Sentence:  I am recommending additional acquisitions of the <WSD>improved</WSD> version of the B-52 ( the B-52 H with the new turbofan engine ) and procurement of the B-58 supersonic medium bomber , together with the supporting refueling tankers in each case . 
Meaning of the word marked with <WSD> tags:  (of land) made ready for development or agriculture by clearing of trees and brush