It depends on the reasoning behind disinfection. If the goal is prevent the possibility of an outside pathogen from being introduced into the enclosure then the use of the plants and materials collected from outside should be avoided. (areas that are subject to pesticide and herbicide drift should also be avoided).
Nonporous materials such as some stones, or gravel may be disinfected with a bleach solution after they have been well scrubbed. The bleach can then be removed with a soak in a solution made with a commercial dechlorinater.
Porous material needs to be boiled or autoclaved for at least 15 minutes to insure that it is sterile. I strongly do not recommend heating any items that may contain water. Once they are heated past the temperature where water boils the item may explode. (This includes green woods). Heating baking them in an oven where they can get above the boiling point of water is exremely risky.
With all of that said, many of the bacterial pathogens are always present in amphibian enclosures. (Such as red leg, Psedomonads and Aeromonada are present in all moist soil and aquatic enclosures). So attempting to avoid these through the use of sterile items does not make sense as they will just recolonize the items later. (However if you do have an outbreak of redleg, I would recommend sterilizing the enclosure on the chance a more pathnogenic strain had developed.)
Avoidance of parasites make more sense but other that a group in the nematode family these are usually transmitted through consumuption of infected food items.) This is not the case in reptiles where they can aquire potentially fatal cryptosporidial infections through contaminated items).
Avoidance of pesticide and herbicide contamination, this is a valid reason but disinfection often will not remove or denature these items.
Ed
