The thermal decomposition of a fuel such as wood is usually referred to as pyrolysis. The actual rate is strongly temperature dependent but is also influenced by mass transfer, in many cases. It's also sensitive to the type of wood and the atmosphere around the wood. Rate information will usually be presented as terms for an (often modified) Arrhenius equation(s) and will usually be different for oxidizing and non-oxidizing atmospheres. Multiple rates may be encountered to describe competing parallel reactions with different or multi-step decomposition.
Although I'm aware of people adapting commercial codes for this purpose, the freely available codes that may be relevant would be the Fire Dynamics Simulator (FDS) from NIST, Gpyro and FireFOAM.
Of those, Gpyro is the most specifically oriented towards pyrolysis modeling, but is a small project that doesn't have a huge amount of support. On the plus side, it can be coupled to FDS as part of a larger model, where Gpyro handles 2D or 3D modeling of pyrolysis in the solid, while FDS takes care of reacting fluid dynamics and general heat transfer elsewhere. FDS can do some modeling of the solid phase, but it's limited to 1D models that operate normal to the surface. FDS also has superb documentation and cites many sources that may be a good jumping off point (see the Validation Guide in particular).
I don't mean to leave FireFOAM out, but I've only encountered it a little bit. It's largely similar in intent to FDS but with some different capabilities (including multidimensional modeling of solids and non-rectilinear meshes IIRC).