Nitrogen-Fixation and Nutrient Relations in Savanna Woodland Trees (Tanzania)

Högberg, Peter

doi:10.2307/2404045

Cited by 74 publications

(54 citation statements)

References 29 publications

(27 reference statements)

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“…for N-fixing species (Schulze et al 1991) and also higher than those found in a Tanzania savanna woodland (Hogberg 1986). The foliar δ 15 N in N-fixing plants has been shown to be close to atmospheric δ 15 N (0-2‰) (Shearer and Kohl 1986;Yoneyama et al 1990).…”

Section: Resultsmentioning

confidence: 72%

“…According to an earlier report, using foliar δ 15 N, C/N ratio and taxonomic classification as indication, there are potential N-fixing forbs and some potential N-fixing trees, such as Baphia, Indigophera, and Tephrosia at the wet end ), but they are less common in the current study site. The mesic site considered in this study also does not exhibit N-fixing genera such as Dalbergia, Dichrostachys, Entada and Xeroderris that were found in Tanzania woodlands under similar rainfall regimes (Hogberg 1986). Soil crusts are also reported to fix N, but soil crust cover is low at the mesic site, probably due to anthropogenic disturbance based on field observations.…”

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confidence: 72%

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Ecosystem-scale spatial heterogeneity of stable isotopes of soil nitrogen in African savannas

et al. 2012

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Section: Resultsmentioning

confidence: 72%

mentioning

confidence: 72%

Ecosystem-scale spatial heterogeneity of stable isotopes of soil nitrogen in African savannas

et al. 2012

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“…It is a small, many-branched tree rarely exceeding 10 m in height and with a bole circumference normally < 120 cm (Lovett, 1988). It is known to fix nitrogen and grows in an ecosystem that usually has poor soils (Högberg, 1986), but otherwise its ecological importance is unknown. The tree gets its name from the dark-coloured heartwood that in the best quality timber is inky black and can reach densities of 1.1 g cm -3 (Malimbwi et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Stocks and exploitation of East African blackwood Dalbergia melanoxylon: a flagship species for Tanzania's miombo woodlands?

Ball

2004

ORX

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East African Blackwood is the common name for Dalbergia melanoxylon, the most valuable timber growing in the Miombo woodlands of southern Tanzania, and a potential flagship species to justify conservation of this habitat. The population density, structure and exploitation of this economically and socially important species were studied in an area of southern Tanzania. Harvestable timber was found at a density of 1.03 m³ ha -1. Multi-stemmed trees, which have a lower marketable value, were more frequent in burned areas. Local people have a number of uses for the species but have replacements for all but its medicinal application. Felling licence and export figures are inconsistent but suggest that illegal harvesting is occurring. The implications of these results for the species' flagship status and options for community-based management are discussed.

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“…It is recommended that fire be applied biannually just before the annual rainfall season (Geldenhuys 1977) to maintain populations of P. angolensis and to enhance recruitment (Geldenhuys 2005) as annual burning adversely affects developing seedlings until the suffrutex root system has fully developed (Groome 1955, Boaler 1966, Högberg 1986). Field observations indicate that fires that occur in areas where biannual burning is not practised, are inordinately hot for the sustainable growth of mature trees and can inhibit recruitment of seedlings and saplings.…”

Section: Possible Contributing Factorsmentioning

confidence: 99%

Die-back of kiaat (Pterocarpus angolensis) in southern Africa: a cause for concern?

Mehl

Geldenhuys

Roux

et al. 2010

Southern Forests: a Journal of Forest Science

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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.

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Nitrogen-Fixation and Nutrient Relations in Savanna Woodland Trees (Tanzania)

Cited by 74 publications

References 29 publications

Ecosystem-scale spatial heterogeneity of stable isotopes of soil nitrogen in African savannas

Ecosystem-scale spatial heterogeneity of stable isotopes of soil nitrogen in African savannas

Stocks and exploitation of East African blackwood Dalbergia melanoxylon: a flagship species for Tanzania's miombo woodlands?

Die-back of kiaat (Pterocarpus angolensis) in southern Africa: a cause for concern?

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