President Pranab Mukherjee on Monday urged probationary officers of the Indian Forest Service to use their "expertise and core competence" for improving the quality in management of forests, a Rashtrapati Bhavan statement said.Addressing a group of officers, including two from Bhutan, of the 2014 batch, the president said as a large number of those present were engineers, they should "use their expertise and core competence for improving the quality in management of forests"."In today's world, environment and climate change are most important issues and pose great challenges. The human race as a collective body needs to respond to these challenges or their very existence might be in danger," he said.Highlighting that the officers will be implementer of policies, Mukherjee said they must not adopt any lopsided or imbalanced approach.