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Huambo, Angola

Delgado-Matas C.,University of Angola | Delgado-Matas C.,University of Eastern Finland | Pukkala T.,University of Eastern Finland
Southern Forests | Year: 2015

This study developed growth models for Eucalyptus saligna Sm., E. camaldulensis Dehnh., E. macarthurii H.Deane & Maiden, E. resinifera Sm., E. siderophloia Benth. and E. grandis Hill ex. Maiden, for the central highlands of Angola, and used these models to simulate the development of stand characteristics. The obtained model set included dominant height, diameter increment, tree height and self-thinning models. The study was based on 10 499 radial increment observations measured on cores taken from about 700 trees growing in 22 plots located in seven sites in the Angolan highlands. The model set makes it possible to simulate stand development on an individual tree basis. Comparison of simulated stand development and measurements indicated good performance of the models. A non-linear fixed-effects diameter increment model performed best for most species, but a non-calibrated linear mixed-effects model used with the Snowdon correction was better for E. saligna and E. macarthurii. This study showed a similar dominant height development of young stands as found in most previous studies done for southern Africa. Some differences emerged at older ages. © 2015, Copyright © NISC (Pty) Ltd. Source


Gritten D.,O people | Gritten D.,The Center for People and Forests | Mola-Yudego B.,University of Eastern Finland | Mola-Yudego B.,Swedish University of Agricultural Sciences | And 2 more authors.
Scandinavian Journal of Forest Research | Year: 2012

Forest conflicts are ubiquitous, and can potentially be very damaging, underlining the need to develop tools for their management based on an increased understanding. There are numerous differences in the conflicts, of which, media coverage and conflict impact and intensity are the focus of this paper: specifically, the relation between media coverage and conflict intensity and potential impact. The aim of the paper is, firstly, to create a methodology to determine the conflicts' potential impact and intensity. Secondly, determine if there is correlation between impact and intensity and international media coverage. These aims were achieved through the examination of 14 forest conflicts, involving forest industry, identified through a detailed screening of publications from various sources. The results show that international media had relatively little coverage of the 14 conflicts, with a couple of exceptions, despite the high intensity and potential impact of many of them. There are numerous implications for the work, not just with the creation of the methodologies, but also highlighting various areas of future research. © 2012 Copyright Taylor and Francis Group, LLC. Source


Delgado-Matas C.,University of Angola | Delgado-Matas C.,European Union | Pukkala T.,University of Eastern Finland
Southern Forests | Year: 2010

This study developed growth models for Pinus patula Schiede ex Schltdl. et Cham. for the Central Highlands of Angola for simulating the development of stand characteristics. The model set included dominant height, individual-tree diameter increment, individual-tree height and self-thinning models. The study was based on 7 656 radial increment observations obtained from increment cores from eight plots located in five sites in the Angolan Highlands. The model set enables the simulation of stand development on an individual tree basis. Despite the fact that site variation among the plots was small, a traditional site category index based on slope catena correlated logically with the observed diameter growth rate of the plots. The developed models showed a high level of accuracy when the simulated stand development was compared to observed development. The shape of the dominant height model is similar to earlier models developed in southern Africa. © NISC (Pty) Ltd. Source


Delgado-Matas C.,University of Angola | Delgado-Matas C.,European Union | Delgado-Matas C.,University of Eastern Finland | Pukkala T.,University of Eastern Finland
Journal of Forestry Research | Year: 2012

A species introduction experiment including several tropical pines and eucalypts was established in 1966/1967 in the Tchianga research station in Angolan Highlands. Despite 27 years of political conflict (1975-2002) and lack of management, the research experiment has remained relatively well conserved. We measured the best conserved plots that were 41 years old in 2007 to obtain information on the growth of different pine species. We calculated stand characteristics including basal area, dominant height, mean diameter, and stand volume for Pinus patula Schiede ex Schiltdl. Et Cham., Pinus pseudostrobus Lindl., Pinus kesiya Royle ex Gordon, Pinus devoniana Lindl., Pinus chiapensis (Martinez) Andresen, Pinus elliottii Engelm., Pinus greggii Engelm. Ex Parl., Pinus montezumae Lamb. and Pinus oocarpa Schiede ex Schltdl. The growing stock volume at 41 years was the highest in P. pseudostrobus, 1,325 m3·ha-1, followed by P. kesiya with 1,200 m3·ha-1. The widely planted P. patula had a growing stock volume of 892 m3·ha-1. P. oocarpa and P. pseudostrobus had the highest stand basal area, over 80 m2·ha-1. Using increment core analyses we studied the temporal development of stand characteristics. Analysis of the mean annual increment (MAI) showed that rotation lengths of 20-30 years would maximize wood production. With these rotation lengths, the MAI of P. pseudostrobus would be 35 m3·ha-1. Other productive species were P. kesiya, P. oocarpa and P. chiapensis. P. patula had a maximum MAI of 20 m3·ha-1. P. greggii had the lowest mean annual volume production, only about 13 m3·ha-1. © 2012 Northeast Forestry University and Springer-Verlag Berlin Heidelberg. Source


Delgado-Matas C.,University of Angola | Delgado-Matas C.,European Union | Delgado-Matas C.,University of Eastern Finland | Pukkala T.,University of Eastern Finland
International Journal of Sustainable Development and World Ecology | Year: 2014

This study used linear programming (LP) to analyse land-use alternatives in the traditional Umbundu farming system in the Angolan central highlands. Farmers of the region have traditionally produced maize and pulses for subsistence and vegetables and timber as cash crops. Different pasture and forest fallow rotations are used along catena production sites. The system is labour-intensive and uses animal traction. LP problems were formulated and solved for a baseline land-use alternative, improved diet alternative and maximal timber production alternative. All three problem formulations included constraints that guaranteed sufficient food and firewood production and sufficient pasture area for animals while being feasible in terms of human labour and animal traction consumption. Of the alternative production systems, cash crops with forest fallow had the highest land expectation value (LEV), while cereals under short grazing fallow showed even negative LEVs. Changing the diet by diversifying carbohydrate and protein sources increased LEV and reduced the need for women labour during the peak season. When timber production was maximised the optimal share of land devoted to pure forestry was 57%, and less labour was required. © 2013 Taylor and Francis. Source

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