The relative water content (RWC), cell permeability (PERM); the activities of superoxide dismutase (SOD) and catalase (CAT), the malondialdehyde (MDA) content produced by lipid peroxidation, and the components offatty acid in membrane lipid of potted persimmon tree leaves were measuredunder different water conditions. The results indicated that as the soil waterpotential (ψ_S) decreased, cell permeability (PERM) increased, the activities of SODand CAT decreased, lipid perxidatin increased, the content of unsaturated fattyacid in membrane lipid reduced, while the saturated fatty acid content raised.It was proved that the changes in all indexes were most obvious as soil water potential ψ_S =-3.80±0.47bar. There were significant correlations between SOD activity, CAT activity, MDA content, PERM, index of unsaturatedfatty acid (IUFA) and leaf tissue relative water content (RWC), as well assoil water potential (ψ_S) under the present experimental conditions for youngpersimmon tree.

The present paper describes a new pteromalid species, Norbanus aiolomorphi. It parasitizes the larva and pupa of mosobamboo eurytomid, Aiolomorphus rhopaloides Walker, 1871(Hymenoptera:Chalcidoidea, Eurytomidae) whichmakes galls on the branchlets of moso-bamboo(Phyllostachys pubescens Mazel) and is a serious pest for the plant in most parts of South China. Norbanus aiolomorphi Yang et Wang, sp. nov. (Figs1-6) Female: 3.2-4.6 mm long. Black, hardly nitidus; basal part of gasterhaving a lemon-yellow spot; antenna yellow brown; legs with coxae black,femora and pretarsi dark brown, tarsi and the apex 1/2 of hind tibia yellowwhite, the others yellow brown; wings hyaline. Head and thorax densely raisedreticulate. Relative measurement: Headwidth 66, height 54, POL 12, OOL 16, frons width 46, the distance betweenthe upper margin of torulus and median ocellus 14, between its lower marginand apex of clypeus 35, malar space 15, scape plus radicula 36, pedicellusplus flagellum 95; thorax 78:56, pronotum median length 7, mesoscutum 29,scutellum 28 (width 32), propodeum 14; marginal vein 36, postmarginal 21,stigmal vein 10; gaster 102:46. Ovipositor not exerted. lst gaster tergite having its hind margin slightly trilobed. The last tarsus expanded, particulalyin female which has it as wide as the intumescent tibia, and with pretarsusvexillum obviously (Fig.6). Male: 2.8-3.9mm long. Similar to female. Its antenna extremely long(Fig. 4), flagellum plus pedicellus 1.02-1.11 times the length of head,thorax and gaster combined and 2.94-3.04 times the width of head; flagellumwith irregular whorles of long dense erect setae on each segment which isnever nodulated; scape curved seriously with broad emargination dorsally onbasal 2/3; legs relatively slender, last tarsus thiner than the tibia; gasterlongelliptical, its length about as long as thorax (72:74), width distinctlynarrower than head and thorax(19:62:52). The new species is close to the Australian pteromalid N. longifasciatus(Girault), 1914, but may be distinguished from the latter by the charactersbelow:1)the new species with female clava gradually sharpening into an sturdyprocess apically; 2) last tarsus expanded extremely, particularly in female;3)gaster sublanceolate with apex sharpening. Biology: Parasitoid of larva and pupa of Aiolomorphus rhopaloides on bamboo Phyllostachys pubescens. Six generations from the beginning of May tothe end of October in a year have been observed and total parasitizing rarateio reached 36.6%. It has played a significant role of controlling the population of the insect pest in the bamboo growing areas of South China. Distribution: Hunan Prov. , probably all the bamboo growing areas inChina. Types: Holotype♀, Hejiadong, Shuangpai Couty, Hunan Prov., 300-600m elev., 1990-X-15, ex bamboo branchlet galls of A. rhopaloides, WangWenxue. Paratypes 12♀♀6(?)(?), same data as for holotype; 10♀♀4(?)(?), thesuburb of Zhuzhou City, Hunan Prov., 80m elev., 1990-IX-16 , Wang Wenxue (All the type specimens above are deposited in the Insect Natural Enemies Research Laboratory, Northwestern College of Forestry); 30♀♀30(?)(?),same data as for holotype(deposited in the Insect Collection of Central SouthForestry College).

Laboratory rearing and simulated field overwintering of Isyndus obscuruswere conducted in Beijing in 1991-1992. It has one generation a year andoverwinters in adult stage. The eggs aggregate in the form of egg masses,and hatch in 12.1±1.0 days after oviposition. There are 5 instars in thenymphal stage and its development lasts for 61-83 days. The adults mate in8-30 days after emergence and oviposit in the following year. Not only its mo-rphology and changes in color after moulting in all stages, but also the bi-onomics were described. Experiments both in laboratory and in the field sho-wed that it's a promising predator and can prey on many species of forestinsects, such as Lymantria dispar Clostera anachoreta, Apocheima cinerarius, Ne-matus sp. , Ivela ochropoda, Cnidocampa flavescens, Dendrolimus punctatus, D.tabulaeformis, Malacosoma neustria testacea etc.

It a fleuxous filamentous virus has been isolated from Ailanthus altissimaMill. showing mosaic symptoms. It was identified as a menber of potyvirusgroup. The virus could infect twenty-one of the twenty-three plant speciescultivas from six families inoculated. The thermal inactivation point was 70-75℃. The longevity in vitro was longer than 5 weeks. The dilution endpoint was 10^-3-10^-4. It was easily transmitted by Myzus persicae Sulz. Thevirus particles were fleuxous rods, about 725nm long. The purified prepareation had an ultraviolet absorption spectra typical of a nucleoprotein (A=260/280=1.20). The virus capsid contained a single protein species with amolecular weight of 35,000 daltons. Antisera to the virus was obtained fromrabbits immunized with purified virus preparations. The virus could be"described" in ISEM tests using antisera for PVY. In addition, electron microscopyof thin sections of infected leaf tissue demonstrated the presence of severaltypes of inclusion bodies similar in appearance to inclusions prevously descri-bed in association with potyvirus infections in other plants.

The new conception of regional wind protection effect of agricultural andanimal husbandry windbreak networks is suggested in this paper. In addition,new evaluation meathod and model are presented based on the data fromwind tunnel experiment and tethered balloon observtion. The example ofapplying it is also given in the paper. The evaluation model can be expressedas

The construction, the function and the bunching production technologyof the self-moving double-drum light winch are discussed. The winch canmove by itself on main skidding roods, suitable for frequently moving work.The guidable bunching production technology established in this paper is ab-vantageous to protect the reserve, the sapling and the ground surface. Thecomprehensive bunching efficiency can be increased by 64.7%, and the prod-uetion cost, reduced by 11.0%.

This paper presented the theory of the measuring mean effective radiiand numbers of capillary in wood. A study on the effective capillary structure of wood was discussed. Linear plots of axial gas permeability vs. Reciprocal mean pressure were obtained for spruce (Picea jezoensis var. komarovii)and pine (Pinus koraensis) in agreement with Klinkenberg equation, whichindicate nearly all of the resistance to flow is due to the pit membrane pore.Mean effective pit membrane pore radius(γ₂) was 0.61 and 0.95μm for spruceand pine. The number of conductive pit membrane pore per cm^{2 of cross section(n_(pc)) was calculated, yeilding valus of 1218/cm2 for spruce and 605/cm2 forpine. The plot of axial permeability vs. reciprocal mean pressure of thebirch (Betula platyphylla) was curvilinear, indicating presence of the conductances in series, which were assumed to be vessel and scalariform perforation plates. The calculated vessel radius (γ₁) and vessel concentration (n_(tc)) were59,8 μm and 645/cm2. The radius of the opening(γ₂) in the scalariform perforation plates was 2.01μm.}

This paper demonstrates strictly the method of measuring mean microfi-bril angles of wood by using X-ray (002) diffractograms, It also explainswhy the microfibril angles mesured before by separation were smaller thanmeasured by other methods, based on recent method, we measured Masson pineand I-69 Poplar, and explained reasonably various shapes of diffractograms,the value of microfibril angles with different annual rings in different zonesof reaction wood is determined, the relationship between microfibril angleand longitudinal tensile strength is also surveyed, diffractograms can be usedto determine the possible existance of g-layer as well as the ratio of thickn-ess between S₁、S₃ and S₂ layers, moreover microfibril angle is an importantfactor reflecting longitudinal tensile strength of wood, while the former islinearly dependent upon the latter.

This paper deals with wood characteristics and their frequencies of occurence in 669 important Chinese wood species including both domestic andexotic species. Softwoods including Gingko biloba possess 169 species and 138wood characteristics and hardwoods possess 500 species and 179 characteristics.In addition, some woods of special identificaion features were enumerated.

The fatty acids and the phospholipids in membrane lipid of two poplarvarieties: chill-resistant P. euramericana cl. I-45/51 and chill-sensitive P.deltoides Bartr. Cv. "Lux"I-69/55 were analysed. There is an evident differe-nce in the unsaturated degrees of the fatty acids between the two Varieties,linoleic acid is the dominant component in the chill-resistant variety, whilepalmitic acid is the major one in the chill-sensitive variety. Index ofUnsaturation of Fatty Acid (IUFA) can be used as a standard to evaluate thechilling resistance of poplar. The phospholipid compositions in two varietiesare similar, they are phosphatidyl choline (PC), phosphatidyl inositol (PI),phosphatidyl ethanolamine (PE), and phosphatidyl glycerol (PG). There areno apparent differences in the distribution of the four phospholipid componentsand the total content of phospholipid between these two varieties, so phospho-lipid composition can not be used as a standard of chilling resistance for po-plar.

In this psper, the effects of forest on ajusting temperature, increasinghumidity and intercepting precipitation, as well as its characteristics of sea-sonal and daily changes, are studied by using the meteorological data of themiddle-mountain humid evergreen broad-leaf forest and bare land outsideforest, measured from 1986-1987 in the natural conservation region of AilaoMountain(24 32'N, 101 01' E altitude 2450m).

The web-spinning sawfly Cephalica danbaica Xiao is an important insectpest of Picea crassifolia Kom,and causes severe infestation in the eastern part of Qinghai Province. It was obsevered that the sawfly took 2 years tocomplete its life cycle which may extend to the third year after infestation. Dueto the succession only with a single year-group, it rests in the soil duringthe year of even number and infests on the trees during the year of oddnumber. The adults and eggs presented in mid June to early July. The firstinstar larvae occurred in July. The mature larvae leave away from the treesin early August to mid September, and dig into the soil where it remainsinactive about 21 months within the earthen cell. The larval stage consistsof 6 instars. In the forest which is infested seriously,the use of insecticidalsmokes to kill the pest on the trees is effective. To the trees of sporadicinfested with the larvae cutting away the larval rests is also effective.

Whan an one-way volume table is worked out by equation V=aD^b,ausual method for fitting this equation is to lineariz it firstly, then calculatethe parameters of a and b by Least-squares method. However, the method usedabove is not optimum. It is suggested that the precision of one-way volumetable will be increased by application of Modified Simplex Method to furtheroptimizing the parameter a and b of the equation V=aD^b.

The necessities and the importance of making forest management plan weredescribed and then the effective path for raising the quality of planmakingand the main strategies for supervising the practice of the plan were discussed.The following aspects were proposed as problems to be considered and solvedin making and practice, enhancing subcompartment and associated aspects investigation, making stand yield table, making reasonable priteria of the designand plans, as well as evaluating the integrated profit of forest farm by a marksystem.

A mathematical model to caculate the economical service life of EQ-140logging truck is established by means of trial caculation. The result showsthat the economical service life is 3.7 years when the purchase cost of a newtruck is $50000 and the interest is 8%;and the averaye cost does not changeobviously when the service life is 3.7 to 5 years; the higher the purchase costof a new truck is, the longer the economical service life is When the purc-base cost between $40000 and $60000, the economical service life is from3.3 to 5.1 years.