His poem reflects the intense and thorough process that one has to go through to kill a tree. The overall message might be that if it is so difficult to kill a tree, should it even be done? Even though the main body of the poem is dedicated to killing a tree, if you look closely at some of the words and descriptions, you can see Patel's reverence for trees. For example, he describes how a tree grows, and that
"It has grown
Slowly consuming the earth,
Rising out of it, feeding
Upon its crust, absorbing
Years of sunlight, air, water,
And out of its leprous hide
This passage shows a reverence for the tenacity of a tree, and that it can "sprout leaves" out of the dirt of the earth's crust. It, against all odds, has risen and become strong. This description shows how Patel respects nature, and is in awe of the miraculous process by which it grows. Later, he describes the core of the tree as
"The source, white and wet, /The most sensitive, hidden/For years inside the earth,"
again showing admiration for the source of the life of the tree.
If you also look at how Patel goes to great lengths to describe the elaborate process of killing a tree, he seems to be exaggerating, and listing all of the details to point out how absurd it is to kill something so alive and rooted in nature. He seems to be against the process. At the beginning, he indicates how one might kill a human, with a "simple jab of the knife," but to kill a tree, it's this long, drawn-out process. It takes a lot more intent, purpose, and commitment, and that seems a bit wrong.
I hope that those thoughts help a bit; good luck!