Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : A cost comparison of aerial and ground based approaches for the control of alien invasive pines in the Western Cape

Auteur : Boast, Kyle

Université de soutenance : Stellenbosch University

Grade : Master of Science (MS) 2021

Résumé partiel
The rugged mountainous areas of the Western Cape fynbos are highly biodiverse, however alien invasive Pines remain a continual threat both in terms of its biodiversity and water supply as they are continually spreading and thriving uncontrollably. Felling has been the main clearing method ; however, it has become too expensive and slow to use within these areas in comparison with the speed of the invasion. These environments are complex in that they can vary from site to site in terms of tree density, slope, surrounding obstructive vegetation and remoteness. These site properties often result in longer walk, removal and site access times which can significantly increase overall costs of labour-intensive methods such as felling. The problem is continuing to get worse over time and demands an investigation into alternative clearing methods. Chemical methods such as the Drill and Fill and Aerial Basal Bark Application (ABBA) method have increased the efficiency and scope of alien invasive Pine removal in other countries which have however not been tested for local conditions. The aim of this study was to determine under what site conditions these chemical control methods and the use of helicopters would be more cost effective compared to traditional felling which would encourage an integrated approach to managing the species. The study thus consisted of two novel clearing methods : the Drill and Fill method, the Aerial Basal Bark Application (ABBA) method and traditional felling currently used in practice. A work rate matrix was constructed which compared the financial implications of each clearing method at the various physical site combinations : tree density, slope, surrounding obstructive vegetation and remoteness

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