There is an old saying that only God can make a tree.  Us mortal model railroaders have to do the best we can do.  I think the SuperTrees from Scenic Express look great and are not that hard to make.  That is, once you get over the initial shock when you see how the pile of tree material looks when it first arrives.  I don't have much room so I made about 6-8 a day in an assemble line fashion.  Each tree came out different from each other which is just like it should be.

I pretty much followed the instructions provided by Scenic Express. The process involved the general steps of pulling the clump provided material apart into tree size chucks, soaking them in matte medium for a short time before hanging them up to dry and straighten.  After that they were spray painted with cheap brown/gray/black paint and various frock and ground foam was applied.

You will end up with a lot of pieces that are too frail to be trees by themselves but when combined with others just like them, they make good looking multi-trunk trees.  I did the same with smaller pieces to make bushes and smaller trees. Since the top surface of my layout is mostly foam, I also embedded a small piece of piano wire into the bottom of the trunk or each tree to allow for easy "planting". 

Hanging upside down to dry and straighten.