the present invention relates to wood that is reinforced with a fiber - reinforced thermoplastic composite that contains a plurality of substantially parallel continuous fibers impregnated with thermoplastic polymer having the following structural units : where z is s or o , and z ′ is s , o , n - alkyl or nh the invention is useful in a variety of applications including glue - laminated structures , laminated veneer lumber , reinforced i - beams , parallel strand lumber , reinforced particle board , and ladders . the use of a thermoplastic polyurethane , particularly the high tg thermoplastic polyurethane as the impregnating resin provides a means of recycling and reusing the reinforced lumber , as well as shaping the composite in ways that would be impossible using conventional fiber - reinforced thermoset composites .