Mountain birch (Betula pubescens subsp. tortuosa (Ledeb.) Nyman) is the only indigenous forest-forming tree species in Iceland, and conservation of the remaining native birch forests is a recognized priority. In the last 30 years, a glacial outwash plain at Skeiðarársandur, southeast Iceland, has been colonized by birch which has now been established on an area > 35 km². Genotyping by sequencing was used to determine the origin of the birch plants in the new population by assessing the genetic variation of its first generation and assessing its relatedness with the three neighboring but geographically isolated woodlands/forests closest to the outwash plain (Núpsstaðarskógar, Bæjarstaðarskógur, and Skaftafellsheiði). In total, 135K single-nucleotide polymorphisms (SNPs) were obtained, and 26K SNPs with the lower allele frequency (MAF) > 5% in 20,562 contigs. The new population on Skeiðarársandur most likely originated from Bæjarstaðarskógur and has slightly less variation than the established forests. Comparisons of the three established forests show that the adjacent forest Bæjarstaðarskógur and Skaftafellsheiði are more similar to each other than to Núpsstaðarskógar.

山桦（Betula pubescens subsp. tortuosa (Ledeb.) Nyman）是冰岛唯一的本土造林树种，保护剩余的本土桦树林是公认的优先事项。在过去的 30 年里，冰岛东南部 Skeiðarársandur 的冰川冲刷平原已经长满了桦树，目前其面积已超过 35 km ²。通过测序进行基因分型，通过评估第一代的遗传变异并评估其与距离冲刷平原最近的三个邻近但地理上孤立的林地/森林（Núpsstaðarskógar、Bæjarstaðarskógur、和 Skaftafellsheiði）。总共获得了 135K 个单核苷酸多态性 (SNP)，在 20,562 个重叠群中获得了 26K 个具有较低等位基因频率 (MAF) > 5% 的 SNP。Skeiðarársandur 上的新种群很可能起源于 Bæjarstaðarskógur，其变异程度比现有森林略少。对三个已建立的森林进行比较表明，邻近的 Bæjarstaðarskógur 森林和 Skaftafellsheiði 森林比 Núpsstaðarskógar 森林更相似。