm the importance of seed dispersal. Protection from fire was found to be the most important facilitation mechanism in this area, with a total fire-induced mortality rate of 43%. However, the rate was comparatively low under F. natalensis, where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. B. floribunda also offered protection from fire, and seedling survival did not differ between these two microsites. However, only a few individual forest tree species naturally established under B. floribunda, indicating that the facilitative mechanism of fire suppression is not the only factor affecting establishment in this tropical woodland. A higher rate of seed dispersal was also observed under F. natalensis compared with the other three microsites, suggesting that dispersal processes are also critical for the establishment of forest tree species in woodland in this region.

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.