I don't know that there's any evidence that they have EVOLVED to be fire-resistant, but they are by nature ~50% water while they are alive. OTOH the timber used for buildings is relatively dry and therefore flammable. Maybe some thought should be given to construction materials, but that'll cost more to build.Some trees have evolved to be fire resistant, coupled with the high winds the fire was moved on by the winds before it had a chance to catch.
Oak, walnut, mahogany are hardwoods so are fire resistant. Poplar, maple, aspen, alder and cherry are also fire resistant. Coniferous or evergreen trees with cones and needles are highly flammable.
A lot of people are suggesting undersea cables as a better alternative.it's why I want energy pylons being built through the eastern spine of the country to get power from where its produced to where its used. Can't see any better alternative I'm afraid.