Laboratory seed germination of Pinus tabulaeformis of different provenances and ecotypes were studied according to their responses to various temperatures (20℃, 25℃, 30℃, 35℃ and 20/30℃ of night/day), light conditions (with and without daily illumination of 8 hours), moisture stress (0, -2, -4, -6 bar) and stratification treatment (chilling at 3℃ for 37 days with moistened vermiculite). The moisture stresses were made using PEG-6000 solutions. Results showed that 20—25℃ and daily illumination with sufficient water supply to be the optimum ecological condition for seeds of this pine as a species to germinate while 30℃, especially higher than 35℃, non-illumination and moisture stress (below-2 bar) being unfavorable. Seeds of different provenances and ecotypes had their own germination charactoristics in that they responded differently to these unfavorable conditions and had distinctive dormancy requirement. The south (S) ecotype was most sensitive to high temperature and moisture stress, followed by ecotypes of north-west(NW), south-west(SW), central(C), east(E) and northeast(NE). The sensitivity sequence illumination (from the most sensitive to the least) was: S, NW, NE, C, SW and E. Stratified seeds of S reached a significanly higher germination percentage compared with control. Seeds of E germinated a little better after stratification while C and SW showed no improvement. On the contrary, the germination percentage of NW and NE were considerably reduced by the pretreatment. It could be concluded that the south ecotype seeds developed dormancy requirement in preventing early germination under rather warm and wet weather.

Six ectomycorrhizal fungi, Boletus edulis, B. sp., Suillus grevillei, S. luteus, Chroogomphus rutilus, Xerocomus chrysenteron, have demonstrated their strong abilities to inhibit the growth of some pathogens of plant roots, such as Fusarium oxysporium, F. solani, Rhizoctonia solani, Pythium aphanidermatum, P. ultimum and Agrobacterium tumefaciens in the lab since 1981.In this antagonism experiment, these mycorrhizal fungi were found to be able to destroy the vegetative mycelia of pathogens, and fed themselves on the hyphae fhis, inhibited the formation and germination of conidia, sporangia and sclerotia of pathogens. In the study of antagonistic mechanism, it seems that mycorrhizal fungi could secrete non-volatile active substances which caused the contraction and lysis of the protoplasm of pathogens such as A. tumefaciens even after high temperature treatment at 60℃ for 30 minates. Volatile active substances were also detected. Several mycorrhizal fungi could parasitize on the hyphae of R. solani with haustoria observed under scanning electron microscope.

Pueraria wallichii DC. Is a new favorable bushy lac host. In order to timely, effectively popularize it in production, its biofeature, yielding lac performance, diseases and pests have studied. Results are as follows: 1. High adaptablity, easy grow up in low nutrient soils and increase soil fertility; 2. Short growth circle, easy to sprout, easy propagation and cultivation; 3. Steady yield lac performance and high lac out-turn; 4. Less diseases and pests, easy to control.

The mixed type saw chain was developed by Northeast loggerfellers. This type saw chain consists of the cutter and planer teeth from straight cutter chain and the curved cutter teeth from chipper chain. This type saw chain has been used widely for many years in the Northeast China. An experiment and study on this type saw chain was conducted with the T-2 saw chain experiment desk. The result shows that the cross-cutting efficiency of the mixed type chain on pine and maple tree species is higher than chipper chain. The angle cutting efficiency is a little lower than chipper chain, but the kerf declination is greater than chipper chain and less than straight cutter chain. The mixed chain has shown great advantage in felling over straight cutter chain. As the mixed type chain has various teeth which perform different functions and the number of teeth is greater, so the force and stress on every tooth is less than that on the chipper chain. The domestic chipper chain often subject to breakage due to low quality material and technology. For the time being, the mixed type saw chain should be widely used in China for felling.

The rheological behaviours in compression perpendicular to grain of the Poplar chips sliced by hand with their thickness of 0.8, 0.5, 0.35, 0.25, 0.15mm are investigated saparatly according to rheological parameters by means of the laminated method to make specimen with thickness of 10mm. The results show that the compliance of the chips is higher than that of solid wood with thickness of 10mm, and the compliance increases as the chip thickness decreases. The fact both higher elastic and plastic deformations of chips might be due to occurring in their slicing process causing the damages of strutures both their high molecules and cell wall. The changing tendency in the elastic and plastic deformations resulting from slicing process in certain extent is similar to that those occurring in compression loading. Apart from those factors affecting the rheological behaviour of both solid wood and chips, there are still two factors-chip thickness aud laminating manner with different grain orientations, which have remarkable effects on the rheological behaviours of chips.

An equipment and procedure are introduced for measuring the hydration temperature of wood-cement-water mixture. The effect of 38 wood species on the exothermic reaction of ordinary Portland cement was studied by this procedure. All the species tested are divided into two groups. 24 species includied in the first proup show a rather moderating influence on the hydration reaction of cement, and a peak of reaction temperature appears within 24 gours for each species. However, the other 14 species inhibi cement hydration completely. According to the maximum temperature o hydration and the time required to reach this temperature, the suitability of each species in the first group is estimatod when used as raw material for production of cement particleboard.

This paper reports the advances of the study on the varieties, its killing mechanism, with its resistance of pests, also the salty testing to human beings and livestocks, and the methods used in control of Benzoy lphenol Urea. This insecticide not only has the advantage of its broad spectrum, high effect, low toxicity, low cost and long residual effect, but also has a remarkable benefical results to society, and the environment. The usage of this insecticide has now stepped into practical stage and no doubt will have a brilliant prospects.

A long-term and stationary observation on litter production of 5 forest types which distribute widey and are representative in subtropical zone in China was made. The results show that the annual litter production of various stands was different, the evergreen broadleaved forest was maximum (7.99t/ha) and Cunning hamia lanceolata forest was minimum (4.25t/ha). As a given forest type, the litter fraction had a certain rate, the percentage of leaf fraction is more steady than others. In Quercus forest, leaf fraction was 76% of annual total litterfall and C. lanceolata forest only was 51%. The litter production of forest varied with stands, the dynamic pattern of litterfall was determined by the genetic characteristics of species and the stand condition, the regression equations between litter production and climatic factors were derived.

Soil water balance of the artificial forestland planted with locust trees has been studied quantitatively for years on the water balance plots sets in Ansai soil and water conservation station of loess hilly region in Shanxi province, based on the soil water balance equetion for the soil of artificial forestland. The analyse result shows that the soil is becoming dry because of intense evapotranspiration and the water-sucking effect due to the development of the root system in deep layer if the artificial forest is made on the loess hilly region with semi-arid climate. The providing function of the water stored in deep layer to adjust the need of water from trees will be vanished, thus, only could the trees grow depending on the precipitation in current year. From this point of view, it is thought that the artificial forests deteriorate their own soil water condition constantly, which makes the trees grow slowly and limits the growth amount with water.

This is one of the serial reports of studies of the main food bamboo for panda. This paper deals with the seed-store methods of Fargesia nitida and Fargesia denudata through different time、location、climate、tool、seed-dressing varied medicines and chemicals ⁶⁰Coγ rays. For 462 days, the experiment has been carried out 5 times treated in 46 groups with 18400 grains of seed. The results show that store-time is appropriate not more than one year, and the arid and cold location over 2500 metres above sea level is a good choice. Store-seeds can be stored in tile jar with quicklime (about 5% of seed weight). The moisture of seeds should be keeped in 6—11%. The seeds mixed in thiophanate-methyl、parathion methyl、parathion depterex methyl (about 0.6% of seeds weight) or radiation treatment dealt with ⁶⁰Coγ rays (1000 roentgen) than mixed with zinc sulfate (50ppm), the rate of germination is increased by 16—24.6%. Especially it can prolong seed life.

It was found that the differences between provenances and families were main sources of variation of seedling growth traits of Masson pine through continued 5 years nursery test, and provenance and family selection may result in high genetic gains. Seedling height and base diameter were under moderate or strong control. There was not significant interaction between family and location. The pollen parents in different years highly influence on seedling height of its offsprings.

This paper is based on the 12 year-old Cunninghamia lanceolata at Dagang mountain in Jiangxi provience, 41 piots and 41 average trees were studied. It dealed with ecological characteristics of Cunninghamia lanceolata plantation, the regulation of density effect in different site conditions, biomass as well as productiviety afforestation. According to the method of b value analysis, the results show that the primary and management density in low index of position area must be more than high index of position area, the difference is 600 tree/ha.

In order to find a way of artifical regeneration after cutting trees in west Sichuan alpine forest region, according to the serious conditions of vegetation and climate, five regeneration test plots were established in Lihuo, Daofu, Wongda counties along altitute from 3620 to 3900m in 1984-1987. Microclimate and stock damage and death on test plots were studied. Some better combination of technique had been found. Using these combination in reforestation, survival rate could reach 97% after transplanting 4 years. Death of young trees was mainly resulted from low temperature in summer and water deficit in winter and spring. By means of change microhabitate silviculture mainly by branch shelter could improve survival rate of trees.

The fascited disease of Tungoil tree (Aleurites fordii Hemsl.) was found in Ziyang county of Shanxi Province, China. The result of the electron microscopy study showed that the Bacteria-like organisms (BLO) were present in the sieve elements of the phloem as well as in some parenchyma cells of the diseased plants, but not in those of the healthy ones.

Matsucoccus shennongjiaensis Young et Lu, was found in sheng-nong-jia virginal forest area in westen-Hubei in 1986. It is the main factor causing out of larg quantity of Pinus armandi in this area.This pest has one generation a year, it overwinters as first stage nympha and egg (in a few cases). The nymphs suck sap from the trunks, causing rotting of cortex, flowing of resin, decline and death of the trees. The dying process can be acceraleted by the attack of the secondary pests such as bark beetle and so on.The damage in mixed forest is less than in the pure forest. The larvae of a Cecidomyiid eat eggs of this pest. It may be utilized as a biotic controlling agent of the pest.

The ultrastructure of the wood from the thinned Populus dividiana trees was studied by means of seanning electronmicroscope. Occurrence of tylosis was found with less amount in heartwood as well as in the transitional zone boundary from sapwood to heartwood. This might be one of the major causes of collapse in the process of wood drying. The anatomical features of collapsed cells and the ultrastructure variance after steaming were also studied in order to justify that collapse could be eliminated by steaming treatment.