1992 Vol. 5, No. 5
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1992, 5(5): 497-505.
[Abstract]
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Abstract:
Nutrient input from throughfall and its loss through the runoff of three small watersheds covered by Phyllostachys pubescent stands were monitered for study on nutrient cycling in southern China during the period from 1986 to 1989. Results indicate that the concentration and the amount of nutrients from throughfall are close relative to the throughfall amount, and show an obvious seasonal variation. The relative abundance of nutrient from throughfall is K+Ca2+Mg2+NH4+-NNO3--NPO43-. The dynamics of the amount of nutrients lost through the run-off in the small watershed correspond to the seasonal variation of the run-off amount. The relative abundance of nutrients of run-off is K+Mg2+NH4+-N plus NO3--NPO43-. Besides the amount of throughfall and run-off, the bamboo growth character, soil microbial activity and human being measures are the main factors which affect the inputs and outputs of nutrients in a bamboo ecosystem. The GM (1,1) model for predicting the K input amount with throughfall in a year at Miaoshanwu experimental site has been established.
Nutrient input from throughfall and its loss through the runoff of three small watersheds covered by Phyllostachys pubescent stands were monitered for study on nutrient cycling in southern China during the period from 1986 to 1989. Results indicate that the concentration and the amount of nutrients from throughfall are close relative to the throughfall amount, and show an obvious seasonal variation. The relative abundance of nutrient from throughfall is K+Ca2+Mg2+NH4+-NNO3--NPO43-. The dynamics of the amount of nutrients lost through the run-off in the small watershed correspond to the seasonal variation of the run-off amount. The relative abundance of nutrients of run-off is K+Mg2+NH4+-N plus NO3--NPO43-. Besides the amount of throughfall and run-off, the bamboo growth character, soil microbial activity and human being measures are the main factors which affect the inputs and outputs of nutrients in a bamboo ecosystem. The GM (1,1) model for predicting the K input amount with throughfall in a year at Miaoshanwu experimental site has been established.
1992, 5(5): 506-511.
Abstract:
31 clones of Metasequoia glyptostroboides have been tested at two sites in Huanggang Region, Hubei Province for 12 years. The main trial consists of three randomized complete block with row plot. The results of variance analysis at the age of 12 year-old showed that there are significant differences in growth traits and crown shape among clones and the clones of inherent rapid growth could be characterized at early stage in field by planting grafts. Correlated responses to selection suggested that the fourth or fifth year would be the appropriate time to select according to the height growth. The tree breeders have embraced testing and selection at early ages in clonal breeding.
31 clones of Metasequoia glyptostroboides have been tested at two sites in Huanggang Region, Hubei Province for 12 years. The main trial consists of three randomized complete block with row plot. The results of variance analysis at the age of 12 year-old showed that there are significant differences in growth traits and crown shape among clones and the clones of inherent rapid growth could be characterized at early stage in field by planting grafts. Correlated responses to selection suggested that the fourth or fifth year would be the appropriate time to select according to the height growth. The tree breeders have embraced testing and selection at early ages in clonal breeding.
1992, 5(5): 512-517.
Abstract:
In the autumn of 1989, plot investigation and statistics analysis were used to study the variation of tree type, branching ability, thorn, fruit color, fruit shape, fruit weight etc. features of the Chinese Hippophae in Chaizhuogou Region, Guandishan, Shanxi Province. The interrelationship between the economic features and the match condition, distribution type and characteristics of population phenotype structure of the main features have been discussed. The results indicated that the Chinese Hippophae there is mainly a multitype population system, whose plants bear fruits of orange color and are nearly round in shape. Its hundred-fruit weightis is bigger and has a high fruit yield. Guandishan Region can be selected as a candidate base for collecting seeds for eco-economic cultivation.
In the autumn of 1989, plot investigation and statistics analysis were used to study the variation of tree type, branching ability, thorn, fruit color, fruit shape, fruit weight etc. features of the Chinese Hippophae in Chaizhuogou Region, Guandishan, Shanxi Province. The interrelationship between the economic features and the match condition, distribution type and characteristics of population phenotype structure of the main features have been discussed. The results indicated that the Chinese Hippophae there is mainly a multitype population system, whose plants bear fruits of orange color and are nearly round in shape. Its hundred-fruit weightis is bigger and has a high fruit yield. Guandishan Region can be selected as a candidate base for collecting seeds for eco-economic cultivation.
1992, 5(5): 518-523.
Abstract:
The genetic variation and genetic correlation on the main growth characters of height, diameter, volume and H/D of trees were analysed according to the data collected from 14 open-pollination progenies at seedling and juvenile stages from an elementary seed orchard of Pinus elliottii Engelm. The results of the test indicated that there were significant differences in the growth characters at the seedling and juvenile stages among the families, which were moderate or strong hereditary; there were close positive correlations in the height and diameter of all of the families among different years and the genetic correlations between the growth characters were also significant; the interaction between family and location was not significant; the volume-growth of three families which grow the fastest increased by 49.50% as compared with that of the check, and 26.37% could be reached in the genetic gain; three families of Pinus elliottii Engelm with fast growth and higher quality were selected through the comprehensive evaluation of their growths and qualities by the Index Selection Method.
The genetic variation and genetic correlation on the main growth characters of height, diameter, volume and H/D of trees were analysed according to the data collected from 14 open-pollination progenies at seedling and juvenile stages from an elementary seed orchard of Pinus elliottii Engelm. The results of the test indicated that there were significant differences in the growth characters at the seedling and juvenile stages among the families, which were moderate or strong hereditary; there were close positive correlations in the height and diameter of all of the families among different years and the genetic correlations between the growth characters were also significant; the interaction between family and location was not significant; the volume-growth of three families which grow the fastest increased by 49.50% as compared with that of the check, and 26.37% could be reached in the genetic gain; three families of Pinus elliottii Engelm with fast growth and higher quality were selected through the comprehensive evaluation of their growths and qualities by the Index Selection Method.
1992, 5(5): 524-530.
Abstract:
Genotypic stability and grown adaptability of 11 clones of Paulcwnia that were six years old at five site were analysed using both of Eberhart-Russell model and Tai's structural model. Variance analysis indicated that the clone effect, site effect and clone x site interaction effect are great significant. Grown adaptability and genotypic stability indexes of paulownia clones were estimated using the regression coefficient (b) and deviation from regression mean square (Sd2) of E & R model, the structural analysis parameters â and λ of Tai's model. The results for analysis of stability and adaptability from two ways are similar.Clones were evaluated based on the genotypic stability and grown adaptability.
Genotypic stability and grown adaptability of 11 clones of Paulcwnia that were six years old at five site were analysed using both of Eberhart-Russell model and Tai's structural model. Variance analysis indicated that the clone effect, site effect and clone x site interaction effect are great significant. Grown adaptability and genotypic stability indexes of paulownia clones were estimated using the regression coefficient (b) and deviation from regression mean square (Sd2) of E & R model, the structural analysis parameters â and λ of Tai's model. The results for analysis of stability and adaptability from two ways are similar.Clones were evaluated based on the genotypic stability and grown adaptability.
1992, 5(5): 531-535.
Abstract:
The plantlets vitro-propagated were grafted on to 4-week young walnut seedling rootstocks. The procedure of micro-grafting has been developed. In micro-grafting could have several advantages: A large number of scions of new walnut cultivars could be vitro multiplicated in one year; after transplanting, the young grafted plants with a strong rootsystem of seedling rootstock grow more vigorously than self-rooted walnut trees by vitro propagation.
The plantlets vitro-propagated were grafted on to 4-week young walnut seedling rootstocks. The procedure of micro-grafting has been developed. In micro-grafting could have several advantages: A large number of scions of new walnut cultivars could be vitro multiplicated in one year; after transplanting, the young grafted plants with a strong rootsystem of seedling rootstock grow more vigorously than self-rooted walnut trees by vitro propagation.
1992, 5(5): 536-541.
Abstract:
Based on the data collected from the fixed sample plots distributed regularly on 200 ha of Phyllostachys pubescens stand in Fenyi County, Jiangxi Province, an appraisal on the relationship between every two year yields of culms and shoots and the productiveness factors, such as stand structure,site and management level, were obtained by means of quantitative theory I. It showed that stand density, soil type, dome direction and management level were the leading factors which made remarkable impact on the stand for harvesting culms and shoots; the maximun yield of culms and shoots were produced by the stand composed of a high stand density, a wide mean eyebrow diameter and a young age average, situated in the southern or southeastern slope of 25~35 degrees where there was a soil depth of more than 80 cm and cultivated by intensive management method.
Based on the data collected from the fixed sample plots distributed regularly on 200 ha of Phyllostachys pubescens stand in Fenyi County, Jiangxi Province, an appraisal on the relationship between every two year yields of culms and shoots and the productiveness factors, such as stand structure,site and management level, were obtained by means of quantitative theory I. It showed that stand density, soil type, dome direction and management level were the leading factors which made remarkable impact on the stand for harvesting culms and shoots; the maximun yield of culms and shoots were produced by the stand composed of a high stand density, a wide mean eyebrow diameter and a young age average, situated in the southern or southeastern slope of 25~35 degrees where there was a soil depth of more than 80 cm and cultivated by intensive management method.
1992, 5(5): 542-547.
Abstract:
A maximum volume yield model, which takes site and age as the interpreting variables, was established on the basis of 88 experimental plots of Pinus tabulaeformis in Taihangsan Area. Improved Chapman-Richards function, nonlinear least squares method and method of improved parallel line were used to construct the model. It supplies a function for site quality evaluation using index of volume and forest production.
A maximum volume yield model, which takes site and age as the interpreting variables, was established on the basis of 88 experimental plots of Pinus tabulaeformis in Taihangsan Area. Improved Chapman-Richards function, nonlinear least squares method and method of improved parallel line were used to construct the model. It supplies a function for site quality evaluation using index of volume and forest production.
1992, 5(5): 548-553.
Abstract:
In this paper, regularity on the change of moisture content of forest inflammable materials in relation with forest fire was studied through the measurement of forest moisture content and observation on the forest microclimate. Studies were conducted in 5 types of forest colonies: oak stand, aspen stand, hard broadleaf stand, larch plantation and forest land with mosses. Besides, the data from the local standard weather stations were also used for comparison for variance analysis. Based on the results, possibility and methods for prognosis of forest fire danger by means of meterological data from the local weather stations were discussed.
In this paper, regularity on the change of moisture content of forest inflammable materials in relation with forest fire was studied through the measurement of forest moisture content and observation on the forest microclimate. Studies were conducted in 5 types of forest colonies: oak stand, aspen stand, hard broadleaf stand, larch plantation and forest land with mosses. Besides, the data from the local standard weather stations were also used for comparison for variance analysis. Based on the results, possibility and methods for prognosis of forest fire danger by means of meterological data from the local weather stations were discussed.
1992, 5(5): 554-558.
Abstract:
The Du-ensiform gall caused by Kaburagia rhusicola is one of the Chinese gallnuts. In their whole life history they undergo following stages in order of seasons: the males and the females, fundatrix, wingless and winged fundatrigeniae on the first host (tree), Rhus potaninii, on which the galls are formed; and wingless aliencolae, winged sexuparae on the second host(moss), Erythrodontium leptothallum. Among the progeny of the same generation of fundatrix, some of them completed a life cycle in a year, some in two years, perhaps some in more than two years. The aphids live in a gall for about three months. The migration from the second hosts to the first hosts occur in spring and from the first hosts to the second hosts in the late summer. No diapause or dormancy can be found in the aphid's life history.
The Du-ensiform gall caused by Kaburagia rhusicola is one of the Chinese gallnuts. In their whole life history they undergo following stages in order of seasons: the males and the females, fundatrix, wingless and winged fundatrigeniae on the first host (tree), Rhus potaninii, on which the galls are formed; and wingless aliencolae, winged sexuparae on the second host(moss), Erythrodontium leptothallum. Among the progeny of the same generation of fundatrix, some of them completed a life cycle in a year, some in two years, perhaps some in more than two years. The aphids live in a gall for about three months. The migration from the second hosts to the first hosts occur in spring and from the first hosts to the second hosts in the late summer. No diapause or dormancy can be found in the aphid's life history.
1992, 5(5): 559-564.
Abstract:
The insecticide-tolerance of Dendrolimus punctatus Walker to fenvalerate was studied in Jiangshu Province through bioassay and the methods of physiology & biochemistry. The results showed that:(1) The insecticide tolerance to fenvalerate increased with the increase of instars and it was 37 times in the 6th instar larvae more than that of the 3rd instar; (2) The resistance to fenvalerate and deltamethrin had not formed yet in Tongshan colony; (3) The activity of carboxyesterase increased gradually with the increase of instars and was greater in Tongshan colony than that in Maoshan colony; (4) The results of dipping and injection showed less difference between the Tongshan and Maoshan colony. The dynamic study on pesticide-penetrating-cuticula of Tongshan colony showed that 43.3% fenvaleratc did not entered cuticula, and that 1.8% fenvalerate remained in integument 8 hours after dipping the larvae.
The insecticide-tolerance of Dendrolimus punctatus Walker to fenvalerate was studied in Jiangshu Province through bioassay and the methods of physiology & biochemistry. The results showed that:(1) The insecticide tolerance to fenvalerate increased with the increase of instars and it was 37 times in the 6th instar larvae more than that of the 3rd instar; (2) The resistance to fenvalerate and deltamethrin had not formed yet in Tongshan colony; (3) The activity of carboxyesterase increased gradually with the increase of instars and was greater in Tongshan colony than that in Maoshan colony; (4) The results of dipping and injection showed less difference between the Tongshan and Maoshan colony. The dynamic study on pesticide-penetrating-cuticula of Tongshan colony showed that 43.3% fenvaleratc did not entered cuticula, and that 1.8% fenvalerate remained in integument 8 hours after dipping the larvae.
1992, 5(5): 565-569.
Abstract:
Studies in the Burgen River Beaver Researve in 1989 stated that the beavers always selected places with depth of around 137cm of the water and height of around 101 cm of the bank with abundant trees to dig burrows and build lodges. Stand density, water and topographic conditions were the primary factors determining the fitness of a habitat. The average home range of a beaver colony was 1.2km along the river, containing 22 burrows and lodges which showed clumped distribution pattern and concentrated near the overwintering burrow (or lodge). It's concluded that the clumped trees is the main reason resulting in the clumped burrows and lodges. The area concentrated with burrows and lodges near the overwintering burrow is the territory of a beaver colony averaging 480 m along the river. The beaver's carrying capacity is about one colony per kilometer along the river. Stand density is the limiting factor of the beavers.
Studies in the Burgen River Beaver Researve in 1989 stated that the beavers always selected places with depth of around 137cm of the water and height of around 101 cm of the bank with abundant trees to dig burrows and build lodges. Stand density, water and topographic conditions were the primary factors determining the fitness of a habitat. The average home range of a beaver colony was 1.2km along the river, containing 22 burrows and lodges which showed clumped distribution pattern and concentrated near the overwintering burrow (or lodge). It's concluded that the clumped trees is the main reason resulting in the clumped burrows and lodges. The area concentrated with burrows and lodges near the overwintering burrow is the territory of a beaver colony averaging 480 m along the river. The beaver's carrying capacity is about one colony per kilometer along the river. Stand density is the limiting factor of the beavers.
1992, 5(5): 570-573.
Abstract:
This paper expounds the relations of outbreak of forest insects in the Jianfengling forest area to natural enemy of parasitic insects, tree introduction, unsuitable tending and thinning, altitude, typhoon, man-made mixed forest and resistance of broad-leaved tree to insects. It is useful for further research.
This paper expounds the relations of outbreak of forest insects in the Jianfengling forest area to natural enemy of parasitic insects, tree introduction, unsuitable tending and thinning, altitude, typhoon, man-made mixed forest and resistance of broad-leaved tree to insects. It is useful for further research.
1992, 5(5): 574-580.
Abstract:
Beginning with an statement of existing problems in eucalyptus tree improvement in South China, this paper discusses some issues relating breeding strategies, breeding plans, hybrid utilization, seed production bases and clonal forestry in accordance with their biological characteristics. It is also pointed out that the success of genetic improvement program depends on the correct breeding strategies and a complete breeding plan. The major tasks of the tree breeders, therefore, are to enhance the management of genetic resources and to further complete and replenish the breeding population. Starting from the overall interests of the whole society, while expending the breeding population and improving the genetic character, the tree breeders must pay attention to supplying mass plantation with high quality planting stocks.
Beginning with an statement of existing problems in eucalyptus tree improvement in South China, this paper discusses some issues relating breeding strategies, breeding plans, hybrid utilization, seed production bases and clonal forestry in accordance with their biological characteristics. It is also pointed out that the success of genetic improvement program depends on the correct breeding strategies and a complete breeding plan. The major tasks of the tree breeders, therefore, are to enhance the management of genetic resources and to further complete and replenish the breeding population. Starting from the overall interests of the whole society, while expending the breeding population and improving the genetic character, the tree breeders must pay attention to supplying mass plantation with high quality planting stocks.
1992, 5(5): 581-583.
Abstract:
Considering the food habit of Ericerus pela (Chavannes), specialists and researchers at home and abroad believe it is a limited or oligop-hagous feeder. However, on the basis of the former researches in this field, we have done further researches in China and found out that this is not true. Our investigations have revealed that E. pela lives on 45 species of host plants which belong to 9 genuses of 6 families: Ligustrum, Fraxinus, Syringa and ChionanthusM of Oleaceae; Castanopsis of Fagaceae; Hibiscus of Malvaceae; Vitex of Verbenaceae; Rhus of Anacardiaceae and Ilex of Aquif-oliaceae. According to this, we think E. pela to be a generalized or euryp-hagous feeder. The application of the term oligophagy to it is not resonable and should be corrected. As a scientific breakthrough, our discovery is of great significance to the development of white wax production in China.
Considering the food habit of Ericerus pela (Chavannes), specialists and researchers at home and abroad believe it is a limited or oligop-hagous feeder. However, on the basis of the former researches in this field, we have done further researches in China and found out that this is not true. Our investigations have revealed that E. pela lives on 45 species of host plants which belong to 9 genuses of 6 families: Ligustrum, Fraxinus, Syringa and ChionanthusM of Oleaceae; Castanopsis of Fagaceae; Hibiscus of Malvaceae; Vitex of Verbenaceae; Rhus of Anacardiaceae and Ilex of Aquif-oliaceae. According to this, we think E. pela to be a generalized or euryp-hagous feeder. The application of the term oligophagy to it is not resonable and should be corrected. As a scientific breakthrough, our discovery is of great significance to the development of white wax production in China.
1992, 5(5): 584-588.
Abstract:
Samplings were conducted continually in large area (more than G5 hectares) from 1981~1989, the life table of 22 generations of pine caterpillar, Dendrolimus punctatus has been established. The sampled forest is typical in Anhui. From this life table, a life systematical model has been worked out. From the model, it can be seen that there are three key periods in population dynamics and that three submodels have been obtained. The key factors in population dynamics are original population density, feeding conditions, the weight of female pupae and sex ratio. The only climatic factor that affects population dynamics is the average relative humidity (%) in September. The sampling method used is in accordance with the method used in forest production. It is believed that this systematical model is practical in pest management, because no artificial simulation has been used in sampling and so the artificial influence has been eliminated.
Samplings were conducted continually in large area (more than G5 hectares) from 1981~1989, the life table of 22 generations of pine caterpillar, Dendrolimus punctatus has been established. The sampled forest is typical in Anhui. From this life table, a life systematical model has been worked out. From the model, it can be seen that there are three key periods in population dynamics and that three submodels have been obtained. The key factors in population dynamics are original population density, feeding conditions, the weight of female pupae and sex ratio. The only climatic factor that affects population dynamics is the average relative humidity (%) in September. The sampling method used is in accordance with the method used in forest production. It is believed that this systematical model is practical in pest management, because no artificial simulation has been used in sampling and so the artificial influence has been eliminated.
1992, 5(5): 589-594.
Abstract:
On the basis of investigation in the forest of Larix gmelinii in Mohe forest area, we realized that the distribution of the forest types is selected correctly. The sample plots are ordinated by means of principal component analysis (PCA). According to Fisher test analysis, the classification were recognized as justified. The research result shows that distribution of forest types is influenced by the situation of slope which is the most important factor. Secondly, aspest, gradient, soil moisture and depth of soil layer are also important factors. The interaction between topographic factor and soil condition affects the distribution pattern of forest types.
On the basis of investigation in the forest of Larix gmelinii in Mohe forest area, we realized that the distribution of the forest types is selected correctly. The sample plots are ordinated by means of principal component analysis (PCA). According to Fisher test analysis, the classification were recognized as justified. The research result shows that distribution of forest types is influenced by the situation of slope which is the most important factor. Secondly, aspest, gradient, soil moisture and depth of soil layer are also important factors. The interaction between topographic factor and soil condition affects the distribution pattern of forest types.
1992, 5(5): 595-600.
Abstract:
In order to select the best provenance of Eucalyptus camaldulensis and provide with the fine seeds for production in Hunan Province, the experiment on E. camaldulensis provenance was made in Spring 1988, with 13 provenances, among which 10 were from Australia, i. e. 15029, 17297, 15441, 13703, 14106, 15223, 15052, 15050, 13941, 15235, and 3 were from local, i. e. 1 from Sichuan, Yunan and Jiangxi respectively. Based on the statistic analysis of 3.5 years' observation, a preliminary appraisal on the growth, cold-tolerance, disease-resistance and stem quality of the young trees was conducted. It indicates that the seed lot No.15223, 15052 and the seeds from Sichuan Province (Dukou) are better in terms of various characteristics, which could be used in middle experiment and in extension while the others used particularly in tree improvement.
In order to select the best provenance of Eucalyptus camaldulensis and provide with the fine seeds for production in Hunan Province, the experiment on E. camaldulensis provenance was made in Spring 1988, with 13 provenances, among which 10 were from Australia, i. e. 15029, 17297, 15441, 13703, 14106, 15223, 15052, 15050, 13941, 15235, and 3 were from local, i. e. 1 from Sichuan, Yunan and Jiangxi respectively. Based on the statistic analysis of 3.5 years' observation, a preliminary appraisal on the growth, cold-tolerance, disease-resistance and stem quality of the young trees was conducted. It indicates that the seed lot No.15223, 15052 and the seeds from Sichuan Province (Dukou) are better in terms of various characteristics, which could be used in middle experiment and in extension while the others used particularly in tree improvement.
1992, 5(5): 601-605.
Abstract:
Twenty-eight Père David's deer (Elaphurus davidanus) in Da-feng Milu Reserve were immobilized with a new anaesthetic compound Miannaining (MNN) and antagonized by Suxingling No.4 (SXL-4). There was a significant difference in mean walk time between unexcited deer (5.03±1.99min) and excited ones (1.68±0.19 min).Some deer become recumbent again after antagonism, but no apparent adverse effects were found. We established a formula (DSI=(C-Dr)/-Dt) to compare the sensitive of Père David's deer to MNN between sex and ages. And formulated the following dosages of MNN for Père David's deer: excited adult males 0.8~1.0 ml/100 kg; adult females 1.2~1.4 ml/100 kg; juveniles 1.0-1.2ml/100kg, unexcited adult males 0.5~0.7ml/100 kg; adult females 0.6~0.8 ml/100 kg; juveniles 0.6~0.8 ml/100 kg. SXL-4 is giving intravenously at a dosage 1.5~2.0 times of MNN.
Twenty-eight Père David's deer (Elaphurus davidanus) in Da-feng Milu Reserve were immobilized with a new anaesthetic compound Miannaining (MNN) and antagonized by Suxingling No.4 (SXL-4). There was a significant difference in mean walk time between unexcited deer (5.03±1.99min) and excited ones (1.68±0.19 min).Some deer become recumbent again after antagonism, but no apparent adverse effects were found. We established a formula (DSI=(C-Dr)/-Dt) to compare the sensitive of Père David's deer to MNN between sex and ages. And formulated the following dosages of MNN for Père David's deer: excited adult males 0.8~1.0 ml/100 kg; adult females 1.2~1.4 ml/100 kg; juveniles 1.0-1.2ml/100kg, unexcited adult males 0.5~0.7ml/100 kg; adult females 0.6~0.8 ml/100 kg; juveniles 0.6~0.8 ml/100 kg. SXL-4 is giving intravenously at a dosage 1.5~2.0 times of MNN.
1992, 5(5): 606-610.
Abstract:
Studies on the cone yields from 3 Chinese Fir seed orchard (6~i3-years-old) showed that there are significant variations in different clones, trees or year. Variation in different year was the biggest, in a range of 62.95%~96.7%, variation in different clones was lower, in a range of0.93%~6.44%. The generalized genetic ability of fruit bearing of individual tree was 0.33, while that of different clone was 0.79. The clone which made up 90% of the total cone yield in orchard was 62.1%. The extreme difference of cone yield was 1.18-6.26 kg per tree and the variation coefficient was 47.16%~90.12%. The variation coefficient reduces gradually as the age increases. The average differences of the cone yield among trees in the same clone was 1.l2~5.09kg per tree. The mean variation coefficient was 54.73%-122.82%. The cone yield extreme difference among the year was great.
Studies on the cone yields from 3 Chinese Fir seed orchard (6~i3-years-old) showed that there are significant variations in different clones, trees or year. Variation in different year was the biggest, in a range of 62.95%~96.7%, variation in different clones was lower, in a range of0.93%~6.44%. The generalized genetic ability of fruit bearing of individual tree was 0.33, while that of different clone was 0.79. The clone which made up 90% of the total cone yield in orchard was 62.1%. The extreme difference of cone yield was 1.18-6.26 kg per tree and the variation coefficient was 47.16%~90.12%. The variation coefficient reduces gradually as the age increases. The average differences of the cone yield among trees in the same clone was 1.l2~5.09kg per tree. The mean variation coefficient was 54.73%-122.82%. The cone yield extreme difference among the year was great.
1992, 5(5): 611-616.
Abstract:
A study was conducted in a split plot design with three replications to investigate the effects of stump height and stand density on the sprout regeneration of 3-year-old Acacia auriculijormis at Yangjiang, Qionghai County (110°30'E, 18°14'N) of Hainan Province. Results showed that both the stump height and stand density had statistically significant effects on the number of sprouts produced per stump, and diameter (50 cm above the point of origin) and biomass production of sprout forests 19 months after cutting. The percentage of stump sprouting, and survival rate of stumps and length of sprouts 19 months after cutting were significantly influenced by stump height but not stand density. To maximize the biomass production of sprout forests of A. auriculiformis,a. stump height of 60 cm is recommended.
A study was conducted in a split plot design with three replications to investigate the effects of stump height and stand density on the sprout regeneration of 3-year-old Acacia auriculijormis at Yangjiang, Qionghai County (110°30'E, 18°14'N) of Hainan Province. Results showed that both the stump height and stand density had statistically significant effects on the number of sprouts produced per stump, and diameter (50 cm above the point of origin) and biomass production of sprout forests 19 months after cutting. The percentage of stump sprouting, and survival rate of stumps and length of sprouts 19 months after cutting were significantly influenced by stump height but not stand density. To maximize the biomass production of sprout forests of A. auriculiformis,a. stump height of 60 cm is recommended.
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