why coconut plant is not found on tropical hills.?

Question

But there are coconut tree in plain land in same region. No hills near sea shows coconut tree.

Answer 1

Coconuts are the seeds of the tree. They float, which is why they are found along beaches. They have no way of getting higher up a hill than their parent tree. They can't float up the hill, and they can't roll up the hill so they don't go up the hill unless a person or animal takes them there.

Answer 2

I don't believe that. Have you taken a look or just seen some photos showing them near the sea?

Here is a link that talks of them growing on land up to about 1970 feet high. http://www.agroforestry.net/tti/Cocos-coconut.pdf