little cubes

I need help. i am creating tree and there is two little cubes and i cant select them what i should do? http://imgur.com/a/acuxS

You’re not making it very easy for anyone who may want to help you !
You’re not going to show us ? We have to piece together your whole scene based on just this ?
You’re not going to supply a download link to your .blend file so we can see what you are talking about ? (YOU must do this for EVERY support question as the very minimum !)

I agree with Richard, a Scene, Image, etc. will help us help you.
Just speculating here… but this could be because everything you are referencing, (Tree, Cube1, Cube2) could all be part of the same object. It just "looks?) like three(3) separate objects to your eyes. Take a look in the Outliner View. You can Select in this view also, but if there is only the one(1) Object, then you will have to Break it apart, to be able to then Delete the parts you want. There are many helpful Tutorials online and Help for Separating parts of a Mesh into separate Objects. Goo luck.

  1. Deselect everything
  2. Right click first cube
  3. Shift + Right Click and select second cube
  4. Press x to delete.
    Ignore step 3 if you don’t want to delete

If it is selecting all 3 at the same time or both cubes at the same time when you click on one of them, then follow this.

  1. Put cursor over desired object
  2. Press L over said object
  3. Press P
  4. Select by selection
  5. Select said object
  6. Delete

Viola

but there is problem i cant select them

Nothing happend when i press P