Sapindus delavayi (Franch.) Radlk. (S. delavayi) is an important biological washing material and biomass energy tree species with a peel rich in saponins and a kernel high in oil content. We used the maximum entropy model (MaxEnt) to predict the suitable habitats for S. delavayi in China, screen the dominant environmental factors affecting its distribution, and analyze the changes in its suitable habitats under future climate change. The results provide a scientific basis for its introduction, cultivation, and germplasm resource collection and protection. Twenty-two environmental variables and China distribution data for S. delavayi were used to construct the species distribution model, and the receiver operating characteristic (ROC) curve was used to verify the model’s accuracy. The dominant environmental factors were screened through the jackknife method, then a geographical information system (ArcGIS) was used to determine the level of suitable habitat division and area calculation. The results showed that the MaxEnt model had an excellent predictive effect for which the area under the ROC curve (AUC) value was as high as 0.959. The annual precipitation (Bio18), minimum temperature of the coldest month (Bio6), temperature seasonality (Bio4), and precipitation of the coldest quarter (Bio19) were the dominant environmental factors that affected the distribution of S. delavayi. Under the current climate, the suitable area for S. delavayi is 1,321,308.07 km², and under the four climate scenarios for the 2050s and 2090s, the suitable area is predicted to change by −3.97%~2.57%. Overall, the centroids of the highly suitable habitats will shift by different degrees to the southwest in the future.

Magnolia sieboldii, an important ornamental tree native to East Asia, comprises two subspecies in distinct regions, with wild populations facing suboptimal survival. This study aimed to understand the potential habitat distribution of these subspecies under future climate-change conditions to support climate-adaptive conservation. The maximum entropy (MaxEnt) model was used with occurrence and environmental data to simulate the current and future suitable habitats under various climate scenarios. Precipitation in the warmest quarter played a crucial role in shaping the potential habitats of both subspecies; however, they exhibited different sensitivities to temperature-related variables and altitude. Magnolia sieboldii subsp. sieboldii is more sensitive to temperature seasonality and annual mean temperature, whereas Magnolia sieboldii subsp. japonica is more affected by altitude, mean temperature in the driest quarter, and isothermality. Currently, the subsp. sieboldii is predicted to have larger, more contiguous suitable habitats across northeastern China, the Korean Peninsula, and Japan, whereas the subsp. japonica occupies smaller, more disjunct habitats scattered in central and western Japan and the southern Chinese mountains. These two subspecies will respond differently to future climate change. Potentially suitable habitats for subsp. sieboldii are expected to expand significantly northward over time, especially under the SSP585 scenario compared with the SSP126 scenario. In contrast, moderately and highly suitable habitats for the subsp. japonica are projected to contract southward significantly. Therefore, we recommend prioritizing the conservation of the subsp. japonica over that of the subsp. sieboldii. Strategies include in situ and ex situ protection, introduction and cultivation, regional hybridization, and international cooperation. Our study offers valuable insights for the development of targeted conservation strategies for both subspecies of M. sieboldii to counteract the effects of climate change.

Cornus officinalis Sieb. et Zucc. is a medicinal and ornamental woody plant whose distribution and production may be increasingly affected by climate change. This study assessed its climatic suitability under paleoclimatic, current, and future conditions to provide a climatic basis for cultivation planning, introduction, and germplasm conservation. An optimized MaxEnt model was developed using 381 spatially filtered occurrence records and five environmental predictors. Model complexity was tuned using spatial block cross-validation, and future projections for 2081–2100 were generated from an ensemble of ACCESS-CM2, BCC-CSM2-MR, and CMCC-ESM2 under four Shared Socioeconomic Pathway scenarios. Cold-quarter temperature, warm-season precipitation, mean diurnal temperature range, precipitation seasonality, and slope jointly shaped the predicted distribution. Under the current climate, climatically suitable areas were concentrated mainly in East Asia, particularly central and eastern China, with additional suitable climatic regions in eastern North America and parts of Europe. Suitable area was smallest during the Last Interglacial, expanded during the Last Glacial Maximum, and approached its current extent during the Mid-Holocene. The current suitable area was estimated at 277.247 × 10⁴ km² and was projected to decrease to 243.689, 206.615, 201.393, and 206.168 × 10⁴ km² under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, respectively. Existing suitable areas contracted in central China, the southern United States, and southern Japan, whereas climatic suitability expanded northward in parts of China, North America, Japan, and Europe. Suitable-area gains did not offset losses under any scenario, and retention of current suitable areas declined from 52.88% under SSP1-2.6 to 19.74% under SSP5-8.5. Most newly suitable areas were supported by at least two of the three climate models, although greater inter-model variation occurred near some range margins. These findings indicate substantial future redistribution of climatic suitability and identify climatically stable and newly suitable regions that may inform climate-resilient cultivation planning and conservation of C. officinalis.