To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,...To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,and potassium fertilizers),each with four levels,using an orthogonal experimental design.A logistic model was used to estimate growth in height.The growth curves for tree height were sigmoid,and the model R^2 values were greater than 0.9,which indicated that the fit was highly significant.ANOVA results for tree height and basal diameter indicated that all sources of variance showed significant differences(p<0.001).The average tree height and basal diameter for all the four clones under the different treatments ranged from 155.39 to 235.04 cm,and from 13.71 to 17.42 mm,respectively.A highly positive correlation between the extreme k value and tree height was observed,suggesting that the k value was an accurate estimation of tree height.For model parameters,the earliest average time point for the onset of the rapid growth period of poplar clones was 131 d,and the highest average increment in tree height during the rapid growth period was 138.78 cm.The highest average tree height for all clones under each factor was 219,210.51,200,and 201 cm when treated with either 1200 mL of water applied every third day,3 g of nitrogen,0 g of phosphorus,or 0 g of potassium,respectively.The most suitable treatment for the early growth of hybrid poplar cuttings,as suggested by the developed logistic model,was 1200 mL of water applied every third day and three applications of 1 g nitrogen(in the form of CH4N2O).展开更多
When planning poplar plantations there are many factors to consider that can influence young plant development. In addition to soil preparation, vegetation management, protection against browsers, and plant-type, it i...When planning poplar plantations there are many factors to consider that can influence young plant development. In addition to soil preparation, vegetation management, protection against browsers, and plant-type, it is important to have information on how soil properties influence young plant development. Comparisons of establishment and growth in different soils are complicated as experimental sites often are geographically distant where temperature, precipitation and vegetation can vary, thus complicate the analysis. In this case study, a new approach of studying growth of different soil at one experimental site are undertaken by translocating agricultural soils, a silty clay loam and a sandy soil, and common forest soil types, forest moraine soil and forest peat to a single experimental site, thus guaranteeing identical climatic conditions. In all soils, transplanted P. trichocarpa cuttings initially developed in to plants. After 4 weeks though, plants grown in forest peat stopped their growth while plants in the other soils gradually continued their growth with no evidence that soil types influenced above ground plant development. Unlike above-ground growth, root growth and morphology were influenced by soil texture with more root growth occurring if soils have sandy texture. These findings give advice to some of the limitations when planning for establishment of poplar plantations either at agricultural or at forest land.展开更多
As a basic measure for forest management,pruning has an important impact on the tree trunk shape,wood qulity,etc. At present,in the process of growing fast-growing and high-yielding plantation,afforestation was took i...As a basic measure for forest management,pruning has an important impact on the tree trunk shape,wood qulity,etc. At present,in the process of growing fast-growing and high-yielding plantation,afforestation was took into account,whereas management after planting was ignored,which had much detrimental effect on woodland’s quality and productivity. The paper studied the topic to find a scientific pruning model that could provide a guideline for the management in forest production. The plantation and the intercropping of poplar-crop were pruned in four different levels in Hebei and Shandong province. The levels were respectively light p1 (1/6 crown was pruned),medium p2 (2/6 crown was pruned),strong p3 (3/6 crown was pruned),heavy p4 (4/6 crown was pruned) and the control (unpruned). Heights and diameters at breast height(DBH) were measured. Diameter growth and cutting-area increment in one year from ten parsed trees were counted. The volume growth of trunk (below 9 m) was calculated. The results were:1) the difference of relative growth rate for different pruning treatment was not significant (P<0.05),which demonstrated the nutrition for height growth came from the branches and leaves of the top crown; 2) The difference of relative growth rate of DBH was significant(P<0.01). That is,the greater of pruning intensity,the smaller relative growth in the DBH. 3) The stem growth of parsed disk at different height was fluctuant among the different treatments. From stem base (0.0 m) to 9 m height of the trunk,the stem increase of the lower half reduced along with the increase of pruning intensity,while the growth of the upper half in pruning trees was bigger than that of non-pruning ones. 4) The difference of volume growth rate for different treatments was significant,all of the pruning treatments were bigger than the control. The medium p2 had the biggest growth,and the order was CK<p4<p1<p3<p2,which suggested that reasonable pruning can improve the growth of volume. However an excessive pruning reduced volume growth. 5) Pruning can decrease relative taper of trunk,make trunk straight and satiety,and increase the rate of volume increasing for one year. 6) In conclusion,in the process of production,the reasonable pruning should be moderate intensity as pruning p2,in which 1/3 crown length was removed.展开更多
基金financially supported by the National Key Research and Development Program of China(Grant No.2016YFD0600404)the Fundamental Research Funds for the Central Universities(2572017DA02)
文摘To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,and potassium fertilizers),each with four levels,using an orthogonal experimental design.A logistic model was used to estimate growth in height.The growth curves for tree height were sigmoid,and the model R^2 values were greater than 0.9,which indicated that the fit was highly significant.ANOVA results for tree height and basal diameter indicated that all sources of variance showed significant differences(p<0.001).The average tree height and basal diameter for all the four clones under the different treatments ranged from 155.39 to 235.04 cm,and from 13.71 to 17.42 mm,respectively.A highly positive correlation between the extreme k value and tree height was observed,suggesting that the k value was an accurate estimation of tree height.For model parameters,the earliest average time point for the onset of the rapid growth period of poplar clones was 131 d,and the highest average increment in tree height during the rapid growth period was 138.78 cm.The highest average tree height for all clones under each factor was 219,210.51,200,and 201 cm when treated with either 1200 mL of water applied every third day,3 g of nitrogen,0 g of phosphorus,or 0 g of potassium,respectively.The most suitable treatment for the early growth of hybrid poplar cuttings,as suggested by the developed logistic model,was 1200 mL of water applied every third day and three applications of 1 g nitrogen(in the form of CH4N2O).
文摘When planning poplar plantations there are many factors to consider that can influence young plant development. In addition to soil preparation, vegetation management, protection against browsers, and plant-type, it is important to have information on how soil properties influence young plant development. Comparisons of establishment and growth in different soils are complicated as experimental sites often are geographically distant where temperature, precipitation and vegetation can vary, thus complicate the analysis. In this case study, a new approach of studying growth of different soil at one experimental site are undertaken by translocating agricultural soils, a silty clay loam and a sandy soil, and common forest soil types, forest moraine soil and forest peat to a single experimental site, thus guaranteeing identical climatic conditions. In all soils, transplanted P. trichocarpa cuttings initially developed in to plants. After 4 weeks though, plants grown in forest peat stopped their growth while plants in the other soils gradually continued their growth with no evidence that soil types influenced above ground plant development. Unlike above-ground growth, root growth and morphology were influenced by soil texture with more root growth occurring if soils have sandy texture. These findings give advice to some of the limitations when planning for establishment of poplar plantations either at agricultural or at forest land.
文摘As a basic measure for forest management,pruning has an important impact on the tree trunk shape,wood qulity,etc. At present,in the process of growing fast-growing and high-yielding plantation,afforestation was took into account,whereas management after planting was ignored,which had much detrimental effect on woodland’s quality and productivity. The paper studied the topic to find a scientific pruning model that could provide a guideline for the management in forest production. The plantation and the intercropping of poplar-crop were pruned in four different levels in Hebei and Shandong province. The levels were respectively light p1 (1/6 crown was pruned),medium p2 (2/6 crown was pruned),strong p3 (3/6 crown was pruned),heavy p4 (4/6 crown was pruned) and the control (unpruned). Heights and diameters at breast height(DBH) were measured. Diameter growth and cutting-area increment in one year from ten parsed trees were counted. The volume growth of trunk (below 9 m) was calculated. The results were:1) the difference of relative growth rate for different pruning treatment was not significant (P<0.05),which demonstrated the nutrition for height growth came from the branches and leaves of the top crown; 2) The difference of relative growth rate of DBH was significant(P<0.01). That is,the greater of pruning intensity,the smaller relative growth in the DBH. 3) The stem growth of parsed disk at different height was fluctuant among the different treatments. From stem base (0.0 m) to 9 m height of the trunk,the stem increase of the lower half reduced along with the increase of pruning intensity,while the growth of the upper half in pruning trees was bigger than that of non-pruning ones. 4) The difference of volume growth rate for different treatments was significant,all of the pruning treatments were bigger than the control. The medium p2 had the biggest growth,and the order was CK<p4<p1<p3<p2,which suggested that reasonable pruning can improve the growth of volume. However an excessive pruning reduced volume growth. 5) Pruning can decrease relative taper of trunk,make trunk straight and satiety,and increase the rate of volume increasing for one year. 6) In conclusion,in the process of production,the reasonable pruning should be moderate intensity as pruning p2,in which 1/3 crown length was removed.
