林地的外观、商业和游憩用途受病害、虫害、火灾和恶劣天气的影响很大。The appearance and commercial and recreational use of forested land is greatly affected by diseases, insects, fire, and adverse weather.其中，病害和木材腐朽造成的损失最大，是树木生长的最大威胁，居于所有其他因子的破坏性之首。Of these, diseases and wood decay cause the greatest losses and present the greatest threat to tree growth, outranking all other agents in destructiveness.

林木病害是一种非常普遍的自然灾害。Forest and tree disease is a kind of very common natural disasters. 林木是活的有机体，对外界环境的变动或其他生物的刺激有一定的适应能力。Trees are living organisms, which have certain adaptability to the changes of external growth environment or the stimulation of other organisms.当环境的变动或受到其它生物的侵袭超出其适应范围的时时候，使得树木正常的生理程序遭到干扰，细胞、组织、器官受到破坏，甚至引起植株死亡，造成经济上和生态上的损失，这种现象我们把它称之为林木病害。When the change of environment or the invasion of other organisms is out of its adaptive range, the normal physiological process of trees will be disturbed, cells, tissues and organs will be damaged, and even plants will die, resulting in economic and ecological losses. This phenomenon is called forest and tree diseases.许多不同种类的生物和非生物因子都可能引起林木病害。Many kinds of biological and abiotic factors may cause forest and tree diseases. 

林木病理学研究的对象为森林树木的病害，也包括城市绿化和观赏的乔灌木病害。The research object of forest and tree pathology is the diseases of forest trees, including urban greening and ornamental and shrub trees diseases. 林木由于生长期长，病害的病程历时也比较长。Infection process of tree diseases is relatively long because of the long growth period of trees. 由于林木病害的发生和发展具有很大的隐蔽性，很多病害只有造成明显的灾害才会引起人们的重视。Many diseases cause people's obvious attention, only after causing obvious disasters, this is because the occurrence and development of tree diseases have great concealment.林木病害指的是对树木正常结构和生长致病性的侵染、异常和干扰。The term “tree disease” covers a wide range of pathogenic infections, abnormalities, and disturbances of the normal structure and growth of a tree. 病害导致林木生长不良，木材年生长量下降，某些病害则造成林木整株死亡，甚至大片森林的衰败。Tree diseases lead to poor growth of trees and decrease of annual growth of wood, some diseases cause the death of whole trees and even the decline of a large area of forest. 历史上，曾经造成了极为严重的生态危害或重大的经济损失，如榆树枯萎病、 板栗疫病、阔叶树的烂皮病等。In history, some tree diseases have caused serious ecological damage or great economic losses, such as dutch elm disease, chestnut blight, cytospora canker of hardwood, and so on.

 欢迎大家来到林木病理学的课堂。Welcome to the class of forest and tree pathology.本门课程将会带领大家共同学习林木病害发生的原因、发生的条件、病原因子的生物学特性，各种林木病害症状、发生规律、防治措施等内容。This course will lead you to learn the causes of forest diseases, occurrence conditions, biological characteristics of biotic factors, symptoms, disease cycle and control measures of various forest diseases.课程除了方便大家对林木病理学内容的学习，也有助于对专业英语的学习与提高。The course is not only convenient for us to learn the content of forest and tree pathology, but also help us to learn and improve professional English.

掌握林木病理学基础知识，了解国内外研究发展动态，提高专业英语阅读能力。

1.《林木病理学（第3版）》 叶建仁等主编.北京：中国林业出版社,2011.

2. 《 森林病理学实验实习指导 》 王占斌等主编 . 哈尔滨 ： 东北林业大学出版社 ,2010 .