I made myself a necklace very similar to this a couple of years ago and have since then recieved so many comments on it that I thought it would be nice to share how I made it.

Its very simple.

Step 1: Materials

You will need;

A small pair of pliars or scissors that you don't mind cutting wire with.
Two different thicknesses of silver craft wire, I had some surprisingly thick and surprisingly thin wire on hand, so that's what I used. Also, if you were so inclined, a tree with a copper trunk and fine green branches would look awesome.
A large metal ring inch and a half to two inches across. You can use something daintier if you so please, or even make your own out of wire, these were just what I had on hand,
A chain, string, or leather strap to hang the pendant on.

Step 2: Starting Your Wire, and the Trunk of Your Tree.

Cut a strand of your thicker wire about 24 inches long.

As in the images above, take one end of your wire and wrap it at least three times around the ring on either side of itself. This will be the root of your tree trunk. You can now either cut off any extra wire off on this end, or you can twist your working end around the trunk of your tree until it's gone.

Now take the other end of your wire and do the same thing straight across. I only made about two wraps at the top to help me distinguish top from bottom. This time when you start wrapping your wire around the trunk of your tree, wrap it so that you end up at the bottom again. Take a single wrap around your ring (Don't cut your wire!!) and you're ready for branches!

NOTE; I wrapped very loosely around my wire. You can wrap tighter, if you want, but it will take more time and you will need more wire.

Step 3: The Tree Has Many Branches

Now that we have the trunk of our tree we can start with the branches.

From the bottom of your tree trunk take a single loose wrap with your wire and then pull off at an angle that looks good to you. Take the wire to the edge of your ring and give it at least two wraps before winding it around itself and back to the tree trunk. Take another wrap around your tree trunk and then take off and make another branch.

I only made three large branches, (I think now that it would have looked better with four) but you can make as many as you desire, just remember that we will be adding in some little branches with the thinner wire in a moment.

Once you're finished with your big branches you can either wind the remainder of your wire back down the trunk of your tree and then tuck it through the little gap at the bottom of your wire (Shown with that half decent picture last in line.) If you do cut it, and even if you don't make sure to leave it tucked as close to the rest of the wire as possible. Otherwise the stray end will end up poking you and generally making a nuisance of itself.

NOTE; if you should run out of wire during this step, no worries! Just wind the last bit of wire around your tree trunk or branch and cut yourself some more. As this is only a pendant and probably won't be under much stress you needn't worry much about how firmly you attach your new piece either, just winding it around the tree trunk should be plenty of hold.

Step 4: Many Many Branches

Now, for all your tiny little twigs you're going to want about 25 inches of your thin wire.

Because this wire is smaller than your other wire it should fit between the wires at the base of your tree fairly easily. Then you can loop around and twist it onto itself (Take a look at the second picture if I'm not making sense)

Now, twist your little wire up the tree trunk and onto the first branch, from there, pick a direction, and follow the same procedure you used for the bigger branches.

Once again, the number of tiny branches you make is dictated solely by your own aesthetic tastes and how much wire you have on hand.

When you're done, twist the remaining wire into a good hiding spot and chop it off if you need to.

Step 5: Making It a Necklace

To make your pendant a bit easier to dangle, take some of your thick wire and make a loop around the ring at the top of your tree. Twist, and trim the wire, then tuck the twisted end away. (If you have pliers handy, they work well for this. Now, all you have to do is thread your chain, string, or leather strap through the wire loop and Ta-da! You have made a silver tree necklace.

You clever thing you.

Happy Making!