Abstract: Investigations were carried by means of visiting and comprehensive inspection, 8 counties that Pingxiang, Tiandeng, Pingguo, Bama, Donglan, Jingxi, Leye and Jinchengjiang where Picrasma quassioides natural forests concentrated were confirmed as tree selection region. Firstly, P. quassioides was selected based on quality, then the method of mean tree comparison was used to select 12 plus trees according with the standard of diameter, height, individual volume were respectively 25%, 15% and 100% higher than the average wood. Select 7 candidate plus trees based on the standards of 15%, 10%, and 50% higher than the average trees in terms of diameter, height, and individual volume. On this basis, according to statutory standards, the compliance of 19 plus trees or candidate plus trees was qualification assessment based on the total alkaloid content and 4,5-Dimethoxycanthin-6-one content as the limit indicator traits. Used the content of active ingredients such as 5-hydroxy-4-methoxycanthin-6-one, 4,5-Dimethoxycanthin-6-one, and total alkaloids as quality analysis indicators, 18 trees were selected, Among them, JCJ101, JCJ102, JCJ103, JCJ201, and JX101 were recommended as propagative material for high-yield and high-quality demonstration forests of P. quassioides.

Key words: Picrasma quassioides, natural forests, plus tree selection

摘要： 在8个苦木Picrasma quassioides天然林集中分布区域，开展优树和候补优树选择。先根据质量标准进行粗选，再采用对比木(平均木)法，按胸径、树高、单株材积分别比平均木高25%、15%、100%的标准，选出12株优树；按胸径、树高、单株材积分别比平均木高15%、10%、50%的标准，选出7株候补优树。在此基础上，依据地方标准，以总生物碱含量、苦木碱丁含量作为限量指标性状，进行19个优树、候补优树的合规性判定；以药效成分苦木碱己、苦木碱丁和总生物碱含量作为品质分析指标，选出达到地方标准规定含量要求的优树和候补优树18株，其中JCJ101、JCJ102、JCJ103、JCJ201、JX101优先推荐作为苦木高产优质示范林造林生产的繁殖材料。

关键词: 苦木, 天然林, 优树选择