East Asian evergreen broadleaved forests (EBFLs) harbor high species richness, but these ecosystems are severely impacted by global climate change and deforestation. Conserving and managing EBLFs requires understanding dominant tree distribution dynamics. In this study, we used 29 species in Quercus section Cyclobalanopsis—a keystone lineage in East Asian EBLFs—as proxies to predict EBLF distribution dynamics using species distribution models (SDMs). We examined climatic niche overlap, similarity, and equivalency among seven biogeographical regions’ species using ‘ecospat’. We also estimated the effectiveness of protected areas in the predicted range to elucidate priority conservation regions. Our results showed that the climatic niches of most geographical groups differ. The western species under the Indian summer monsoon regime were mainly impacted by temperature factors, whereas precipitation impacted the eastern species under the East Asian summer monsoon regime. Our simulation predicted a northward range expansion of section Cyclobalanopsis between 2081 and 2100, except for the ranges of the three Himalayan species analyzed, which might shrink significantly. The greatest shift of highly suitable areas was predicted for the species in the South Pacific, with a centroid shift of over 300 km. Remarkably, only 7.56% of suitable habitat is currently inside protected areas, and the percentage is predicted to continue declining in the future. To better conserve Asian EBLFs, establishing nature reserves in their northern distribution ranges, and transplanting the populations with predicted decreasing numbers and degraded habitats to their future highly suitable areas, should be high-priority objectives.

Subtropical montane moist evergreen broadleaf forests (MMEBFs) have a unique environmental envelope harboring a high percentage of endemic biota. This ecosystem is highly vulnerable, and little is known about its possible response to future climate change. In this study, we used Lithocarpus hancei (Fagaceae), a dominant tree in East Asian subtropical MMEBFs, as a proxy to investigate MMEBF distribution dynamics and key distribution restriction factors. In total, 607 L. hancei occurrence points were obtained after being gathered and filtered. The random forest model was selected as the best model. Eight environmental variables were selected to simulate the potential suitable areas of L. hancei under the Last Glacial Maximum (LGM), present, and future (2041–2060, 2061–2080, 2081–2100) climate change scenarios, including four shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). Our results showed that precipitation of the warmest quarter, the precipitation of the driest month, the mean diurnal range, and temperature seasonality are the key factors affecting the spatial range of L. hancei with 11.2%, 10.9%, 8.1%, and 7.6% contributions, respectively. The current distribution of L. hancei is mainly within East and South China, with a scattered distribution in North Indo-China and the Southeast Himalayas. The highly suitable area only accounts for 9.7% of the total distribution area. The distribution area of the current suitability area is the smallest compared to that under LGM and future scenarios. In all the future climatic scenarios, the highly suitable areas of L. hancei would decrease or even disappear, whereas the medium- and low-suitability areas might increase with the centroid of the total suitable area northern. Its distribution in Central China, the Southern Himalayas, and Northern Indo-China will be lost in the future. Overall, our study predicted a prominent degradation of East Asian MMEBFs in the future. In situ and ex situ conservation on East Asian MMEBFs should be prioritized and enforced.

Phenological synchronicity of different tree parts and habitats can provide valuable insights into the physiological relationships and regulatory factors of different phenologies. The earlywood (EW) to latewood (LW) transition of the xylem is a critical process closely related to the key functions and physiological processes of trees. This study investigated the phenology phase of the EW–LW transition in branches and stems of Smith fir (Abies forrestii var. smithii Viguié & Gaussen) along an altitude gradient (3600 m, 3800 m, and 4000 m) in Jiaozi Mountain, Yunnan, China, in 2021. The study aimed to test the hypothesis that branches transition earlier than stems, but the elevation does not affect the transition time. We monitored the EW–LW transition dates weekly using microcores and then correlated them to the climatic conditions and developmental processes. Our findings revealed that the EW–LW transition timing varied among the different parts of the tree but was synchronized across the different elevations. Furthermore, the transition always occurred earlier in branches than in the stem, but the difference narrowed with increasing altitude. The EW–LW transition was mainly influenced by photoperiod, which plays a crucial role as a signaling factor. Additionally, the tree crown was more sensitive to environmental changes than the stem. The transition time of stems was less sensitive to environmental factors than that of branches. Therefore, our results suggest that the earlywood to latewood transition is regulated by developmental factors, and the photoperiod may indirectly regulate the developmental process of trees as a signaling factor, thus regulating the earlywood to latewood transition time. Our study provides new insights into the developmental regulation and climate sensitivity of tree ring formation.

Climate is a key driver shaping the distribution pattern of organisms. Cenozoic climate change has led to extensive biota turnover. Untangling the distribution dynamics of a representative lineage of flora can provide deep insights into biodiversity conservation. Diplopanax is a notable relict lineage of the Tertiary mastixioid flora with abundant fossils in the Northern Hemisphere. Diplopanax stachyanthus Hand.-Mazz. is a representative relic lineage of the mastixioid flora, which was once widespread in the Northern Hemisphere of the early Tertiary period, but with only endemic distribution in the (sub)tropical humid forests of East Asia. It offers a unique chance to understand how climatic drivers shape the Boreotropical flora. In this research, we investigated the distribution dynamics of D. stachyanthus at the last glacial maximum (LGM), mid-Holocene (MH), current, and three periods of the future (2041–2060, 2061–2080, and 2081–2100) at four shared socio-economic emissions scenarios pathways. Our results indicated that the Precipitation of the Wettest Quarter (32.6%), the Precipitation of the Driest Quarter (21.2%), and the Precipitation of the Coldest Quarter (17.3%) are the key factors affecting its distribution. The current high suitable distribution areas are primarily in southern China and northern Indo-China. The enforced winter monsoon seasons in East Asia since the late Pliocene period are the key climatic drivers reducing its once widespread distribution in the Northern Hemisphere. Under future scenarios, centroid transfer analysis suggests that its distribution center will shift southwestward, but the potentially suitable habitats in the coastal regions of southern China and northern Indo-China will be lost. These coastal populations should be prioritized for ex situ conservation. Expanding the nature reserve within its long-term stable distribution range in southwest China is an effective strategy for the in situ conservation of the ancient mastixioid flora.

Climatic conditions strongly control the geographic distribution of treelines; long-term in situ climatic measurements at the treeline are still rare. While microclimatic differences between trees and shrubs at treeline ecotones are already well established and explained, supporting empirical data remain limited. In this study, we compared in situ microclimate measurements in the canopy, stem, and root zones of tree and shrub plots of Juniperus squamata Buch.-Ham. ex D.Don at the treeline ecotone of Jiaozi Mountain, Yunnan, China, in 2022. Although the shrubs experienced higher wind speeds compared to the trees at the treeline ecotone, the short stature of shrubs created warm stem and soil temperatures that are more suitable for plant growth and survival. Shrub distribution at higher elevations may be due to higher soil temperatures. The inability of shrubs to grow upright may be attributed to the fact that their canopy is limited by lower temperatures above the canopy during the frost season. This can provide new insights into the mechanisms of treeline formation.

Our paper analyzes a slotted two-dimensional probability multi-channel and random multi-access protocol based on two kinds of system models: the symmetry access model and the load equilibrium model on the Markov Chain. It analyzes the systemic throughput of the STPMR protocol along with the result of throughput based on priority under the two system models. The computer simulations show that our theoretical analysis is in concordance with the simulations.