树木病虫害缺陷精准检测方法的综述和展望

Review and prospects of accurate detection methods for wood defects caused by diseases and pests

我国疆土辽阔,有着丰富的森林资源。近年来,随着外来昆虫的入侵,全国树木病虫害的暴发率逐年上升,对我国生态经济造成了巨大的影响,但是树木病虫害的监测只能在局部地区,因而只能在已经暴发了较严重的病虫害后才能够发现和治理。树木病虫害如在早期未被发现和处理,可能会造成暴发的严重形势,且预防和治理将变得被动,因此,进行树木内部病虫害缺陷精准检测尤为重要。为更早和更加准确预报树木病虫害的发生,需要进行定期的检测和监控。针对早期传统方法如目测法、敲击辩声法和解剖观测法等方法的准确性低、时效性差和易对树木造成不可逆损害等缺点,近些年研究出了新的检测方法,包括指向性好、能量大的超声波检测法,低成本、穿透性强的应力波检测法,以及成像准确、适用于不同环境的电磁波检测法等。不同的检测方法分别有着相对应的成像算法,如走时法、频域分析法和Born近似法等。这些成像算法在分辨率、准确度、精度和计算速度上各有优势。通过对这3种检测方法的发展现状进行总结,了解各类检测方法的优缺点,有助于更好地针对不同情况下的树木病虫害做出精准检测,能够把树木病虫害暴发后的被动治理变成暴发前的主动预防,以提早做出应对方案。

China has a vast territory and abundant forest resources.With the invasion of alien insects,the outbreak rate of tree pests and diseases in China has increased year by year,causing a huge impact on China’s ecology and economy.However,monitoring of tree pests and diseases can only be carried out accurately after the outbreak of pests and diseases in some areas.If tree pests and diseases have not been discovered and treated in the early stages,they may cause an explosive and serious situation,and the prevention and control work will be in a passive situation.Therefore,it is particularly important to accurately detect internal defects of wood caused by diseases and pests.For earlier and more accurate predictions of tree pests and diseases,regular testing and monitoring are required.The early traditional methods such as visual inspection,percussion discrimination and anatomical observation have the disadvantages of low accuracy,poor timeliness and irreversible damage to trees.In recent years,modern detection methods have been developed,including the ultrasonic testing methods with good directivity and high energy,the low-cost,highly penetrating stress wave testing methods and the electromagnetic wave testing methods with accurate imaging suitable for different environments.Different detection methods have corresponding imaging algorithms,such as travel time method,frequency domain analysis method and Born approximation method.These imaging algorithms have advantages in resolution,accuracy,precision,and computational speed.By summarizing the development status of these three detection methods,understanding the advantages and disadvantages of various detection methods will help to better detect the pests and diseases of trees under different conditions,turning passive control after the outbreak of tree pests and diseases into active prevention before the outbreak of tree pests and diseases so as to make early response plans.