In China, preserving historic trees and ancient timber structures has attracted more attention from researchers and institutions. Nondestructive testing (NDT) technology has gained momentum in the application and research in recent years. This paper presents some examples of the application of NDT techniques in the protection of historic trees and ancient timber structures in China. A total of nine NDT techniques were applied, including five techniques of visual inspection, sounding, Resistograph, stress wave transmission velocity, stress wave tomography for both historic trees and ancient timber structures, two techniques of the pulling-test and ground-penetrating radar (GPR) for historic trees alone, and two techniques of acoustic emission (AE) and digital imaging for ancient timber structures. Based on field testing, there is a very good detecting effect for visual inspection and Resistograph, but sounding works unsatisfactorily. The stress wave transmission velocity is found to be excellent in screening for the internal defects of historic tree trunks, but performs badly in screening for the internal defects within the wood members of ancient timber structures. AE is less successful but digital imaging performs well in long-term monitoring and damage warning of wood structures. The stress wave tomography successfully obtains images of internal defects inside tree trunks. The anchorage of some historic trees cannot be quantitatively evaluated with the pulling test if the tree is too large. GPR’s resolution and accuracy are very low, which limit its application. Theoretical research on NDT and promotion of NDT technology are still an essential part of the work in the future.
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The detectionof treeroots has always been adifficultissueforNDT of trees. GPR is decfoencstisadnedrerdoo ttod biset raibutiopnotaernetdietaecltesodlusuticceosns ftuol ltyhiusinsgpGrPoRb.lHeomw. evIne rt,hfiorscopmropjelectte, trunk’s i nternalde-fects androot distributionare detected successfully using GPR. However, forcomplete be large biases in the results actually. non-destructiveness, no other NDT techniques are used for cross-validation, and there may be large biases in the results actually. Slender West Lake Park is located in the northern suburbs of Yangzhou City, Jiangsu (7Pr2.3. thcenturyovince,Historic AD)China.TandSlenderrees in has beenWSlenderinexistenceestLakeWesParktforcanLake Parmorethandatebackk 1400years.With fundingfromto asearly astheSui Dynasty Slender West Lake Park is located in the northern suburbs of Yangzhou City, Jiangsu a research team from Jiangnan University initiated an NDT research of ancient trees in th Province, China. Slender West Lake Park can date back to as early as the Sui Dynasty (7 Slender West Lake Park in 2016 . century These researAD) chersand hconducteas beend a detailedin existence investigationfor more thwith a combinationan 1400 years. of visualWith funding from the NationalNatural Science Foundation ofChina and Jiangsu ProvincialGovernment, a re-searchteamfromJiangnanUniversityinitiatedan NDT researchofancienttreesin Slen-157 ancient trees including 33 species were surveyed in the project. The tree ages ranged frder Wesom90to300tLayears.ke PaAcombinationrkin2016of[5visual0]. inspection,stresswavetomography,GPR,
Funding: This project was supported by the China Postdoctoral Science Foundation (NO. 2018M641225), the Science and Technology Project of the Beijing Municipal Education Commission (KM201910005019), and the National Natural Science Foundation of China (No. 31328005).
Yongling, which is the eighth tomb of the Ming Tombs with a history of 484 years, is located in the Changping district, Beijing, China. According to the preliminary statistics and classification, there are about 1200 trees in Yongling including 87 Chinese red pines, 1088 Chinese arborvitaes, and 27 lacebark pines with 688 historic trees over 100 years old. A study on the impact of trees on the preservation of ancient buildings was initiated in 2019 by a research team at Beijing Forestry University with the financial support of the Beijing Municipal Government and authorization from the National Cultural Heritage Administration .
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- Ancient timber structures
- Historic trees
- Nondestructive testing