Abstract: Three spatial structure indices of stand, i.e., neighborhood pattern, neighborhood comparison, and mingling, were used to analyze the spatial structure of Pinus tabulaeformis f. shekannesis  community on Loess Plateau. The tree species composition in the stand was 7:2:1 for Pinus tabulaeformis f. shekannesis , Quercus liaotungensis, and other tree species. The stand density was 1325 trees·hm², and Pinus tabulaeformis f. shekannesis  population was on an obvious dominant position. The average mingling in Pinus tabulaeformis f. shekannesis stand was 0.33, showing that the stand was at the transition period of weak mixed status to moderate status, and the isolation degree of the stand was moderate. The average neighborhood pattern of the stand was 0.57, indicating that the stand was assembly distributed. The average neighborhood comparison of DBH and tree height in the stand was 0.52 and 0.53, respectively, and the distribution of neighborhood comparison was quite even. The average neighborhood comparison of DBH and tree height was in great consistent advantage in reflecting tree growth.

Key words: Dinghushan, Acid deposition, Chemical properties