Quantitative relationships between vegetation and several pollen taxa in surface soil from North China

According to the vegetation investigation and pollen analysis of surface sa mples sampled along a precipitation gradient of the Northeast China Transec t (NECT), several pollen taxa, including Pinus, Betula, Quercus, Tilia, Ace r, Ulmus, Artemisia, Chenopodiaceae, Gramineae and Cyperaceae, were chosen to make the regression and correlation analyses. The results indicated that there exists a close relationship between vegetation and pollen taxa in su rface samples. The regression parameters for ten taxa in the forests in the eastern part of NECT were different from those in the steppes in the weste rn part. Pinus, Betula, Artemisia and Chenopodiaceae, which have large slop e and y-intercept terms, were over-representative taxa. Acer, Gramineae and Cyperaceae, which have small slope and y-intercept terms, were under-repre sentative taxa. Quercus, Tilia and Ulmus whose slope terms have negative co rrelation with y-intercept terms were equi-representative taxa, The pollen taxa with large slope or large y-intercept terms have small variability coe fficients, implying that the slope and y-intercept terms for these pollen t axa are of high accuracy in the estimation of plant abundance from pollen f requencies.