That's only for the purpose of legislation. As suggested in the article, politicians want to make things easier for developers to side step environmental laws. It's not an issue of botanical definitions, it's a "developer versus environmentalist" issue. So (if they do change the legislation/regulations) if you hug a coconut in Goa legally you won't be a tree-hugger.
But personally I believe there are a number of different types of tree, one of them is a Palm Tree.