Stress effects on canopy growth and architecture: a case study on sal mortality

Abstract: Disturbances and fragmentation of the study areaBarkot Range (Moist Deciduous Sal Forest, Dehradun Forest Division) resulted in changes in the physical environment due to microclimatic variations, altered species composition and soil properties and had severe implications on the physiological functioning of the Sal trees. Two Shorea robusta (Sal) stands one containing many Sal trees with canopy dieback, mortality site (MS) and the other with healthy green, full crowns, non-mortality site (NMS) were selected. The paper investigates the soil moisture status of the two sites and evaluates effect of nutrient and water stress on the canopy growth and architecture of the Sal trees. In the present study, the difference in the average soil moisture percentage in the NMS (14.30%) and MS (12.74%) was statistically significant, indicating lower moisture availability in the mortality site in comparison to the non-mortality site. Tree growth increment was affected especially leaf production and lateral branching, which was greatly reduced. Sal stressed trees of the mortality site had highly reduced canopy growth. The crown height increased invariably however the crown width had greatly reduced. In general, canopy height was positively correlated to the bole height of the healthy Sal trees in the nonmortality site. No such relationship was obtained for stressed Sal trees in the mortality site.