Dalbergia sissoo mortality in Bangladesh plantations: correlations with environmental and management parameters

Widespread mortality of Dalbergia sissoo in Bangladesh has been observed, but no studies have investigated the relationships between environmental and plantation characteristics with sissoo mortality. We investigated the relationship between sissoo mortality and environmental and plantation characteristics across 72 mixed plantations in five districts of Bangladesh. Overall, mortality (consisting of dead + dying trees) was high, with median farm mortality rates ranging from 39.5% to 55% of the sissoo population. Our results suggested that death rates were not correlated with age, suggesting that preventative investments cannot be focused on any particular stage of the plantation's cycle, and that farmers cannot enjoy reduced uncertainty of loss at any time. No soil parameters (texture, pH, organic matter, sand, silt or clay content) were correlated with sissoo mortality. Planting density and the percent of total plantation trees being sissoo were strongly and positively correlated with the percent of sissoo population dead or dying from disease. While this suggests that theoretically, lowering planting densities would reduce mortality, economic analysis should be conducted to determine whether feasibility could be achieved. We conclude one logical response of farmers in Bangladesh would be to change plantation species rather than to change management strategies, similar to the response of rural farmers in Nepal. Investments in new species trials are also recommended.