Classification of the indigenous forests of Mpumalanga Province, South Africa

• Detailed floristic survey of the indigenous forests in and around Mpumalanga Province, South Africa, is presented.
• A subtype classification for forests in Mpumalanga is presented, nested within the current national forest types.
• Forest subtypes are described in terms of their structural and floristic characteristics.
• Results contribute towards a national fine-scale forest classification that is required for management of forest resources.

This paper presents a hierarchical system of forest communities of Mpumalanga Province (South Africa) compatible with the existing South African National Forest Classification (NFC). It describes and interprets floristic and physiognomic differences between the communities and the relevant higher-rank vegetation unit. A total of 434 relevés (rectangular plots, each 0.04 ha; listing all species in the plots in Braun-Blanquet cover-abundance scale), sharing 619 species, served as the basis of the classification. The data were classified using the Flexible beta clustering (β = − 0.25) in combination with the Bray–Curtis similarity measure. The proposed forest subtypes are described in terms of dominant plant families and genera, growth forms, seasonality or leaf retention characteristics, and the proportion of forest dependent species. Fourteen forest subtypes are distinguished within three national forest types, with no subtypes being recognised within the Lowveld Riverine Forest Type. We propose that the Wakkerstroom Midlands Forest Subtype be embedded within the Northern Highveld Forest Type, and not the Low Escarpment Mistbelt Forest Type as is currently recognised in the NFC. A total of 125 plant families and 375 genera were identified to occur in the Mpumalanga forests, with the most abundant species per family being Rubiaceae, Fabaceae, Celastraceae, Orchidaceae, Euphorbiaceae and Aspleniaceae. 76% of all forest plant species were obligate forest species and 80% of all tree cover is evergreen.