Shisham is one of the most important timber species in Pakistan. It is indigenous to the Indo—Pak subcontinent provides income to local people and becomes an important agroforest species. Shisham mortality research has suffered from a false dichotomy of drought vs biotic attack. In this study, the inherent problem associated with the understanding of shisham dieback was addressed by comparing the ecology and soil characteristics of Shisham evolved under high water demand, low salinity, and non–existing waterlogged conditions at its place of origin. Shisham was introduced to semi–arid regions characterized by low water availability, long and frequent droughts, flooding, and salinity thus predisposing shisham to completely new selective factors such as abiotic and biotic stresses that are not known at its place of origin. Shisham dieback is thus a result of prolonged and frequent exposure to abiotic factors in its non–native planting sites. The recent dieback outbreaks were due to water shortage and the lowering of the water table because of different drought episodes. Soil comparison revealed electrical conductivity was higher in diseased than the healthy plants that show high salinity or low moisture conditions in the rhizosphere. These findings further emphasized the importance of the abiotic factors in the shisham dieback in Pakistan. It is concluded that the dieback is mainly caused by abiotic factors such as drought, waterlogging, and salinity. It is therefore suggested that shisham plantations must be established on lands without waterlogging and salinity and drought conditions. Secondly, water availability must be ensured in the plantations by channeling canals through the plantations to ensure water supply as well as to help keep the water table high to maintain healthy shisham plantations.

Keywords: Dalbergia sissoo., Ecology., Climate change., Dieback., Drought., Salinity., Waterlogging., Abiotic stresses