Modelling cost-effective clearing solutions for invasive alien trees: A case study on wilding conifers

Area of Science:

• Ecological restoration
• Invasive species management
• Cost-benefit analysis

Background:

• Alien plant invasions pose significant ecological and economic challenges.
• Effective management requires selecting appropriate, cost-efficient clearing methods tailored to site conditions.

Purpose of the Study:

• To develop and test a cost-based model for identifying the most cost-effective alien clearing method.
• To compare the cost-effectiveness of traditional felling, drill-and-fill, and aerial-basal bark application (ABBA) for Pinus removal in the Cape Fynbos biome.

Main Methods:

• A cost-based model was developed, integrating site parameters (infestation density, slope, vegetation density, access) with unit-costing data.
• The model was applied to various scenarios in the Cape Fynbos biome, South Africa.
• Three clearing methods (traditional felling, drill-and-fill, ABBA) were evaluated.

Main Results:

• The drill-and-fill method was found to be the most cost-effective in most tested scenarios.
• Aerial-basal bark application (ABBA) proved more cost-effective for isolated Pinus in dense, difficult-to-access, steep (≥45°) Fynbos.
• Traditional felling was prohibitively expensive due to safety requirements and equipment handling.

Conclusions:

• The developed model enables accurate, cost-effective planning for alien clearing operations.
• Site managers can utilize the model to select the optimal clearing method based on specific site characteristics.
• Informed method selection can lead to significant cost savings in invasive species management.