Table 2.
Sound absorption properties and apparent density of evergreen broad-leaved trees

Speices	Leaf layer thickness (cm)	Leaf specimen size
		0.5 × 0.5 (cm)		1.0 × 1.0 (cm)		2.0 × 2.0 (cm)
		SAC ave.	ρ (g/cm3)	SAC ave.	ρ (g/cm3)	SAC ave.	ρ (g/cm3)
		D. morbiferus	1.00	0.356±0.003Cb	0.29	0.413±0.016Bc	0.28	0.479±0.028Ab	0.28
			1.75	0.586±0.004Aa	0.29	0.563±0.005Bb	0.29	0.578±0.009Ba	0.29
2.50	0.575±0.013Aa		0.28	0.593±0.002Aa	0.30	0.589±0.013Aa	0.28
F. japonica	1.00	0.279±0.002Cc	0.26	0.307±0.007Bc	0.25	0.414±0.019Ac	0.26
	1.75	0.422±0.003Cb	0.25	0.518±0.002Bb	0.24	0.564±0.007Aa	0.24
	2.50	0.601±0.002Aa	0.26	0.585±0.004Ba	0.26	0.530±0.012Cb	0.27

Sound absorption coefficient, data are average values from 3 replications
means that different capital letters in a row within each thickness differ significantly (p<0.05)
means that different small letters in a column within each size differ significantly (p<0.05)