In every organism of paulownia tree,nutrient element concents is the highest in flowers and leaves,the least in the trunk.Leaves and branches are the storehouse of nitrogen,the contents of nitrogen in the leaf account for 42—45 percent of the total of a tree.Root is the storehouse of phosphorous,the contents in it account for 40—56 percent.Potassium is stored mainly in branches and roots.Calcium is stored mainly in trunk (40—57 percent of the total).Paulownia forest absorbs 320kg/ha nutrient element a year,89kg of which is distributed into newborn organisms,132kg returns to litter fall and 102kg is leached away by rain and stemflow. The absorbed nutrient elements in a year include calcium (104kg/ha·a),potassium and nitrogen(70—100kg/ha·a),phosphorous and magnesium (26—27kg/ha·a).The nutrient cycling percentage of paulownia forest is high, 74% of which is returned to the forest floor and only a small is consumed. So long as certain manure is added,productive forces can be well maintained.

Graphical method is studied for the multi-dimensional data of phenotype test in Cunninghamia Ianceolata Hook.with the PC-1500 pocket computer.Tree graphs of 14 samples are drawn.The graph includes leaf,crown,stem,branch and root composed of 22 variables.The tree graph represents visually the growth characteristic of the phenotype characters of the parents.It is useful in studying the resemblance and classify among the characters and the parents.

Age structure and regeneration strategy of six major species of the broadleaf koreanpine forest in Changbaishan Biosphere Reserve are discussed in detail.Two types of the regeneration strategy are identified.Pinus koraiensis,Fraxinus mandshurica and Qurcus mongolica are of discontinuous,regeneration type.Tilia amurensis,Acer mono and Ulmus propinqua are of continuous type.A tolerance scale of the major species is preliminary suggested as Q.mongolica→F.mandshurica→P.koraiensis→ U.propingua→T.amurensis→A.mono (in an increasing order of shade-to-lerance).

Seven strains of cytoplasmic polyhedrosis viruses of Dendrolimus spp. were isolated and pured by sucrose gradient ultracentrifugation and examined under scanning electronic microscope.A comparison study on their RNA genome segments had been made.There was only one sedimental band formed after ultracentrifugation in 5 of them-JDS-CPV,JGDP-CPV,JYDPW-CPV,JADP——CPV,and CYDPW-CPV.But there were two sedimental bands formed in both JHDS-CPV and CGDP-CPV.The shape of the cytoplasmic polyhedral bodies from the sedimental bands of the 5 CPVs and the lower sedimental bands of JHDS-CPV and CGDP-CPV appeared to be typical hexagonal.The RNA genomes extracted from the CPBs in vertical slab 3% PAGE or 1% agarosegel electrophoresis similar to Bombyx type.But there were differences between JDS-CPV in 3% disc PAGE and its replicates.The shape of the CPBs from the upper sedimental band of JHDS-CPV and CGDP-CPV appeared to be pyramidal.The RNA genome of JHDS-CPV and CGDP-CPV had 13 segments in 1% agarose gel electrophoreses and belonged to neither Bombyx type nor anyone of 12 genome types suggested by C.C.and C.F.Rivers.For this,both JHDS-CPV and CGDP-CPV might be a mixture of two strains of CPV,which has not been reported before.

The results of controlling overwintering Dendrolimus tabulaeformis by Paecilomyces farinosus and Beauveria bassiana are discussed.D.tabulaeformis overwinters under stones,in the soil and in a thick growth of grass where the higher humidity and lower temperature are combined of suitable for fungal infection.The spores of the two fungi can geminate at 5℃,P.farinosus is more suitable for the control of overwinteing D.tabulaeformis because it is more suitable for low temperature than B.bassiana.In autumn,put fungal preparation of wheat bran under the stones,in spring of next year took some samples for test.According to the counts of plate dilution culture,the spore contents were only decreased slightly. The mortality of the pest can reach about 70% during winter time.

A comparative resistance of several pine species to brown spot needle blight was studied by means of a field survey and some natural and artifical inoculations.Pinus massoniana appeared to be most resistant and P.elliottii most susceptible.P.taeda and P.caribea belonged to intermediate types.This resistance could be differentiated by the number and type of the needle spots. At the room temperature and at 5℃ the pathogen,lecanosticta acicola,may survive for over 7 months in pieces of the infected leaves,which were always carried along with seeds.The cultural characteristics.and the pathogenicity of the P.thunbergii isolate from Jiangxi Province were significantly different from those of P.elliottii isolates from Guangdong,Guangxi and Fujian Province.Presumably the pathogens of brown spot needle blight on P.elliottii were introduced from U.S.A.in 1970's.

In this article,a simulating method of computer which is used in the stochustic vibration of tracked skidder is presented.The tracked skidder is simplified into a system of vibration which has three degrees of freedom of skidder-seat. Employ the J-50 type skidder made in China as a example.the field test result compares favourably with the result of simulating calculation on the DPS8 type computer. In addition,make use of the method of this calculation,the authors researched the construction parameters influence on riding comfort of the tracked skidder and suggested some opinions to improve the riding comfort of the J-50 type skidder.

The forest site productivity (present forest productivity,intensive managed forest productivity and potential forest productivity) and forest suitability (or limitedness) are form the basis for site classification. There are four principles for forest site classification:1.identification of physical forest site factors and its group;2.similarity of forest site productivity and forest suitability;3.identification of factors,on which forest site is formed and limiting factors;4.identification of developing stage of forest site and forest management direction. The system of forest site classification is composed of forest site region,forest site district,forest site class,forest site type group,forest site type and plant association type.

This paper contains two parts.One is of discussing several problems about site classification with two comrades and the other is concerned with a principle of forest classification in China. According to the principle above mentioned,it may be divided into five grade unites,namely: 1.Site type district;2.Site subtype district;3.Site type group;4.Site type subgroup;5.Site type.

The seasonal change of water contained in soil and its effect on tree growth were studied in Jiulongshan,Beijing in 1984.Also,there was an analysis of relationship between tree growth and the yearly change of water stress.Based on the study,the conclusions were drawn that soil water has a violant change according to the seasonal and yearly distribution of precipitation,and that main factors causing the severe water deficit to tree growth are the unevenly seasonal and yearly distribution of the precipitation and the low water retention ability of the soil.

The sixteen respectiye species pollen which belongs to five sections have been collected and observed by using Scanning Electron Microscope.Pollen grain of Populus is ellipse in shape,no colpi and pori,the diamter of polar is 17—26μm and the eguatorail is 16—23μm.At high magnification the exine sculpturing of pollen grains show there are some diffrences in different sections.Pollen grain sculpture of Turanga present separated wart;Trepidae present separated wart and thorn,Albidae also present but arranged densely;Aigeiros,Tacamahacca and Leucoides are mainly cloud flake in shape.This result coincides with Professor L.Dode who proposed a populus texonomy system.This study provides the materials of some poplar pollen exine structure,that is important to populus taxonomy,hybridization.

In this paper,the main results show that the seedlings of pine,China fir and cypress can use ³²P labelled iron phosphate as a phosphorous source.Although a relatively small amount of phosphorous is absorbed from iron phosphate,both the amounts of phosphorous absorbed by the plants,from ³²P-labelled calcium superphosphate and iron phosphate are found to be increasing constantly during two experiment period in 1984—1985.The ratio of the amounts of iron phosphorous to calcium superphosphate absorbed by cypress reached 10.5%,at the 93th days in 1985.The results indicate that even if the soluble phosphate change into insoluble iron phosphate in soil,the latter still can be used by these plants.

Errors in the determination of the Stem volume of felled trees based on experimental datum were calculated by the appropriate formular in the past studies. Theoreitically,This paper discusses the nature and quautity of errors in the determination of volume of felled trees by Huber's,Smalian's formulas and Huber's sectional measurement formula (When form-exponent is equal to 2 or 3 q.v.the equations (3),(4),(10),(12)). The appropriate formula is proved as follows: V≈1+r+r(r-1)/2/1+r ·G·L Given V,G and L,r₁ and r₂ can be obtained by above equation.Moreover,a new method of constructing volume table could be obtained and Kunzes' equation Y²=PX^r could be applied to practice when r_{1 or r2 is regarded as a parameter.}

The white grub,larva of Eublemma amabilis Moore (Noctuidae,Lepidoptera),is a serious pest causing loss of raw lac in the production areas in the world.The most effective measure to cope with it has been proved to be biological control taking advantage of Bracon greeni Ashmead, an ectoparasite of the grub.The general characteristics of reproduction of this braconid,such as supplementary nutrient for egg-ripening,ha—bits of egg-laying,fecundity,sex ratio etc.are studied in laboratory in 1979-1983.Some conclutions drawn as following: 1.The adult of the braconid needs a sufficient amount of honey as supplementary nutrient for egg-laying through its life. 2.The female is able to find its host under cover with tiny mesh,which is necessary for egg-laying,by smell of the excrement of the grub or the body itself and by the feeling with its ovipositor.But it lacks the ability to distinguish true host from false in laboratory. 3.The range of reproduction period and egg number are directly related with the longevity,the longest being 211 days with an average of 119,5 days.And it is found that the longevity decreases generation after generation in laboratory. 4.The sex ratio of the braconid is about 3:1 in nature and the males become more in number in laboratory,for example,in the first generat on the ratio is 1.2:1 in the second 0.7:1,and in the third 0.4:1.

This article makes hierachical and graphical partition clustering analysis to mixed type (qualitative and quantitative) data of nine items of 39 sample plots from secondary growth area.The aim of this study is to classify forest land of various flammabilities. The result shows that the class classified by multivariate statistical analysis methods are the similar to forest types and both the clustering and ordination can be finished at the same time using the graphical method.The interpretation of ordinal relation of various forest land types is given.

The hepialid moth,Phassus nodus Chu et Wang,is a new serious forest pest in China.The larvae bore and tunnel into the pith of tree stems; consequently the trees wilt and die. The paper described the host-plant species,the adult and larval behaviour,and their living environment.

This paper deal with the difference of chemical compoition in different host tree under different kind strain,age and whether the lac insect take in nutrition from bark of host tree and the influence on chemical composition of branchs suitable for growing lac insect under a great number of blossom and bearing fruit.The result shows that there are tannin and phenol in many species of host plant.Contrast branchs in which lac insect are parasitized with branchs in which lac insect are parasitized have ceported that contents of tannin in branchs with lac insect is 5.36%.It is more than the contents (4.06%) of branchs in which lac insects are parasitized.But contents of sugar are contrary. A great number of blossom and bearing fruit of host plant can reduce the content of inorganic element in branchs.It can also affect synthesis and transport of carbohydrate,amino acid etc in nutritive organ of plant. This will affect growth and secreting lac of lac insect.Treat with wiping out flower buds can enhance the contents of organic substances in branchs suitable for growing lac insect.Thus it can promote quality and output of seed lac in winter generation.

According to the characteristics of machinery repair in the productive process of forestry logging,in a certain province,the author applied one branch of Operations Research-Queueing Theory,to optimum design of machinery repairing abillity in the repair network,and applied the theory of location to the proper distribution of optimum machinery repairing ability.Form the financial effects,therefore,A lot of money would be saved per year.