School of Geography, University of Exeter, Exeter, UK.
Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
Glob Chang Biol. 2024 Mar;30(3):e17209. doi: 10.1111/gcb.17209.
Active restoration through silvicultural treatments (enrichment planting, cutting climbers and liberation thinning) is considered an important intervention in logged forests. However, its ability to enhance regeneration is key for long-term recovery of logged forests, which remains poorly understood, particularly for the production and survival of seedlings in subsequent generations. To understand the long-term impacts of logging and restoration we tracked the diversity, survival and traits of seedlings that germinated immediately after a mast fruiting in North Borneo in unlogged and logged forests 30-35 years after logging. We monitored 5119 seedlings from germination for ~1.5 years across a mixed landscape of unlogged forests (ULs), naturally regenerating logged forests (NR) and actively restored logged forests via rehabilitative silvicultural treatments (AR), 15-27 years after restoration. We measured 14 leaf, root and biomass allocation traits on 399 seedlings from 15 species. Soon after fruiting, UL and AR forests had higher seedling densities than NR forest, but survival was the lowest in AR forests in the first 6 months. Community composition differed among forest types; AR and NR forests had lower species richness and lower evenness than UL forests by 5-6 months post-mast but did not differ between them. Differences in community composition altered community-weighted mean trait values across forest types, with higher root biomass allocation in NR relative to UL forest. Traits influenced mortality ~3 months post-mast, with more acquisitive traits and relative aboveground investment favoured in AR forests relative to UL forests. Our findings of reduced seedling survival and diversity suggest long time lags in post-logging recruitment, particularly for some taxa. Active restoration of logged forests recovers initial seedling production, but elevated mortality in AR forests lowers the efficacy of active restoration to enhance recruitment or diversity of seedling communities. This suggests current active restoration practices may fail to overcome barriers to regeneration in logged forests, which may drive long-term changes in future forest plant communities.
通过造林措施（补植、砍除攀援植物和抚育间伐）进行主动恢复被认为是采伐森林的重要干预措施。然而，其促进更新的能力对于采伐森林的长期恢复至关重要，但目前对此知之甚少，特别是对于下一代幼苗的产生和存活。为了了解采伐和恢复的长期影响，我们在婆罗洲北部，对采伐 30-35 年后未采伐和已采伐森林中，林分自然更新的森林（NR）和通过抚育性造林措施（AR）主动恢复的森林中，在林分主结实后立即萌发的幼苗的多样性、存活率和特征进行了追踪。在一个未采伐森林（ULs）、自然更新的采伐迹地森林（NR）和经过恢复性造林措施（AR）主动恢复的采伐迹地森林混合景观中，我们对 5119 株从萌发开始监测了约 1.5 年，共监测到 15 个种的 399 株幼苗。主结实后不久，UL 和 AR 林分的幼苗密度高于 NR 林分，但 AR 林分在前 6 个月的存活率最低。不同森林类型之间的群落组成存在差异；AR 和 NR 林分在主结实后 5-6 个月的物种丰富度和均匀度均低于 UL 林分，但 AR 和 NR 林分之间无差异。群落组成的差异改变了不同森林类型的群落加权平均特征值，与 UL 林分相比，NR 林分的根生物量分配更高。主结实后 3 个月左右，性状对死亡率有影响，与 UL 林分相比，AR 林分中更具掠夺性的性状和相对地上部分投资有利于幼苗存活。我们发现，幼苗存活率和多样性降低表明，采伐后林分更新存在较长的时间滞后，特别是对某些类群而言。采伐迹地的主动恢复恢复了初始幼苗的产生，但 AR 林分中较高的死亡率降低了主动恢复提高幼苗群落的补充或多样性的效果。这表明，当前的主动恢复实践可能无法克服采伐森林中更新的障碍，这可能会导致未来森林植物群落的长期变化。
