Firstly, as AuntAnnie has stated, it all depends there the artwork came from and who, if anyone, owns the copyright?
Once you have sourced this information you might have more success getting someone to digitise it for you.
On the other hand.....
If you are only after the tree, or trees, then I'm sure Mother Nature has no copyright on trees in general and any photograph you may have taken (of similar trees) could be turned into a negative image for a digitiser to work from.
hugs n roses, Meganne
Is it possible the original digitizer will consider resizing for a price? That way it would be run through the same software and have the best chance of a good result. However, I'm thinking it's going to be hard to maintain that amount of detail in something so small. Perhaps a simpler tree?
You will need to have written permission from the copyright owner to supply to the digitizer in order to reproduce this design--unless, of course, you are the original artist. It is a very nice design!
Your picture is missing. Could you edit your post by adding it?