Ultrasound and Wood Science at the Forestry Research Centre in Nancy, France, for a period of twenty years, between 1979 and 1999

Topical Issue - Development of European Acoustics in 20th Century

Open Access

Table 10.

Ratio of acoustic invariants for several wood species [41].

Harwood species	Ratio of acousticinvariants	Softwood species	Ratio of acousticinvariants
Poplar	0.47	Spruce-resonance wood	0.42
Tulip tree	0.43	Red spruce	0.42
Beech	0.52	Pine	0.47
Pernambuco	0.61	Sitka spruce	0.50
Correlation between the ratio of acoustic invariants and wood density R ² = 0.678 *** [37]

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