1994 Vol. 7, No. 3
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1994, 7(3): 239-246.
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Abstract:
Based on the discussion of the bioecological characteristics of D.margaritae,in this paper,the cultivation techniques including seedling raising,plantation establishment and management,harvest,and economic benefit of the plantation are presented.The region located to the south of 23°30'N with an annual mean temperature 20～24.5℃,absolute minimum temperature-2.8℃,15℃ active accumulated temperature5800℃/year,and annual rainfall l200 mm,is suitable for cultivation of D.margaritae.The appropriate site should be sheltered(50% in relative light intensity),moist soil with the content of organic matter in top soil 2%,total N0.1%,total P0.01%,and pH 4.4～6.7.The seeds can be stored for 6 months without losing their vitality at the controlled condition,The integrated quality indexes are listed below: qualified seedling(1 year old)should have more than 4 leaves and over 25 cm in height;superior seedling more than 5 leaves and over 35 cm in height;number of stems in each clump should be more than l3 in 8 years old plantation;and yield of l2 years old plantation reaches 7 000 kg/hm2.Moreover,the standard sets for the fast-growing rattan plantation is that the average number of stems per clump50,total length of stems100 m per clump,and yield l0 000 kg/hm2.This paper also deals with the technical maturity, harvest rotation,management methods,and evaluation of economic benefit of rattan plantation.The results showed that in a 25-year management period of the rattan plantation,the output value is greater than l50000 yuan/hm2,net income130 000 yuan/hm2, NPV16 000 yuan/hm2,and investment recovery period11 years.
Based on the discussion of the bioecological characteristics of D.margaritae,in this paper,the cultivation techniques including seedling raising,plantation establishment and management,harvest,and economic benefit of the plantation are presented.The region located to the south of 23°30'N with an annual mean temperature 20～24.5℃,absolute minimum temperature-2.8℃,15℃ active accumulated temperature5800℃/year,and annual rainfall l200 mm,is suitable for cultivation of D.margaritae.The appropriate site should be sheltered(50% in relative light intensity),moist soil with the content of organic matter in top soil 2%,total N0.1%,total P0.01%,and pH 4.4～6.7.The seeds can be stored for 6 months without losing their vitality at the controlled condition,The integrated quality indexes are listed below: qualified seedling(1 year old)should have more than 4 leaves and over 25 cm in height;superior seedling more than 5 leaves and over 35 cm in height;number of stems in each clump should be more than l3 in 8 years old plantation;and yield of l2 years old plantation reaches 7 000 kg/hm2.Moreover,the standard sets for the fast-growing rattan plantation is that the average number of stems per clump50,total length of stems100 m per clump,and yield l0 000 kg/hm2.This paper also deals with the technical maturity, harvest rotation,management methods,and evaluation of economic benefit of rattan plantation.The results showed that in a 25-year management period of the rattan plantation,the output value is greater than l50000 yuan/hm2,net income130 000 yuan/hm2, NPV16 000 yuan/hm2,and investment recovery period11 years.
1994, 7(3): 247-252.
Abstract:
A dynamic economic analysis procedure with compacted cash flow was presented.In this procedure,each investment and benefit be expressed as a function of cost elements,e.g.cost of regeneration could be described as:regeneration cost/hm2=(site cleanlabour force demand/hm2+site preparation labour force demand/hm2+planting labour forcedemand/hm2)*wage per labour per day+seedling price * stems/hm2.Compacted cash flowcould be transferred to present value with multiplier[(1+i)f-1)]/[i(1+i)t+f-1],here i=discount rate,t=initial time of a period with equal investments and benefits,f=years of theperiod,and with which dynamic economic analysis can be done more smoothly than with ordinary cash flow.With a sophisticated data adapter,the algorithm could be easily involved into stand simulation system.Set of cost elements,recorded in a text file,could be redesignedand the functions,written in a equation library,could be recreated by user,so that a standsilviculture model would be more suitable to the occasion concerned.
A dynamic economic analysis procedure with compacted cash flow was presented.In this procedure,each investment and benefit be expressed as a function of cost elements,e.g.cost of regeneration could be described as:regeneration cost/hm2=(site cleanlabour force demand/hm2+site preparation labour force demand/hm2+planting labour forcedemand/hm2)*wage per labour per day+seedling price * stems/hm2.Compacted cash flowcould be transferred to present value with multiplier[(1+i)f-1)]/[i(1+i)t+f-1],here i=discount rate,t=initial time of a period with equal investments and benefits,f=years of theperiod,and with which dynamic economic analysis can be done more smoothly than with ordinary cash flow.With a sophisticated data adapter,the algorithm could be easily involved into stand simulation system.Set of cost elements,recorded in a text file,could be redesignedand the functions,written in a equation library,could be recreated by user,so that a standsilviculture model would be more suitable to the occasion concerned.
1994, 7(3): 253-258.
Abstract:
year-old clones of Populus deltoides Martr from the gene-pool in Changqing County,Shandong Province were used as testing material.Their wood basic density,fiber length,tree height and DBH were measured and analysed.The results show:asignificant variance was observed in 4 traits among the 36 clones.5 fine clones with higherdensity,longer fiber and faster growth were selected to be the best clones by optimization.Genetic variation of wood basic properties and tree growth were analysed.The broad-senseheritabilities for basic density(0.32),fiber length(0.40),tree height(0.43),DBH(0.71)of 36 clones were calculated.These results showed that these basic wood properties and treegrowth were under moderate and stronger genetic control.There was a slight negativegenetic correlation between the wood basic density and tree growth rate, as well as a positivegenetic correlation between the fiber length and tree growth rate.The traits of density andlength can be selected independently.The genetic parameters of wood basic properties andtree growth were put forward for the introduction of P.deltoides.Moreover,the wood basicdensity, fiber length,tree height and DBH of female and male trees were compared.The differences of 4 traits between female and male trees were not significant.
year-old clones of Populus deltoides Martr from the gene-pool in Changqing County,Shandong Province were used as testing material.Their wood basic density,fiber length,tree height and DBH were measured and analysed.The results show:asignificant variance was observed in 4 traits among the 36 clones.5 fine clones with higherdensity,longer fiber and faster growth were selected to be the best clones by optimization.Genetic variation of wood basic properties and tree growth were analysed.The broad-senseheritabilities for basic density(0.32),fiber length(0.40),tree height(0.43),DBH(0.71)of 36 clones were calculated.These results showed that these basic wood properties and treegrowth were under moderate and stronger genetic control.There was a slight negativegenetic correlation between the wood basic density and tree growth rate, as well as a positivegenetic correlation between the fiber length and tree growth rate.The traits of density andlength can be selected independently.The genetic parameters of wood basic properties andtree growth were put forward for the introduction of P.deltoides.Moreover,the wood basicdensity, fiber length,tree height and DBH of female and male trees were compared.The differences of 4 traits between female and male trees were not significant.
1994, 7(3): 259-262.
Abstract:
Wood density and mechanical properties of 32 Chinese fir(Cunninghamia lanceolata(Lamb.Hook.)were determined and analysed.The results showed that therewere remarkable differences in wood density,MOE,MOR,and crushing strength amongthe clones,and there were also considerable intraclonal differences as well.Significant positive correlations at 0.01 level were exhibited between wood densitv and MOE,MOR,crushing strength with the correlation coefficients 0.3957,0.8368,and 0.9020 respectively.Wood density was negatively correlated to the diameter at breast height.
Wood density and mechanical properties of 32 Chinese fir(Cunninghamia lanceolata(Lamb.Hook.)were determined and analysed.The results showed that therewere remarkable differences in wood density,MOE,MOR,and crushing strength amongthe clones,and there were also considerable intraclonal differences as well.Significant positive correlations at 0.01 level were exhibited between wood densitv and MOE,MOR,crushing strength with the correlation coefficients 0.3957,0.8368,and 0.9020 respectively.Wood density was negatively correlated to the diameter at breast height.
1994, 7(3): 263-268.
Abstract:
Inheritance and variation of growth and wood quality were studied through 81 open-pollinated families of 9-year-old.It was found that there were significant differencesbetween families for tree height,DBH,bole straightness,limb characteristics and wood basicdensity which were moderately inherited,and while marked effect of family for tracheidlength was not found.The poor posiive or negative genetic correlation between growth andbasic density indicated that growth rate is not an accurate indicator for wood density.Thegrowth and wood density could be manipulated indirectly by selecting bole straightness andbranch size.Branch angle was a specific trait independent of other ones.Unrestricted and restricted index were effective methods for selecting fast-growing and high wood quality families.Finally,the problems on selection strategy and multitrait selection of paperpulp woodwere discussed.
Inheritance and variation of growth and wood quality were studied through 81 open-pollinated families of 9-year-old.It was found that there were significant differencesbetween families for tree height,DBH,bole straightness,limb characteristics and wood basicdensity which were moderately inherited,and while marked effect of family for tracheidlength was not found.The poor posiive or negative genetic correlation between growth andbasic density indicated that growth rate is not an accurate indicator for wood density.Thegrowth and wood density could be manipulated indirectly by selecting bole straightness andbranch size.Branch angle was a specific trait independent of other ones.Unrestricted and restricted index were effective methods for selecting fast-growing and high wood quality families.Finally,the problems on selection strategy and multitrait selection of paperpulp woodwere discussed.
1994, 7(3): 269-276.
Abstract:
In the field studies conducted in Dayi County,Sichuan Province in 1993,30 species of the natural enemies of gypsy moth Lymantria dispar were collected,including 19 parasitoids,9 predators,one NPV and one fungus Entomophaga maimaiga.3 of them were natural enemies in egg stage,the egg-parasitic wasps can make a parasitism of 27.06%±0.54% in average,Ooencyrtus kuwanae was the dominant one.13 of them were parasitoids in larval stage,the dominant species of Meteorus pulchricornis,Hyposoter vierecki,Glyptapan-teles liparidis and NPV can kill the larvae with a proportion of 51.59%±6.48% in average,NPV was the most important one in this stage.Tachinid maggots parasitized a lot of gypsy moth larvae,which came out from larvae with a percentage of 26.5% and from pupae 73.5%.There were 4 kinds of parasitoids in the pupal stage with a parasitism of 32.91%±26.40% in average,which are tachinids,Brachymeria lasus,Thqeronia atalantae gestator etc.About 87.62% of the gypsy moth individuals were killed by natural enemies from egg to pupal stage.The biology and habits of 7 natural enemy species were also introduced in this paper.
In the field studies conducted in Dayi County,Sichuan Province in 1993,30 species of the natural enemies of gypsy moth Lymantria dispar were collected,including 19 parasitoids,9 predators,one NPV and one fungus Entomophaga maimaiga.3 of them were natural enemies in egg stage,the egg-parasitic wasps can make a parasitism of 27.06%±0.54% in average,Ooencyrtus kuwanae was the dominant one.13 of them were parasitoids in larval stage,the dominant species of Meteorus pulchricornis,Hyposoter vierecki,Glyptapan-teles liparidis and NPV can kill the larvae with a proportion of 51.59%±6.48% in average,NPV was the most important one in this stage.Tachinid maggots parasitized a lot of gypsy moth larvae,which came out from larvae with a percentage of 26.5% and from pupae 73.5%.There were 4 kinds of parasitoids in the pupal stage with a parasitism of 32.91%±26.40% in average,which are tachinids,Brachymeria lasus,Thqeronia atalantae gestator etc.About 87.62% of the gypsy moth individuals were killed by natural enemies from egg to pupal stage.The biology and habits of 7 natural enemy species were also introduced in this paper.
1994, 7(3): 277-285.
Abstract:
An investigation was made on the seedling and juvenile stage of 47 open-pollination families in Pinus taeda L..The results show that the variance of preservation percentand height of seedling between the families are significant.The perservation percent is correlated with seedling height, but the seedling height growth is not correlated with saplingheight growth.The differences of height growth between families are significant.There isover 1/5 of the 47 families superior in height growth.In addition,the influence of statisticanalysis method and selection critirion on selection effect were studied,effectiveness of elimination of inferior seedlings was also investigated.
An investigation was made on the seedling and juvenile stage of 47 open-pollination families in Pinus taeda L..The results show that the variance of preservation percentand height of seedling between the families are significant.The perservation percent is correlated with seedling height, but the seedling height growth is not correlated with saplingheight growth.The differences of height growth between families are significant.There isover 1/5 of the 47 families superior in height growth.In addition,the influence of statisticanalysis method and selection critirion on selection effect were studied,effectiveness of elimination of inferior seedlings was also investigated.
1994, 7(3): 286-293.
Abstract:
The vegetation in Dagang Mountain,Jiangxi Province was investigated using the method of quadrate and plotless sampling.Main types of vegetation can be classified as tollows:evergreenchinkapin and phoebe forest;theropencedrymion; bamboo and broadleaf mixed forest;Chinese fir plantation;montane meadow.Main forest stands in that area are Chinese fir plantation and moso bamboo forest,however, the primary zonal community,such as evergreen broadleaf forest,has remained to be secondary woods in declining odd pieces.Two new concepts have been introduced for the division of the forest condition:1.naturality──the distance from vegetation site to the virgin climax community i.e.the stage of successive process for secondary natural community under human disturbance or the proportion of natural components for artificial and semiartificial community which is divided into 5 classes in total.2.managerial intensivity——the intensive level of management of natural and artificial communities which shows the degree of effect due to managing behavior(5l evels in total).Combining with relevant maps, the evaluation has been made in 2 forestfarms by naturality and managerial intensivity.32.26% of the total area is well-managed,but 1/4 of the total forest is poorer.The natural forest accounts for 35.99%of the total beloging to the forest of low managerial intensity level(=2).
The vegetation in Dagang Mountain,Jiangxi Province was investigated using the method of quadrate and plotless sampling.Main types of vegetation can be classified as tollows:evergreenchinkapin and phoebe forest;theropencedrymion; bamboo and broadleaf mixed forest;Chinese fir plantation;montane meadow.Main forest stands in that area are Chinese fir plantation and moso bamboo forest,however, the primary zonal community,such as evergreen broadleaf forest,has remained to be secondary woods in declining odd pieces.Two new concepts have been introduced for the division of the forest condition:1.naturality──the distance from vegetation site to the virgin climax community i.e.the stage of successive process for secondary natural community under human disturbance or the proportion of natural components for artificial and semiartificial community which is divided into 5 classes in total.2.managerial intensivity——the intensive level of management of natural and artificial communities which shows the degree of effect due to managing behavior(5l evels in total).Combining with relevant maps, the evaluation has been made in 2 forestfarms by naturality and managerial intensivity.32.26% of the total area is well-managed,but 1/4 of the total forest is poorer.The natural forest accounts for 35.99%of the total beloging to the forest of low managerial intensity level(=2).
1994, 7(3): 294-300.
Abstract:
The relationships between the phenology of fifteen tree species grown in the Tropical Arboretum at Jianfengling of Hainan Island and some meteorological factors such as temperature,rainfall,sunshine,etc.were analyzed by using the multivariate statistical analvsis.Results showed that the most important meteorological factors influencing the phenological periods of the tree species were mean daily temperature,rainfall and mean daily sunshine.Through using the clustering analysis,the leaf expansion period,the flowering period,the fruit maturing period and the leaf discoloring period were divided into four types respectively.
The relationships between the phenology of fifteen tree species grown in the Tropical Arboretum at Jianfengling of Hainan Island and some meteorological factors such as temperature,rainfall,sunshine,etc.were analyzed by using the multivariate statistical analvsis.Results showed that the most important meteorological factors influencing the phenological periods of the tree species were mean daily temperature,rainfall and mean daily sunshine.Through using the clustering analysis,the leaf expansion period,the flowering period,the fruit maturing period and the leaf discoloring period were divided into four types respectively.
1994, 7(3): 301-305.
Abstract:
There have been many reports published on the introduction and cultivation of Leucaena leucocephala(Lam.)de Wit,but there has been no the report on its ecoadaptation.In this paper,introduced L.leucocephala from 11 provenances were collected and cultvated in Jingdong County,Yunnan Province in 1990.The results indicated that the ecoadaptability of this tree species was comparatively high, and among them,Mengla,Yuanmou,Yuanjiang grew best,the east Pulau Java K×1,K×3C showed strong hybrid vigor.The study has provided scientific basis for popularizing the cultivation of L.leucocephala in the tropical and southern subtropical zones of our country.
There have been many reports published on the introduction and cultivation of Leucaena leucocephala(Lam.)de Wit,but there has been no the report on its ecoadaptation.In this paper,introduced L.leucocephala from 11 provenances were collected and cultvated in Jingdong County,Yunnan Province in 1990.The results indicated that the ecoadaptability of this tree species was comparatively high, and among them,Mengla,Yuanmou,Yuanjiang grew best,the east Pulau Java K×1,K×3C showed strong hybrid vigor.The study has provided scientific basis for popularizing the cultivation of L.leucocephala in the tropical and southern subtropical zones of our country.
1994, 7(3): 306-310.
Abstract:
The seedling growth increment,nodulation increment and nitrogen fixationactivity of Myrica rubra(Lour)Sieb et Zucc cultured in four kinds of soil have been measured.The result is A:garden soilB:red soil+sand(proportion 2:1)C:sand+gardensoil(proportion 10 :1)D:red soil.Three testing factors mentioned above for A are 31.687 g/plant,1.789y/plant and 3.420μmol C2H4/(g fresh nodules·h)respectively;for B:20.501 g/plant,1.638g/plant and 3.252 μmol C2H4/(g fresh nodules·h);for C:18.327g/plant,6.654g/plant and 1.973μmol C2H4/(g fresh nodules·h);for D:8.322g/plant,0.333 g/plant and 1.315 μmol C2H4/(g fresh nodules·h).When applying lime (CaO),15g/pot,in the red soil to adjust its pH in the range of 5.4～6.0, the seedling growth,nodulation and nitrogen fixation activity are the highest,they are 18.524 g/plant,1.182 g/plantand 2.524μmol C2H4/(g fresh nodules·h)respectively.Sufficient water supplement is alsoimportant,especially for nodulation increment which rises to 3.519 g/plant;The seasonaldynamic curve shows that there are two peaks in a year for nodule nitrogen fixing activity,one is in June and the other is in October,January is the lowest period.There are also twopeaks for the daily variation of nodule nitrogen fixing activity,one is at noon,the other inthe midnight.
The seedling growth increment,nodulation increment and nitrogen fixationactivity of Myrica rubra(Lour)Sieb et Zucc cultured in four kinds of soil have been measured.The result is A:garden soilB:red soil+sand(proportion 2:1)C:sand+gardensoil(proportion 10 :1)D:red soil.Three testing factors mentioned above for A are 31.687 g/plant,1.789y/plant and 3.420μmol C2H4/(g fresh nodules·h)respectively;for B:20.501 g/plant,1.638g/plant and 3.252 μmol C2H4/(g fresh nodules·h);for C:18.327g/plant,6.654g/plant and 1.973μmol C2H4/(g fresh nodules·h);for D:8.322g/plant,0.333 g/plant and 1.315 μmol C2H4/(g fresh nodules·h).When applying lime (CaO),15g/pot,in the red soil to adjust its pH in the range of 5.4～6.0, the seedling growth,nodulation and nitrogen fixation activity are the highest,they are 18.524 g/plant,1.182 g/plantand 2.524μmol C2H4/(g fresh nodules·h)respectively.Sufficient water supplement is alsoimportant,especially for nodulation increment which rises to 3.519 g/plant;The seasonaldynamic curve shows that there are two peaks in a year for nodule nitrogen fixing activity,one is in June and the other is in October,January is the lowest period.There are also twopeaks for the daily variation of nodule nitrogen fixing activity,one is at noon,the other inthe midnight.
1994, 7(3): 313-318.
Abstract:
The acarid Asetacus cunninghamiae Kuang heavily damaged Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]in the juvenile stand of Wuyi, Jinhua and othercounties of Zhejiang Povince.To control the pest,seven insecticides were tested in laboratory and field,five of them(dicofol,omethoate,fembutatin oxide,amitraz,danjiamei)hadgood effects.Fenbutatin oxide(1:2000)was used to control the acarid in the large forestarea.The mortality reached 88.6%and the cost was 24.89 RMB yuan/hm2.
The acarid Asetacus cunninghamiae Kuang heavily damaged Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]in the juvenile stand of Wuyi, Jinhua and othercounties of Zhejiang Povince.To control the pest,seven insecticides were tested in laboratory and field,five of them(dicofol,omethoate,fembutatin oxide,amitraz,danjiamei)hadgood effects.Fenbutatin oxide(1:2000)was used to control the acarid in the large forestarea.The mortality reached 88.6%and the cost was 24.89 RMB yuan/hm2.
1994, 7(3): 319-324.
Abstract:
This paper reviews the types of rooting inhibitor G and grandinol,their distribution and content in Eucalyptus plants.The inhibiting effects of G and grandinol on therooting of Eucalyptus and othef plants,on the germination of seeds,and on the photosynthesis of leaves,the regulating effect of G and grandinol on the openness and closure of plantstomata,and the auxin-like function of G and grandinol,are discribed.The seperation and pu-rification methods of G and grandinol are also discribed.
This paper reviews the types of rooting inhibitor G and grandinol,their distribution and content in Eucalyptus plants.The inhibiting effects of G and grandinol on therooting of Eucalyptus and othef plants,on the germination of seeds,and on the photosynthesis of leaves,the regulating effect of G and grandinol on the openness and closure of plantstomata,and the auxin-like function of G and grandinol,are discribed.The seperation and pu-rification methods of G and grandinol are also discribed.
1994, 7(3): 325-329.
Abstract:
Yunnan is a mountainous province, which is rich in living matter resources,but a lat of then are nat reasonably exploited for geographical or historical reasons.One ofthem is lac resources.Based upon investigations on lac production of the past and current situations,the authorhas sunimarized and expounded 5 superiorities of lac exploitation in this province,namely,1.favourable natural circumstances and suitable climatic conditions;2.vast lands suitable forlac cultivation;3.rich host plants for lac insects;4.masses in lac producing areas know wellthe practice techniques and posses rich production experiences;5.initiativeness of the mountaineers.Besides,the author has put forward some concrete suggestions to improve lac production in this province.
Yunnan is a mountainous province, which is rich in living matter resources,but a lat of then are nat reasonably exploited for geographical or historical reasons.One ofthem is lac resources.Based upon investigations on lac production of the past and current situations,the authorhas sunimarized and expounded 5 superiorities of lac exploitation in this province,namely,1.favourable natural circumstances and suitable climatic conditions;2.vast lands suitable forlac cultivation;3.rich host plants for lac insects;4.masses in lac producing areas know wellthe practice techniques and posses rich production experiences;5.initiativeness of the mountaineers.Besides,the author has put forward some concrete suggestions to improve lac production in this province.
1994, 7(3): 330-333.
Abstract:
Complex nitrophenol sodium(CNS)(2% aqueous agent)is a new kind ofplant growth regulator.The results of three trials with CNS(cutting soaking,spraying andirrigation)showed that it could significantly increase the growth of poplar cuttings i.e.theheight increased by 5.3%～11.2% and the ground diameter 5.7%～19%.The effective concentration of CNS for poplar was 4～10 ppm.
Complex nitrophenol sodium(CNS)(2% aqueous agent)is a new kind ofplant growth regulator.The results of three trials with CNS(cutting soaking,spraying andirrigation)showed that it could significantly increase the growth of poplar cuttings i.e.theheight increased by 5.3%～11.2% and the ground diameter 5.7%～19%.The effective concentration of CNS for poplar was 4～10 ppm.
1994, 7(3): 334-336.
Abstract:
Zizyphus mauritiana(Lam.)is an important host plant for the exotic species of lac insect,Kerria sindica Mahd..Seeds of the trees taken from 5 districts in Yunnan Province,China and Narkum,Burma were used in the experiment and the result shows that there is a close relationship between their characters,germination and growth patterns of the seedlings and young trees and their geographical distribution and climatic condition.These would provide scientific basis for the distribution boundary and classification of the climatic ecotypes,and would be helpful for choosing better forms of the tree.
Zizyphus mauritiana(Lam.)is an important host plant for the exotic species of lac insect,Kerria sindica Mahd..Seeds of the trees taken from 5 districts in Yunnan Province,China and Narkum,Burma were used in the experiment and the result shows that there is a close relationship between their characters,germination and growth patterns of the seedlings and young trees and their geographical distribution and climatic condition.These would provide scientific basis for the distribution boundary and classification of the climatic ecotypes,and would be helpful for choosing better forms of the tree.
1994, 7(3): 337-341.
Abstract:
ln this paper,a new singletree competition measure──Relative Effective Crown Ratio(RECR),which is independent of distance,is put forward,based on the sunnedeffective crown and the relationship between the sunned effective crown diameter and the DBH of trees in Larix principis-rupprechii stands of different densities in Saihanba Forest Farm,Heibei Province.This measure,which is the ratio of the sunned effective crown diameter of the tree in the stand to that of the open-grown tree with the same DBH,mav be usedin many aspects in even-aged stands,such as the stand growth dynamic prognosis,stand density control and management etc.
ln this paper,a new singletree competition measure──Relative Effective Crown Ratio(RECR),which is independent of distance,is put forward,based on the sunnedeffective crown and the relationship between the sunned effective crown diameter and the DBH of trees in Larix principis-rupprechii stands of different densities in Saihanba Forest Farm,Heibei Province.This measure,which is the ratio of the sunned effective crown diameter of the tree in the stand to that of the open-grown tree with the same DBH,mav be usedin many aspects in even-aged stands,such as the stand growth dynamic prognosis,stand density control and management etc.
1994, 7(3): 342-345.
Abstract:
Investigating method on density estimation for the pine caterpillar Dendrolimus punctatus through counting larvae on short pine trees was studied.The resultssliowed that the criterion for tall and short trees is 2.5m.The estimation of pest density inthe crown project area(larvae/m2) is not affected by forest stand conditions.When proportion of short trees is more than 40%, there is no significant differences between pest densityof tall trees and that of short trees.It's indicated that the estimation of pest density in thecrown project area (larvae/m2)is much better than that by larvae per tree.
Investigating method on density estimation for the pine caterpillar Dendrolimus punctatus through counting larvae on short pine trees was studied.The resultssliowed that the criterion for tall and short trees is 2.5m.The estimation of pest density inthe crown project area(larvae/m2) is not affected by forest stand conditions.When proportion of short trees is more than 40%, there is no significant differences between pest densityof tall trees and that of short trees.It's indicated that the estimation of pest density in thecrown project area (larvae/m2)is much better than that by larvae per tree.
1994, 7(3): 346-350.
Abstract:
Dinerent tree species,parent rock,soil,stand age,and snow injury are thefive factors that affect the occurrence rate of shoot dieback of exotic pines.The degree ofinfluence of these factors in terms of partial correlation coefficients follows the descending sequence respectively,Tree species,parent rock,soil,stand age and planting quality compre-hensively affect the damage degree of the shoot dieback in terms of partial correlation coefficients being in the descending sequence respectively The composite correlation coefficient ofeach factor with the occurrence rate is 0.838 209 8.The composite correlation coefficient ofeach factor with the severity degree is 0.8687435.
Dinerent tree species,parent rock,soil,stand age,and snow injury are thefive factors that affect the occurrence rate of shoot dieback of exotic pines.The degree ofinfluence of these factors in terms of partial correlation coefficients follows the descending sequence respectively,Tree species,parent rock,soil,stand age and planting quality compre-hensively affect the damage degree of the shoot dieback in terms of partial correlation coefficients being in the descending sequence respectively The composite correlation coefficient ofeach factor with the occurrence rate is 0.838 209 8.The composite correlation coefficient ofeach factor with the severity degree is 0.8687435.
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