Growth, biomass, carbon storage and nutrient distribution in Gmelina arborea stands on red lateritic soils in central India

Background

Large-scale plantations are being established on degraded lands in India to restore the productivity of these soils and landscapes and to sequester atmospheric carbon. Gmelina arborea is a fast-growing indigenous tree used for timber, fuelwood, pulp and fodder already in use in reforestation projects. However, its growth and biomass production has been inadequately studied, particularly in the poor red laterite soils that dominate degraded landscapes.

Research goals & methods

The study was conducted at three red lateritic sub-humid tropical sites in central India. Seedlings were planted at 4x3m over six years to generate six age classes. Sampling of all age classes was conducted at year 6. Stand biomass increased from an average of 3.94 Mg ha^-1 in one-year-old stands to 53.67 Mg ha^-1 in 6-year-old stands. Nutrient accumulation also increased with age. Soil organic carbon increased from 8.46 Mg ha^-1 at baseline to 14.02 Mg ha^-1 in six-year-old stands. Available N and K increased while P decreased. The net change in total C was 31.37 Mg ha^-1, or 5.22 Mg ha^-1 y^-1.

Conclusions & takeaways

G. arborea can tolerate nutrient-poor acidic soils and the toxic levels of Al found in red laterite soils and had higher growth rates than several other species studied elsewhere. Despite a slow start, growth rates increased 3 years after planting. Phosphorus additions are recommended for plantations in lateritic soils.