In plain english:
The first part of the poem...he is talking about the personal glory of being a soldier fighting to better the world...but when he starts getting vauge in the middle he is talking about powers behind the war...forces which create it in the first place..then he goes to the tree how it is life and how a child fell with the hammok (sp) and that represented the soldier and how the powers that be in war could care less about the individual soldier who dreams of glory as he falls (dies). In other words, he becomes a pawn and is disillusioned.