This is a relativery easy project, especially for the people that they are into using wire for jewelry making. Personally, I don't have much experience on these things. The tree of the photo is the first one that I have made, but it don't look bad anyway, just a little bit dusty hehe :P
I hope that you can understand my english.
UPDATE: Photos of the last steps are lost long time ago, I'm sorry for that. I would try to fix it somehow. Thanks for looking!
Now -for each group- put again the two parts toghether and then separate it randomly at two or three different parts of strands. Each of these two parts you will handle like the "group" of the previous step. Remember... as above so below. The roots are like the branches but you work the the opposite way; then you fused, now you divide.
Again, avoid symmetry for more realistic results.
So continue the same proccess of separating, dividing and twisting to make the root branches as needed or until you use all the wire left.
Finishing touches; twist the trunk a little bit harder if needed, cut the extra wire that don't fit in the roots and fix the position of the branches.
Your tree is ready!
You can use something to attach your tree to. A single stone is a good choice. You can use some glue if the roots don't help. You can also put your tree in a bowl with smaller stones or inside a jar. You can even make a little garden or forest. By using different materials and colors, you can create more elegant, spooky, colourful or bonsai-like trees. The possibilities are endless.
I'm looking forward to see your versions :)