1. Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
2. Biology and Sustainability Research Division, Malaysian Palm Oil Board, Selangor, Malaysia
3. Soils and Plant Nutrition Division, Tea Research Institute of Sri Lanka, Talawakelle, Sri Lanka
4. Department of Wood and Fiber Industries, Faculty of Forestry and Environment, Universiti Putra Malaysia, Serdang, Selangor, Malaysia