The answer is a tree
I reach up to the sky and back down to the ground. Sometimes I reach far to the sidesto touch my brothers. I conceal people and things. What am i?
For some, I am used to get around. I never even touch the ground. Sometimes I fall in a large open tank and sometimes I float in the air and then rise. What am I?
I sleep by day and fly by night. The moon hides me from mortal sight. Reach for me but always fail. Trust in me when you set sail. What am I?
I go up and I go down, towards the sky and the ground. I'm present and past tense too. Let's go for a ride, me and you. What am i ?