A great and inexepensive deterant is to simply automate a few flood lights. Motion sensors are cheap, and no need for special lights, any appliance module will do.
The motion sensors could be mounted on the tree's themselves, aimed towards a row of bushes ect. When tripped, flood the area with light.
I can't immagine a thief continueing to steal the tree when he is completely lit up, and the possibility that someone turned those lights on certainly crosses the mind. To go a step further, have a couple lights in the house come on, and maybe a pourch light at the same time to continue that rouse.
With a W800 you can get pretty good range for the motion detectors. If you do not have one, a tranceiver plugged in close to the area with the motion sensors should pick up the signals.
A friends mailbox is down by the road. No way to get a stable Motion sensor signal from that far. Luckily he has a light post with power down there. He simply plugged in a tranceiver to it, and is able to get the signals through the wiring back to the house to know when the mail came.
With wild life, ect, it can most certainly false trip, but point is, it will trip when really needed. And with some stragetically placed detectors, you should be able to narrow the beam and reduce the false triggers. With a bit of duct/electrical tape, none of my motion sensors see from the waist down in the house/yard so my dog or outside animals trip them.
The better way to go about it, if/when you do install the camera's, is to get software with motion detection. Many of those packages let you maks out area's such as tree limbs that will blow in the wind and cause a trigger. Good part is it will only record when motion is detected. Many of these programs will also allow you to execute any program or a script when the motion event triggers. This will easily allow you to send a signal to your HA system to then control lights in that area ect.
HERE IS A GOOD simple discussion, and some software package recomendations, as well as some free software that allows camera motion detection.