ABSTRACT Mixing tree species could be a silviculture model that allows early harvest of short-rotation trees, while longer-rotation crop trees remain in the stand. We examined the effects on growth and tree characteristics in a planted experiment with lodgepole pine (LP) and elite-bred Scots pine (SP) in mixed (50/50) and monospecific plots in three different spacings (at 28 years of age after planting). The future development under different thinning regimes, including net present value for one rotation, was analyzed using the Heureka simulation software. As expected, LP had higher survival and initially more rapid growth than SP, with highest stand productivity and biomass production in LP monoculture during a rotation period as a result. However, intimate mixtures of SP and LP at the two widest spacings could give greater production and economic benefits, compared to SP in monoculture. It seems that elite-bred SP will differ in competitiveness against LP, depending on spacing for growth and some quality traits (branch and bark thickness, height of green crown). The findings support developing management systems for combining sparsely planted, and expensive, elite-bred SP in mixture with other trees that maintains high stem volume production and secures certain properties of trees and stands.

中文翻译：

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通过与黑松混合提高苏格兰松种植园的产值

摘要 混合树种可能是一种造林模式，允许早期收获短轮伐期树木，而长轮伐期作物树木留在林分中。我们在三个不同间距的混合（50/50）和单种地块（种植后 28 岁）中研究了黑松 (LP) 和精英繁殖的苏格兰松 (SP) 对生长和树木特性的影响）。使用 Heureka 模拟软件分析了不同减薄制度下的未来发展，包括一转的净现值。正如预期的那样，LP 比 SP 具有更高的存活率和更快速的初始生长速度，因此在轮作期间，LP 单一栽培中的林分生产力和生物量产量最高。然而，与单一栽培中的 SP 相比，SP 和 LP 在两个最宽间距的紧密混合可以带来更大的生产和经济效益。似乎精英繁殖的 SP 与 LP 的竞争力会有所不同，这取决于生长间距和一些质量特征（枝条和树皮厚度，绿冠高度）。研究结果支持开发管理系统，将稀疏种植的、昂贵的、精英培育的 SP 与其他树木混合，以保持高茎产量并确保树木和林分的某些特性。