An extensive survey was made of the adaptive character and species choice of main planting trees of farmland shelterbelt in the Pearl River Delta.On the basis of investigation and analysis,the acidity of soil,the total content of salt and the height of water level were determined as the main site factor affecting the growth of forest by means of mathematical statisties.The optimum equation was selected by regression: y_D(over pH6.1)=8.0927-0.6473x₁-0.5059x₂ y_D(under pH6.1) = 3.7641-16.6671x₁-0.0027x₂ Taxodium distichum,Taxodium ascendens,Casuarina equisetifolia,and Glyptostrobus pensilis are the main planting tree species of farmland shelterbelts in the Pearl River Delta.pH6.1 is the optimum value of soil acidity suitable to Taxodium distichum and Taxodium ascendens,and pH 7.0—8.0 suitable to Casuarina equisetifolia and Glyptostrobus pensilis.All the 4 species of trees have certain salt-resistant capability,when they are planted on the salinized soil the total salt content of which is 0.38%,they still grow well; but growing speed of Taxodium distichum and Taxodium asoendens shows negative correlation to the total salt content of soil.Water-resistant and moisture-resistant species Taxodium distichum,Taxodium asoendens,and Glyptostrobus pensilis on the planting point,i.e.50cm and 30cm above the water level,show the best performance. 5 site types are classified in the Pearl River Delta,i.e.lower downland leaching type,the plain fresh water type,the network tide-irrigating type,the seashore acid overflówing type and the seashore sandy type.Various tree species suited for planting in the farmland shelterbelt are recommended according to different site types.

Water is usually the limiting factor for the survival and normal growth of Poplar.The deep planting technique introduced from Italy can be helpful to solve this problem.According to the deep planting experimants thrice in Shansi,Inner Mongolia and Beijing,a survival rate by more than 95% was obtained and the early growth rate of newly planted trees was also increased under the condition.Without irragation deep planted Poplar trees have more and deeper roots and are also able to absorb the ground water directly through the end sections of the sets.This is the reason for high survival rate of the deep planting.The soil temperature of deep layer in the winter satisfies the demand of the sets for slow rooting.The sets deep planted in autumn have already rooted rather profusely before the opening of the buds in next spring.This benefit the survival of young trees planted in autumn. The transpiration rate of deep planted Poplar trees is higher by 2.3—4.4 times and its average daily water consumption of transpiration is higher by 1.83—15.41 times than those of trees planted in the ordinary way.In addition,compared with ordinary planting the deep planted Poplar trees have higher leaves water potential,higher water content and lower water saturated deficit.The active water metabolism shows the superiority of the deep planting technique.

Aimed at improving silviculture practice of Cunninghamia lanceolata by providing a better understanding of site conditions,the present paper offers the recent research finding on systematic geographic regionalization and site classification based on systematic studies of climate (water,heat),topography,bed rock,soil and vegetations associated with chinese fir.3 zones and 5 regions are recognized,with special reference to climate and physiography. The regions are subdivided into subregions.Site types are grouped into groups and distincts based on mesorelief,microrelief (aspect,slope position), soil and vegetations.In addition,the site index table is prepared based upon tree hieght in definite age;another is besed upon relief and soils with method of multi-factor.The application of site classification and site quality evaluation are proposed for silviculture practice. Findings mentioned above provides guide lines for intensive cultivation of chinese fir.It is hoped to be useful to locating commercial production bases,choosing suitable sites and predicting productivity as well as handling silvicultural treatments with the purpose to raise the productivity of Chinese fir plantation.

The Wolong Natural Reserve is situated in the eastern borders of the Qinghai-Xizang Plateau,extending from 102°52' to 103°24' E,and 30°45' to 31°25' N with an area of about 2 thousand Km~2,within this area,peaks rise up as high as 5000—6250m.in altitude.The steep slopes and deep valleys cause all kinds difficuty in transportation.The altitude not less about 500m,some place 200m.Forest soil resources is rich in the Wolong Natural Reserve,and its vertical zonations are quite distinct. On these forest areas,there are mountain yellow soils under evergreen forests,mountain yellow brown forest soils under mixed forest of evergreen and deciduous trees zone,mountain brown forest soils under deciduous and broadleaf forest belts,mountain dark brown forest soils under mixed forest belts of coniferous,deciduous and broadleaf trees mountain brown dark coniferous forest soils under fir forests,subalpine meadow soils,alpine meadow soils under subalpine meadow,alpine meadow zone,alpine desert soils in glacial drift,alpine tundra under ever lasting snow zone. In this paper,the physico-chemical property of main type of forest soils in Wolong Natural Reserve and its vertical distrbution are discussed.

The growth and photosynthetic characteristics of Populus deltoides Bartr.cv."Lux" (ex.Ⅰ-69/55) and P.×euramericana (Dode) Guinier cv.Ⅰ-214, which are clones of the tribe Algeiros;and P.×Opera Hsü and P.×popularis Hsü which are hybrids of P.Simonii,were studied under the controlled condition both in greenhouse and field during 1979—1981.Special attention was paid to determine their diurnal and seasonal changes of net photosynthetic rates and other related photosynthetic index.The light compensation points in the two clones of Algeiros were 2×10³ Lux,the light saturation points were 3—4×10⁴ Lux and the dark respiration rates were 2.87—3.75mg CO₂.dm^-2.hr^-1.While those in the two hybrids of P.simonii were respectively 3—4×10³ Lux,4—5×10⁴ Lux and 2.25—2.52mg CO₂.dm^-2.hr^-1.The diurnal changes of net photosynthetic rates of the studied four hybrids showed bimodal curve's patters from July to September,but monomodal patter in October.Their highest net photosyntheic rates appeared in July (15—19mg CO₂.dm^-2.hr^-1),the lower ones appeared in June,August and September (10—15mg CO₂.dm^-2.hr^-1),and the lowest in October (3—7mg CO₂.dm^-2,hr^-1).Under the similar environmental condition,the net photosynthetic rates of the two hybrids of P.simonii were higher than that of the clones of Algeiros.However,the growth rates and biomass of the latter were rather higher than the two hybrids of P.simonii,because of their larger total leaf area.Therefore,it is feasible to determine the growth potantial of Populus seedlings according to the magnitude of both net photosynthetic rate and total leaf area.

The present paper describes five species of sawflies of the genus Diprion from China.Of which four are new to science and one is recorded for the first time in China.All the type-specimens are preserved in the insect collection of the Division of Forest Entomology,Forest Research Institute,Chinese Academy of Forestry. 1. Diprion Liuwanensis Huang et Xiao sp.nov. The new species is closely related to Diprion hutaoharernae Smith;but it differs from the latter in the following points:Apical portion behind pterostigma of fore wing of female infuscated;lancet longer,with 11 annuli; ventral lobes 2—6 rather deeply emarginated,7—11 truncated;scopal pad shorter,not in the shape of sausages. 2. Diprion wenshanicus Xiao et Zhou sp.nov. The new species is close to Diprion hutacharernae Smith;but it distinguished from the latter by lancet with 11 annuli;teeth on annuli smaller;ventral lobe 2 with its hind angle projecting as a mammilla;annuli 3—5 slightly emarginated,scopal pads storter.not sausage-shaped. 3. Diprion tianmunicus Zhou et Huang sp.nov. Body elongate,lancet narrower and longer,distance between annuli 1 and 2 particularly widened,annuli 3 and 4 divergent dorsally,ventral lobe 2 rather deeply emarginated,scopal pads long oval in shape.By the conbination of all above characters the new species may be separated from Diprion similis (Hartig) and from Diprion hutacharernae Smith. 4. Diprion nanhuaensis Xiao sp.nov. The new species is very similar to Diprion hutacharernae Smith,with the following principal exceptions:in the female,most clypeus,supraclypeal area,most mesoscutellum,and metascutellum black;lancet with ventral lobes 2—5 imarginated;scopal pads shorter,not in the shape of sausages;in the male,labrum yellowish brown; abdominal tergite 1 with only median portion punctured;penis valve with apex slightly flat and with ventral side emarginated not as deep as that of Diprion hutacharernae Smith.

Paulownia Sieb.et Zucc.is a native genus of Eastern Asia.It has been introduced into Europe,America and Australia.This genus consists of about 9 species and 2 varieties which all of them grow in China.In order that the trees grow very fast,and the timbers provide with excellent physical properties (e.g.,stable in dimension,poor in thermal and electrical conductivity,good in resonance,etc.) and have been utilized universally,we are now making great efforts to plant them in large proper areas as one of the most important commercial timbers. Paulownia timbers have been used extensively through experience to make Chinese string instruments (sounding boards),chests,insulators,carvings and so forth.In ancient times,owing to the scientific research conditions were confined timbers for making wood products were selected only depending on wood craftmen's experience.So that a systematical and comprehensive study on anatomical characters and chemical,physical and mechanical properties of paulownia wood is needed and has been done in this paper.The purposes are: 1. To obtain the scientific experimental data of wood properties; 2. To make verification or clarification of some doubtful or mistaken popular traditions and plagiarized records of wood properties or uses (It is said that paulownia wood possesses the high-classed qualities of resistance of decay and abration,non-permeable to fluid,etc.),but the opposite experimental evidences have been shown from our tests. 3. To propose some desirable timber uses according to the appropriate wood properties.

This reivew is a survey in tissue culture of forest trees and the methods of clonal propagation of woody plants.Tissue culture offers an important technique for the rapid clonal propagation of forest trees.So far about 124 species belong to 30 families of woody plants have been regenereted as plantlets.Significant progress has been made in the past six years in vitro propagated conifers.In addition,a list over 70 species of woody plants may be cloned by somatic embryogenesis. The three principal types of clonal propagation of woody plants were discussed:aseptic shoot cuttage,organogenesis and embryogenesis.Eucalyptus (Eucalyptus leickow №1) regenerated in vitro via embrogenesis has been applied to forestation in Guangxi Region of our country. Finally,materials of the woody plants propagation were briefly reviewed in the 5th IAPTC.

During the planning of regional projects,common problem usually occurred in discussion is how to illustrate differences among them objectively and intuitively.In this paper,solution is attained by the theory of quantification and the computer simulation technique.