Sentence:  In January or February the "<WSD>hacker</WSD>," with his keen-bladed ax, begins the round which ends the season. [...] About a quart of sap is taken from each box by means of the trowel-shaped scoop used by the dipper, and then the <WSD>hacker</WSD> comes along and starts the flow afresh by wounding the tree again. 
Meaning of the word marked with <WSD> tags:  Particularly, one who cuts with rough or heavy blows.