I am so sorry, I meant to include that. The trees are part of the terrain tile "Tree" or "Forest". The farms are also a terrain tile named "Farm". These arent objects you can place, they are terrain tiles and scenery. And to raise terrain, go to the "Terrain" interface and look for: Set Alt. Which is under the list of terrain tiles. The number inside that box by default is "1000". If you want a particular part of your terrain to be higher than "1000" feet, you can change that number.
NOTE: Terrain is only increased by "100" feet. So you cant type in: 1245 Feet. It has to be done using hundreds!
(Use "Grid" for this.) Now, click on the area of the terrain you want to raise. It doesent matter if it's a blue or green arrow, just as long as you have some terrain selected. Then, right-click on your mouse to raise the terrain to the specified altitude.