ABSTRACT

The productivity of Teak (Tectona grandis Linn. f) varies significantly across different geographic zones due to variations in climate, soil type, altitude and other environmental factors. Understanding these variations is crucial for optimizing Teak plantation practices. Identifying the most productive zones can help in better resource allocation, ensuring that efforts are concentrated in areas with the highest growth potential and also provide insights into how to maximize yield while ensuring the long-term sustainability of Teak plantations. In order to identify the most productive zones and age-class an experiment was carried out in three different geographical zones of Uttara Kannada district in Karnataka viz., Yellapur, Haliyal and Karwar.
Observations on growth parameters like total tree height, clear bole height, GBH, basal area, total volume and clear bole volume etc., were recorded in 31.62 m × 31.62 m sample plots and average data per hectare was calculated. The research used a factorial randomized block design to evaluate tree productivity and the impact of soil chemical properties across different age classes and zones. The tallest trees were found in Yellapur (22.66 m) for the 91-110 years age class, with Karwar and Haliyal following. Clear bole height was highest in Yellapur (13.78 m) for the same age class, while Karwar showed consistent but lower growth. Girth at breast height under the age-class 91-110 was largest in Karwar (1.21 m) and basal area per hectare was also highest in Karwar (20.05 m2 ha-1) under same age-class. Total tree volume per hectare was highest in Karwar due to its larger basal area in 91-110 year age-class. Clear bole volume was greatest in Yellapur (119.20 m3 ha-1) under 91-110 age-class.
Soil pH was highest in the 31-50 years age class across all zones, with Karwar showing the highest pH (6.25). Electrical conductivity peaked in the same age class, with values similar across zones. Organic carbon, nitrogen, phosphorus and potassium levels were highest in the 91-110 years age class, with Karwar consistently showing superior levels. Calcium and manganese concentrations were also highest in the 91-110 years age class, with Karwar leading in both.