Mordern alluvial pollen varies with geomorphic setting and depositional facies in sediments of the Yellow, Hutuo, and Luan rivers and in Baiyangdian and Hengshuihu lakes. Most of the arboreal pollen is derived from the mountains, whereas most of the nonarboreal pollen is derived from the plain itself. Alluvium dominated by Pinus pollen and Selaginella spores was deposited during a flood. Hydrodynamic sorting of alluvial pollen exists in the sediments of floodplain, central bar, natural levees, and point bar. In reconstructing the ancient vegetation and past climate based on pollen in alluvium, it is important to consider sedimentary facies and geomorphologic setting.

燕山南部花粉散布特征研究表明，空气中的花粉反映的是植物花期的季节性变化；表土花粉是植物多年花粉散布的混合；冲积物花粉与空气中和表土花粉显著不同，是取样点上游表土花粉的混合，与取样点周围植被关系较小。因此，根据冲积物花粉恢复古植被，反映的是整个流域的植被面貌，而不是某一点的植被特征。

本文依据地处39°28′08″N，110°09′92″E，海拔1219m的伊金霍洛旗杨家湾古土壤剖面取得的高时间分辨率孢粉分析和炭屑含量统计资料揭示：4500a B. P.之前，鄂尔多斯东部的毛乌素沙地地区曾出现明显的流沙扩展，此后，气候变得比较湿润，流动沙丘逐渐被固定下来；4200～3500a B. P.是本区的气候适宜期，这里曾有针阔叶混交林生长；3500a B. P.以后，气候变得干燥起来，森林从本区消失；2700～2400a B. P.，草原植被中藜科植物增加，气候进一步向干的方面发展，但降水量仍比现在高；2400a B. P.以后，在全新世晚期气候变干和人类活动的共同作用下，全新世中期本区发育的黑垆土遭到严重破坏，流动沙丘再次活跃起来。鄂尔多斯杨家湾古土壤剖面的炭屑浓度变化、考古遗址的发现较好地反映了人类活动强度的变化。

依据位于燕山南部迁安盆地蚕姑庙村和余家洼村具放射性碳年代测定支持的埋藏泥炭剖面的孢粉分析资料，揭示了迁安盆地5000 a BP以来自然植被变化和人类活动对自然环境的影响。在4600～3100 a BP期间，迁安盆地曾经生长着以栎为主的落叶阔叶林，至3100 a BP以后，森林中阔叶树成分显著下降，喜凉耐干的松树比例增加，1600 a BP后，迁安盆地人类农耕活动进一步加剧，森林遭受到大规模的破坏。孢粉分析资料揭示迁安盆地人类栽培板栗的历史可以追溯到1600 a BP左右，种植水稻的历史可以追溯到700 a BP左右。

DH99a sediment core recovered at the center of Daihai Lake in north-central China was analyzed at 4-cm intervals for pollen assemblage and concentration. The pollen record spanning the last ca 10000 yr revealed a detailed history of vegetation and climate changes over the Daihai Lake region during the Holocene. From ca 10250 to 7900 cal yr BP, arid herbs and shrubs dominated the lake basin in company with patches of mixed pine and broadleaved forests, indicating a mild and dry climatic condition. Over this period, the woody plants displayed an increasing trend, which may suggest a gradual increase in warmth and humidity. The period between ca 7900 and 4450 cal yr BP exhibits large-scale covers of mixed coniferous and broadleaved forests, marking a warm and humid climate. Changes in the composition of the forests indicate that both temperature and precipitation displayed obvious fluctuations during this period, i.e., cool and humid ca 7900-7250 cal yr BP, warm and slightly humid ca 7250-6050 cal yr BP, warm and humid between ca 6050 and 5100 cal yr BP, mild and slightly humid ca 5100-4800 cal yr BP, and mild and humid ca 4800-4450 cal yr BP. The period can be viewed as the Holocene optimum (characterized by a warm and moist climate) of north-central China, with the maximum (dominated both by warmest temperatures and by richest precipitations) occurring from ca 6050 to 5100 cal yr BP. During the period of ca 4450-2900 cal yr BP, the woody plants declined, and the climate generally became cooler and drier than the preceding period. This period is characterized by a cold, dry episode from ca 4450 to 3950 cal yr BP, a warm, slightly humid interval between ca 3950 and 3500 cal yr BP and a mild, slightly dry episode from ca 3500 to 2900 cal yr BP, and appears to be a transition from warm and humid to cold and dry climatic conditions. Since ca 2900 cal yr ago, the forests disappeared and the vegetation density decreased, reflecting a cool and dry climate. However, a relative recovery of the woody plants occurring between ca 1700 and 1350 cal yr BP may denote an increase both in temperature and in precipitation. Fluctuations in the climatic condition of the Daihai Lake region were not only related to changes in the seasonal distribution of solar insolation and in the axis and intensity of the ocean current in the western North Pacific but were also closely linked to variations in the position and strength of polar high-pressure systems and in the pattern and intensity of the Westerly winds.