Abstract:

In order to make nondestructive evaluation of the health of standing trees,120 standing trees including 4 species were detected by Arobotom,Resistograph and RSM-SY5 ultrasonic instrument respectively. The data on the propagation velocity of stress wave and ultrasonic wave transmitting in indefectible cross section of standing trees were analyzed. Results showed that: when standing tree was detected with 8 testing points, stress and ultrasonic wave transmitted most slowly along Path A (adjacent point) and most quickly along Path D(radial direction) on indefectible cross section, the propagation velocity was increasing from Path A to Path D. For indefectible Populus simonii,Ulmus pumila,Salix matsudana and Fraxinus mandshurica,the radial propagation velocity of stress wave tested by Arobotom was 788.46,1 025.45,940.62 and 1 146.06 m ·s^-1 respectively; the corresponding radial propagation velocity of ultrasonic wave tested by RSM-SY5 was 1 159.57,1 537.5,1 323.15 and 1 558.6 m ·s^-1 respectively. Through regression analysis,the correlation between the radial propagation velocity of stress wave and ultrasonic wave was significant,R²>0.77,so it was feasible to non-destructive test standing trees with these two instruments.

Key words: stress wave, ultrasonic wave, resistograph, standing trees, propagation velocity, indefectible cross section