Woody plants having improved growth properties

A method for producing a genetically modified woody plant having increased biomass and/or wood density compared to a corresponding non-genetically modified woody plant of the same species, said method comprising:

• a) reducing the expression of at least one polypeptide having the amino acid sequence of SEQ ID NO.:
• 98 or an ortholog or paralog thereof in a woody plant, a woody plant cell or a part thereof;
• b) generating and/or selecting a woody plant, woody plant cell or a part thereof with improved biomass and/or wood density as compared to a corresponding non-genetically modified woody plant;
• and
• c) growing the woody plant, the woody plant cell or the part thereof under conditions which permit development of a woody plant.