Indigenous plantations could be the next big thing in foresty

In a report to the Water Research Commission (WRC) distributed recently the scientists investigated the growth rates, water-use and economic viability of a selection of indigenous trees and forests across South Africa, and compared their findings to current exotic plantation systems such as eucalyptus and pine. When considering water-use efficiency in terms of the volumes of wood produced relative to the amount of water used by the trees, the exotic plantations consistently outdid their indigenous counterparts. However, when an economic measure for water-use efficiency was used, the southern Cape indigenous forests and a yellowwood plantation compared favourably. “The improved performance of the indigenous systems based on economic criteria is because they have lower maintenance costs with substantially higher product prices. Also, levelling benefits and costs ensures that systems with large upfront costs and long rotations – typical of stands of indigenous trees – can be compared with shorter-rotation plantations and not unfairly selected against,” commented co-author Dr Russell Wise. Further economic benefits from indigenous plantations may be gained from by-products such as traditional medicine, fruits, recreation, climate-change mitigation through carbon storage and tourism. The project team now aims to provide a short-list of indigenous tree species with low water-use rates and high economic potential, together with their suitability for plantations in different regions of South Africa. You could contribute to the project! While the distribution of natural indigenous forests in South Africa is fairly well understood, knowledge of the true extent and diversity of plantations of indigenous tree species in this country is limited, and the researchers are appealing to growers of indigenous trees to assist them with information. Details that would be particularly useful include the location (e.g. latitude and longitude) of any indigenous tree plantations, the species (or species combinations) planted, the extent of the plantings (e.g. size of the plantation in hectares, or the number of trees planted), the planting density (stems per hectare) and the current age of the trees (or planting date). All information received will be acknowledged and treated with the strictest confidence. Please send any relevant information by email to Mark Gush at mgush@csir.co.za Tel: 033 260 5446.