Both poems talk about the destruction to the world.
In the poem "Flower fed Buffaloes," because of industrialism, the railroads took way the land that belonged to the buffalo and the Pawnees and the Blackfeet.
Sadly enough, people on the trains chose to shoot the buffalo. The railroads took over the buffalo's range. Thirty thousand buffalo have turned into three hundred because of the advancement of civilization. The railroad has taken over the land.
In the poem "Lament," the natural part of the land is destroyed because of war. War has taken its toll on the turtles, the dolphins, the sea birds, etc.
A soldier is on fire. The earth is burnt. The ocean is scalded. The "vengeance and ashes of language" is the way the poet describes the horrors of war.
Two major destructions of the natural world are the railroad and war. So much for civilization.