We planted a horse chestnut tree many years ago at our cottage. It grew slowly for a number of years but has now taken off. The Main branch is approaching 10 feet high. There is a second branch which starts about 6 inches off the ground and rises to about 8 feet, It is not a thick as the main branch but is reaching up and competing with the main section. In the spring when the leaves were growing vigorously it would lean over and looked to be under a lot of tension. The question we have is should we trim off the bottom branch to force the growth to the main branch system, If so when is the best time to trim. The tree is quite healthy.