Data from: Genetic consequences of selection cutting on sugar maple (Acer saccharum Marshall)

Selection cutting is a treatment that emulates tree-by-tree replacement for forests with uneven-age structures. It creates small openings in large areas and often generates a more homogenous forest structure (fewer large leaving trees and defective trees) that differs from old-growth forest. In this study, we evaluated whether this type of harvesting has an impact on genetic diversity of sugar maple (Acer saccharum Marshall). Genetic diversity among seedlings, saplings and mature trees was compared between selection cut and old-growth forest stands in Québec, Canada. We found higher observed heterozygosity and a lower inbreeding coefficient in mature trees than in younger regeneration cohorts of both forest types. We detected a recent bottleneck in all stands undergoing selection cutting. Other genetic indices of diversity (allelic richness, observed and expected heterozygosity and rare alleles) were similar between forest types. We concluded that the effect of selection cutting on the genetic diversity of sugar maple was recent and no evidence of genetic erosion was detectable in Québec stands after one harvest. However, the cumulative effect of recurring applications of selection cutting in bottlenecked stands could lead to fixation of deleterious alleles, and this highlights the need for adopting better forest management practices.择伐（Selection cutting）是一种针对异龄林的逐株更替模拟经营措施。该手段在大面积林分内营造小型林隙，通常会形成与原始林不同的同质化林分结构——即大型保留木与缺陷木的数量更少。本研究旨在评估此类采伐方式对糖枫（*Acer saccharum* Marshall）遗传多样性的影响。我们对比了加拿大魁北克地区择伐林与原始林分中，幼苗、幼树及成熟木的遗传多样性差异。研究结果显示：两类林分的成熟木均较其更新世代的幼龄个体具备更高的观测杂合度与更低的近交系数；且所有实施过择伐的林分均检测到近期遗传瓶颈效应。两类林分的其余遗传多样性指标（等位基因丰富度、观测杂合度、期望杂合度及稀有等位基因）均无显著差异。本研究得出结论：择伐对糖枫遗传多样性的影响仅为短期效应，单次择伐后的魁北克林分尚未出现可检测到的遗传侵蚀现象。然而，在已发生遗传瓶颈的林分中反复应用择伐措施，其累积效应可能引发有害等位基因的固定，这一发现凸显了优化森林经营措施的必要性。