Heating wood can make it more durable. The ancient Britons knew when building their timber palisade enclosures to put the pointed end of each timber into the fire to char before banging them into the ground to make a long lasting defence. The charring and heating of wood makes it less likely to rot. The modern day equivalent are innovative products like Brimstone, a thermally modified British hardwood that is more durable and used for long lasting exterior cladding on buildings.
Wood structure is like a bundle of drinking straws. Under a microscope the end grain of wood you can see the many tubes and vessels that are bound together to form the wood structure. These ‘drinking straws’ were used to transport water and nutrients up and down the tree when it was growing. We know that water can enter the end grain of wood 1000 times quicker than water entering the side (tangential or radial) face as the water is drawn up the ‘straws’ by capillary action.