AutoCAD blocks are useful to import in SketchUp; you can quickly setup a 3d model by turning blocks 3d. Import tree blocks in SketchUp and place a 3d component in it and all tree blocks are 3d. Whereas a lane or row of trees in a plan drawing has to look repetitive to show the relation between them in 3d it is a different story. In real life a row of trees never consists out of exactly the same tree because no tree is the same. So when making a 3d model trees should also appear different. With randomizing tools it is easy to achieve this. By creating slight differences in the scale and by rotating them randomly you can use the same tree for the blocks. They will differ in size and because of the random rotation you look at the same tree from a different angle so it appears different. By doing this in AutoCAD the tree position stays the same; the insertion point doesn't change.