Growth Characteristics Of Poplar I-107 And Narrow-crowned Black Poplar Clones

Poplar has many unique advantages such as fast growth,high yield,cold resistance,drought resistance,disease and insect resistance.As an important tree species for fast-growing and high-yield forests,it has been widely cultivated and applied worldwide.China has been cultivating poplar plantations in the northern region since the middle of the last century,and has achieved remarkable results.The selection,cultivation,and management of poplar plantations vary in different cultivation regions.This study compared the growth patterns,model predictions,biomass,photosynthesis,and other factors of three narrow crown black poplar clones in Laiyang City,Shandong Province,using I-107 poplar tree species as a control.The differences in growth characteristics of these poplar clones were explored,and the following conclusions were drawn:1.The growth laws of poplar clones such as tree height,ground diameter,chest diameter,and volume:For narrow crown black poplar clones,all indicators follow the"slow fast slow"growth law,with the fast growing period from May to August each year and the later growth period after September.The period from May to August is an important stage for the growth of black poplar,and water supply and fertilization should be strengthened,and management methods should be optimized.2.The growth extreme values of seedling height,diameter at breast height,and volume of poplar clones:The growth models of seedling height,diameter at breast height,and volume of four poplar clones were simulated using logistic curve equations,and it was found that their fitting accuracy was high(R~2=0.954);The relationship between the maximum growth values of the seedling height of the test materials is as follows:Narrow crown black poplar1>Narrow crown black poplar 2>I-107>Narrow crown black poplar 11;The relationship between the maximum growth values of DBH is as follows:I-107>Narrow Crown Black Poplar 11>Narrow Crown Black Poplar 2>Narrow Crown Black Poplar 1;The relationship between the maximum growth values of volume is as follows:I-107>Narrow crown black poplar 11>Narrow crown black poplar 1≈Narrow crown black poplar 2.3.The measurement characteristics of net photosynthetic rate and transpiration rate of poplar clones:The net photosynthetic rate and transpiration rate of the tested materials showed a daily variation curve with double peaks,with the first peak appearing around 9am and the other peak appearing around 3pm.The relationship between the apparent quantum efficiency of the test materials is as follows:Narrow crown black poplar 1>Narrow crown black poplar 2>I-107>Narrow crown black poplar 11;The size relationship of water use efficiency is as follows:Narrow crown black poplar 1>I-107>Narrow crown black poplar2>Narrow crown black poplar 11 has the lowest value;the size relationship of light saturation point is as follows:Narrow crown black poplar 2>I-107>Narrow crown black poplar1>Narrow crown black poplar 11;The variation curve formed by the light compensation point of four poplar clones is consistent with the variation curve of their light saturation point.4.Differences in growth characteristics such as tree height,diameter at breast height,and volume among poplar clones:By comparing and analyzing the 5-year-old narrow crown black poplar clones with reference object I-107,it was found that there were no significant differences in growth characteristics such as tree height,diameter at breast height,and volume between them.The relationship between the growth of the test materials is as follows:(1)DBH growth:I-107>Narrow Crown Black Poplar 1>Narrow Crown Black Poplar 2>Narrow Crown Black Poplar 11;(2)Tree height growth rate:Narrow crown black poplar 1>Narrow crown black poplar 2>Narrow crown black poplar 11>I-107;(3)Volume growth:I-107>Narrow crown black poplar 1>Narrow crown black poplar 2>Narrow crown black poplar 11.5.Morphological characteristics and biomass distribution of various organs of poplar clones:By analyzing the growth characteristics of the rotating branches of four poplar clones,it was found that the overall length of the rotating branches of poplar I-107 was smaller than that of the other three narrow crown black poplar clones.The relationship between the average diameter of the first level lateral branch base of the test materials is as follows:I-107>Narrow Crown Black Poplar 1>Narrow Crown Black Poplar 11>Narrow Crown Black Poplar 2.The relationship between the average angle of the first level lateral branches is as follows:I-107>Narrow crown black poplar 1>Narrow crown black poplar 2>Narrow crown black poplar 11.The relationship between the distribution of biomass in various organs of the test materials is as follows:trunk>branches>roots;The relationship between the biomass of the test materials is as follows:I-107>Narrow Crown 1>Narrow Crown 2>Narrow Crown 11;The size relationship of underground biomass is as follows:I-107>Narrow Crown 2>Narrow Crown 1>Narrow Crown 11;The size relationship of root to shoot ratio is as follows:Narrow crown black poplar 11>Narrow crown black poplar 1>Narrow crown black poplar 2>I-107.