Through investigation of 77 gaps in a 3. 2hm² virgin old-growth Korean pine-broadleaved forest in Jiaohe forest farm, regeneration responses of 13 main tree species to gap size and gap developmental phase were studied. The result showed that the regeneration densities of trees changed with gap size, revealing a unimodal curve. Regeneration densities of three tree species among the 13 peaked at the gap size of 40~60m², while those of the other 10 species peaked at the gap size of 20~40m². The responses of tree species to gap developmental phase revealed three types i.e. the unimodal curve type, the double-modal curve type, and the no significant response type. The regeneration density of each tree species in gaps was greater than their corresponding regeneration density in non-gap stands.

A 1.5 kb fragment of ACC synthase cDNA fragment prepared from total RNA of soybean was amplified by polymerase chain reaction (PCR) and cloned into pGEM^®-T vector. The cloned ACC synthase gene was further inserted into a binary vector, pBin438, in an inverted orientation between the CaMV 35S promoter and Nos 3'termination sequence (pBACS). Transgenic poplar plants were obtained by regeneration of Agrobacterium-mediated transformation of leaves of Populus deltoides. PCR and Southern blotting analyses confirmed the integration of a single antisense ACC synthase gene in transformed poplar genome. The results form reverse transcription PCR (RT-PCR) of RNAs isolated from transgenic poplar leaves confimed that the antisense RNA of ACC synthase presented in these transgenic plants. The amount of ethylene released from transgenic poplar was reduced significantly to about 22% of that released from non-transformed control poplars.

In a small watershed with an area 21370 m² covered, with the mixed forest of Pinus massoninana and broad-leaved trees, the cycling process of K、P、Ca、Mg、Zn、Cu、Fe and Mn, including their accumulation, retention, leaching, return, uptake and average budget has been studied from 1993 to 1995.The experimental results show that the total amount of mineral elements in the rainfall input into the mixed forest ecosystem was more than the output from the system in the runoff from 1993 to 1995, and the stand was on positive succession with higher using and cycling efficiencies.

The sample plot investigation and stem analysis were conducted in order to study growth rhythm of 30-year-old Manglietia hainanensis and to analyze the relationship between the growth and site environments. The resuits indicated that:(1) Manglietia hainanensis, an indigenous timber tree species, grew quickly, and its annual increment of tree height, stem basal and breast height diameter, and tree volume had many peaks. (2) The time with high peak of annual growth increment of breast height diameter was the llth year after planting, it was ahead of the time of tree height growth peak. (3)In the early 8 years of growth, the tree volume growth was extremely slow with annual growth increment less than 0.0009m³, then the annual increment became quickly, and the first high peak value(0.00868 m³)appeared in the 17th year. (4)In the view of mean annual increment, the change of stem basal diameter icrement was quite, the increment of breast height diameter was going up steadily from 0.1 to 0.59 cm/a in the early 14 years and then descended extremently slowly, the tree height increment presented ascendant tendency in the early 19 years and then declined slightly, the tree volume increment continuously increased along with age increase. (5) The difference in soil moisture, soil fertility and other environment conditions of different slope position caused the distinct growth of Mangtietia hainanensis, the tree height and breast height diameter in down slope site were larger 37.5% and 29.1% respectively than these in upper slope site. (6) The change tendency of annual growth increment of tree height, stem basal and breast height diameter was in accord with that of the rain/evaporation rate(R/E)in this area.

This paper deals with the relationship between storage temperature and sprouting of the chestnut. The results showed that the dormancy state was strongly effected by storage temperature. When chestnut was stored at 0℃~2℃, the dormancy state was 3 months, that was 1 month longer than stored at room temperature(20℃~22℃). Dormancy was relieved in March when chestnut stored at the temperature of 0℃~2℃, the respiration and the contents of the phytohormones (IAA, GA₃, ZR) in embryonic bud were increased, the seeds began sprouting. The author tried regulating the storage temperature from 0℃~2℃ to-2℃~-4℃ at the end of February before the dormancy was relieved. It was appeared that the respiration and the hormones were not increased, the seeds remained in the dormant status and not sprouting. The chestnut and their embryo were not in jured, and had a normal vigor and quality after storing for 8 months.

The fungal group, including the genera of Dothiorella Sacc. (its sexual phase is Botryosphaeria Cas.), Dothichiza Lib., Cytospora Ehrenb. and Coniothyrium Sacc. presently are the most important forest pathogens in China. In this paper, the tested fifteen isolates of the group are divided into four clusters by the methods of 28S rDNA-PCR-RFLP and RAPD analyses. Each cluster just corresponds to one genus. So, the objectivity of the traditional taxonomy of these genera is proved in the molecular level.

Seventy-six imlates from root-knot nematodes(Meloidogyne spp.)eggs and adults were tested on water agar for the parasitism to eggs of M. Incognita. There was substantial variability in parasitism among isolates of the same species and the different species, which showed that this is a good method to test the parasitism of fungi to eggs. The parasitic rates of 10 of the 76 isolates were over 50%. As for Paecilomyces lilacinus, Verticillium chlamydosporium and V.lamellicola, the parasitism to eggs had no obvious difference among M. Incognita, M. Arenaria and M. Javanica, which indicated that these 3 fungal species may be effective agents for controI of root-knot nematodes. The experiment of the culture filtrates of parasitic fungi on the root-knot nematodes was firstly carried out. The result indicated that the culture filtrates of most parasitic fungi are highly toxic to juveniles. The culture filtrates of 24 of the 28 isolates in gliotoxin-fementation medium had high toxic to the juveniles of M. Incognita in 4 hours. Juveniles inactived rates were 56%~l00%. The culture filtrate of P. Lilacinus 54 resulted in 100%of the juveniles inactived in 4 hours, 100%mortality in 48 hours. The pot experiment of tomato seedlings in autoclaved soil showed that P. Lilacinus 54, 326 and F. Oxysporum 494 were more effective for control of M. Incognita, the root-knot index reduced 76.7%, 60.5%and 53.5%, respectively. All six isolates tested reduced 34.9%~93.5%of the number of galls.

The effects of AMF alkaline phosphatase(ALP)activities on Hippophae rhamnoides drough-resistance under water stress condition were studied with the histochemical techniques.The result shows in the mycorrhizae the total hyphae and functional hyphae form the base for the active hyphae,and amounts follow the order of total hyphae > functional hyphae > active hyphae.Active hyphae play an important role in the biomass accumulation of the hosts; the hyphae with phosphatase activity have a positively strong effect on Hippophae rhamnoides growth and its drought-resistance,and with the rise of ALP,the fresh weight of the host trees increases and wilting coefficient lowers.The direct participation of ALP in the exchanges of P nutrient substance of host trees can improve the nutrient and water condition,and raise the drought-resistance of the trees as well.

In Heilongj iang,Jilin and Liaoning Provinces,the distributions of Ice Nucleation Active (INA)bacteria on poplar trees were universal.The bacteria produced INA under-4℃~-6℃temperature. They belonged to 3 genera and 5 species or varieties:Pantoea ananas Serrabo; Erwinia uredovora(pon et al.)Dye; Pseudomonas syringae pv.syringae Van Hall; P.Syringae pv.lachrymans(Smith & Bryan) Dye and P.Syringae pvs..In nature,freezing inj ury of poplar trees can be increased by INA bacteria. The duration produced freezing injury by INA bacteria was the early stage of poplar tree buds sprouting in spring.Most of INA bacteria strains were isolated from large lesion cankers caused by Dothiorella gregaria Sacc..Lowest of INA bacteria strains were isolated from blister lesion cankers caused by the same fungus. After inoculation of INA bacteia and freezing at -6℃temperature 6 h,the incidence infected by D. Gregaria was increased and large lesion cankers were formed.It proved that,the freezing injury and otherwounds are the major reasons to form the large lesion cankers caused by D.Gregaria.It is suggested that integrated control are necessary to the freezing inj ury caused by INA bacteria and canker caused by D. Gregaria on poplar trees.

The composition of larch cone and foliage volatiles mainly consist of monoterpenes with mostly αpinene,β-ocimene,β-pinene,laurene,3-carene,β-phellandrene There are only quantitative differences between volatile emission of cone and foliage. However,volatile composition varies significantly at different cone development stages which corresponds to larch cone fly (Strobilomyia spp) development In early May before cone fly laying eggs,there are no dominant volatile components and all six monoterpenes are relative low. From midMay to late May when cone fly oviposition peak occurs,the contents of the six monoterpenes are obviously higher in the cones being laid eggs by cone fly than cones without eggs. We also found that relative quantity of cone volatiles varies greatly among different clones or different trees of the same clone,the same is true with cone damage rate. Lightly damaged cone showed the higher content of laurene and β-phellandrene. While heavily damaged cones showed lower content of the two compounds But the lowest damaged cone group revealed relativly higher content of β-pinene,laurene,3-carene and β-phellandrene. In the foliage volatiles,when relative quantities of the six components are very low,cone damage is low. Cone damage increases as the relative quantities of β-pinene and 3-carene increase.

This paper studies the mechanism and origin of linear flow components (viscous flow and slip flow, or Knudsen diffusion) and nonlinear flow component, which occur in fluxes of the compressible fluid permeating through wood. The viscous flow exists in all the capillaries which the fluid flows through, and the slip flow only exists in those whose dimension of pore crosssection is equal to or less than mean free path of fluid molecule. Due to kinetic energy loss at the entrance and exit of a capillary, the nonlinear flow may be brought about when the compressible fluid permeate through wood. In case of the occurrence of the nonlinear flow, Darcy's and Poiseuille's laws are no longer applicable to the permeating flow. One must affirm whether there is the nonlinear flow and avert its effect on the permeability when calculating the wood fluid permeability and equivalent radius of the capillary by means of Klinkenberg equation and Adzumi equation with the measurement data. There is relationship in some degree between wood permeability to compressible fluid and flow pattern of the permeating fluid.

Milled wood lignins(MWL)is isolated from Chinese fir and poplar"Sanbei"No.1 wood.The lignins are characterized on the basis of FTIR,UV,HPLC,¹HNMR spectroscopy and elemental analyses. The results show that:(1)The carbon content in Chinese fir lignin is 1.23%higher than that in poplar "Sanbei"No.1 lignin,but the hydrogen and oxygen contents are respectively 0.22%and 0.85%lower than those in poplar"Sanbei"No.1 lignin.(2)The empirical formulas of C₉ are calculated for Chinese fir lignin and poplar"Sanbei"No.1 lignin as C₉H_8.08O_2.46(OCH₃)_0.94 and C₉H_7.86O_2.33(OCH₃)_1.41,respec-tively based on their nlethoxyl contents and elemental composition.(3)The OH_aliph is 78.8%in total numbets of hydroxyl groups of Chinese fir lignin,and the OH_ph is 21.2%.The OH_aliph is 67.5%and the OH_ph is 32.5%in the poplar"Sanbei"No.1,lignin.(4)The IR spectra of Chinese fir lignin shows the typicalsoftwood characteristics,but the poplar"Sanbei"No.1 is not absolutely coincident with the IR spectra characteristics for the temperate hardwoods.(5)The per-C₉-unit average proton numbers of β—O—4 structures in Chinese fir lignin and poplar"Sanbei"No.1 lignin are 0.33 and 0.50,the β-5 structures are 0.23 and 0.16,and the β-β structures are 0.92 and 0.67 respectively.

Paulownia is a famous fast-growing species with characteristics of fast-growing,super property and multi-purpose and a major species for afforestation in plain region and etc.Since Paulozvnia top buds die of frost in the north of China,its natural trunk extension forms by means of fake two fork branches. Thereby,Paulozvnia has grest sharp degree of stem,small stem form rate,and its wood production is greatly lost.Therefore,For near 40 years Paulownia researchers have been studying Paulownia stem form including heredity improvement of Paulownia stem form,Paulozvnia robust nursery stock cultivation,artificial trunk extension,prune,the relationship between density of stand andmingled plantation and Paulownia stem form aS well as the relationship between above-mentioned measures and Paulownia witches broom etc.A1l research contents Above-mentioned are summarized and a certain number urgent problems about Paulownia stem form cultivation are put forward and discussed in this paper.

The three taxa of the genus,Larix gmelinii(Rupr.)Rupr,L.olgensis Henry and L.principis-rupprechtii Mayr.,are very important timber species in China. However,the classification of these three taxa has been very arguable because different traits are employed by different authors. Thus,elucidation of their genetic relationships is of great singnificance in practice,such as the potential utility of heterosis between the taxa. Recent studies assessed using allozymes and cpDNA markers showed that there were very closely genetic relationships among the three taxa,implying that their divergences probably occurred very recently. In this review the probable process for the formation of L.olgensis and L.principis-rupprechtii was discussed in detail,including possible routes,the time scale for divergence and the definition of species. According to the concept of biological species and the genetic variation of different traits,it would be more reasonable to consider L.olgensis and L.principis-rupprechtii to be two varieties of L.gmelinii other than two separate species.

We propose that:(1)To price natural resources is the prerequsite for implementing sustainable development.(2)To establish complete operable compensation system for forest ecological benefits is the basis of sustainable forestry.(3)Using long-term measurement of forest ecosystems, together with relative data provided by forest resource inventory, hydraulic and meterorological departments, we estimate the various forest benefit values of Heilongjiang Province, including those for visible and invisible products. Transferring the"products"to currency value using equivalent replacement of beneficial products for currency and standard dimension, the total value is 498.687×10⁸ yuan which takes up 32.7% of the total annual average provincial production(1522×10⁸ yuan).In the total forest benefit value, the ratio of visible (economical)to invisible(public benefits)product value is 1:5.83.(4)The total annum compensation value for visible products is calculated, based on national and provincial situations, to be 13.79×10⁸ yuan, and that for invisible 83.78×10⁸ yuan.At last we put forward different compensation approaches and shared value depending on various compensation hosts.

Succession of the aerial seeding vegetation in the Maowusu Sandyland can be divided into three periods or stages, the first stage is aerial seeding plants dominated communities stage, the second one is dominated by both aerial seeding plants and natural plant, especially Artemisia ordosica, and the third stage is called natural plants or A. ordosica dominated community stage. With regard to the time of each stage maintained or the rate of succession, the stage dominated by aerial plants is no more than 20 years at most. The period of the first two stages together is less than 35 years, that is to say, 35 years after the aerial seeding A. ordosica will occupy predominance in communities, and the aerial plants will exist only as accompanying species.

Constant head method was used to measure saturated hydraulic conductivity(Ks)of 26 soil profiles between 100 to 1000 m above sea level.The relationship between Ks and soil texture and.Soil bulk density, the regulation that Ks changes with soil depth, the difference of Ks between undisturbed and disturbed soil were analysed in this article.It was also pointed out in this article that the range of Ks in Beijing Xishan is between 1.3·10^-2cm/min and 14.9·10^-2cm/min; the value of Ks drops from 6.5·10^-2 cm/min to 3.7·10^-2cm/min with the depth increasing; the value of Ks goes down with the increasment of content of clay particle; the value of Ks in undisturebed is two time larger than that of disturbed soil, but they were in the same quantify degree.

Olive leaves began to fall off from branches in early October, between early November and end of December was the peak stage of lear abscission, up to next February, over 95%biennial leaves detached from branches.This lear abscission law was very different with original region of olive.During Ieaf abscission phase, SOD activity was quickly decreased, in biennial leaves, the SOD activity decreased from 280μg^-1 FW in early October to 130μg^-1 FW in early December, and productivity increased from 7.1×10^-2μmol·g^-1 FW in early October to 31.4×10^-2μmol·g^-1 FW in middle November, afterwards, it decreased.The lipid peroxidation was increased, MDA content increased from 13 nmol·g^-1 FW in early October to 41 nmol·g^-1 FW in middle November.During leaf abscission phase, the total polyamines content was quickly decreased, which in biennial leaves from 42.5μg·g^-1 FW in early October to 18.6μg·g^-1 FW in early November, among 3 polyamines, putrescine relative content was increased, the relative content of spermidine and spermine was decreased.

The humic composition(HA and FA), light density of humic acid, combined forms of the soils in the stands of broad-leaved forest and Chinese fir stand of the first, the second, the third planting were studied comparatively.The results indicated that, with the substitution of Chinese fir plantation for broad-leaved forest and the increasing continuous planting of Chinese fir, the soil organic matter and humus decreased, the ratio of HA to FA and E₄ value went down, E₄/E₆ increased, loosely and tightly combined humus contents and its ratio descended.The soil humus quality declined obviously, which is one of the main reasons for soil degradation at the sites with continuous planting of Chinese fir.

Experiment was established to study the impacts of site management on productivity of multiple generation plantations of Chinese fir.Five treatments(site management schemes) were applied at the harvested site of the first generation of Chinese fir plantation.The second-generation plantation was established at the harvested site and observations were made one year after plantation.Results indicated that:(1)BL₃BM₀ was the most favorable treatment for the growth of Chinese fir and most unfavorable for the ground vegetation.The Chinese fir with treatments BL₂BM₀ and BL₂BM₁ had similar growth to each other, indicating that clearance burning had no significant effect on the growth of Chinese fir for the first year, but the burning significantly reduced the biomass production of the ground vegetation.(2)The total biomass production of one-year-old Chinese fir stand varied with treatments in a same way as the biomass production of the ground vegetation.The biomass of ground vegetation was prominent in the total biomass production of 1-year-old Chinese fir stand.

The syntheses and it's bioactivity of halo-amino-phosphatidic lignin was studied. The aim of syntheses is to obtain the halo-amino-lignin by halogenation and amination of lignin separated from the waste liquor of paper-making factory at first, and then reacted with alky1-phosphochloride to get the halo-amino-phosphatidic lignin. The compound has higher bioactivity to the bacteria through the bacteriostasis testing.