Analysis Of Catalpa Bungei Plantation Forest Stand Structure And Photosynthetic Characteristics Of Seedlings

This study is based on the knowledge and methods of physiology,forest managerial science and related statistics.The study of photosynthetic production capacity,tree growth characteristics and forest stand structure of Catalpa bungei seedlings by sample survey and photosynthetic characteristics analysis.The study was conducted to provide theoretical support for the research and management of Catalpa bungei plantation forest and to provide technical reference for forestry production and construction.The main conclusions of this study are as follows.?1?The diameter distribution curve and tree height distribution curve of the six forest ages obeyed normal distribution.The normal distribution function and the Weibull distribution function were fitted separately,and the accuracy of the normal distribution function was found to be satisfactory.higher and more suitable for fitting the diameter structure and tree height structure of the different forest ages of Catalpa bungei.?2?The spatial structural parameter size ratios and angular scales of the six forest ages showed that the competitive state of the reference trees within the sample plot was overall In the intermediate state,the mean angular scales were all around 0.5,the 15 a and 25 a stands showed an even distribution,and the remaining forest age samples were showed random distribution.?3?The correlation analysis of the photosynthetic characteristic indicators showed that the net photosynthetic rate?Pn?of different vegetative systems in different seasons was associated with the Photosynthetically effective radiation?Par?is positively correlated with atmospheric relative humidity?RH?,which is positively correlated with air temperature?Ta?.Negative correlation;net photosynthetic rates of Catalpa bungei cuttings were negatively correlated with temperature in spring,and netphotosynthetic rates of cuttings,tillers,and grafted seedlings were The rate was positively correlated with temperature in summer and autumn;the net photosynthetic rate of Catalpa bungei cuttings in summer was positively correlated with atmospheric CO₂ concentration?Ca?The correlation was positive for tillers,seedlings,and grafted seedlings with atmospheric CO₂ concentration in autumn.?4?The relationship between photosynthetic rate and stomatal conductance was very close,but not linear,indicating that the decrease in photosynthetic rate was not correlated with stomatal conductance,except for the decrease in stomatal conductance.Controlled by non-stomatal factors in addition to stomatal closure.The siesta was not evident in rowan tiller seedlings,whereas it was relatively evident in other propagation methods of rowan.The Catalpa bungei cuttings were the most light-adapted and had the widest range of light energy utilization than those of other propagation methods.?5?A study of the growth process of different vegetative strains of Catalpa bungei in the Fengyishan Experimental Forest found that seedling height and ground diameter between different vegetative strains during the seedling stage The differences were significant,and the seedling height and ground diameter of No.76 and No.4 were significantly larger than No.75?control?.A study of the growth process of different vegetative lines of the Fengyi Mountain test forest golden rowan found that Nos.76 and 4 grew faster relative to other vegetative lines.However,the difference was not significant.Significantly greater over 15 years of growth compared to No.75?control?.breast diameter,tree height and The total growth volume of wood volume was significantly lower than that of the vegetative and control lines of Catalpa bungei tree in the phoenix-winged mountain test forest,indicating slower growth at young ages.The vegetative photosynthetic properties of Pn 75 and 4 were significantly higher in summer,with a maximum value of 22 ?mol-m^-2s^-1,respectively.and 22.57 ?mol-m^-2s^-1,thus these two vegetative lines are well adapted to light.The analysis of the growth indexes of seedlings and parsley wood,and their photosynthetic characteristics showed that the excellent vegetative lines of golden rowan 76,4 It has a good potential for photosynthetic production,and is suitable for the construction of excellent plantation stands with optimized structure,reasonable spatial distribution and high production potential.