Soil-tree relationship and site factors in young teak (Tectona grandis) plantations in the Western zone of the Panama Canal

Abstract

This study was carried out in approximately 3000 ha of teak, located in the Western zone of the Panama Canal, using a stratified sampling design (36 monitored permanent plots) for the analysis of tree growth. Plots of 42 months of age were stratified by mean annual total height increments and terrain slope. As site characteristics the nutritional status of the soil and foliar concentration of the trees were analysed, in addition to mean annual increments of height (MHI), diameter (MDBHI), and volume (MVI) of the trees. The sampling design allowed finding that 29% of plots is located in the lower growth class (2.9-4.3 m3 ha-1 year-1), while 59% is located in the middle growth class (6.3-8.3 m3 ha-1 year-1), and 12% belongs in the high growth class (10.3-13.3 m3 ha-1 year-1). The acidity saturation percentage and the Ca saturation percentage proved to be the most limiting factors for each yield and growth, which contributes to explain the condition related to the different growth classes. Optimal conditions were given when acidity saturation was less than 8% and when Ca saturation was more than 40%. This situation was even more evident with soils with pH <5.5. In regard to foliar condition, in general, the contents of the studied elements are located in a middle nutritional foliar class. Two models selected for on-site valuation by stepwise linear regression and multiple linear regressions were also developed.