Effect of Trees Knot Defects on Wood Quality: A Review

This paper reviews the research progress of effect of trees knot defects on wood quality, including the research strategy, technology, model, and research directions. Firstly, the effect of the knot on the appearance, mechanical properties, mechanical processing properties, chemical composition and bonding properties of wood were summarized. Secondly, the relationship between the influence of the knot on the quality of the wood and the size, position, color, type, shape and distribution of the knot were analyzed. Then, the advantages and disadvantages of different non-destructive testing methods and different prediction models were analyzed and compared. The following conclusions on future research trends can be drawn from the literature review and analysis: 1) Improve the fitting degree of the prediction model of the influence of the knot on the wood quality; 2) Optimize the single detection method and multiple detection methods to combine organically, and the test results are combined with the artificial cultivation of trees to fundamentally reduce the impact of knots on wood quality; 3) Develop on-line technology to measure the effect of knots on wood quality, and make different wood products based on the test results to maximize the utilization of wood.