There are more types of trees than fruit trees you can plant and harvest for XP. It's just a matter of budgeting and planning a route through all the tree plots you can use. This method can be pricey, so you have to calculate and judge the best GP/XP ratio of the tree runs you ...
This means you have moved to a location north and slightly east from the observatory. Each square on the Runescape ground is two numbers higher or lower from the adjacent squares depending on in what direction you move. This picture shows the location of a square at the Tree Gnome Stronghold...