Woody vegetation stocking, composition and diversity in Miombo Woodlands in Tanzania: A case study of Mgori forest reserve in Singida District

Participatory forest management (PFM) model is aimed at improving both forest resources conservation and livelihoods of local communities. In Tanzania, PFM is widely spread in forest reserves bearing the names of joint forest management, co forest management and community based forest management. However, despite the wide spread, less so far has been done to assess its contribution to conservation of the forest resources and livelihoods of local communities. The study, however, majored on assessment of forest resources by describing woody stocking, and species composition and diversity at Mgori Forest Reserve, in Tanzania. Mgori forest reserve (MFR) is one of the reserves in Tanzania, which are under the model. MFR is within miombo woodlands of Tanzania allocated along the western side of the country. Inventory data were collected from four village forest reserves, which are part of MFR. Atotal of 136 plots of the size 20 x 50 m (0.1ha) were laid in different clusters. The study enumerated a total number of 79 tree/shrub species. DBH distribution followed an inverse ‘J’ shape. Stem density in the study ranged between 494 and 885 N ha-1, while basal area and woody volumedistribution followed a ‘J’ shape. The basal area varied from 9.65 to 18.50 m2 ha-1, while the woody volume was averaged to 65.99 m3 ha-1 with a range of 54.49 to 104.47 m3 ha-1. The most dominant tree species in the study were Brachistigia spiciformis and Jubernadia globifolia. Importantvalue index of tree species ranged between 4.29 and 10.00, while Shannon Weiner index was between 2.54 and 3.04. Index of dominance in this study was between 0.03 and 0.11, while species diversity index ranged from 38.46 to 89.36 and species richness and evenness ranged between 9.65 and 21.04 and 1.55 and 1.81 respectively. The study concludes that woody stocking parameters as well as tree/shrub species composition and diversity indices are normal and similar to any other reserved forests in miombo woodlands.Key words: miombo woodland, stem density, basal area, woody volume, species composition, diversity, participatory forest management, village forest reserve

Tree species diversity under pastoral and farming systems in Kilosa District, Tanzania

Loss of tree diversity through improper land use practices such as overgrazing and poor farming practices in tropical areas and other natural ecosystems is one of today's most worrying environmental problems. This study was conducted to assess the impact of farming and pastoralism on tree species diversity in two forests each owned and managed by pastoral and farming communities in Kilosa District. Household survey solicited information on perceptions of local communities on drivers that influenced tree stocking and diversity of their forests. A forest inventory was conducted involving twenty circular in each system plots laid along two transects. In each plot, trees and shrubs with DBH > 5 cm were measured for DBH and height. A total of 48 different species were recorded out of which 75%were tree species and 25% shrubs species. The forest under pastoral system had a Shannon - Wiener Index (H’) of 3.13 as opposed to farming system with an index of 2.05. Average stocking for the forest under pastoral system was 235 stem ha-1, whereas that of farming system was 209 stem ha-1. Basal areas of 13m2ha-1 and 6m2 ha-l were recorded for forests under pastoral and farming systems respectively. Standing volume showed the same tendency where 216m3ha-1 was recorded from the forest under pastoral system as opposed to 100.12 m3ha-1 from the other forest. The high loss of species diversity and stocks particularly in the forest under farming system were attributed to anthropogenic disturbances including cutting trees for farm expansion, charcoal making and house construction. Although the assessment on the community perception on the loss of tree diversity in the area showed conflicting interests between the two societies each blaming activities of each community as major causes of forest degradation. This calls for more enforcement of rules and regulations and tree planting in degraded areas predominantly in the farming communities. The study further revealed that the existing tensions over land resource ownership between the two communities of farmers and pastoralists may be contributing factors of unsustainable use of tree species and other forest resources. It is recommended that interventions should be done to settle conflicts over land resource ownership and management between the two villages as well control proliferation and dominance of Acacia nilotica as a way to improve pasture and improve species diversity in the area. Key words: Tree stocking - rules and regulations - anthropogenic disturbance

The impact of community-based forest management and joint forest management on the forest resource base and local people’s livelihoods: Case studies from Tanzania

In recent years, there has been a move in eastern and southern African countries from centralised and state-driven management of natural resources towards decentralised and people-centred based regimes. In Tanzania, the inception of the 1998 national forest policy has led to institutionalisation of community-based forest management (CBFM) and joint forest management (JFM). A number of years later, it is worth assessing the impact of this policy on the resource base and people’s livelihoods. This paper uses two case studies of forest reserves under participatory forest management to explore this issue. Secondary data was gathered from various studies conducted in those two forest reserves. In addition to the analysis carried out by the various authors, further analysis involving content and structural analysis and synthesis of documented information was done. The results of the study revealed that CBFM at Duru-Haitemba had a positive impact on the resource base and people’s livelihoods – the forest is healthier than before and people are satisfied with the products they collect from the forests. On the other hand, the impact of JFM at Kwizu Forest Reserve has not yet produced desirable results since illegal activities are still rampant and, apparently, forest exploitation has increased instead of decreasing. The reasons behind the success at Duru-Haitemba and relative failure at Kwizu are varied, but are most probably linked to ownership of resources and law enforcement. Clear definition of rights, returns and responsibilities and adequate incentives are important for sustainability of people-centred management of natural resources.Center for Applied Social Sciences, University of Zimbabwe Institute for Poverty Land and Agrarian Studies (PLAAS

Impacts of savanna trees on forage quality for a large African herbivore

Recently, cover of large trees in African savannas has rapidly declined due to elephant pressure, frequent fires and charcoal production. The reduction in large trees could have consequences for large herbivores through a change in forage quality. In Tarangire National Park, in Northern Tanzania, we studied the impact of large savanna trees on forage quality for wildebeest by collecting samples of dominant grass species in open grassland and under and around large Acacia tortilis trees. Grasses growing under trees had a much higher forage quality than grasses from the open field indicated by a more favourable leaf/stem ratio and higher protein and lower fibre concentrations. Analysing the grass leaf data with a linear programming model indicated that large savanna trees could be essential for the survival of wildebeest, the dominant herbivore in Tarangire. Due to the high fibre content and low nutrient and protein concentrations of grasses from the open field, maximum fibre intake is reached before nutrient requirements are satisfied. All requirements can only be satisfied by combining forage from open grassland with either forage from under or around tree canopies. Forage quality was also higher around dead trees than in the open field. So forage quality does not reduce immediately after trees die which explains why negative effects of reduced tree numbers probably go initially unnoticed. In conclusion our results suggest that continued destruction of large trees could affect future numbers of large herbivores in African savannas and better protection of large trees is probably necessary to sustain high animal densities in these ecosystems

Indigenous plant uses and use values in Uluguru mountains, Morogoro, Tanzania

To assess plant uses and use values in Uluguru Mountains a study was carried out using household surveys and interviews on various uses of the plants. Descriptive statistics and use-value analysis techniques were used in data analysis. Of the plant species identified, 92% were used for fuel wood and 83% were used for construction materials. A significant difference in use values among the species was realized (Χ2 = 7.815, Hc =16.585,

Incentive optimising model for communities living adjacent to catchment forest reserves in Tanzania

Most Catchment Forest Reserves (CFRs) in Tanzania are managed in collaboration between government and communities through Joint Forest Management (JFM). In these forests, harvesting of timber and other valuable products are strictly prohibited. This led to minimal incentives for communities’ participation in conservation. To readdress this anomaly, ecosystem goods and services are optimised to provide compensation fordeferring timber benefits. This study aimed at developing an optimisation model based on sale of carbon and beekeeping activities. The study was conducted in Morogoro and Iringa regions in and around Kimboza and New Dabaga Ulongambi-(NDU) FRs respectively. The incentive model was developed using two decision variables (carbon and honey) and a set of constraints using linear programming. The model output revealed optimal returns ranging from USD 2025 to 6144 per forest per year in Kimboza andNDU FR respectively. Small returns in Kimboza were associated with small size of the forest reaching maximum at threshold between 615 and 1536 ha from a combination of carbon and honey. It is recommended to involve higher forest size (more than 600 ha) for community to maximise incentives particularly when carbon alone is considered. With lower forest size beekeeping activities become important.Keywords: Catchment Forest Reserves- Communities-Incentives-LinearProgramming-Carbon-REDD+NTFPs- Honey-Tanzani

Influence of forest land tenure regimes on forest condition in Uluguru mountains, Tanzania

The paper scrutinizes the current wave of forest land tenure reforms since the inception of the new forest policy in 1998. It explores which type of forestland tenure regime had more positive influence on forest condition in the Uluguru Mountains, Tanzania. The assessment was done with reference to vegetation types of montane and miombo woodlands. The study showed that for the montane vegetation, state regime (Uluguru Nature Reserve) had higher stocking (volume 1,233m3/ha; basal area 78m2/ha; density 777 stems/ha) and tree species diversity (H’ 3.48) compared to communal regime (Chief Kingalu Sacred Forest) which had low stocking(volume 798m3/ha; basal area 49m2/ha; density 1,020 stems/ha) and tree species diversity (H’ 3.21). For the miombo vegetation, corporate/private regime (Tangeni Roman Catholic Church  Forest Reserve) had higher stocking (volume 122m3/ha; basal area 27m2/ha and density 2,573 stems/ha) and tree species diversity (H’ 2.60) compared to communal regime (Misumba Village Land Forest Reserve)which had low stocking (volume 23m3/ha; basal area 10.8m2/ha and density 4,200 stems/ha) and tree species diversity (H’ 3.53). The study concludes that state regime represented by Uluguru Nature Reserve showed improved forest condition compared to communal tenure regime(Chief Kingalu Sacred Forest) for the montane vegetation type while private regime (Tangeni Roman Catholic Church Forest Reserve) was more effective in conservation than communal regime (Misumba Village Land Forest Reserve). The study recommends that sustainable management of forests could not be addressed by tenure reforms in the forestry sector alone, but requires 'cross-sectoral', 'inter-disciplinary' and 'participatory'approach along with secure tenure. Moreover, it is essential that an in-depth forest inventory is conducted at predetermined intervals to quantify stocking of tree, shrub species and forest disturbances to understand the level of resource extraction for each tenure regime.Key words: Tenure regimes, reforms, forest condition, Uluguru Mountains,Tanzania

Biomass Increases Go under Cover: Woody Vegetation Dynamics in South African Rangelands

<div><p>Woody biomass dynamics are an expression of ecosystem function, yet biomass estimates do not provide information on the spatial distribution of woody vegetation within the vertical vegetation subcanopy. We demonstrate the ability of airborne light detection and ranging (LiDAR) to measure aboveground biomass and subcanopy structure, as an explanatory tool to unravel vegetation dynamics in structurally heterogeneous landscapes. We sampled three communal rangelands in Bushbuckridge, South Africa, utilised by rural communities for fuelwood harvesting. Woody biomass estimates ranged between 9 Mg ha^-1 on gabbro geology sites to 27 Mg ha^-1 on granitic geology sites. Despite predictions of woodland depletion due to unsustainable fuelwood extraction in previous studies, biomass in all the communal rangelands increased between 2008 and 2012. Annual biomass productivity estimates (10–14% p.a.) were higher than previous estimates of 4% and likely a significant contributor to the previous underestimations of modelled biomass supply. We show that biomass increases are attributable to growth of vegetation <5 m in height, and that, in the high wood extraction rangeland, 79% of the changes in the vertical vegetation subcanopy are gains in the 1-3m height class. The higher the wood extraction pressure on the rangelands, the greater the biomass increases in the low height classes within the subcanopy, likely a strong resprouting response to intensive harvesting. Yet, fuelwood shortages are still occurring, as evidenced by the losses in the tall tree height class in the high extraction rangeland. Loss of large trees and gain in subcanopy shrubs could result in a structurally simple landscape with reduced functional capacity. This research demonstrates that intensive harvesting can, paradoxically, increase biomass and this has implications for the sustainability of ecosystem service provision. The structural implications of biomass increases in communal rangelands could be misinterpreted as woodland recovery in the absence of three-dimensional, subcanopy information.</p></div