Effect of Temperature on Acoustic Evaluation of Standing Trees and Logs: Part 2: Field Investigation
Effect of Temperature on Acoustic Evaluation of Standing Trees and Logs: Part 2: Field Investigation
复制标题
DOI：
--
复制
发表时间：
2013-01
影响因子：
1.4
通讯作者：
Shan Gao;Xiping Wang;Lihai Wang;R. B. Allison
中科院分区：
文献类型：
--
作者：
Shan Gao;Xiping Wang;Lihai Wang;R. B. Allison
本研究的目的是研究季节温度变化对在直立树木和绿色原木上测量的声速的影响，并开发补偿温差的模型，因为声学测量是在不同的气候和季节进行的。在威斯康星州Arena的一个有45年历史的人工林中，对20棵红松（松脂松）树和10棵新砍的红松原木进行了现场测试。连续12个月监测红松、原木的声速和环境温度。结果表明，当冬季温度低于冰点时，环境温度对树木和原木的声速有显著影响。当环境温度降至0℃以下时，声速显著增加，但当环境温度降至-2.5℃以下时，声速的增加幅度减小。在冰点以上，声速对环境温度变化不太敏感。从实际的角度来看，在不同气候和季节测量的树木和原木的声速可以调整到一个标准温度，如果测量是在远高于或远低于冰点的温度下进行的。然而，在冰点附近进行的测量可能会导致温度调整的复杂性。当木材温度在冰点附近时，用户应避免进行现场声学测试。
The objectives of this study were to investigate the effect of seasonal temperature changes on acoustic velocity measured on standing trees and green logs and to develop models for compensating temperature differences because acoustic measurements are performed in different climates and seasons. Field testing was conducted on 20 red pine ( Pinus resinosa ) trees and 10 freshly cut red pine logs at a 45-yr-old plantation stand in Arena, WI. Acoustic velocities of the red pine trees and logs and the ambient temperatures were monitored for 12 consecutive months. Results indicated that ambient temperature had a significant effect on acoustic velocities of trees and logs in winter when temperatures were below the freezing point. Acoustic velocities increased dramatically as ambient temperature dropped to below 0°C, but the increase became less significant when the temperature decreased to below -2.5°C. Above the freezing point, acoustic velocities were less sensitive to ambient temperature changes. From a practical standpoint, acoustic velocities of trees and logs measured at different climates and seasons can be adjusted to a standard temperature if measurements are conducted well above or well below freezing temperatures. However, measurements conducted around freezing temperatures could cause complications in making temperature adjustments. Users should avoid conducting field acoustic testing when wood temperature is around the freezing point.