Cellulosic and lignocellulosic structural materials and methods and systems for manufacturing such materials

A method of treating wood, the method comprising:

• irradiating wood having a first molecular weight with electron beam radiation while controlling a gas blanketing the wood through which the electron beam passes, electrons of the beam having an energy of about 0.5 to about 5 MeV, to provide treated wood, in the form of sawn lumber or a finished wood product selected from the group consisting of solid wood objects and plywood, in which a cellulosic component of the wood has a second, relatively higher molecular weight at least about 10% higher than the first weight.