| This study was carried out in the Hybrid larch (Larix olgansis×Larix leptolepis) forest (the experiment plot was approximately 6.9hm2) which is located at Mengjiagang of Jiamusi. The ecological factors (slope gradient, slope aspect, slope position, slope shape, soil temperature and soil water physical properties, etc) on the microsite slope surface scale of 1m×1m had been investigated to research the effects on growth of hybrid larch 5a. The results showed that:1. Microsite slope gradient (the slope gradient) has a significant effect on the surface soil (0～10cm) bulk density, capillary porosity, total porosity, temperature and soil water content (P<0.01). The maximum surface soil bulk density and temperature on the slope gradient of >15°(0.67g/cm3 and 17.18℃, respectively), the minimal on the slop gradient of 2°～8°(0.62g/cm3 and 16.97℃, respectively); capillary porosity and total porosity on the slop gradient of<2°were the highest (50.59% and 63.70%), on the slope gradient of 8°～15°were the lowest (46.52% and 61.09%, respectively); soil water content on the slope gradient of<2°was the highest (72.85%), on the slope gradient of>15°was the lowest (63.15%);2. Except total soil porosity (P=0.911), microsite location (the slope position) had no significant influence on soil bulk density, non-capillary porosity, capillary porosity, soil temperature, and soil water content (P<0.01). Soil bulk density and total porosity, soil temperature in the upper were greater than the middle and the down, soil capillary porosity, soil water content in the down were greater than the upper and the down;3. Microsite slope shape (the slope shape) has no significant effect on soil temperature and the total porosity (P= 0.095, P= 0.082), but has significant effect on soil bulk density, non-capillary porosity, capillary porosity and soil water content (P=0.003, P<0.01, P<0.01, P= 0.002). Soil bulk density, soil temperature of concave slope were lower than linear slope and convex slope; the capillary porosity, total porosity, and soil water content of convex slope were lower than the linear slope and the concave slope;4. Microsite slopes orientation (the slope aspect) had no significant effect on soil bulk density, saturated water and non-capillary porosity (P=0.292, P=0.286, P=0.356), and had significant effect on soil capillary water holding capacity, capillary porosity, total porosity, soil temperature and soil water content (P=0.013, P<0.01, P<0.01, P<0.01, P=0.001). The capillary porosity, total porosity, soil water content of shady (north, northeast) and semi-shade (east, northwest) were higher than sunny (southern, southwest) and semi-sunny (southeast, western) which the soil temperature is higher than the former;5. The slop aspect had no significant effect on height and diameter (P=0.477, P=0.132), the slop gradient (P=0.004, P=0.039), the slop position (P<0.01), the slop shape (P=0.021, P=0.009) had significant effects on growth of hybrid larch. The best growth seedlings distributed on the slope gradient of> 15°,height and diameter was 162cm and 23.4mm, respectively, the lowest on the slope gradient of<2°which is shorten 22.6cm and 2.5mm in height and diameter. Hybrid larch seedlings'height and diameter on the upper (162.8cm and 24.80mm) grew best, followed by middle slope (151.1cm and 22.16mm), the last is the down(135.0cm and 20.10mm). The concave slope grew best with the height and diameter (155.4cm and 22.81mm), followed by the linear slope (151.1cm and 22.75mm). The last is the convex (128.7cm and 18.73mm);6. The relationship of seedling height and diameter with soil bulk density, saturated water holding capacity, total porosity and soil temperature were not significant. But have significant relationship with other variables. Positively correlated with non-capillary porosity, have negative correlation with others;7. Suitable for the growth of microsite Hybrid larch is the slop surface of>15°, upper and concave.
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