In northern Europe, there are high risks of severe pine weevil (Hylobius abietis) damage to newly planted conifer seedlings. Site preparation is one of the most important measures for reducing these risks and as several studies have shown the damage is highly dependent on the amount of pure mineral soil around the seedlings. We investigated effects of three site preparation techniques: (1) disc trenching with a conventional Bracke T26, (2) MidiFlex unit and (3) soil inversion with a Karl Oskar unit on characteristics of the planting spots, growth and pine weevil damage and survival rates of untreated and insecticide treated planted Norway spruce (Picea abies) seedlings. All three site preparation techniques reduced pine weevil damage in comparison with no site preparation, and the proportion of spots with pure mineral soil they created was inversely related to the rate of mortality caused by pine weevil. The results indicate that the quality of the planting spots depends on the technique used. In areas where pine weevil is the major threat to seedling survival, the amount of mineral soil in the planting spots is the most important factor in order to protect the seedling from damage. Without site preparation most planting spots consisted of undisturbed humus. Generally, the Karl-Oskar created the most spots with pure mineral soil, but on very stony soils the Bracke T26 created more mineral soil spots than other methods. Site preparation is a valuable tool in order to improve survival in regeneration areas and it is of great importance to make the right choice of technique depending on the particular circumstances on the actual site.

中文翻译：

---

不同场地准备技术的比较：种植点质量，幼苗生长和松象鼻虫危害。

在北欧，对新种植的针叶树幼苗造成严重的松甲象鼻虫（Hylobius abietis）破坏的风险很高。场地整备是减少这些风险的最重要措施之一，而且多项研究表明，破坏高度依赖于幼苗周围纯净矿物土壤的量。我们研究了三种场地准备技术的影响：（1）使用常规的Bracke T26进行盘式挖沟，（2）MidiFlex装置和（3）使用Karl Oskar装置进行土壤倒置对种植点，生长和松象鼻虫的危害及生存特征的影响未经处理和经杀虫剂处理的挪威云杉种植率（Picea abies）幼苗。与不进行场地准备相比，所有三种场地准备技术均减少了松象鼻虫的危害，它们所产生的纯矿物土壤斑点的比例与由松树象鼻虫引起的死亡率成反比。结果表明，种植点的质量取决于所使用的技术。在松果象鼻是幼苗生存的主要威胁的地区，种植点的矿质土壤量是保护幼苗免受损害的最重要因素。没有现场准备，大多数种植点由不受干扰的腐殖质组成。通常，Karl-Oskar用纯矿物土壤产生的斑点最多，但在非常石质的土壤上，Bracke T26比其他方法产生的矿物斑点更多。