According to previous studies, the Lixiahe area in the east of the Jianghuai River was an alternate environment of land and sea in the middle Holocene, and it was not until the late Holocene that the eastern Jianghuai completely became a terrestrial environment. However, recent archaeological studies have found that the extensive Neolithic sites in the Lixiahe area have recorded the rich human activities and cultural connotations of the prehistoric civilization in the Middle Holocene. In this paper, the Gangxi section of Jianhu Lake, Jiangsu Province (GX2) was selected and pollen analysis was fulfilled, then the geomorphic evolution process of the study area from sea to land was investigated according to the palynological assemblages and algae fossils of brackish water, semi-saline water, fresh water and terrestrial in the section strata. During the period of 8500–3800 cal. BP, GX2 was affected by multiple factors such as sea surface fluctuation, ocean flow and sediment deposition carried by seagoing rivers. Since 5800 cal. BP, the area east of the Grand Canal between the Yangtze River and the Huaihe River, and the west of the Yangzhai town, Funing–Longgang town, Yancheng–Dagang town and Yancheng–west of the Dongtai–Hai’an line, have become a terrestrial environment. After the eastern Jianghuai became a land, the Liangzhu culture (5300–4300 cal. BP) in the Taihu Lake basin in the south wing of the Yangtze River delta expanded to the eastern Jianghuai area, and the Longshan culture and Yueshi culture in the Haidai area in the north also migrated south to the eastern Jianghuai area. Admittedly, the main reason in the process of Neolithic cultural development is the internal motivation that the ancient ancestors struggled with nature and pushed forward the continuous development of civilizations. However, our study explains the palaeogeographical origin of Neolithic culture in the eastern and coastal areas of Jianghuai in the middle Holocene, and meanwhile, provides an example for the man–land relationship research on Neolithic culture.

Precisely dated paleoclimatic records are essential for understanding natural and anthropogenic climate influences. Here, an annually resolved absolutely dated Juniperus saltuaria tree ring width chronology from the Haizi mountain, southeastern Tibetan Plateau (TP) was developed. The chronology shows the annual- to decadal-scale paleoclimatic variability of the southeastern TP over the past 903 years (1115–2017 CE). The tree ring widths correlate significantly with mean annual temperature (T_mean). A linear regression model between ring width and T_mean, accounting for 57% of the variance in temperature from 1959 to 2017 CE, was used to reconstruct the past 903 years of T_mean variation in the southeastern TP. The chronology aligns with other temperature records from the TP, Asia, and the Northern Hemisphere (NH), indicating a marked temperature increase since the late twentieth century, with 1998–2017 CE identified as the warmest period. The coldest thirty years occurred in 1115–1145 CE. Solar activity and the Atlantic Multidecadal Oscillation exert notable influences on temperature fluctuations in this region. Superposed epoch analysis indicates that volcanic eruptions had significantly impacted southeastern TP temperatures, causing dramatic cooling for 2–4 years. Our study presents the longest width chronology developed by Juniperus saltuaria to date, offering a long-term perspective on recent climatic shifts across the southeastern TP. This work enhances understanding of historical climate variability, providing critical insights to refine projections of future climate variability.

The Liangzhu culture (5300–4200 cal BP) was the most famous Neolithic culture of who settled near the lower reaches of the Yangtze River in China. The core and initial distribution area of Liangzhu originated around Taihu Lake, located on the south bank of the Yangtze River delta. Recently, archaeological studies believe that the Jianghuai area and Huanghuai area north of the Yangtze River are also important distribution areas of Liangzhu culture. The route for Liangzhu culture migrating across the Yangtze River is inferred as follows: One would have crossed the Yangtze River from Nanjing-Zhenjiang belt and continued to migrate northward; while the other would have crossed the River near the estuary before moving north along the ancient coastline to the Jianghuai during the late period of Liangzhu, or crossed the Yangtze River from the east of the present Beijing-Hangzhou Grand Canal to Jianghuai and Huanghuai. According to the formation of the Yangtze River delta during the Holocene and the evolution of the estuarine sand bar, it is believed that there were large shoals in the Yangtze River channel in the middle-Holocene. The Liangzhu ancestors around 5000 cal BP had the ability of making canoes over 8 m. Based on the archaeological research of the Neolithic period, the evolution of the Yangtze River channel in the Holocene, the history of ancient Chinese shipbuilding, and the modern examples of crossing the Yangtze River with boat, it can be concluded that the present Changzhou–Jiangyin–Zhangjiagang line should be the main and reasonable route for the Liangzhu culture migrating across the Yangtze River.

Characterized as a climatologically sensitive region, the southeastern Tibetan Plateau (STP) is an ideal location for dendrochronological research. Here, five tree-ring width (TRW) chronologies were developed: three for Picea likiangensis along altitudinal gradients from 3600 to 4400 m a.s.l. and two for Sabina saltuaria and Abies squamata from 4200 m a.s.l. Significant differences in the growth rates and age composition of Picea likiangensis were observed at various elevation gradients. The chronology statistics (mean sensitivity, etc.) fluctuated with the elevation gradient. Picea likiangensis showed distinct growth patterns in response to climatic variability along the altitude gradient: the minimum temperature influenced tree growth at lower and middle altitudes, while higher altitudes were affected by precipitation. The radial growth of different tree species growing in the same region is controlled by the same climatic factors. Sabina saltuaria and Abies squamata exhibited similar growth responses to Picea likiangensis. Stand conditions (wind speeds, slope, and elevation) and biotic factors (the depth of root, forest type, tree age, and sensitivity) can partially explain why the ring width–climate relationships change with altitude.

Two annually resolved and absolutely dated Juniperus saltuaria (JS) tree ring width chronologies from the Haizi mountain, southeastern TP were reported in here. We sampled two sites in different landscapes, one is located at the forest line at ca. 4200 m above sea level beside an incised valley, and the other at the plateau surface, ca. 4500 m in elevation. Comparisons of statistical parameters between two sites and their tree ring index correlation coefficient with meteorologic data of DaoCheng shows that the latter site exhibits higher value than the former one. These indicate that those trees growing along the valley side may be more susceptible to local environment, and those on the plateau surface can provide reliable record for regional climate. Based on the latter chronology, a 903a long annual mean temperature (Tmean) series (1115-2017 CE) was reconstructed. It is the longest width chronology reconstructed by JS at present. The entire sequence shows consistent warm-cold patterns with other temperature reconstructions of the TP, Asia, and Northern Hemisphere. The warmest (coldest) period occurred at 1998-2017 CE (1115-1145 CE), respectively. There was no doubt that temperature raised sharply since the end of the 20th century. In addition, the sequence demonstrates multi-decadal, decadal and inter-decadal variations, further multi-taper method reveals dominant periodicities are 147, 36, 18, 7 and 2-2.6a, likely been affected by the Atlantic Multidecadal Oscillation and solar activity. The forcing of volcanic eruptions resulted to subsequent 1-3 years temperature drops.