Periodical investigation and systematic study of Populus euramericana cv. Ⅰ-214 stand have been conducted for 7 years from planting stock to tree technical maturity according to orthogonal design. The main results show that the tree growth grown in poor soils can be promoted obviously by application of fertilizers. The greatest increment of timber volume in fertilized plots was 132% compared with control plots. The effects of various fertilizers are different, of which Nitrogenous fertilizer is outstanding.The best effect could be got by rational fertilization of nitrogenous, phosphatic and potassic fertilizers.

Axillary shoots were induced with modified DKW medium + 6-BA 1.0mg/L from the dormant axillary buds collected from young trees,mature trees and stump sprouts of walnut. The formation of adventitious multiple shoots was observed in the subculture with modified DKW medium + 6-BA 1.0mg/L+IBA 0.01mg/L. The efficiency of shoots multiplication was near 600% in one month. After being treated in the medium with IBA 5.0 mg/L for 7 days then cultured the medium contained activated carbon, but without growth regulators for 20 days, 54% shoots rooted. Somatic embryos were induced in darkness from immature embryos (from the middle of May to the early of June) cultured in the modified DKW medium+6-BA 1.0mg/L for 30 days. The somatic embryos germinated in the germinating medium without growth regulators within 7 days in darkness. Suspension culture was established from the embryogenetic callus of walnut.

This paper reported the results obtained from both trials of progeny and clonal tests with 46 plus trees of Ulmus pumila selected in Henan province. It was found out that there was no significant differences in growth (height growth and DBH) among plus trees and between the plus trees and control also in progeny test, which might cause by complicated growth conditions and low precision of selecting plus trees, as well as gene recombination But it was revealed that there was significant difference among genotype of plus tree in the some material of clonal test. Thercfore. Phenotypic selection for this species was not so effective as for other conifers, whereas breading by clonal selection was better than mixed selection in cost and effects.

A study on the decline of China fir was made during 1985 —1988. This is a popular disease now occurred in Fujian province of China. The enlarged roots of the trees became as cock-foot caused by the damage of nematode Tylenchulus semipenetrans Cobb,a new host just discovered in addition to citrus. The nematode has 10—12 generations per year. Their generation is metagenesis. Individual development is uncoreplete. Its sex ratio is 56:1 between female and male. Rate of egg hatch in root soaking water is 90%. Its maximum temperatuee for growch is 35℃. Death point of eggs is 40℃. Density of nematodes are increased with the ages of trees and are highest in south slope and lowerest in a mixed stand with Choerospondias axillaris. Distribution of nematodes in soil is coincided with the nutrition roots. Their amounts are mostly in 30—40cm deepth in the middle and lower slope. The aspiration strength and the amounts of N, P, K contained in diseased roots are larger than thoes in healthy ones as well as the activities of multiphenol oxidase, hydrogen peroxidase and iso-peroxidase. Invasion of nematodes induced the parasite of Fusaria in soil; thus caused the decay of roots. Hot water treatment in 40—50℃ soaking the diseased roots had prominently effect to kill the nematodes. Using methamidophos,Carbofuran and ALdicarb in an area of about 24000 acres an effective results of control is 70 —80%. Mixed stands with Paulownia spp.,Choerospondias axillaris, or Sassafras tzumu had less population of nematodes. Cryptomeria fortunei and wild persimmon are also descovered as new hosts.

This paper presents a taxonomic study on the genus Tetraponera Smith, belonging to the subfamily Pseudomyrminae, in China. One species is new to science; one species is reported for the first time in China. All the type specimens are preserved in the Insect Collections of the Forest Research Institute, Chinese Academy of Forestry, Beijing, China. Tetraponera microcarpa Wu et Wang n. sp.Worker (Holotype) : TL 3.4mm; HL 0.72mm; HW0.55mm; CI76; head length with mandibles 0.80mm; scape length 0.35mm; greatest diameter of eye 0.12mm.Head with almost parallel sides, a little narrower behind the eyes; the occipital angles round and the occipital border near straight; antennal scapes short,reaching up to the middle of eyes; antennal segments 3—11 broader than long, the 2nd and last ones longer, the last four segments forming a club; eyes large, placing at lateral and a little to the front of the middle of the head, anterior border of the clypeus as fig. 1. Pronotum and mesonotum rather flat, somewhat convex, marginate at sides; promesonotal suture distinct, unemarginate; mesoepinotal suture strongly emarginate; epinotum raised, very convex. Petiole petiolate; the length of the petiolate part half as long as the one of the 1st node; nodes rounded, the 2nd broader than the 1st. Gaster long and narrow. The tarsal claws simple, without middle teeth.Whole body smooth and shining, densely longitudinal striation on the front of the head, including the clypeus and mandibles. Hairs and pubescence almost wanted except more at the front of the head and the tip of the gaster.Color dark reddish brown, epinotum darker and petiole lighter; mandibles, clypeus, antennae, tibiae and tarsi yellow to yellow brown.Variation: TL 3.3—4.0mm; HL 0. 68—0. 80mm; HW 0.55—0.59mm;CI 75—80. The coloration of this insect variable, from reddish yellow to dark reddish brown.Holotypet worker, Taishan County, Guangdong Province, 25. Ⅷ. 1983, Wu Jian leg.. Paratypes: 24 workers, data as holotype; 2 workers, Fenyi County, Jiangxi Province, 26. Ⅳ. 1989, Wang Changlu leg.The new species resembles T. allaborans (Walker) ,but differs from it by the shape of the clypeus, the ratio between the petiolate part and the 1st node, smaller size, and lighter color.Tetraponera nigra (Jerdon) n. rec.Distributions: Guangxi Province, and Yunnan Province of China; Southeast Asia.

In most of the reported studies on spatial pattern of insect populations,the natural habitat unit (NHU) of population individuals is essentially assumed as point,i.e., the number of individuals within a NHU as basic unit for surveying,assessing and interpreting spatial pattern, But in fact the NHU of insect population is generally a multidimensional structure rather than point. Therefore the much spatial information may be lost owing to this inappropriate assumption. In this paper, pine tree,the NHU of Dendrolimus tabulaeformis,is considered as one-dimensional axis composed of strata of verticillate-branches(SVBs) rather than points. Based on the above idea,spatial patterns of Dendrollmus tabulaeformis larvae and pupae on every SVB were assessed and interpreted with Taylor's power law model and the author's reinterpreted Taylor's power law,and the law of spatial patterns varying among strata was analysed with Fuzzy Clustering Analysis (FCA),Grey Clustering Analysis (GCA) and Trend Curved Surface Analysis (TCSA)methods. Also within-pine-tree vertical distribution aggregation of population was discussed. It coneiudes that: (1)according to the author's reinterpreted Taylor's power law, the spatial pattern of larvae and pupae on every SVB follows inverse densitydependent aggregation,and the critical density m of the population aggregation was calculated, so the spatial pattern continuum on every SVB can be deseribed quantitatively; (2)the resuits of FCA,GCA,and TCSA show that the alw of spatial pattern aggregation varying among Strata is non-liner and oscillatory,and the Strata can be clustered into several types according to the characteristics of the population aggregation; (3)within-pine-tree vertical distribution also follows inverse density-dependent aggregation.

The analysis of the loading force of the home-made and introduced saw chain shows that the designed parameters of the cutting teeth components of the existing universal saw are not completely reasonable. LF serulfs in concenfration of the resulfant of normal pressure, causes leaning wear of links,and shortens the working life of chain. Meanwhile, the function of the worn cutting teeth component is considerably reduced, which affects the mechanical properties of chain saw. In order to reducl there problems, the cuffing teeth component is redesigned in order that the resulfant of normal pressure is distributed uniformly on many points, it is demonstrated through pooduction and tests on the test platform that the working life of the new chain is as about two times as that of the Romemade ones and 1.5 times as that of STIHL in West Germany, its cutting efficiency is 35—116.7 percent higher than that of home-made chain and 3—5 percent than that of OREGON. At the same time, the cutting teeth component is always in a good cutting state and keeps main parameters of the original derignation in the whole production. It is proved that the desiging theory"resultant of normal pressure is distributed uniformly on mang points"is a reliable way to overcome leaning wear of links.

A measuring method of soft x-ray was developed to analyse the variation of propcrtics of wood growth ring. Fourteen species of wood were surveyed and analysed. The results were satisfactory.

The mathematical model of bending logs of curved elliptical cylinder is analysed with the elliptical-archimedes spiral envelope in cylindric coordinate. This kind of logs are definited ar C-typed bending. Based on the measurement of bending by log length and the bending bow back, this papre proposes a formula, by which the bending log volume with practically measured parameters can be calculated. Therefore, the loss of log voeume resulted from bending in calculation bas been quantitatively reduced. with this method and theory the optimum wood recovery of bending logs and optimum cutting of bending tree length can be obtained. This provides a thcoretical base for working out software of numerical control in sawing.

Sampling sites were selected at both burned and unburned stands of Larix gmelinii at Tuqiang Forest Bureau, Da Xingan Ling. The impluence of litter layer or living ground cover on germination of larch seeds and the role of fire in it were investigated in 1988. Significantly negative effect of litter layer or living ground cover on seed germination was fourd, and which can be remitted by fire as a result of removing the litter layer. Another reason was the charcoal produced by fire, which can improve the seed germination conditions to promote germination of Larix gmelinii. In conclusion, fire was a favorable factor for natural regeneration of L. gmelinii in Da Xingan an Ling.

The study on short rotational cultivation began in many countries in the 1970's. In China, the experiment with Populus euramericana cv.' Sacrau 79' on short rotation (spacing of 2×2, 2×3, 3×3m) and mid-short rotation (spacing 3×6, 4×6, 5×6, 6×6m) was initiated in Zhanghe Forest Farm of Handan Prefecture, Hebei Province in 1978. The main results from it are as follows.1. Timber from all three spacings in short rotation stand were good for rafter use by the 4th year, more than 90% of them reached to the commercial maturity standard, and to the purlin standard by the 5th year. The highest productions in both years were from 2×3m spacing.2. The annual mean volume increased by 32—66%, and the annual net income by 560—1961 yuan (according to the timber price in 1983), at the second rotationage compared with the first rotationage, spacing 2×3m had the best economic benefit.3. Higher volume increment and,annual net income were found in about rotation stand including all three spacings at the 10th year. In 2×3m spacing of short rotation stand per ha volume and the net income were 104m~3 and 5055 yuan respectively higher than that in 4×6m spacing of mid-short rotation stand.

Isozyme technique is an important tool for genetic study of forest tree species.The technique has been widely used since seventies. To effectively apply this tool it is necessary to start with distinguishing the allozymes. comprehending the inheritance of isozyme patterns and choosing applicable isozyme markers. In this paper isozyme patterns has been. analyzed and the selection of enzyme and loci are discussed mainly with Pinus tabulaeformis Carr and scots pine clones. This method is universal for conifer species in isozyme studies.

The eslablishment of arificial multi-storied community structure by intercropping paulownia with tea have made the ecological conditions of tea plantation improved. It was shown, on one hand, that the ecological environment regulated by paulownia trees under 37% shading condition was optimum for the growth of new tea shoots, and for improvement of tea quality as a result of increasing the beneficial composition of tea leaves. On the other hand, it can increase the paulownia timber and economic benefit of per unit aera because of sufficient utilization of sun energy in forest land.

Fastidious prokaryotes limited in vascular bundle of several yellow diseased plants were successfully recovered by means of vacuum extraction and alternative centrifugation. Fastidious bacteria were obtained from apple scar peel disease, pear scar peel disease and persimon proliferation disease. MLO associated with paulownia witches' broom disease was also recovered by this method. Electron micrographs showed the noticeable feature of these prokaryotes.The fastidious bacteria are rod-shaped cell, 0.5—1.0×1.0—3.0μm, with rippled cell walls. The globular wall-less cells with a single unit membrane were observed in the case of paulownia witches' broom.The fastidious bacteria extracted from apple scar peel disease were used as antigen to immunize rabbits. The antiserum obtained reacts obviously with the bacteria recovered from apple and pear plants with scar peel disease. It does not show any visible reaction with the corresponding samples made from healthy plants.