气候变化领域集成服务门户

Dieback of forest trees is considered as serious problem in most parts of the world. Shisham an important multipurpose tree of the Indian subcontinent is suffering from dieback. Changing climate in most parts of the world is considered an important factor of ecosystem disturbance. Impact of environmental variables, tree age and water table on the dieback of shisham was examined in different regions of Punjab, Pakistan. Significant correlation was observed between environmental variables and dieback in minimum, moderate and maximum infected trees among three age classes. Water table and rainfall expressed non- significant correlation. A multiple regression model was developed to determine the relationship between environmental variables and dieback. Coefficient of determination value (R-2 = 0.89) depicts that model is statistically good. Model indicated that most of the predictor variables has minor role in disease development except age and time span. With one unit increase in age and time span disease will increase 4.15 and 5.25 units respectively. Values of partial R-square indicated that age class (0.5253), time span (0.2943) and relative humidity (0.0552) are major contributors in disease development. It was concluded form the study that age and time span are significant predictor of dieback.