Successive cultivation of pure coniferous plantations has many defects. Planting mixed coniferous broad-leaved forests. is one of the most available methods to dispel these defects. Thus in 1982, we introduced a dozen of broad-leaved tree species, and established 35 hm². coniferous broad-leaved forests at Lu' an, Anhui Province, in order to select the appropriate mixture combinations, mixture pattern and proportion. This report deals with a part of the research of project. The results, from experimental study done in the past several years, showed that the mixed stand of Pinus massoniana and Liquidambar formosana with rational proportion and mixture pattern had significant economical and ecological benefits. The mixtures were suitable for maintaining soil ferdlity and site producdvity in long-term, promoting its growth and establishing a stable, man-made forest ecosystem. The growing stock in 12-year-old mixed stands was from 47.823 m³/hm² to 62.201m³/hm², 13.9%-72.5% higher than that of the pure stand of masson pine. The content of organic matter in the soil increased by 52.3%, total N increased by 24.1%, quickacting N, P, K increased by 13.7%. 25.2% and 26.8% respectively. The microclimatic condition was improved apparently. Meanwhile, the mixtures increased accumulation of chlorophyl in the leaves of masson pine. The daily average rate of net photosynthesis of masson pine in the mixed stand was 7.72 mgCO₂·Dm^-2·h^-1, 20.8% higher than that of the control.

The species relations were studied by comparing the biomass of tree, root system, vegetation under tree crown, forest floor in the mixed forests with that in the pure forests. The effects of different mixed spacings on the growth or pine trees were observed in the mixed forests in Longhua County, Hebei Province. The results showed that the relations of two tree species in the mixed forests were basically in harmom state in spite of the existence of restraining role of Betula trees on the growth of pine trees when the mixed distance was less than 250cm. The vegetation biomass under tree crown in the mixed forest stands was much more than that in the pure pine stands, while litter accumulation was less in the mixed stands than in the pure pine stands because of high decomposition rate of litter in the mixed stands. These factors benefit the improvement of physical and chemical propeties of soil as well as stand nutrition state. The paper suggests that the mixed forest should he planted in the model of group mixture and the distances of two species should be larger than 250cm.

By systematic analysis, selection and breeding of 184 germ plasm resources and 275 local varieties, half-sib families, full-sib families and clones from ten provinces or districts, the hereditary parameters of main characters of Aleurites fordii were found out. The conclusion that Aleurites fordii is a tree species of normal cross pollination has been drawn. The progamme and way for Aleurites fordii breeding have been laid. Three fine families, four fine clones, one 'dwarf, early and high yield' fine variety and one fine hybrid combination have been selected. 451 germ plasm resources were collected from the producing area of Aleurites fordii throughout the whole country. 13×10⁴kg elite seeds were produced and spread, with which the hereditary gain (△G) was 34.0%-59.8%. The theoretical basis was provided for production and hereditary improvment of Aleurites fordii in this study, part of data were provided for seed selection and production.

Taking 258 plots of Larix plantation as the experimental material, probability density function parameters fitted to Weibull distribution of every plot were calculated. It was found that the parameters increased with increasing of upper height and diameter, but decreased with increasing of density. Thus, the Richards model extended relations between stand factor and parameter, among parameters was established. The combination of parameter model with density, upper height, and diameter model was determined the best, after precision, significance, applicability, and the average diameter of basal area were tested. The tree distribution of a forest stand can be predicted by the model. And the model can provide the base for intermediate cuttings at different growth stages and intensities, and predicting stand volume.

In order to disdnguish the juvenile wood from mature wood in plantation or natural forest of China fir (Cunninghamia lanceolata) and Japanese larch (Larix kaempferi), a variation distribution of the averge tracheid feature value was applied to the logatithmical fonmula y=a+blnx, where y was the tracheid feature value (tracheid length, tracheid width and fibril angle), x was the ring number or dislance from the pith, and the effect of growth rate on the increment of juvenile wood were Studied.The results show that the regression curves oblanied from this logarithmical formula agreed well with the actual variation and the coefficient of correlation R between tracheid length and ring numher or distance from the pith (0.98), so the ratio among tracheid length, tracheid width and fibril angle was suitable to he used to differentiate the juvenile wood zone. Furhemore, the increasing rate in tracheid length of annual rings was estimaled by the regression curve ovtanied, and the juvenile and mature wood could be differentiated at the point of one percent of annual increasing rate in tratcheid length. It. Was considered to he an effective method. The annual rings or distance from the pith of juvenile zone differentiated by this method ranged from 20 to 22 or 12.9- 13.2cm for plantation, from 16 to 18 or 4.1-4.5cm for natural forest of China fir, from 19 to 23 or 8.7-10.5 for plantation and from 23 to 24 or 2.9-3. 1 cm for natural forest of Japanese larch respectively. The increment of juvenile wood was in direct proportion to the growth rate.

A test by crossing inoculation of 6 isolates of Pseudomonas solanacearum to 7 Casuarina clones demonstrated that there were significant variations in disease severity among clones and isolates; the interaction between clones and isolates was also significant. The results suggested that both horizontal and vertical resistance existed in the pathosystem and their implication in selection and breeding of resistant Casuarina clones was discussed.

Expeditions were made to Yunnan and Sichuan, southwest of China for searching the potential natural enemies of hemlock woolly adelgid, Adelges tsuga Annand. The collections under report contaid 45 coccinellid specimens. 8 species belonging to 4 genera are enumerated in this paper. Of those, 5 species were described as new to science: Scymnus (Scymnus) najaformis Yu, S.(Pullus)yunshanpingensis Yu, S. (Neopullus) sinuanndulus Yu et Yao, S.(N.) camptodromus Yu et Liu, Pseudoscymnus truncatulus Yu. 2 species of Scymnini remain undetermined. S: (N.) sinuanodufus and camptodromus are found to be the predator of the adelgid through laboratory feeding. The type specimens are preserved in the authon', insdtutes by indicating IPEP for the first author's and RIFP for the latter's in the following text.1. Scymnus (Scymnus)najaformis Yu (Fig. 1) Body length 2.19-2.50mm, width 1.35-1.76mm. Body oval. Head brown with darkish brown eyes; pronotum brown with a Mack basal marking, extending to 2/3 to 3/4 of pronotal length, nearly oval or sexangular in shape; scutellum black: elytra black with 3 pairs of spots, usually interconnected, the extemal spot sometimes disappears or the three spots are entirely wanting; black part of elytron extending posteriorly along the suture, leaving about 1/10 sutural line brown. Venter brown with black pterothorax and basal segments of abdomen, or venter dark to black; legs brown, or femora and tibiae dark brown.Holntype: ♂(IPEP), 26-X-1995, Yunshanping, Lijiang (27.1° N, 100.2°E): Allotype: ♀(IPEP); Paratypes: 1♂2 ♀(RIFP), same data as holotype.This species resemhles the palaearctic species S. (S.) interruptus (Goeze), but the latter varies in coloration with reladvely narrow median piece of tegmen in ventral aspect and the postcoxal line extending to the hind margin of lst abdominal sternite. This species is named after the shape of infundibulum which resembles a Cobra(Naja naja).2. Scymnus (Pullus)yunshanpingensis Yu(Fig. 2)Body length 2.23-2.40mm, width 1.49-1.63mm. Body elongate oval. Head brown with slightly darker eyes; pronotum brown: scutellum black; elytra black with one pair of reddish brown spots, long oblique oval and being at basal 2/5 of elytron, connected to reddish brown apex (1/3 of elytral length), but the black sutuml line extending to 5/6 of elytron; somctimes the spots are separated from the apex if forming one small spot. Venter brown with black pterothoax and basal two segments Of abdomen.Holotype: ♂(IPEP), 26-X-1995, Yunshanping, Lijiang, Yunnan; Allotyep: ♀(IPEP); Paratypes: 1♂1 ♀(RIFP), same data as holotype.The new species has a peculiar coloration, and if the elytral markings disappear, it resembles S. (P.) dichorionicus Pang et Huang in outline, but differs in male genitalia and punctuation on lst abdominal stemite.3. Scymnus (Neopullus)sinuanodulus Yu et Yao (Fig. 3)Body length 1.91-2.14mm, width 1.25-1.37mm. Body elongale oval with nearly parallel sides. Head brown in male and dark brown in female, eyes brown or darkish brown; pronotum brown with a Back basal marking (the marking may enlarge, but the anterior and lateral margins of pronotum are distinctly brown): scutellurm black; elytra brown with a black marking on the base and a pair of long oblique oval spots, along the suture extending to 1/3 elytral length and the lateral sides extending to 2/3 elytral length, lateral marking slightly expanded posteriorly; the spots being at apical 2/5 of elytron, the distance to suture line shorter than that to lateral side. The spots are occasionally connected by the lateral marking. Underside of body Mack with apical part of abdomen brown, sometimes mouthparts, prothorax also brownish; legs brown to dark brown or black, usually darker in female.Holotype: ♂(IPEP), 1-XII-1995, Ningliang (27.2°N, 100.8°E, Lijiang); Allotype: ♀(IPEP), 22-X-1995, Heyuan(26.7°N, 99.9°E, Lijiang); paratypes: 1♂ 2 ♀(IPEP), same data as allotype; 3♂ 3♀ (RIFP), 26-X-1995, Yunshanping. Lijiang.The differences are given with next species.4. Scymnus (Neopullus)camptodromus Yu et Liu (Fig. 4)Body length 1.89-2.19mm, width 1.16-1.35mm. Body elongate oval. Head brown in male, dark brown or black in female with brown mouthparts and Hack eyes: pronotum black with brown narrow anterior margin, sometimes with brown anterior comers; scutellum black; elytral brown with triangular marking at base, along the suture line extending to 1/ 3 of elytral length at most; basal 4/7 of lateral sides Back. The Back area on elytra are always contmcted, leaving only the elytral base dark, but superftcially the figured marking can be observed for the tmnsparent elytra and the dark scutum and scutellum of metathorax. Venter black with apical segments of abdomen brown; legs brown with femora and tibiae largely black, or undenide entirely black.Holotype: ♂(IPEP), 22-X-1995, Heyuan. Lijiang; Allotype: ♀(IPRP); Paratypes: 12 ♀(2 in IPEP, 10 in RIFP), same data as holotype; 5♀ (RIFP), 14-X-1995, Ningliang, Lijiang: 1 ♂, 13-V-1995, Baoxin(30.3°N, 102.8°. Sichuan); 1♀, 15-Vl-1995, same place as previous One.Some specimens of the above two species have incomplete postcoxal line of lst abdominal sternite. The former speceis is named after the sinuate inner margin of nodulus of receptaculum semnis and the latter one is named after the nearly arc-shaped inner margin of nodulus. The two new species resemble each other, although quite different in colour pattern and are distinguishable frorn the following chamcters: S. (N.) sinuanodulus with median piece of tegmen distinctly longer than lateral lobes, infundibulum of female invisible; S. (N.) camptodromus with median piece slightlyshorter than lateral lobes, infundibulum visible. The latter species also resembles S. (P.)suturalis, but differs from the male genitalia and female infundibulum.5. Pseudoscymnus truncatulus Yu (Fig. 5)Body length 2.05mm, width 1.45mm. Body oval. Head yellow with Mack eyes, mouthparts yellow with reddish brown terminal part of maxillary palpi; pronotumyellow; scutellum yellowish brown; elytra black with basal extemal corners yellow andapical 1/5 yellow, sutural line brownish. Venter yellow with black pterothorax anddarkish basal part of lst abdomen; legs yellow.Holotype: ♂(IPEP), 22-X-1995, Heyuan (Lijiang, Yunnan).The present species is closely related to P.fulvihumerus Yang et Wu from Taiwan, but the latter's hind margin of 6th abdominal sternite is emarginate and the medianpiece of tegmen is relatively broad. It is named after the nearly truncate hind marginof 6th abdominal sternite medially.

The differences and radial variation patterns of tracheid length, width. slendemess and the relationship between the mechanical properties and tracheid morphology among different heights and four cardinal sides within 5 Chinese Fir trees from Zhejiang province were detemined and analysed. The profiles of tracheid morphology at different heights and different carinal sides are roughly similar (except the profiles of slendemess at cardinal sides). There are significant positive comalations between the tracheid morphology and age. Boad variance analysis shows that there are no significant differences between tracheid morphology at different heights and different cardinal sides(except the slendeness at cardinal sides). There are significant diffbrences between tracheid morphology at different ages. MOR, one of main mechanical properties, significantly comelates with tracheid length, any correlations between other mechanical properties and tracheid morphology cannot find.

Molecular species of phosphatidylglycerol in leaves of Ginkgo biloba, Chinese fir and Poplar were analyzed by HPLC on a C₁₈ column with acetonitoile-2-propanol (80 : 20, v / v) as mobile phase. 8 molecular species of PG were found in these 3 trees, they are (18:3/16:1〈3t〉)PG. (18:3/16:0)PG. (18:2/16:1〈3t〉)PG. (18:2/16:0)PG. (18:1/16:1〈3t〉PG, (16:0 /16:1〈3t〉PG, (18:1/16:0)PG, (16:0/16:0)PG, The relative amounts of these 8 molecular species in 3 bees are significantly different: (mol%) Ginkgo biloba, 30.5, 12.6, 1 7.9, 22.4, 0.2, 5.1, 4.0, 5.3, Chinese fir, 6.4, 16.1, 1 1.5, 33.2, 0.3, 3.0, 19.8, 7.3, Poplar, 10.1, 10.6, 10.6, 14.1, 8.4, 22.3, 12.5, 11.3.

In this paper, relation formula of spindle speed, cutting speed and time of lathe, and relationship of dynamic moment total cutting resistance, motor rotation andchange of block diameter are found out by the study and calculation of basic theory of lathe principle, peeling curve, dynamic moment dynamic and static power and combining mechanics with electdcity. It gave out dependable theory foundation for the caculation peeling time, producdvity and producing cycle, determining process parameter, peeling speed and rotation, calculating dynamic and static power and therange of adjusting motor rotation.

Nutrient contents, chemical properties and enzyme activity of soil in a Larix principis-rupprechtii forest plantation were investigated in middle zone of south-facing slope of the Qinling Mountains. Compared with the soil of Picea wilsonii forest and that of mixed stands of coniferous with broad leaved species at similar site, nutrient contents of the soil in the larch forest were lower, especially the available phosphate; capacity of exchangeable cation capacity of exchangeable base and degree of base saturation of the soil were less, ability to preserve fertility and fertility index was decreased; the enzyme activity was obviously lower, in particular that of phosphatase. Simillar variation was found between nutrient contents and enzyme activity in the soil profile.

Dictyophora echinovolvata Zhang. Zeng et Hu. is a new species of the genus Dictyophora, which is closely related to D. indusiata and other species in sporophore form, its sporophore is always covered with echinulate myceliot projection. Though its sporophore is smaller, it has significant VB, VC and aminoacid contents. This species is thermophilic and has maximum of basidiocarp growth at 30℃-35℃ or above.

The bethylid wasps, Scleroderma sichuanensis Xiao is a new natural enemy of the longhom beetle, Semanotus sinoauster (Gressitt), which is a destructive insect pest of the Chinese fir, Cunninghamia lanceolata (Lamb.) Hook. It was firstly found in Lu County Forest Farm of Sichuan Province in 1994. Under laboratory conditions, it can reproduce on a series of hosts such as longhom beetles, wasps and lepidopterous larvae.There are 3 to 4 generations during a year in Lu County. Winter is passed as adults in the pupal tunels. The adults are longevous, and the females have high fecundity and sex ratio. The developmantal threshold of the eggs is of 1 4.4℃ and the accumulative effective temperature is of 346 degree day.