Radial variation of wood anatomical and chemical properties in eight poplar clones

Wood properties are crucial for the development and application of poplar clones. Here, the effects of clone and age on anatomical and chemical properties were analyzed in eight poplar clones (50, Zhonglin46, 108, 36, N179, Danhong, Sangju, and Nanyang) from Henan province, China. The results show that the effects of clone and age are both significant for these wood properties. The eight clones were grouped into three clusters according to their annual ring width, fiber quality, and chemical properties. For some properties, including annual ring width, fiber length, and microfibril angle, all clones displayed the same radial variation trends; however, for other properties, such as holocellulose content, the radial variation trends were different depending on the clones. The culmination of the mean annual increment corresponded to the turning ages of wood properties such as annual ring width in the eight clones, and holocellulose content in the partial clones except for fiber length, microfibril angle, and vessel length. The recommended rotation age of these poplar clones is 8–9 years based on the fiber quality and chemical components. These results indicate strong genetic and age control of the wood properties and highlight the rich source of variation for poplar clone selection.