Abstract

Harvesting of commercial conifer species from conifer-hardwood mixtures can leave residual stands dominated by hardwoods. Removing unwanted hardwoods by cutting or herbicide makes growing space available to residual trees and regeneration and can restore conifer dominance. Forest managers of north coastal California need guidance on how such treatments affect subsequent growth of planted redwoods (Sequoia sempervirens [D. Don.] Endl.) or natural regeneration, as well as proliferation of undesirable species. Our observational study reconstructed growth of 108 regenerating redwoods in 26 treated stands. Residual stand density was the main driver of height and diameter growth in the new cohort of redwoods, irrespective of whether hardwoods were cut or received herbicide frill treatment (prevents resprouting). At lower residual stand densities, there were higher densities of natural regeneration (ingrowth) of conifers and hardwoods, which affected diameter at breast height (dbh) growth of regenerating redwoods. After heavier cutting of hardwoods, this ingrowth comprised a greater proportion of unwanted hardwood regeneration. Therefore, frill treatment is recommended when the objective of management is to reduce hardwood stocking and regeneration. Combining partial harvesting of conifers with cutting or frill treatment of hardwood is another option that reduces stand density to promote height and dbh growth of regenerating redwoods.

中文翻译：

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针叶树部分采伐和硬木管理后红木再生的发展

摘要

从针叶树－硬木混合物中收获商品针叶树种可能会使残留的林分以硬木为主。通过砍伐或除草剂清除多余的硬木，可为残留树木和再生树提供可用的生长空间，并可恢复针叶树的优势。加利福尼亚北部沿海地区的森林管理者需要有关如何处理如何影响随后种植的红木生长的指南（美国红杉）[D. Don。] Endl。）或自然再生，以及不良物种的繁殖。我们的观察性研究重建了26个经过处理的林分中108个再生红木的生长。在新的红木队列中，不论是否砍伐硬木或进行过除草剂褶皱处理（防止再次发芽），残留林分密度是导致其高度和直径增长的主要驱动力。在较低的剩余林分密度下，针叶树和硬木的自然再生（向内生长）的密度较高，这会影响再生红木的胸高（dbh）生长时的直径。在对硬木进行较重的切割之后，这种向内生长的部分包含了较大比例的不需要的硬木再生。因此，当管理的目的是减少阔叶木的蓄积和再生时，建议进行褶边处理。