Okay, I have a world just like ours. There is only difference: 1 out of 100.000 people wield the magic to change the form of wood.
They touch it and can form it to whatever form they think of, from easy things like sword and shield to the most complex of forms, but it remains plain wood. They also can't change the mass or other properties of the given wood, really only the form.
The transformation is pretty fast. A shield to protect the mage is done in a second or two, depending on the size. And even 2 meter tall, detailed statues e.g. wouldn't take longer then mere minutes.
If they form something that would break under its own weight, then it breaks as soon as the transformation is complete and the magic vanishes. They can't let trees grow faster, either.
Could these mages somehow influence our ecosystem?
Edit:
I want to know if this magic could be used to influence the ecosystem in a way, that would NOT be possible without said magic.
Simply destroying forests is something we (normal people) could do as well.