摘要
Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley The newly introduced P. radiata are exposed to two kinds of forest health risks： they may be attacked by （a） indigenous pathogens and pests against which they may not possess any resistance or （b） by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical appmach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding conifemus forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are pmvided to improve forest vigour and to reduce the forest health risks posed by indigenous as well as exotic pests and pathogens to the introduced P. radiata. Ways to increase the ability to manage the forest health risks once a particular pest infestation and disease eventuates are also recommended. Although detrimental to the survival and growth of the introduced P. radiata, the impact of identified forest health risks are not considered to be fatal to the long term success ofP. radiata in this area.
20世纪90年代,在实施水土保持造林项目的过程中,辐射松被引种到四川阿坝干旱河谷地区。气候匹配研究显示该区域有26000公顷土地适宜辐射松生长,另外还有63000公顷土地也可能具备种植辐射松水土保持林的环境条件。该区域的辐射松人工林以小片林的形式分散在干旱河谷沿岸陡峭和退化的坡地上。这些引种的辐射松面临两种森林健康风险:(a)它们可能不具备抵御当地原有的病原和昆虫侵害的能力,(b)也可能受到外来有害生物入侵的威胁。本文对可能威胁辐射松的潜在的有害生物进行了调查分析,并对其所面临的长期森林健康风险进行了初步评估。评估方法结合了文献研究、周边针叶林病虫害发生历史记录、野外调查、标本采集鉴定,对主要有害昆虫和病原侵袭的可能性以及侵害发生后将造成的影响进行了专家分析。结果表明该地区辐射松引种成功面临着一些特定的长期健康风险。这些风险和侵害两种乡土树种――油松和华山松的有害生物密切相关。因为这些昆虫和病原菌随着时间的推移很可能会传给并危害辐射松。对辐射松引种有潜在威胁的外来有害生物应列为检疫对象。根据评估结果,本文提出了增强森林生长活力和降低健康风险的建议。文中也提到了一旦有害生物侵入并构成危害时,如何提高控制森林健康风险的能力。尽管这些森林健康风险对辐射松生长是有害的,但尚不能对辐射松引种成功构成严重影响。
