All you need to do is get close to the tree or house by using the arrow keys. Up arrow is to zoom in, down arrow is to zoom out, right arrow is to slide to the right, and left arrow is to slide to the left. Make sure the black looking plus sign is on the item. Then hold the space bar and its going to disappear. To do it again just click the green flag. Enjoy! (Sorry for the intro that goes over and over again when you click the green flag to start over the game)
Credit to @UnicornFlufff because I wanted this project to be on my account to!!!