Soils and vegetation of Angai forest: ecological insights from a participatory survey in South Eastern Tanzania S. Dondeyne 1, *, A. Wijffels 2 , L. B. Emmanuel 1 , J. Deckers 2 and M. Hermy 3 1 Naliendele Agricultural Research Institute, 1 PO Box 509 Mtwara, Tanzania, 2 Laboratory for Soil and Water, Catholic University of Louvain, V. Decosterstraat 102, B-3000 Leuven, Belgium and 3 Laboratory for Forest, Nature and Landscape Research, Catholic University of Louvain, V. Decosterstraat 102, B-3000 Leuven, Belgium Abstract Soils and vegetation of a woodland in South Eastern Tanzania were studied in support of a project fostering community participation in the management of a pro- posed forest reserve. In nine sites within an area of 500 km 2 , soils were characterized, frequency of occur- rence of woody species was assessed and diameter at breast height of timber species recorded. Villagers iden- tified 133 species of which only 56% were scientifically identified. However, as ordination axes derived from the complete data set were highly correlated with those derived from the restricted data set, the latter could be used. On the undulating plains, deep, sandy soils (Hyp- oluvic Arenosols, Profondic and Arenic Luvisols) occurred low in organic carbon, exchangeable bases and extractable aluminium content. Most common canopy species were Brachystegia spiciformis/B. boehmii and Pter- ocarpus angolensis. On the dissected plains on shallow, clayey soils (Leptic Cambisols) with higher organic car- bon, exchangeable bases and extractable aluminium content, Acacia nigrescens and Markhamia spp. were the most common tree species. On deeper, fertile clayey soils (Profondic Lixisols and Chromic Phaeozems) vegetation consisted of species found in the two vegetation groups. Pterocarpus angolensis and Pericopsis angolensis were the only valuable timber species commonly found, most fre- quently on the undulating plains. As soils of this area are unfavourable for agriculture, it seems sensible to set this area aside as a forest reserve. Key words: soil classification, soil characteristics, miombo woodland, Brachystegia, Pterocarpus, Markhamia Re ´sume ´ Les sols et la ve ´ge ´tation d’une fore ˆt du sud-est de la Tanzanie ont e ´te ´ e ´tudie ´s en support d’un projet en- courageant la participation communautaire dans la ges- tion d’une fore ˆt propose ´e pour devenir une re ´serve forestie `re. On a de ´fini les sols sur neuf sites compris dans une superficie de 500 km 2 , de me ˆme que la fre ´quence des espe `ces ligneuses et on a releve ´ le DBH des espe `ces d’arbres. Les villageois en ont identifie ´ 133 espe `ces dont 56% seulement ont e ´te ´ scientifiquement identifie ´es. Ce- pendant, comme les axes d’ordination de ´rive ´s des donne ´es comple `tes e ´taient en forte corre ´lation avec ceux de ´rive ´s du set de donne ´es restreint, on pourrait n’utiliser que celui-ci. Dans les plaines ondule ´es, les sols profonds et sableux (Hypoluvic Arenosols, Profondic et Arenic Luvisol) apparaissaient faibles en carbone organique, en bases e ´changeables et en aluminium extractable. Les espe `ces les plus communes de la canope ´e e ´taient Brachystegia spici- formis/B. boehmii et Pterocarpus angolensis. Sur les plaines de ´coupe ´es, sur les sols argileux peu profonds (Cambisols leptiques) avec un taux plus e ´leve ´ de carbone organique, de bases e ´changeables et d’aluminium extractable, Acacia nigrescens et Markhamia spp. e ´taient les espe `ces d’arbres les plus communes. Sur les sols fertiles, argileux et plus profonds (Profondic Lixisols et Chromic Phaeozems), la ve ´- ge ´tation se composait d’espe `ces observe ´es dans les deux groupes de ve ´ge ´tation. Pterocarpus angolensis et Pericopsis angolensis e ´taient les seules espe `ces d’arbres a ` grumes de valeur trouve ´es couramment, le plus souvent dans les plaines ondulantes. E ´ tant donne ´ que les sols de cette re ´- gion ne conviennent pas pour l’agriculture, il semble raisonnable de proposer d’accorder a ` la re ´gion le statut de re ´serve forestie `re. *Correspondence: Stephane Dondeyne, Sint Pieterslaan 7, B-3060 Bertem, Belgium. Fax: 32-16-329760; E-mail: stefaan_dondeyne@ yahoo.co.uk 198 Ó 2004 African Journal of Ecology, Afr. J. Ecol., 42, 198–207