Method for manufacturing enriched knotwood powder, comprising the following steps: a) recovery of wood chips; b) mechanical sorting of the wood chips and taking off of the fraction having a density greater than a threshold density and/or a size greater than a threshold size, the threshold density corresponding to the mean density of the wood chips and being situated between 0.7 and 0.9 g/cm 3 and the threshold size corresponding to the threshold size defining the residue of screening for excessive size in the wood chip sorting step in a method for manufacturing thermomechanical pulp and/or the threshold size being equal to 35 to 45 mm; c) optical sorting of the fraction of chips taken off at step b) with collection of the chips having knots with a size greater than a threshold size in one of the dimensions and free from contaminants; d) grinding of the chips collected at step c) to a threshold particle size of between 6 and 8 mm; e) drying of the ground material obtained at step d) until the moisture content thereof is below a threshold moisture content; f) sorting of the ground material by density and separation of the fraction having a density greater than a threshold density; g) micronisation of the fraction separated at step f) in order to obtain a powder having a maximum particle size below a threshold particle size, the threshold particle size being 1 mm; a method wherein the other variables may take the following values: - the threshold size of step c) is equal to 1 cm; - the threshold density of step f) is equal to 1; - the threshold degree of moisture of step e) is less than 15%; - the contaminants eliminated at step c) comprise in particular pieces of bark, chips attacked by mould or fungi, chips without knots or elements of Douglas fir. a) recovery of wood chips; b) mechanical sorting of the wood chips and taking off of the fraction having a density greater than a threshold density and/or a size greater than a threshold size, the threshold density corresponding to the mean density of the wood chips and being situated between 0.7 and 0.9 g/cm 3 and the threshold size corresponding to the threshold size defining the residue of screening for excessive size in the wood chip sorting step in a method for manufacturing thermomechanical pulp and/or the threshold size being equal to 35 to 45 mm; c) optical sorting of the fraction of chips taken off at step b) with collection of the chips having knots with a size greater than a threshold size in one of the dimensions and free from contaminants; d) grinding of the chips collected at step c) to a threshold particle size of between 6 and 8 mm; e) drying of the ground material obtained at step d) until the moisture content thereof is below a threshold moisture content; f) sorting of the ground material by density and separation of the fraction having a density greater than a threshold density; g) micronisation of the fraction separated at step f) in order to obtain a powder having a maximum particle size below a threshold particle size, the threshold particle size being 1 mm; - the threshold size of step c) is equal to 1 cm; - the threshold density of step f) is equal to 1; - the threshold degree of moisture of step e) is less than 15%; - the contaminants eliminated at step c) comprise in particular pieces of bark, chips attacked by mould or fungi, chips without knots or elements of Douglas fir.