The experiment was carried out on five different species ofPaulownia for callus induction from leaves. MS medium was adopted as basic medium, and from different combinations of NAA and BA the suitable media were determined for callus induction, bud differentiation, and root differentiation of five different species. MS+0.5NAA+4BA, MS+0.3NAA+2BA, MS+0.5NAA+4BA, MS+0.3NAA+6BA, and MS+0.3NAA+8BA were suitable media of callus inductions of leaves, respectively, forPaulownia tomentosa, Paulownia australis, Paulownia fortunei, Paulownia elongata andP. tmentosa x P. fortunei, and MS+0.3NAA+12BA, MS+0.3NAA+12BA, MS+0.5NAA+12BA, MS+0.5NAA+12BA, and MS+0.7NAA+12BA were suitable media for bud differentiation from leaf callus respectively for above five species. The rooting media was determined as 2MS+0.1NAA, 1/2MS+0.1NAA, 1/2MS, 1/2MS+0.3NAA, and 1/2MS+0.5NAA. These results provide reference data for breeding new fine varieties with different kinds ofPaulownia protoplasts fusions.

Black locust (Robinia pseudoacacia L.) is one of the most important stand-forming tree species in Hungary and its importance is increasing in many countries. Black locust plants are commonly produced by two methods, by seed and by root cuttings. Tissue culture propagation can be considered as a relatively new method. Growing trees from seed is a relatively simple method for reliably producing seedlings on a large scale under a variety of circumstances. Mechanization of the method is easy and the production cost is relatively low. Propagation from root cuttings and tissue culture are valuable for reproduction of superior individuals or varieties. By applying these methods, superior traits of the selected trees can be preserved in the clones. Recent experiments demonstrated that micropropagated trees could be successfully transplanted into soil, hardened and grown in the field.

Many important advances in forest biotechnology have been made. The use of genetic transformation and the applications of transgenic trees in modern forestry is now an important field. Two basic methodologies particle bombardment andAgrobacterium-mediated transformation have been used on conifers. However, routine procedures exist for only a limited number of conifers. As a result only a few species have been successfully transformed into stable transgenic plants. The use of a particle bombardment has been more successful and transgenic plants have been produced inPicea abies, Picea glauca, Picea mariana, andPinus radiata, although the level of production of stable transgenic plants is lower than that ofAgrobacterium. At present, breeding programs have been directed toward improving bole shape, growth rate, wood properties, and quality, as well as toward improving root and shoot performance, pest resistance, stress tolerance, herbicide resistance, and ability to resist stresses, which will drive forestry to enter a new era of productivity and quality. This article provides a brief overiew of the current state of knowledge on genetic transformation in conifers.

The exoticSonneratia apetala in Leizhou Peninsula, has shown outstanding fast-growing ability in restored mangrove forests, at the middle and high tide intertidal zone, with year-round fresh water input from drainage. By setting plot and selecting standard tree, investigation and measurement on height growth, diameter growth, biomass, productivity, and so on, were made in aS. apetala plantation at age of six at Lanbel, Fucheng, Leizhou Peninsula in May 2001. The investigating results showed that the mean annual height growth of plantation was 2.03 m and mean annual growth of diameter at breast height (DBH) was 2.35 cm. There exists a significant correlation between the diameter at ground surface (DGS) and DBH. The average biomass of a single standard tree in dry weight was 95.647 kg/m². A ratio of above-ground biomass to under-ground biomass was 1.60. The stand biomass of unit area was 22.955 kg/m², singletree wood volume was 88.23 dm³, and the annual wood volume productivity (P _A) of the same year was 0.407. The forest energy accumulation was 424.851 MJ/m², with annual solar energy fixing rate of 40.68×10⁻⁷%. It is concluded thatS. apetala species had characteristics of outstanding high biomass accumulation and could be used as coastal planting tree species in southern China.

Two-year-old seedlings ofPinus koraiensis, Pinus sylvestriformis andFraxinus mandshurica were treated in open-top chambers with elevated CO₂ concentrations (700 μL·L⁻¹, 500 μL·L⁻¹) and ambient CO₂ concentrations (350 μL·L⁻¹) in Changbai Mountain from June to Sept. in 1999 and 2001. The net photosynthetic rate, dark respiration rate, ribulose-1,5-bisphosphate carboxlase (RuBPcase) activity, and chlorophyll content were analyzed. The results indicated the RuBPcase activity of the three species seedlings increased at elevated CO₂ concentrations. The elevated CO₂ concentrations stimulated the net photosynthetic rates of three tree species exceptP. sylvestriformis grown under 500 μL·L⁻¹ CO₂ concentration. The dark respiration rates ofP. koraiensis andP. sylvestriformis increased under concentration of 700 μL·L⁻¹ CO₂, out that ofF. mandshurica decreased under both concentrations 700 μL·L⁻¹ and 500 μL·L⁻¹ CO₂. The seedlings ofF. mandshurica decreased in chlorophyll contents at elevated CO₂ concentrations.

Soil samples were taken from depth of 0-12cm in virgin broad-leaved Korean pine mixed forest, in Changbai Mountain in July 2000. The effects of temperature, soil water content, pH, NH₄ ⁺ and NO₃ ⁺ on N₂O emission and CH₄ uptake of a forest soil were studied in laboratory by the method of orthogonal design. It was observed under laboratory conditions in this study that there were significant correlations between N₂O emission rate, CH₄ oxidation rate, soil pH and temperature. Nevertheless, N₂O emission rate also showed a significant positive correlation with CH₄ oxidation rate. The results suggested that pH and temperature were important factors controlling N₂O emission and CH₄ oxidation under this experiment conditions.

This study was conducted to investigate the population characteristics of small rodents in different habitats with the artificial presence and absence of dead wood, and understory vegetation after forest cutting at natural deciduous forest in north-eastern South Korea from April to December in 1997 and 1998. Two forests, one hectare each (100×100 m), were selected and designated as the control and the treatment area. Forest structure of mid and high canopy layers in both study areas was similar. But number and volume of fallen trees, and coverage of understory vegetation were higher in the control area than in the treatment area. Total captures of small rodents in two areas combined comprisedEothenomys regulus (55.5%, n-211) andApodemus peninsulae (44.5%, n=169). Total abundance ofE. regulus andA. peninsulae, and population stability were significantly greater in the control area than in the treatment area. The difference in the captured number of two small rodents between the two sites was caused by the difference in reproduction and residency. The structure of forest floor appears to be important to small rodents. The presence of dead wood and understory vegetation after the forest cutting would be necessary for the maintenance of small rodent population in the forest cutting areas.

Root mat method described by Kuchenbuch and Jungk was used to study the rhizosphere processes. The experiment was carried out on two years oldPinus koraiensis seedlings. Soil samples collected from the upper 20-cm soil layer in Changbai Mountain were treated with three different forms of nitrogen fertilizers: NO₃ ⁻−N, NH₄ ⁺−N and NH₄NO₃. The results showed that the soil pH and available P near the roots were all lower than in the bulk soil in control treatment. NH₄ ⁺−N application greatly decreased the soil pH near the roots compared to the control treatment and promoted the absorption of phosphorus, which led to a more remarkable depletion region of available P. On the contrary, the rhizosphere soil pH was higher than in the bulk soil in treatments with NO₃ ⁻−N and retarded the P absorption, which led to a nearly equal available P contents to the bulk soil. In treatment with NH₄NO₃, the rhizosphere soil pH was only a little lower than that in the control treatment and its effects on P absorption is mediate between the treatments with NH₄ ⁺−N and NO₃ ⁻−N.

This paper discussed the keystone species concept and introduced the typical characteristics of keystone species and their identification in communities or ecosystems. Based on the research of the keystone species, the concept of species importance (SI) was first advanced in this paper. The species importance can be simply understood as the important value of species in the ecosystem, which consists of three indexes: species structural important value (SIV), functional important value (FIV) and dynamical important value (DIV). With the indexes, the evaluation was also made on species importance of arbor trees in the Three-Hardwood forests (Fraxinus mandshurica, Juglans mandshurica, andPhellodendron amurense) ecosystem.

Using the methods introduced by Bier, X.H., Buchinock, Wang Jing-wen, Shi Riheet al., different varieties of poplar (poplar-MeixQing, Poplar-A₁₀₀, Poplar-Xiaohe₁₄ et al.) were inoculated with poplar ice nucleation active (INA) bacteria respectively in 1997–1999. The water content, relative turgidity, lignin content, phenylalanine ammonialyase (PAL) activity, electrolyte effusion rate, and inorganic element content of poplar bark were measured before and after inoculating. The results showed that after the poplar trees were inoculated with INA bacteria, the moisture content of bark decreased but relative turgidity increased, electrolyte effusion rate increased and had a peak at temperatures of −4 and 5°C, lignin content increased and positively correlated with poplars’ disease-resistance and the plenylalanine ammonialyase activity increased and also showed a significant positive correlation with poplars' disease-resistance. For the contents of inorganic element, Cu and Fe decreased but K and Zn increased obviously, while Mn, Ca and Mg changed little.

This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technologgy, as well as the existing problem and applying foreground were also discussed.

An experimental area of poplar was established in Songyuan of Jilin Province in 1999 for testing the resistance of different poplar stains toSaperda poplnea. Incidence ofS. poplnea on ten poplar strains were investigated, and the main trophic component of branches of these poplar trees were measured and analyzed in April 2001. The results showed that there existed significant difference in population size ofS. poplnea on different poplar strains, and the branches of these poplar strains have significant difference in nutrient component and content of amino acids. The population size of this pest had a significantly positive correlation with dissolvable total sugar and water content but had no significant correlation with content of total nitrogen and protein nitrogen.

The main mechanical properties of scrimber and Parallel Strand Lumber (PSL), were researched through technological test. Experimental materials of scrimber are small log of Aspen, Dahurian larch and Birch. Experimental materials of PSL come from fishtail veneer strips at plywood plant of Aspen and Birch. In the laboratory conditions low quality small log and wood residues can yield scrimber and PSL with high strength. After the technological conditions of scrimber were compared with that of PSL, the main factors of influencing their properties were separately pointed out and the reasons influencing properties have been analyzed in this paper. The results showed that the hot-pressing pressure is an important technological factor for scrimber. The ratio of veneer-strand length to thickness is a key technological factor for PSL.

Homalotglus flaminus (Daiman) is an important natural enemy of theChilocorus kuwanae. Its biological characteristic, life history, the action style on hosts were studied at Hongqi Forest Farm, Daqing City, Heilongjiang Province from June 1998 to October 2000, in order to controlH. flaminus and raise the control ability ofChilocorus kuwanae toQuadraspidictus gigas pest. The observed results indicated thatH. flaminus has two generation one year in study area, the pupating span is 12.7 d, life span of females and males is 17.6 d and 10.8 d respectively, egg span is 10 d, and the sex ratio of females to males is 1∶3

Phalaris arundinacea L. is fine perennial herbage of Gramineae. Eight treatments including N, P, K, NP, NK, NPK, PK and controls were done for studying its absorbing efficiency of soil nutrition. At tillering stage, the coefficient of absorbing and utilizing of N. P, and K from soil and fertilizer were analyzed according to M.K. Kaeomobk’s formula and the contents of crude protein and fat were also measured. The yields of fresh crop, hay and seed were measured at ripening stage. For N absorbing coefficient ofPh. arundinacea from soil (Kn%), the composition PK treatment is best (12.36%) and K treatment is worse, while for N absorbing coefficient from fertilizer (Ky%), all the treatments are higher than control but the composition NPK treatment presented the highest (14.78%). For the absorbing coefficient of P from soil (Kn%), composition NK treatment is highest (19.30%), but K treatment was lower than control, while for that of P from fertilizer (Ky%), all the treatment were higher than control but the composition NP treatment showed the highest (19.52%). As to K absorbing coefficient from soil (Kn^), NP treatment is the best (19.2%) and single P treatment is worst, while for that (Ky%) of K from fertilizer the composition NPK treatment was best (28.44%). As concerns treatments for the outputs of fresh and dry crop, the composition NP treatment was best and all the treatment were higher than control. The composition NK treatment produced highest yield of seed and highest content of crude protein as compared to other treatments For content of crude fat, the compositions NK and N treatments are best. The experiment indicates that application of fertlizer at proper proportions could increase the yield ofPh. Arundinacea and raise the utilizing efficiency of nourishment element from soil and fertilizer.