Temperate forests in Northeast China have been severely exploited by timber harvesting in the last century. To reverse this trend, China implemented the Classified Forest Management policy in the Natural Forest Conservation Program in 1998 to protect forests from excessive harvesting. However, the policy was unable to meet the 2020 commitment of increasing growing stock (set in the Kyoto Protocol) because of high-intensity harvesting. Accordingly, China banned all commercial harvesting in Northeast China in 2014. In this study, we investigated the long-term impacts of the no commercial harvest (NCH) policy on ecosystem services and biodiversity using a forest landscape model, LANDIS PRO 7.0, in the temperate forests of the Small Khingan Mountains, Northeast China. We designed three management scenarios: The H scenario (the Classified Forest Management policy used in the past), the NCH scenario (the current Commercial Harvest Exclusion policy), and the LT scenario (mitigation management, i.e., light thinning). We compared total aboveground forest biomass, biomass by tree species, abundance of old-growth forests, and diversity of tree species and age class in three scenarios from 2010 to 2100. We found that compared with the H scenario, the NCH scenario increased aboveground forest biomass, abundance of old-growth forests, and biomass of most timber species over time; however, it decreased the biomass of rare and protected tree species and biodiversity. We found that the LT scenario increased the biomass of rare and protected tree species and biodiversity in comparison with the NCH scenario, while it maintained aboveground forest biomass and abundance of old-growth forests at a high level (slightly less than the NCH scenario). We concluded there was trade-off between carbon storage and biodiversity. We also concluded that light thinning treatment was able to regulate the trade-off and alleviate the negative effects associated with the NCH policy. Our results highlighted limitations of the NCH policy and provided new insights into sustainable forest management and the interdependence between human society and the forest ecosystem.

Ecosystem services (ESs) are essential for balancing environmental sustainability and socio-economic development. However, the sustainability of ESs and their relationships are increasingly threatened by global climate change and intensifying human activities, particularly in ecologically sensitive and agriculturally-intensive regions. The Songnen Plain, a crucial agricultural region in Northeast China, faces considerable challenges in sustaining its ESs due to the overexploitation of agricultural land, environmental degradation, and climate variability. This study assessed five key ESs in the Songnen Plain from 2000 to 2020 across multiple scales: habitat quality (HQ), soil conservation (SC), water yield (WY), food production (FP), and windbreaking and sand fixing (WS). We evaluated the trade-offs and synergies between these ESs, as well as the driving factors of the main ES trade-offs. Our findings indicate that provisioning services (WY and FP) and regulating services (SC and WS) improved over time, with FP exhibiting the most significant increase at 203.90%, while supporting services (HQ) declined by 32.61%. The primary ecosystem service multifunctionality areas were those that provided FP, SC, and WY, accounting for 58% of the total. ES trade-offs and synergies varied across spatial scales, with stronger synergies being observed at the pixel scale and more pronounced trade-offs at the county scale. Climate factors, particularly precipitation and temperature, played a more significant role in shaping ES trade-offs than anthropogenic factors. Our study provides valuable insights into the restoration and sustainable management of ESs in temperate agriculturally-intensive regions, with significant implications for the protection of the northeastern black soil region and safeguarding national food security.

Alpine tundra, covering 3% of the Earth’s land surface, harbors approximately 4% of higher plant species. Changes in this vegetation significantly impact biodiversity and ecosystem services. Recent studies have primarily focused on large-scale and long-term vegetation changes in polar and high-latitude regions. However, the study of short-term vegetation changes and their primary drivers has received insufficient attention in alpine tundra. This study aimed to investigate vegetation changes and their dominant drivers in the alpine tundra of Changbai Mountains-located at the southern edge of the alpine tundra distribution in Eastern Eurasia-over a short period by re-surveying permanent plots in 2019 and comparing them with data from 2014. The results showed that significant changes were observed in alpine tundra vegetation during the study period. The importance values of typical alpine tundra plants such as Rhododendron chrysanthum, Vaccinium uliginosum, and Dryas octopetala decreased noticeably, while those of herbaceous species such as Deyeuxia angustifolia and Sanguisorba sitchensis increased significantly. Species richness, diversity, and evenness at different altitudinal gradients showed varying degrees of increase. A distinct expansion trend of herbaceous species was observed in the alpine tundra, contributing to a shift in plant community composition toward herbaceous dominance. This shift might result in the meadowization of the dwarf shrub tundra. Our findings further revealed that soil nutrients rather than climate factors, dominated the changes of plant communities over a short period. These findings provide scientific references for the conservation and management of biodiversity, as well as for projecting future vegetation dynamics in alpine tundra.