1. When forestry resources are managed correctly timber can be considered as a renewable construction material. 2. The anisotropic properties of wood result from 90% of the unit cells being aligned in the same direction. 3. The stiffness and strength of timber are independent of the material's moisture content. 4. The large pore volume and controlled collapse of the cell walls helps explain the high toughness of timber. Which of the above statements are true? 1, 3 and 4 only All of them 1, 2 and 4 only 1, 2 and 3 only 2 and 4 only