手法を比較

	木の収縮	ヤンカ硬度
分野	林学	林学
系統	Process / pipeline	Process / pipeline
提唱年	1950	1934
提唱者	Carl Skaar	Gabriel Janka
種類	moisture response test	hardness test
原典	ASTM D143-19. (2019). Standard test methods for small clear specimens of timber. ASTM International.	ASTM D1037-21. (2021). Standard test methods for evaluating properties of wood-base fiber and particle panel materials. ASTM International.
別名	dimensional change, anisotropic shrinkage	wood hardness, resistance to indentation
関連	2	3
概要	Wood shrinkage is the dimensional change that occurs as wood loses moisture from green (freshly felled) to oven-dry condition. Wood shrinks anisotropically: tangentially (along growth rings) more than radially (from center to edge), and both more than longitudinally (along the grain). Measuring shrinkage percentages is essential for understanding wood drying behavior, predicting checking and warping, and selecting materials for applications sensitive to dimensional change (flooring, cabinetry, musical instruments).	The Janka hardness test measures wood resistance to indentation and denting by forcing a steel ball into the wood surface under standard load. Developed by Gabriel Janka in 1934, the test is a simple, nondestructive indicator of wood durability, wear resistance, and suitability for flooring, furniture, and other wear-prone applications. Janka hardness is one of the most widely used wood property metrics in wood science and commerce.