Having little knowledge about tropical and subtropical trees (except some growing in Delhi), I tend to mix them. This was the tree growing along Nainital lake and known as Bangar (as a local told me). The other tree identified by Satish ji as Lannea coromedelica grows common along hillsides.
Could this be what Nidhan ji suggested as Boswellia serrata, a very wild guess though. Perhaps two forms are growing side by side, one with perfectly green leaves and one having leaves with reddish tinge.
Dr. Gurcharan Singh
Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089