Site Potential

Forest management decisions, ranging from strategic to operational scales, already require some type of site information in almost all instances.  An improved understanding of site potential and using this to make more effective site-specific management decisions will be vital to plantation forestry facing uncertain future conditions.  This focus area consists of a suite of projects intended to advance our capability to manage site potential.

The aim is to provide improved understanding of ecosystem process and how this is influenced by variation across the diverse range of site conditions in South Africa, as well as to develop refined site-specific recommendations to improve forestry practice and hence contribute to increased yields, reduced risk of crop loss and improved wood quality.

Research Projects

ICFR trial measurement database

The ICFR, and formally WRI, has conducted many field trials over nearly 70 years.  These trials represent an opportunity to advance our understanding of site productivity (spatially and temporally) as well as the site-specific nature of various silviculture treatments.  This project is designed to create, populate and manage a single database that will facilitate mining of data so as to enable meta-data based projects aimed at improved site-specific understanding and recommendations of silviculture practice.

Spatial Technologies: Forestry Site Classification

Plantation forestry in South Africa occurs across a geographic range of sites which also range in production potential from high to low. Risks to production vary widely due to biotic, climatic and edaphic constraints. Site classification is therefore essential for the South African forestry sector, to provide a decision support system for site-specific forest management and interface between research and operational practices/forest management systems, scenario building for risk evaluation, and understanding of ecological processes.

Landform and terrain classification

Terrain analysis and classification attributes are important descriptors of site potential as they affect the availability of the inputs that regulate tree growth (water, nutrients, light). Moreover, they determine the choice of site management practices particularly with regard to mechanised harvesting and site preparation for re-establishment. This project aims to develop key spatial landform and terrain datasets for the development of a national terrain and landform classification system, and specifically terrain-based predictors of site productivity potential.

Site-specific Fertiliser Recommendations

International experience in planted forests managed for wood production shows fertiliser application can be one of the most practical and cost-effective methods of improving commercial plantation stand productivity. Fertilisation is mainly used to improve early site capture and stand uniformity, increase final stand yield and quality, and sometimes to overcome inherent site nutrient limitations of both short and long-rotation stands.

Regolith Water & Nutrient Supply

Production potential and drought risk associated with South African forest plantation sites are dominated by water and nutrient supply. To predict potential productivity, drought risk and nutrient supply potential at a compartment or finer scale requires knowledge of potential rooting depth and water/nutrient storage and supply capacity of the deep regolith (the unconsolidated layer overlying bedrock and consists of soil and underlying saprolite/ saprock, and colluvial and alluvial layers).