The theoretical background to wood production is outlined and the factual background is given by reviewing measured rates of wood production. It is recommended that differences in wood production be analysed, not by statistical methods, traditional growth analysis or by comprehensive models, but by using a ‘light use analysis’, where wood production is determined by (1) the amount of light intercepted by the canopy, (2) the light use efficiency, net of respiration, (3) the proportion of assimilates partitioned to wood, and (4) mortality losses. These four components are discussed.