Abstract: In order to prove the new regions of introduced Eucalyptus urophylla × E.grandis tree growth and the physicochemical properties of soil,some observation plots were set in the northwest of Guangxi Leli forest district for Eucalyptus urophylla × E.grandis continuous growth age sequence to determinate the stand diameter at breast height,tree height,volume and soil physical and chemical properties of soil.The results are as follows:(1) 1-4 years Eucalyptus urophylla × E.grandis average DBH total growth in turn are 5.0,8.0,9.7 and 10.7 cm;The tree height average total growth in proper order are 5.1,8.8,11.2 and 12.1 m;The average total stand volumes respectively are 8.29,31.76,51.45 and 71.89 cubic meters per hectare。(2) The stand (0-100 cm) soil bulk density is 1.188-1.498 grams per cubic centimeter,total porosity is 46.79% to 59.90%,among them the capillary porosity is 10.34%-28.50%。(3)The soil pH value is 5.44-5.60;Organic matter content is 0.78%-2.51%;The total N and total P content respectively is 0.04%to 0.11％;The total K content is 0.40 %-0.50 %;The available K(42.7-63.5mg/kg)>the effective Mn(5.91-22.59mg/kg)＞the available P(1.4-6.8mg/kg)＞the effective Zn(0.61-1.72mg/kg)＞the effective B(0.07-0.35mg/kg).The results show that in the northwest of Guangxi Leli forest district for Eucalyptus urophylla×E.grandis the plot soil bulk density is larger,the main nutrient contents of soil generally are deficient and tree growth is low.

Key words: Eucalyptus urophylla×E.grandis, observation plot, growth, the physicochemical properties of soil, the Northwest of Guangxi