Wild pear (Pyrus pyraster (L.) Burgsd.) (P) and wild service tree (Sorbus torminalis (L.) Crantz) (S) are sporadic European tree species that are valued for their high-quality timber production. Although mixed plantations including companion species enhance timber quality of several trees, the performance of the association of P and S is not well known. The objective of this study was to assess growth and survival of P and S in pure plantations and in plantations mixed with other companion tree or shrub species in a non-native habitat. To answer the question of whether growth of these species is enhanced by mixtures, specific combinations of the main and companion species were established in central Chile and monitored for a 12-year period after planting. Besides each main species monoculture, five mixtures were tested: Mix1: P+S; Mix2: P+S+ the N-fixing tree Italian alder (Alnus cordata (Loisel.) Duby); and three associations of P and S including shrubs (Mix3: P+S+ Corylus avellana L., Mix4: P+S+ Sambucus ebulus L., and Mix5: P+S+ Sambucus nigra L.). Both P and S presented the highest height growth in Mix2, being 48.6% and 53.4% higher than in the monoculture, respectively. DBH growth was also enhanced in Mix2 for S. Wild service tree, which showed lower growth and survival than P, was more benefited from the mixture including Italian alder than P. Height growth, vigor and survival of the main species were highest in Mix2, even higher than in pure plantations and in Mix1 without companion species. Specific tree associations might increase the probability to obtain high-quality timber of noble species if a timely and adequate management of companion species is provided.

中文翻译：

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混合 Pyrus pyraster 和 Sorbus torminalis 种植园，包括伴生树种，可提高优质木材生产

野梨 (Pyrus pyraster (L.) Burgsd.) (P) 和野生服务树 (Sorbus torminalis (L.) Crantz) (S) 是欧洲的零星树种，因其高品质的木材生产而受到重视。虽然包括伴生树种在内的混合种植园提高了几种树木的木材质量，但 P 和 S 联合的表现并不为人所知。本研究的目的是评估纯种植园和非本地栖息地中与其他伴生树或灌木物种混合的种植园中磷和硫的生长和存活。为了回答这些物种的生长是否通过混合物增强的问题，在智利中部建立了主要和伴生物种的特定组合，并在种植后进行了 12 年的监测。除了每个主要物种单一栽培外，还测试了五种混合物：Mix1：P+S；混合2：P+S+ 固氮树意大利桤木 (Alnus cordata (Loisel.) Duby)；和三个 P 和 S 组合，包括灌木（Mix3：P+S+ Corylus avellana L.，Mix4：P+S+ Sambucus ebulus L.，Mix5：P+S+ Sambucus nigra L.）。P 和 S 在 Mix2 中的高度增长最高，分别比单一栽培高 48.6% 和 53.4%。在 Mix2 中，S. Wild service 树的 DBH 生长也有所增强，其生长和存活率低于 P，从包括意大利桤木在内的混合物中获益更多，而不是 P。Mix2 中主要物种的高度生长、活力和存活率最高，甚至高于纯种植园和没有伴生物种的 Mix1。如果提供及时和充分的伴生树种管理，特定的树木协会可能会增加获得优质树种木材的可能性。