Foliage

These values are defined as constants:

final int treeX = 200, treeY = 45, treeW = 125, treeH = 55;  // tree leaves

To add the foliage to the tree,
the following methods call will be added to the applet:

gr.setColor( Color.green );
gr.fillOval( treeX, treeY, treeW, treeH );

The fillOval() method is like the drawOval()
method, except that it fills the figure with the current color.

Next, look at the green lines that make up the rolling hills
in the background

(click here to see them).
Estimate an (X, Y) value for each line’s endpoints.
If a values already has a name, like houseX,
or can be calculated, do that.