i have a small dead austalian pine tree thats been dead for years and infested with termites and ants.i knocked half of it over and got some real pretty large pieces of bark come off of,almost looks like cork bark halves.is the pine tree bark safe to decorate a hisser enclosure?i heard that pine isnt good for insects but im not sure.

If it's dead for years it should be no problem.
The "toxins" inside are mainly essential oils in the resin and they evaporate over time. These vapors could harm insects in a tiny enclosure and that seems to be the main problem; they won't eat it if there is still harmful resin inside .