Closed forests are concentrated in two major masses, one in the Dembos region, between latitudes 6° 30´ and 9° 30´ S and longitudes 14° and 15° 30´ E, in Uige and particularly Cuanza Norte provinces, the other in the northern half of the Cabinda enclave (or Angolan Mayombe). There are also numerous scattered gallery forests, mainly in the northern half of the country. These stands are generally low to medium altitude semi-deciduous moist closed forests, with several storeys reaching as much as 60 m in height.
The Dembos forest, situated between 400 and 700 m, has been seriously degraded by coffee plantations that retain some forest cover, "consisting of a small number of species chosen for their capacity to provide shade" ("secondary coffee forest" with Celtis, Albizia, Morus, Ficus), in Grandvaux Barbosa´s classification. A number of prized wood-producing species have been extracted, for example trade iroko, Chlorophora excelsa; Pteleopsis diptera, trade white mahogany, Khaya anthotheca; trade padouk, Pterocarpus tinctorius; Entandrophragma spp.; Diospyros mespiliformis and Albizia spp.
The semi-deciduous closed forest of Mayombe is similar to that of neighbouring countries (the Democratic Republic of the Congo and the Republic of the Congo). The most exploited timber species have been trade tola Gossweilerodendron balsamiferum; trade limba, Terminalia superba; trade tchitola, Oxystigma oxyphyllum; Entandrophragma spp. and trade iroko; Chlorophora excelsa.
Vestiges of mountain forest situated in ravines and depressions along watercourses cover very small areas in the highlands of Benguela and Huila provinces ("montane dry conifer forest"). Muxito pine, Podocarpus milanjianus, the only Angolan conifer, is predominant here, accompanied by broadleaved species such as Parinari spp., Faurea saligna, Chrysophyllum spp. and Syzygium huillense.
Gallery or riparian forests cover a fairly large area. North of the Cuanza basin (north of latitude 9° S) as well as further inland, they are distinguished by trade kapok, Ceiba pentandra and Lonchocarpus erinaceus, associated with introduced species such as mango Mangifera indica; Elaeis guineensis and Spondia mombin.
Semi-deciduous and even evergreen forest species such as trade ilomba, Pycnanthus angolensis, trade bilinga, Nauclea diderrichii; Chlorophora excelsa and Khaya anthotheca; are found here because of favourable edaphic conditions. Moving southward, these forests steadily become smaller and poorer in species until they are reduced to lines of small trees or shrubs, in particular Syzygium. South of latitude 15° S they cannot be picked out on satellite images, if indeed they still exist.
Grandvaux Barbosa distinguishes evergreen dry closed forests in the upper Zambezi region (east of Moxico province), with a rainfall of 1 100 to 1 200 mm, dominated by Cryptosepalum exfoliatum and covering over 150 000 ha in the neighbourhood of Macondo. Although the dominant storey is sometimes sparse as a result of repeated fires, these forests have been classified as closed broadleaved forests, as in Zambia, because of the almost total absence of a grassy layer.
Mangroves and swamp forests
Mangroves are found at the mouths of all the large rivers, becoming more shrub-like further south and disappearing completely south of Benguela. Rhizophora mangle is the main species, followed by R. racemosa, Avicennia nitida, Chrysobalanus ellipticus, Annona palustris, Pandanus spp., Erythroxylon emarginatum and Conocarpus erectus.
Swamp forests or periodically flooded forests cover considerable areas, for example between the marshes and savanna near the Congo, on the edge of the Congo mangroves, or as small stands in swamps and on the edge of lakes at sea level. Mitragyna stipulosa, Homalium stipulaceum, Anthothesma aubryanum, Xylopia spp., Alstonia gilletii, Nauclea diderrichii, Symphonia globulifera, Uapaca guineensis, Raphia spp., etc., are the most common species. Most of these forests are found in Cabinda and Zaïre provinces in the far north of the coastal zone.
Bamboo and palms
Palms (Hyphaena spp.) are very common near the coast, sometimes forming almost pure stands, and an introduced species, Anacardium occidentale, is also spreading naturally.
Borassus palm, Borassus aethiopium stands, which are found especially in the north of Uige, Malanje and Lunda provinces, are a type of tree savanna.