The vertical distribution characteristics of Monochamus alternatus on the trucks of infested Pinus yunnanensis were investigated both in field and laboratory.The results showed that the quantity distribution of oviposition scar in trunk was lower part > middle part > upper part;and the density distribution of oviposition scar had not significant difference(P>0.05).The quantity distribution of entrance hole in trunk was middle part > lower part > upper part;and the density distribution of entrance hole was upper part > middle part > lower part.The quantity distribution of exit hole in trunk was middle part > upper part > lower part;and the density distribution of exit hole was upper part > middle part > lower part.There were positive correlations between the quantities of oviposition scar or entrance hole in lower part of trunk and the entrance hole or exit hole in whole trunk,respectively.The linear regression equations of the quantity of oviposition scar in lower part(x1),the entrance hole in lower part(x2) and the quantity of oviposition scar in whole trunk(y1),the entrance hole in whole trunk(y2),the exit hole in whole trunk(y3) are y1=7.117+2.283 x1,y2=24.220+0.701 x1,y3=8.794+0.434 x1,y2=28.805+2.211 x2,y3=20.367+0.778 x2.All partial correlations had reached the very signiticant level.
Soil properties of healthy,sub-healthy and unhealthy Pinus yunnanensis secondary forest were measured and their correlation with the health conditions of Pinus yunnanensis forest were analyzed.The results revealed that,the soil water content,bulk density,porosity,sand content,cosmid content,CEC and radily available K content changed regularly with the health condition changes of Pinus yunnanensis forest.Correlation analysis revealed that,there were positive correlation between soil water content,porosity,cosmid content,CEC,radily available K content and health conditions of Pinus yunnanensis forest;and negative correlation between bulk density,sand content,meal content and health conditions of Pinus yunnanensis forest.By stepwise regression analysis,the regression models about health conditions of Pinus yunnanensis forest and soil properties were established.
Diurnal changes of photosynthesis of Pinus yunnanensis and its influencing factors were studied in dry season.The results indicated that in the dry season,the diurnal course of photosynthesis of P.yunnanensis occurred regularly with the environmental factors change.The curve of net photosynthetic rate(Pn) and transpiration rate(Tr) had a diurnal change with one-peak curve,the peak of Pn occurred at 14:00 and the peak of Tr appeared at 15:00.There was no "midday depression of photosynthesis".The different meteorological factors influencing the photosynthesis were different.The photosynthetic active radiation(PAR) was the ecological factor directly effecting on the Pn and stomatal conductance(Cond) of P.yunnanensis,the main factors affecting Tr were temperature leaf(Tl) and CO2.The course of air humidity on the dry season were lower,and its effects on photosynthesis was not significant,which showes that the P.yunnanensis has a strong physiological adaptability on dry season.
