Paint a little wood-rot treatment on there (get it in B&Q or similar). seems like just about the only way. the wood will be treated anyway though so I'd not worry too much.
In both of my cases, previous owners had modified the boats and not sealed things properly which allowed the wood to get wet and rot
- Entirely my point - so long as the wood is used properly its fine. if its not sealed, or is allowed to get damp then that's a big no no.
On the flipside, compared to many rivals, wood is far more environmentally friendly and sustainable, has incredible sound deadening properties, high strength rate (even when flexed time and time again) and also should last 20-30 years minimum if used right - who needs a new boat to last longer than that?! The engines going to need replacing before the wood does in many cases.