 A row of fifty Norway spruce trees lines the main driveway leading to the farm . These trees represent the fifty U.S. states , and were given to Eisenhower as birthday presents from each of the state Republican Party chairmen in 1955 . The furthest one from the house was the tree representing Texas , and it was seen as a mark of Eisenhower 's recovery that he was able to walk that far after his heart attack . 
