Determining the mechanism of 'protective effects' of hardwoods on spruce budworm defoliation of balsam fir

确定硬木对香脂冷杉云杉芽虫落叶的“保护作用”机制

• 批准号: 239857-2013
• 负责人: MacLean, David
• 金额: $ 2.4万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=547261
• 关键词: Determining; mechanism; protective; effects; hardwoods

Balsam fir-spruce susceptibility and vulnerability to spruce budworm defoliation are reduced by the presence of hardwoods. Fir stands sustain less budworm defoliation when >30-60% hardwood composition is exceeded. The greatest effect of higher hardwood content is reduction of fir mortality, thought to result from higher parasitism rates of budworm or greater losses of dispersing first- and second-instar spruce budworm larvae in stands with greater hardwood content. Hardwood composition effects on defoliation also influence fir-spruce tree growth, as lower mean radial growth reductions have been observed with higher hardwoods.

硬木的存在降低了香脂冷杉对云杉幼虫落叶的敏感性和易感性。当硬木成分超过30%-60%时，杉木林遭受的芽孢子虫落叶较少。硬木含量较高的最大影响是减少冷杉死亡率，这被认为是由于硬木含量较高的林分中较高的芽孢虫寄生率或分散一、二龄云杉幼虫造成的较大损失。落叶的阔叶木成分效应也会影响冷杉的生长，因为较高的阔叶木的平均径向生长减少量较低。