my 2 cents of 20 yrs of running camera's
metal boxes are the ONLY way you stand a chance
BUT NOT all metal boxes are made the same
you NEED one that also protects the lock, and the best way to mount them is , the one's you can lag bolt box to the tree, so this way camera is in BOX< and as is the lock,
only part that can be reached is the key hole
so there is NO way for them to CUT a lock off or a cable
which both can be cut real easy and fast with cheap bolt cutters!

the only flaw with these boxes is, in many places its illegal to both into a living tree(think state/federal lands in m,any states)

from MY experience( with using well over a 100 camera's over the yrs)
I recommend these types of lock's, shrouded type pad locks, they are harder for them to get bolt cutters on in a GOOD metal box!
http://www.1st-in-padlocks.com/6321p...cks-p-738.html

and IMO< maybe NOT the best camera's
but they used to make the best OEM metal box, was the Cuuddy back camera's , they were the ONLY company that made boxes that again, protected the lock and the camera, NOT Just the camera!
HUGE difference in any higher risk place
ONLY flaw with them for me has been when folks cannot CUT lock off they have shot my camera's ion the box, and or beat them with ?? bats or sticks and ruined the camera' but most stayed on tree
and one guy came back with a chainsaw and cut tree down and took camera that way
, some crooks are pretty brave and extreme,?
as they say, IF they want it bad enough, they will get it?