Theory:

No,
The root is to be pulled out –
One of the anchoring earth;
It is to be roped, tied,
And pulled out – snapped out
Or pulled out entirely,
Out from the earth-cave,
And the strength of the tree exposed
The source, white and wet,
The most sensitive, hidden
For years inside the earth.
 
Then the matter
Of scorching and choking
In sun and air,
Browning, hardening,
Twisting, withering,
And then it is done.
Explanation:
  
So can a tree be killed easily? No. The poet uses sarcasm to deliver the point to the readers about what it takes to kill a tree after years of nurturing it. In the following stanzas, the poet explains how we can kill the tree. The roots must be pulled out from where it is firmly fixed to the ground.
 
uproot tree.jpg
A tree uprooted from its anchoring earth!
  
It has to be tied to a rope and broken with a sharp movement so that it is uprooted completely; then removed entirely from the cave under the earth's layer. That is when one can witness the actual strength of the tree. All the power that had been contained for many years within the earth's wet topsoil, the most delicate and concealed part of the tree has to be brought out to the surface - a tree can be killed only after such laborious effort.
 
cut tree rope.jpg
The tree is roped, tied and snapped out of the ground!
  
Once all the above is done, the job becomes simple. The tree will soon be dried in the hot sun. It cannot breathe air anymore, as the roots have been cut down. It becomes brown, dry, hard, twisted and wrinkled. Finally, the tree is killed.
 
man cutting a tree.jpg
Finally, man has completed his job of killing the tree!
  
The poet has personified the tree and explained how painful it is to "kill" a tree. He has used the term "killing" instead of "cutting" the tree to equate it to human emotions. He uses sarcasm to explain that it is very difficult to cut/kill a tree, but humans are constantly trying to cut trees. He describes the disappointment behind the cutting process and thereby sensitize the readers to protect our trees.
  
Meanings of difficult words:
  
No.
Words
Meanings
1
anchoringprovide with a firm basis or foundation
2
snappedbreak suddenly and completely, typically with a sharp cracking sound
3
scorchingvery hot, blazing 
4
chokingprevent (a plant) from growing by depriving it of light, air, or nourishment
5
witheringbecome dry and wrinkled
Reference:
State Council of Educational Research and Training (2019). Term-2 English Standard-9. On Killing a Tree - Dr. Gieve Patel (pp. 146-152). Published by the Tamil Nadu Textbook and Educational Services Corporation.