Workmen from the Department of Building and Grounds, unable to attend the day's sales, observed George Washington's birthday yesterday by cutting down a tree-although it wasn't cherry. The tree, which was on the east side of the Rotunda, is one of several condemned to firewood by the University Tree Committee. A spokesman for the department said that more trees on the Grounds that have been dead for some time will get the axe in the coming few weeks, adding that whether or not the trees would be replaced depended on the location. They would be replaced, he said, if the process would not hinder the growth of other trees and if the newly planted trees had a good chance for survival.