Carpenter Bee, damaged on the wood.

Beetles,
Powder Post Beetles are found in a variety of wood products. They infest everything from wicker baskets to hardwood floors and pianos. They are usually detected by seeing very fine saw dust or little holes in wood surfaces...

Dry-Rot (fungus),
Dry rot (Latin name Serpula lacrymans), is the cause of sever timber decay in buildings. Described as a brown rot, it often occurs in damp timber which is un vented space and in contact with, or embedded in, wet brickwork or masonry. The fungus is sensitive to high temperatures, air movement and rapid drying. Exposed timbers and timbers where there is good ventilation are rarely affected. Affected timber takes on a very dull brown colour, mostly developing deep cracks along and across the grain. The timber loses weight and will crumble between the fingers. The dry rot fruit body is often found on a timber to wall joint, this can some times be a reaction to unfavourable conditions. The body is quite tough and fleshy to feel, and develops a pancake like shape. The centre is a yellow ochre when it is young and this develops to a deep rust colour when it is older. The deepening in colour is a result of the fine, brown spores it produces which are generally gathered in a dust below the body. The edges of the fruit body will be white or grey. The fruit body may be the first visible sign of dry rot out break.