Optimal management of the Umbundu traditional land use system in the central Highlands of Angola

Abstract

The study reviews one publication on the traditional land use system in Angolan highlands, three publications on modelling the growth and yield of nine tropical pine and six eucalypt species, and one publication on optimising the land use in Angolan highlands. The sources of data for the land use system analysis were two years field research and a review of previous studies going back to colonial times. The growth models were based on 19,388 radial increments from 1,059 measured pine trees and 10,499 radial increment observations measured on cores taken from 803 eucalypts trees. Linear programming (LP) was used to optimize the combination of alternative production systems. LP problems were formulated and solved for a baseline land use, improved diet, and maximal timber production land uses. The first study has implications for land use management (e.g. regarding length of fallow) and conflict management in Angola and elsewhere. The developed growth and yield model set included dominant height, diameter increment, tree height and self-thinning models for all the studies pine and eucalypt species. The model set makes it possible to simulate stand development on an individual tree basis. They showed good accuracy when the simulated stand development was compared to the observed development. Therefore, they can be used as a management planning tool in tropical pine and eucalypt plantations in Angola. The developed models were used in the last study to calculate the timber production in short-and long-rotation forestry. The last study showed that among the alternative production systems, cash crops under forest fallow showed the highest land expectation value (LEV). Changing diet by diversifying carbohydrate and protein sources increased LEV and reduced the seasonal need for women labour. In the maximal timber production alternative under food sufficiency constraint the optimal share of tree plantations was around 57% of the total land area.Keywords: Land use management, Pinus spp., Eucalyptus spp., linear programming, growth models, Umbundu Land Use System (ULUS). ABSTRAKTIVäitöskirjan tutkimuskokonaisuus kattaa yhden julkaisun perinteisestä maankäyttösysteemistä Angolan ylänkömailla, kolme julkaisua yhdeksän trooppisen mäntylajin ja kuuden eukalyptuslajin kasvusta ja tuotoksesta, sekä yhden julkaisun maankäytön optimoimisesta Angolan ylänkömailla. Maankäyttösysteemien analyysin aineisto on peräisin kahden vuoden kenttätyöstä ja kirjallisuuskatsauksesta, joka ulottuu aina siirtomaa-aikoihin. Kasvumallit perustuivat 19,388 läpimitankasvuhavaintoon 1,059:sta männystä ja 10,499 läpimitankasvuhavaintoon 803 eukalyptuksesta. Vaihtoehtoisten maankäyttömuotojen optimaalinen kombinaatio haettiin lineaarisella ohjelmoinnilla (LO). LO-ongelmat muodostettiin tämänhetkistä ruokavaliota tavoittelevalle maankäytölle, parannetulle ruokavaliolle sekä vaihtoehdolle, jossa maksimoidaan puuntuotosta niin, että ruuan tuotanto paikalliselle väestölle on samalla riittävää.Ensimmäisellä tutkimuksella on vaikutuksia maankäytön suun...

Dynamic Patterns of Trees Species in Miombo Forest and Management Perspectives for Sustainable Production—Case Study in Huambo Province, Angola

“…The agricultural period in this zone begins after the original miombo forest is slashed and burned (Appendix A), and then new fertile areas are opened. After four to 15 years of cultivation, the land becomes poor and unsuitable for agricultural activities [121,122], and it is covered by grass and small shrubs. If natural regeneration processes are not interrupted, this zone becomes an MZ-C with areas of open miombo where shrubs and small miombo trees persist (Appendixs A and C).…”

“…This zone is a transition of MZ-D to MZ-E and is mainly a combination of agricultural lands and grassy vegetation. Agricultural lands become useless after five periods of continued cultivation and the fields are eventually only used for pastoral activities [122]. It is recommended that agroforestry systems would be a good fit in this zone.…”