1995 Vol. 8, No. 5
Integrated whole stand growth and yield model(ISGM)is such a model that its estimate of growth is compatible with the estimate of yield.Any model like this can be used to predict the growth rate of the stand.The nominal age method which is based on ISGM and Marsh hypothesis is a good method to predict the net growth rate of the stand.The calculation approach of this method is stated step by step in this paper. This method has been used to estimate the growth rates of two tree species in Daqingshan Experimental Bureau and the result is promising. This method can get unbiased estimate of growth rates. Accuracy of this method for one type of stands is equivalent to the accuracy for investigating 1～4 permanent plots. Therefore,this method is suitable for estimating general growth rate of many types of stands in an area.
The research was conducted in 1989～1993 in Longhu Forest Farm of Shaowu City, Fujian Province. The randomized blocks design included eleven treatments and three repetitions. The main results were as follows:(1)The nutrient content in the leaves,roots and soil changes with different season or year,which is closely related to the growth characteristics and yield of bamboo forest;(2)The content of N,P and K in the leaves and roots reduces with the increase of their age. There were similar nutrient contents in the leaves of the same age;(3)In the shooting stage,the order of importance of N,P, K in leaves and soils were PN,but in spring the soil hydrolysable N was closely related to the output Qf shoots and clums. This study provides some theoretical basis for nutrient diagnosis and reasonable fertilization.
According to the special feature that two-stage cluster sampling has the same efficiency as the systematic sampling or simple random sampling when there are no differences among clusters,the term of error expansion factor is presented in this paper. Besides the correlation coefficient for critical state,when efficiency coefficient equals to l,is formulated,which provide important reference of implementing cluster sampling design and sampling efficiency assessment.In addition,the relationship between efficiency of two-stage cluster sampling and distance between plots in a cluster is further studied with an example demonstrated in detail.Finally,the efficiency assessment of two-stage cluster sampling in forest inventory is also discussed.
After the introduction of aridity-tolerant acacias from Australia to Luokeng area where there are serious water and soil erosion,the face of the barren hill has been obviously changed and the water and soil erosion was preliminarily controlled.As for the result of 3 years'trial,there are 9 species and 19 provenances better than others,such as A. concurrens 17141,A. auriculiformis 16355,16147,16484,A. flavescens 15481,14968,14590,A. leptocarpa 16110,15478,A. colei 17906,17050,A. holosericea 16643,15732,A. crassicarpa 91000,A. ampliceps 14668 and A. brassii 17718,15480,16134. These species and provenances have good adaptability to poor site,fast growth and high biomass. In the first planting year they can close the crown,produce lot of litters to'cover the land and play an important role in the water and soil conservation.
This paper reports a new species of the genus Nematus——N. prunivorous Xiao from China. It is injurious to Prunus armeniaca L. in Chunan County, Zhejiang Province. Female:Black with purpulish blue lustre. Antennae black or blackish brown;mandible black with blackish red teeth;lateral sides and center of supraclypeal area each with a pale part.Cenchri deep yellow;wing hyaline with apical part slightly infuscated;stigma black sometimes with a obsolete yellow spot on basal part;costa,basal part of anal vein blackish yellow;other veins black;leg black with apices of coxae,trochanters,basal parts of femora and tibiae yellowish white:tarsi blackish brown or black.Pubescence on head and thorax yellowish brown. Anterior margin of clypeus deeply imarginated,nearly arcuate;frontal carina distinct;median fovea round,small and shallow;lateral sutures deep;transverse and coronal sutures distinct;OOL:POL:OCL=1.1:1.0:1.1;antennal length about 2 2/3 times head width;head behind eye in dorsal view widened;Pubescence on clypeus and labrum long and dense.Lancet see fig.1-1. Head finely and sparsely punctate; mesonotum except for scutellum with fine and densepunctures;mesepisterum with very fine and sparse punctures, interspace between punctures1～2 times diameter of puncture;abdomen without punctures but wirh obliquely distributedsculptures. Body length 10 mm;relative lengths of antennal segments=1.7:1.0:7.9:8.1:7.8:5.9:5.8:5.2:5.3. Malk:color similar to female, but fore and median tibiae paler andyellow spot on basal part of stigma sometimes more distinct;OOL:POL:OCL=1.6:1.0:1.7;antennal length about 2 1/3 times head width;head behind eye in dorsal view not widened;Penis valve see fig.1-2.Pubescence on head, mesoscutum,mesepisterum coarse and dense,rugose;ab-dominal terga 4～8 with coarse punctures. Body length 9 mm;relative length of antennal segments=1.5:1.0:5.6:5.9:5.8:4.8:4.5:4.2:4.5.Other characters as for the female.
The results of a progeny trial of E. tereticornis involved 14 provenances and 100 open-pollinated families at age 32 months in western Guangdong Province showed that the growth differences among 14 provenances were highly significant while the growth differences among families were also highly significant.The most of better families were from QLD provenances 13659,16558,15826, 13544,and from PNG provenance 13398.The poor families were from NSW provenances 13308 and 13319.The volume of the best family Fam-51 from 1 km North of Laura QLD was 4.6 times larger than that of the poorest family Fam-33 from Sirinumu Sogeri PNG. The height growth,DBH,volume,stem form and current survival of E. tereticornis were highly significant and negatively correlated with the latitudeand longitude of its native habitat.The paper identifies 25 promising families suitable forplanting in the west of Guangdong Province.
This paper is a review of authors'research results on genetic improvement of pulp wood of masson pine. At fist the breeding objectives for pulp production of masson pine are defined,then the genetic variation,genetics,genetic correlation and stability of wood yield,wood quality and paper/pulp-making properties are discussed systematically,the optimum provenance zones and seed sources for pulp wood through comprehensive evaluation on wood yield,wood quality and paper/pulp-making properties were determined,finally a lot of families and individuals with high growth rate and good wood quality were selected.The selection strategy and future research emphasis of pulp wood breeding of masson pine is also discussed.
Research on effect of undergrowth in Chinese fir plantation on the soil properties in the 5～15 cm layer was conducted in the Dagang Mountain,Shan Xia Forest Farm,Jiangxi Province. The results show that the amount of bacteria,actinomycetes,fungi,bacillus spp in bacteria,grey hyphae in actinomycetes and trichoderma pers,ex Fr,Aspergillus in fungi increase with the increase of the undergrowth coverage, Soil enzyme activity,and carbon content of various composition of humus in the 16 and 18 site index plots also increase in positive proportion with the increase of the undergrowth,however,in the 14 site index plot,the results turn out contrary to the former. Amount of soil organic matter,available N and total exchangeable base in the 16 site index plot increase with the increase of the under-growth coverage. Amount of soil organic matter,total N,available N,P,K and Ca2+,Mg2+ cotent in the 18 site index plot also increase with the increase of the undergrowth coverage.
The slope vegetation succession in Shanxia Reservoir Area has been changed from the subtropical evergreen forest to the natural coppice forest,barren herb slope and plantations. Its forest coverage decreased from 45.5% in 1940 to 21.7% in 1985 and the forests distributed unevenly,shaping like island,speckles and blocks. The deterioration of the slope vegetation led to the unfertile soil characteristics:content of stone particles in the soil is 6%～30%;thickness of soil layer 40～60 cm;texture of soil soft.During·the heavy raining season (April～October),soil erosion is serious. Besides,the irrational land exploitation in this area intensified the soil erosion. To bring the change of the slope vegetation and environment under control,the technology of planting bio-living-fence and agroforestrywas adopted.The method is using the tree species,which are fast-growing,easy-sprouting and good at fixing N for contour line planting to prevent the slope from further erosion. The plant species selected are:Robinia pseudoacacia,Vitex negundo,Coriaria sinica,Leucacena leucocephala,Amorpha fruticasa,Vetiveria nigritana,Carex spp.,arbor,shrub and herb species. 3 years after the cultivation he forest coverage increased to 35% and the content of mud and sand in the running water from the slope was 3.3g/m2,while that on the land without vegetation was 37.97 g/m2.
Two studies were established to investigate the effects of rotation length and repeated harvesting on the sprouting reproduction of Acacia auriculiformis in Shangyong Village Forest Farm (19°14'N, 110°28'E)of Qionghai City of Hainan Province.The first study was conducted in a split plot design with three replications involving three rotation lengths of 4,5 and 6 years as the main plot and three stand densities(6 667, 5 000 and 4 444 trees planted per hectare)as the sub-plot.Results showed that both the rotation length and stand density had no significant effects on the percentage of stump sprouting and the number of sprouts produced per stump. The DBH and length of sprouts decreased significantly with the increase of rotation length.The differences in DBH and length of sprouts between the stands with different densities were not significant.The total biomass and volume production from the first harvest together with the standing sprouting forests decreased with the increase of rotation length.To maximize the sprouting reproduction of A. auriculformis,a rotation length of 4 years is recommended. In the second study,eight combinations of rotation lengths of 2+3+4,3+2+4, 3+3+3, 2+4+3, 4+2+3, 2+7, 3+6,4+5 years were involved into a repeated harvesting trial for A. auriculiformis.Results showed that it is possible to establish the second sprouting forest of this species by sprouting,and coppicing can return it to juvenility.There was no significant differences in the percentages of stump sprouting and surviving rate between the first and the second harvest. The total volume and biomass production between the tested eight combinations of rotation lengths were not significantly different.For minimizing the production cost and increasing the economic profits,a combination of rotation length of 4+5 years is recommended for a management period of nine years.
Based on the principle that the exudation from root can stimulate the germination and growth of the mycorrhizal fungus,the method of growing pine seedlings by cutting their apexes off and inoculating with mycorrhizal fungus is proposed.The results show that the pine seedlings developed in this way can promote the development and growth of root system and ectomycorrhizae formation,increase the biomass of seedling and improve the quality and yield of plantable seedlings. The number and total length of lateral root,percent of seedlings with ectomycorrhizae,percent of feeding roots with ectomycorrhizae,height,root collar diarneter,fresh and dry weight increased,on the average,by 20.0%～960.O%,56.2%～389.5%,0.0%～400.0%, 56.2%～1792.0%,22.3%～179.3%,31.2%～253.3%,33.3%～918.2% and 21.8%～740.0% respectively,and with the survival rate of seedlings and percent of the first grade seedlings increased by 9.0%～22.1%and 49.3%～ 150.0% respectively and percent of the second, third grade, and cull seedlings decreased by 40.6%～77.3%,61.6%～88.5% and 82.5%～100.0% respectively. The survival rate,height,root collar diameter and volume index of the seedling increased,on the average,by 5.5%～46.0%,13.0%～56.4%,25.5%～61.7% and 87.8%～450.0% respectively. The benefit analysis confirms that the use of this method has significant economic and social bene-fits,with a countable value of ￥44 662 5 yuan/hm2 in nursery alone.
Tracheid length in radial direction first gradually increases and then levels off from pith to bark.It decreases along the stem height.Variation in tracheid length-width ratio is similar to that in tracheid length.Tracheid length,length-width ratio,double wall thickness-diameter ratio and diameter-width ratio vary from 1.403 mm,46.7,0.381 and 0.711 to 4.456 mm,70.1,0.496 and 0.786 respectively within 16 years old trees of loblolly pine. Specific gravity increases from 0.324 g/cm3 at pith to 0.428g/cm3 at bark and it decreases from 0.401 to 0.314 g/cm3 along the stem height.The mean value of specific gravity at a given height between trees is not related to that of tracheid length. Cellulose content asends from pith(37.04%)to bark (43.91%),lignin and pentosan contents descends from pith (28.78% and 14. 59%)to bark(25.74% and 12.05%)and the extractives content is between 8.38% and 2.12%. The juvenile period of its wood is about 10 to 13 years old.According to basic demands of pulpwood properties,variation in wood characteristics of different age tree and the growth property of tree,rotation age of loblolly pine for pulpwood is about 12 to 13 years old.
The result showed that effect of inoculation on casuarina seedling with pure culture of Frankia is obvious. Inoculated seedling`s height,basic diameter,number and fresh weight of nodule and biomass were higher than those of the uninoculated seedlings,Among four tested Frankia strains,Br behaves best.Height of seedling inoculated with Br were 3.45 times that of the control, and 2.73 times in basic diameter. Strain P1 was the better one. Effect of inoculation became more significant as time went on. Seedling's height,basic diameter and biomass appeared to be extremely positively correlative with the number and fresh weight of its own nodule.
Pristiphora beijingensis, distributing in North China,is an important pest in poplar nursery.It attacks mainly poplar trees belonging to Section Aigeiros. With both amphimixis and parthenogenesis it can develop 8～9 generations a year in Beijing area and over-winters as prepupae in cocoon in the soil.It produces only males if without mating,but both males and females after mating. The females have five instars while males have four instars.According to the study in 1991～1992,the spatial pattern of P. beijingensis is aggregation,the basic unit is clump. Temperature is the key factor for the population dynamics,which influences emergence and hatching. Under the condition of sufficient food and suitable temperature,the population will have an exponential increase with the inner natural increase rate R0=1.4.Using PbNPV,B.t.,and entomopathogenic nematodes to control it,the mortality could reach 92.9%,100% and 85.1% respectively.
Successive surveys were made in bamboo(Phyllostachys pubescens)groves in Dagangshan region,Jiangxi Province from 1985 to 1991. Based on those data,the factors to affect yield such as stand structure,site condition and management method and their adjusting method were discussed.The results show that the most important factor was stand density which should be maintained in optimum situation,The optimum density of bamboo grove in the Jiangxia Forest Farm varied with the site condition and has been given as follows:4 950～5 550(1):4350～4800(2)、3 450～4 200(3)、2 400～3 300(4)、1 800～2 250(5) stems/hm2 respectively,Main site factors affecting productivity are soil and humus thickness,soil tightness and P content of soil.Fertilization can bring up a good output and high economic benefit,the increment in yield is 20%～100% and the increment is 22%～81% with the changes of the site conditions,so it should be used in suitable areas.
The seasonal susceptibility of masson pine caterpillar to insecticides were studied.It was found that the larvae before hibernation was the most sensirive to deltamethrin and dimilin Ⅲ in Nangjin, Jiangsu Province and Guangzhou,Guangdong Province. The total haemocytes counts,esterases activity was found to be lowest and it was also the suitable time to control this pest by chemical insecticides. The mechanism of the seasonal adaptation of the larvae was discussed.It was suggested that the chemical control strategies should be focused on the selection of suitable chemical and the timing of application to coincide with the susceptible life stages.
Analyses was conducted based on the data from a 9-year-old open-pollinated progeny test of P. elliottii in northwestern Zhejiang.The measurement of growth traits were taken annually for the first 5 years and at the 7th and 9th year,while the form traits were assessed visually at the 7th year.There were significant family variations in height,stem diameter,stem straightness and branch angle, and middle to high level family-mean heritabilities.The age trends of growth traits in family variances,juvenile-mature correlations and response to early selection were examined,5 to 7 years old was the optimum age for early indirect selection. Genetic gains were examined on the height,stemdiameter,stem straightness,and branch angle in selection indices. The results suggested that it is impossible to achieve substantial simultaneous improvement in both growth and form. Based on restricted indices constructed by using equal emphasis weights,three superior families were selected.
Study on the effect of different spacing on the typhoon resistance of young Eucalyptus plantation showed that "wide row spacing and narrow tree spacing" is the best planting spacing to resist typhoon. The effect of 4.5 m row spacing is better than that of 3 m line spacing if their narrow tree spacing is the same. The effect of 1 or 1.5 m tree spacing is better than that of 3 or 2.5 m tree spacing if their wide row spacing is the same. Planting spacing of 3 m×3 m is the worse one.
The survival rate of fertilization trial of masson pine and slash pine plantation was investigated.The results show that under the same planting condition,the survival rate of masson pine with N(urea)fertilization before planting would be decreased by 8%,and that of slash pine decreased by2%～8% There was no effect on the survival rate by P,K appli-Cation.
This paper reports the study of invertase activity in seed lings of Chinese fir(Cunninghamia lanceolata).Results obtained from several determinations indicated that the enzyme activity was the highest during pH 5.0 and Michaelis constant was 9.3×10-2mol.When the enzyme extracts were stored at 4℃ for 24 h,invertase activity in leaves and shoots decreased by 55.6 and 86.3 percent,respectively.There were differences of invertase activity among the leaf at the top,young leaf and mature leaf.The enzyme was most active in the leaves at the top of the seedlings and the enzyme activity in mature leaves was the lowest.They were 11.50,3.11 and 1.57 sucrose hydrazed μmol/h·g of fresh weight respectively.But invertase activity in young branchlet was five times as high as that in young leaves on the branchlet.Higher invertase activity was found in the fast growing clone seedlings than that in the slow growing clone seedlings.Correlation between invertase activity and seedling growth rate,and the possibility of determinating seedling growth potential by level of invertase activity were discussed.