The seasonal dynamics of soil nitrogen transformation in the three forest ecosystems (Primary fir forest, Fir-birch mixed forest and Secondary fir forest) along a subalpine elevational gradient of western Sichuan were investigated using a method of in situ top-closed incubation. The result showed that there were obvious seasonal variations in the rates of soil net nitrogen ammonification, nitrification, mineralization and fixation. The rates of net nitrogen nitrification, mineralization and fixation were higher in the non-growing season than in growing season, but net ammonification rate was very low and negative. Soil net nitrogen mineralization rate was the lowest in the early growing season, but the highest in the middle growing season. Soil net ammonification rates varied significantly with elevations (P<0.05). During the experimental period, soil nitrification contributed mostly to soil nitrogen mineralization and had a similar seasonality with soil nitrogen mineralization. The rate of soil net nitrogen mineralization at B was relatively lower than those of other two elevations, but there was no significant difference between them. Soil net nitrogen fixation rate was relatively higher in the non-growing season than in the growing season.

To investigate the effect of soil moisture conservation measures and drip irrigation on dynamics of mineral nutrition elements in Ziziphus jujuba‘Linyilizao’ (‘Linyilizao’) leaves, an experiment was conducted in loess hilly regions. The seasonal dynamic changes of nine mineral nutrition elements (including N, P, K, Ca, Mg, Cu, Mn, Zn and Fe) in‘Linyilizao’ leaves under six treatments,i.e. A.drip irrigation and fertilizer, B.drip irrigation, C.straw mulching and fertilizer, D.straw mulching, E.fertilizer, and F.control) were examined. The results showed that the contents of N, P, K, Mg, Mn and Cu elements were increased under drip irrigation and fertilizer treatment. The contents of P, K, Mn, Cu and Zn were lowest in straw mulching treatment, which were improved with fertilizer addition. With the exception of Mg element, contents of the other eight elements were relatively high with fertilizer treatment. The similar dynamics of mineral elements were observed in the growth period. N, P and K contents showed a trend of decrease while Ca, and Mn contents increased; Mg content rose to a stable level, then experienced fall; Zn and Cu contents fluctuated. Fe content increased and then decreased. Accumulation of mineral elements in leaves showed a synergistic or antagonism effect, and the different moisture conservation measures and drip irrigation changed the correlation degree between the elements. The‘Linyilizao’ yield in different treatments exhibited an order of drip irrigation and fertilizer > drip irrigation > straw mulching and fertilizer > fertilizer > straw mulching> control, and the yield of drip irrigation and fertilizer was increased from 47.47% to 143.67% compared with other treatments.

Cold spell often happens in later spring, which causes chilling injury to young leaves of trees. The effects of simulated cold spell in later spring on young leaf vigor of Populus tomentosa were studied in this paper. The results showed that there was a gradual decline in photosynthetic vigor of younger leaves of P. tomentosa with the decrease of temperature (20, 15, 10, 5, 0,-5℃), demonstrated by lowered electron transport efficiency per RC and light reaction activity per excited cross section (ABS/CS_o, TR_o/CS_o, ET_o/CS_o). As a result, structure and function index (SFI_ABS), performance index (PI_ABS), driving force for photosynthesis (DF) and net photosynthetic rate (P_n) of younger leaves of P. tomentosa gradually dropped with the decrease of temperature. The temperature under 10℃ had an obvious effect on light reaction activity of the young leaf. A sharp decrease in light reaction activity and a significant increase in permeability of cell membrane of the young leaf were found at-5℃. However the maximal efficiency of PSII photochemistry (F_v/F_m), energy absorption and trapping flux efficiency per RC (ABS/RC, TR_o/RC) and permeability of cell membrane of younger leaf of P. tomentosa remained steady at 0-15℃. Therefore, the injury of 0-15℃ to younger leaf of P. tomentosa was not serious. However, low temperature caused a significant decrease of chlorophyll and soluble protein content, and a significant increase of malondialdehyde content in younger leaf of P. tomentosa. The above results suggest that decreased chlorophyll and soluble protein content, increased level of membrane lipid peroxidation, and reduced fluidity of thylakoid membrane in the younger leaf caused by low temperature are probably the main reasons, which would lead to a smaller plastoquinone pool (S_m) and a less RC density per excited cross section (RC/CS_o) in younger leaf of P. tomentosa. In addition,-5℃ caused obvious water-soaked injury to the younger leaf. The increased proline and soluble sugar contents in the leaf at low temperature may facilitate P. tomentosa to resist cold spell in later spring.

This article investigated the absorption and accumulation characteristics of Q. acutissima seedlings of different provenances (Wushan and Wulong, Chongqing and Lingbao, Henan) under the combined pollution of Cd²⁺ and Pb²⁺ in the field. The result showed that, under the combined pollution of Cd²⁺ and Pb²⁺ in soil, the average contents of Cd²⁺ and Pb²⁺ in roots of Q. acutissima seedlings were 0.235-12.460 mg·kg^-1, 7.428-370.268 mg·kg^-1, the average contents in the stem were 0.115-7.588 mg·kg^-1, 4.757-142.960 mg·kg^-1, and the average contents in the leaf were 0.072-4.772 mg·kg^-1, 2.873-61.923 mg·kg^-1. The contents and bioconcentration coefficient of Cd²⁺ and Pb²⁺ in the seedlings of the three provenances were in an order of root > stem > leaf. Under the Cd²⁺ and Pb²⁺combined pollution, there was an obvious interaction between Cd²⁺ and Pb²⁺ for the absorption and accumulation in Q. acutissima seedlings. Pb²⁺ promoted the accumulation of Cd²⁺ in each organ of the seedlings. Cd²⁺ promoted the accumulation of Pb²⁺ in the root, and inhibited Pb²⁺ to accumulate in aboveground part. The accumulation and transport capacities of Cd²⁺ were greater than that of Pb²⁺ in the seedlings. The seedlings of Lingbao,Henan provenance could be applied to repair the heavily polluted soil by Cd²⁺, while the seedlings of Wushan,Chongqing provenance could be applied to repair the moderately polluted soil by Pb²⁺.

In order to overcome the low germination rate and plantlet quality of Picea asperata, partial desiccation factors, such as drying approaches, drying time and universality, were investigated with highly synchronized somatic embryos, and a crucial partial desiccation indicator was established based on variation in the embryos morphology and color. The results indicated that the "paper vessel method" was more appropriate for the partial desiccation treatment, and the maximum germination rate was obtained with drying treatment for two weeks. Meanwhile, this study provided a drying treatment program which showed a general applicability for somatic embryos of P. asperata. The marked embryos of green cotyledon, hypocotyle and red radical could universally obtain high germination rate(average 83.63%)and good plantlet quality.

The SRAP-PCR reaction system of Liriodendron was optimized with an orthogonal design to choose the most proper concentrations of Mg²⁺, dNTPs, primers, Taq polymerase and template DNA at four levels. The concentrations of Mg²⁺, Taq polymerase, template DNA were further fine-adjusted with a single-factor design. The optimized SRAP-PCR system (total 20 μL)was as follows: Mg²⁺3.0 mmol·L^-1, dNTPs 0.3 mmol·L^-1, primer 0.9 μmol·L^-1, Taq polymerase 2.0 μmol·min^-1 and DNA template 90 ng, 2 μL 10×PCR buffer and ddH₂O. With the system, genetic diversity of 10 provenances of Liriodendron was analyzed. The results showed that, 182 loci were generated from the 15 screened primer pairs, of which 149 loci were polymorphic. The percent of polymorphic loci was 81.87%. The dendrogram of Liriodendron was constructed based on cluster analysis (UPGMA) with the Package of POPGEN 32.The genetic distance and relative relationship of the 10 provenances of Liriodendron was shown by the dendrogram distinctly. It indicated that SRAP molecular marker could be widely used in genetic diversity analysis of Liriodendron.

The germination rate of annual branches of 11 poplar (Populus) clones were used as a judging indicator to investigate the cold resistance after cold hardiness treatment with low-temperature and freezing-thawing at-40℃ for 24 hours and then transferred to 20℃ for 24 hours repeatedly four times. Five parameters, such as relative electric conductivity, relative water content, water saturation deficit, MDA and soluble sugar, were selected by using correlation analysis for studying physiological and biochemical substances, physical characters, growth traits and phenological phases etc. The parameters were highly significantly or significantly correlated to the hardiness. The five parameters were further converted to integrated index by principle component analysis, with the combination of their subordinate functions to establish an assessment system. Integrated index value of cold resistance of each variety was obtained by measuring the weight and its function value. According to composite index, the sequence of cold resistance from strong to weak was P.×xiaohei, P. ×xiaozhuanica ‘Poplar’, P. deltoides ×(P. nigra var. thevestina ×P. nigra), P. simonii, P. ×canadensis ‘N3016’, P. ×canadensis ‘Guariento’, P. ×canadensis ‘Sacran-79’, P. ×deltoides ‘Liaoyu3’, P. ×euramericana ‘97’, P. ×euramericana ‘Zhongliao1’, P. ×euramericana ‘L35’. The result was consistent with the performance in cold resistance of the clones in field. These clones of poplars could be divided into four groups by cluster analysis. The first group, the first 4 clones in the resistance sequence, had the strongest cold resistance. The second group, including the 5-7^th in the sequence, had medium cold resistance. The third group, including the 8-10^th in the sequence, had relative weak resistance. The last one in the sequence was the worst. The evaluation system provided a technical support to judge the ability of cold resistance of seedlings of different clones, and would be beneficial to others such as breeding for cold resistance, varieties classification.

In this paper, we investigated phenological phases and measured annual growth of two-year-old seedlings of 75 Larix kaempferi and its hybrid clones after afforestation in Dagujia forest station in Qingyuan County, Liaoning Province. The results showed that the hybrid clones, derived from a cross with L. kaempferi as the female parent, behaved matroclinous inheritance in the phenological phases. Variance analysis was performed for analyzing phenological variation among L. kaempferi and its hybrid clones, principal components analysis was used for phenological type classification of L. kaempferi and its hybrid clones and correlation analysis (simple correlation analysis and canonical correlation analysis) were used to analyze relationship between growth and phenological factors. All the phenological phases were significantly different among clones. The seventy-five clones were divided into four phenological types according to the principal components analysis. There were weak negative correlations between spring phenological factors and growth. Initial apical bud formation at the later stage of growth season, apical bud fully formation, and growth period were strongly positively correlated with growth. Leaf unfolding of branches, leaf full expansion from leader bud, initial apical bud formation and apical bud fully formation could be used well to forecast the performance of volume at age 7, and these phenological factors should be considered seriously in early selection.

In this paper, 1-year-old, 2-year-old and 5-year-old Ginkgo biloba L. seedlings were used to investigate the influence of stump, lying seedlings horizontally and transplant on occurrence, morphology, biomass and water content of rooted chichies. The results showed that the chichi occurrence rate of 1-year-old G. biloba. seedlings was 22.00%. The occurrence rate of the stumped 2-year-old seedlings was 58.81% which was highest with the treatment. The occurrence rates of platted or transplanted 5-year-old seedlings were 100.00%. The average No. of chichies per plant of 1-year-old G. biloba seedlings was 1.11. The average No. of root chichies of stumped seedlings was 1.99 in 2-year-old seedlings, which was highest, while the untreated control was 1.08. In 5-year-old seedlings, the average No. of rooted chichies of stumped seedlings was 1.81, while the control was only 1.07. The average basal diameter of root chichies of 1-year-old seedlings was 0.38 cm. The average basal diameter of root chichies of stumped 2-year-old seedlings was 1.39 cm while the control was only 0.99 cm. The mean basal diameter of rooted chichies of stumped 5-year-old seedlings was 2.67 cm while the control was 1.93 cm. The average length of root chichies of 1-year-old seedlings was 0.20 cm. The maximum average length of root chichies of platted 2-year-old and 5-age seedlings were 1.15 cm and 3.93 cm, which those of the controls were 0.58 cm and 2.51 cm. The 1-year-old seedlings had no adventitious roots occurred from root chichies. The stumped 2-year-old and 5-age seedlings had the greatest average No. of adventitious roots, and were 2.58 and 4.06. The 5-year-old control seedlings had 1.93 adventitious roots. The average length of adventitious roots of stumped 2-year-old seedlings was 9.44 cm. The average length of adventitious roots of platted 5-year-old was longest and 25.36 cm. The thickness of chichies was thicker than that of roots and there was a significant difference between them. The proportion of chichi xylon of 1-year-old seedling was 16.98% while the root was 25.29%. The maximum proportion of xylon in stumped 2-year-old seedlings was 23.19%, while the maximum proportion of root in transplanted seedlings was 26.88%. In transplanted 5-year-old seedlings, the proportion of xylon was 35.85%, and the proportion of roots was 32.54%. There was a significant difference between the two and the root. Stumping, keeping plat and transplanting had significant influence on the fresh and dry weight of chichies. The bark moisture content was more than that of xylon, and there also was significant difference in the moisture content between chichies and roots, and the difference became greater as the seedlings grew older. In this article, influence of the different treatments on morphology, biomass, adventitious roots of rooted chichies was discussed.

Effects of drought and rewatering on growth, osmoregulation, and antioxidants of two-year-old potted Quercus variabilis seedlingswere investigated. A weighting method was used to control soil water content, by which produced a different water stress gradient. The results showed that: 1) the plant height, basal diameter, leaf number, dry and fresh weight of root, stem and leaf declined with drought stress. Length of tap and secondary roots increased with the increase of stress degree. 2) Activities of antioxidant enzymes including peroxidase, superoxide dismutase, catalase in leaves elevated firstly and then decreased with the increase in duration and degree of drought stresses. Content of malondialdehyde (MDA) increased, while soluble protein and proline contents increased and then decreased during three-week drought treatment. 3) Under drought stress, the Na⁺ content in root, stem and leaf of Q.variabilis seedlings declined, whereas the content of K⁺ changed little; Zn²⁺ concentration decreased in root and stem, but increased in leaf. 4) After rewatering, activities of the antioxidant enzymes recovered to the control level; but MDA content decreased, with MDA content under severe drought stress was significantly higher than that of control. The content of soluble protein and proline decreased, showing no significant difference with control. Mineral elements in different plant organs also recovered to the control level. Thus, the Q.variabilis seedlings reduced aboveground growth and increased the belowground growth to adapt to drought stress. In addition, under light and moderate drought stresses, the Q.variabilis seedlings protected their leaves from damage through increased activities of antioxidant enzymes and osmotic regulation. With the aggravation of drought stress (duration and stress degree), activities of antioxidant enzymes, contents of soluble protein and proline decreased. After rewatering, physiological parameters of Q.variabilis recovered, indicating that Q.variabilis seedlings have a strong tolerance to adapt to drought stress.

To determine the capacity of transmiting Bursaphelenchus xylophilus by the vector Monochamus alternatus adults, the supplementary nutrition on cortical part of twigs was investigated in glass jars indoor and in wire mesh in forest with pine sawyer beetle adults newly eclipsed throughout its lifespan. The results indicated that the main parts that pine sawyer beetles feeded on were the cortical part of 1-year-old young twigs (accounted 81.96%), 2-year-old and 3-year-old branchs. The adults' feeding area in wire mesh was compared with the feeding area in forest. The data showed that one M. alternatus adult could kill 4.06(1.0-12.9) of P. massoniana plants at 18(14-23)-year-old, demonstrating that M. alternatus adults had a huge transmitting capacity of B. xylophilus. In the epidemic area of pine wilt disease, the death number of host trees caused by the disease and the disease occurrence area could be predicted through the survey on the population of pine sawyer. Simultaneously, the data also showed that control of pine sawyer beetles was a key link of combating with pine wilt disease.

Stratified sampling method, macro-group classification method, and statistical method were used to study the community composition and structure of soil insects in seasonal wet meadow in Zhalong wetland. A total of 4 974 insect specimens were collected, which belonged to 13 order 73 families and 134 species. At the level of order, the individual number of Diptera, Coleoptera and Collembola was absolutely dominant (respectively accounting for 41.7%, 27.1% and 16.7% of the total number of soil insects). The characteristics of horizontal structure of insect community showed that diversity indexes and evenness index in Yuweichang were maximum, richness index in Yantongtun was maximum, in which diversity index, evenness index and richness index of large soil insects in Tumutai were maximum, while the three index of small and medium-sized soil insects were maximum, and the three index in Guanliju were minimum. Cluster analysis showed that four sample plots were divided into three classes.The insect communities in Tumutai and Yuweichang were more similar, and they shared one class.The other two plots each formed own class. The seasonal dynamic of insect community showed that species and individual number in July and September were relatively more, while those in May and November were less. The diversity index and evenness index in July were the maximum.The correlation analysis of diversity index, evenness index and richness index showed a positive correlation. Species-abundance analysis showed that insect community distribution in Guanliju, Yantongtun and Yuweichang conformed to a logarithmic normal distribution, while the insect community distribution in Tumutai conformed to a logarithmic series distribution.

This study aims to explore the effects of ectomycorrhizal colonization on soil microbial community and function of Pinus massoniana seedlings grown in acidified soils by using sole-carbon-source-utilization (BIOLOG). we set three levels of acid treatments, pH3.5, pH4.5 and pH5.6 (control), and applied two ectomycorrhizal treatments (inoculated Pisolithus tinctorius, non-inoculated) in a pot experiments. Masson pine seedlings were inoculated with P.tinctorius (ECM) for 210 days in acidified forest soil originating from Chongqing, Southwest China. The results showed that: 1) Compared with the control treatment (pH 5.6), high acid stress reduced the average vitality, soil microbial richness and diversity indices; 2) With the control treatment, ectomycorrhizal fungi counteracted the effects of mild acid on soil microbial community; 3) With high acid stress treatments, ectomycorrhizal fungi increased soil microbial activity, richness and diversity, and changed the utilization pattern of carbon source.

In this study, experimental sites were respectively set in evergreen broadleaf forest(EBF), coniferous forest(CF), subalpine dwarf forest(SDF)and alpine meadow(AM) along an elevational in the national natural reserve of Wuyi Mountains, and the phospholipid fatty acid analysis(PLFA) was used to examine variations in soil microbial community diversity and its influencing factors. The results showed that: There existed 25 PLFAs that were significantly different in the soil samples from different elevations. The EBF soil exhibited richer PLFAs distribution both in type and amount than the other vegetation types. The microbial activity and functional diversity were decreased with increasing elevation, and in an order of EFB>CF>SDF>AM. The PLFAs biomarkers of three species with the highest contents were 18:1ω9c, 16:1ω7c, 16:00 and cy17:0. The bacterium had the richest distribution, followed by fungus and actinomycetes at different elevations. The Simpson index, Shannon-Wiener index, Brillouin index and McIntosh index of EBF were holistically higher than those of AM. Component analysis(PCA)identified 2 principal component factors in relation to microbial community diversity, explaining 59.23% and 35.46% of the variation, respectively. The PLFAs, which play a major role on first principal component, are 16:1ω9c,a17:0,18:1ω9c and 16:1ω7c, and, which play a major role on second principal component, are i17:0,16:1ω5c and cy17:0. The PLFAs of different microbial groups were closely correlated to the soil physicochemical property and enzyme activities, and the TOC, TN and catalase were positively correlated with the PLFAs of bacteria, actinomycete and protozoon. The soil microbial community diversity was decreased along the elevation in Wuyi Mountain, and vegetative biomass, forest litter, soil nutrient, microzoon and plant roots might be the major factors controlling soil microbial community diversity.

To solve the cost-benefit balancing problem of the oasis farmers operating shelterbelt forest tenure reform, from the oasis of shelterbelts structure and wind effects principle, the points deduction a wide range of oasis protection forest structure management, the rural property rights system shelterbelt windproof benefits evaluation parameter:stumpage index. The stumpage index definition is the protection forest growing stock volume per unit area oases have. The size of the parameters can be more aptly express the pros and cons of the windproof benefits: the larger the individual trees, save the trees more,the better the protective effect, the greater the index of stumpage. It can easily converge with conventional forestry, agriculture statistical indicators, broken down to the county, township and village households, convenient and forestry subsidies, linked to the preferential agricultural policy subsidies. Oasis protection forest inventory control system to provide the basis, in line with the new forest right system rural shelterbelts under dynamic management requires a practical parameters.

Manganese peroxidase(MnP) is secreted by white-rot fungi, it can degrade lignin and various xenobiotics efficiently. Cerrena unicolor was firstly cultured under initial conditions and the curve of its MnP activity was gained. Then, 5 kinds of carbon sources and 5 kinds of nitrogen sources were selected, and two orthogonal tests were conducted to optimize medium compositions and culture conditions of C. unicolor producing MnP. Optimized extracellular MnP solutions were determined to decolour 5 kinds of dyes. Results showed that the most optimal culture parameters for MnP production was fructose 10 g·L^-1, ammonium nitrate 0.2 g·L^-1, Mn²⁺2.67 mmol·L^-1,pH 5.5, 70 mL culture solution in 250 mL flask at 150 r·min^-1 shaking condition, 9 tablets of Ø=8 mm inocula, and temperature 34℃. The highest MnP activity reached 95.47 U·L^-1 after 7 d culture, which was 5.2 times than that produced at initial conditions. Decolorization test showed that optimized extracellular MnP solutions of C. unicolor had effectively decoloring ability to 5 kinds of dyes belonging to 3 kinds of group. The decolorization rate of the 5 kinds of dye all reached maximum after 8 d. On 8 days of incubation, reactive black was almost completely decolorized, the decolorization percent was as high as 98.4%, and at that time the decolorization percents to congo redr, reactive red, crystal violet, and neutral red were also as high as 72.3%-89.4%.

The equation to calculate transverse displacement in mid span of sandwich beam was derived by revision of Reissner theory and considering indentation deformation of central loading. It was shown that the resistance to the shear force of skin was equivalent to the half thickness of honey-comb core. By comparison with test results, Revised first-order theory(RFOT)had higher accuracy than classical first-order theory(CFOT)in general to calculate the transverse displacement of sandwich beam. Furthermore, the transverse displacement of "∥" direction specimens were bigger than "⊥" direction ones because of shear deformation. It was also indicated the transverse displacement including bending and shear deformation were all decreased gradually with increasing core thickness, but the proportion of shear displacement to the total became larger step by step. In addition, shear displacement and cross-sectional stress calculated by RFOT was less than CFOT, but the two theories tended to be identical with increasing core thickness.

This paper presents a new method to study the fractal feature of wood fractures implementing the 3D scanning technology. Abies holophylla and Populus alba were chosen as the materials. The results indicated that the 3D scanning technology could be used effectively in analyzing the fractal feature of wood fractures. It revealed a strong linear correlation between the cross section area of the wood fracture and the logarithm of its distance to the origin. Further, the study showed that the fractal dimensions on the fracture section between the highest point of the wood fracture and the cross section decreases gradually as the cross section moving to the bottom of the fracture. Finally statistically significant differences were discovered among different wood types in fractal dimensions of wood fractures. The mean fractal dimensions of Abies holophylla and Populus alba wood fracture were 2.050 and 2.091.

In this paper, starch was modified by α-amylase, saccharifying enzyme,and hydrogen peroxide. Strongly acid process was used in this paper, the effect of modified starch (MS) addition during the synthesis of UF resins at different pH environments were investigated in detail. The addition of MS had good performance (0.12%-0.179%) in reducing free formaldehyde compared with the unmodified UF (0.3%), formaldehyde emission can reduce from (2.5-1.0 mg·L^-1) to the unmodified UF 4.3 mg·L^-1. Compared the structures of modified UF and the unmodified UF, the carboxyl in modified starch can react with amino group and imino group, which will introduce the glucose five-membered ring into the UF chain. And at the same time, the formation of ester group which was formed by the reaction between carboxyl and hydroxymethyl, the reaction between formaldehyde and hydroxyl in the glucose ring, in some way, also could introduce the glucose five-membered ring into the UF chain, which would play a role in the enhance of the bonding strength and reducing the formaldehyde emission.

Establishment of mixed forests is an essential way to improve the stability of forest ecosystem. In order to select appropriate tree species for mixing with Pinus sylvestris var. mongolica, leaf litters from P. sylvestris var. mongolica and other 10 tree species were collected. The litter samples were cleaned, air-dried, and then cut and mixed with 1:1 ratios. The mixed litters were placed in nylon litterbags and incubated in the potting soil for a 345-day decay period under constant temperature and moisture in lab. The weight and concentrations of 8 nutrient elements in the litters before and after the decay were determined. The results showed: the leaf litter of P. sylvestris var. mongolica had the poorest substrate quality with the highest C concentration and C/N ratio, but the lowest N concentration; The mixed leaf litter decay had greater impacts on microelement release than on macro-elements; Mixture of leaf litters from Platycladus orientalis, Larix principis-rupprechtii, Ulmus pumila or Hippophae rhamnoides with that from P. sylvestris var. mongolica accelerated the release of C, N, P, Cu, Zn, Fe and Mn; Mixture of leaf litters from Populus simonii with that from P. sylvestris var. mongolica accelerated the release of N, P, Cu, Zn, Fe and Mn; Mixture of leaf litters from Caragana microphylla with that from P. sylvestris var. mongolica accelerated the release of C, N, P, Cu and Fe, and mixture of leaf litters from Amorpha fruticosa with that from P. sylvestris var. mongolica accelerated the release of N, P, Cu and Zn. According to a comprehensive analysis, mixed litters of P. sylvestris var. mongolica respectively with L. principis-rupprechtii, H. rhamnoides, P. orientalis and U. pumila showed positive impacts on decay and nutrient release, but negative influences when mixed with R. pseudoacacia, B. platyphylla and Q. liaotungensis.

Fine roots in a forest ecosystem played an important role in global C cycle. We investigated fine root biomass and morphology in 9-year-old Alnus formosana plantations with and without Lolium multiflorum mixture in Danling County of Sichuan Province. The results showed that fine root biomass and average diameter of A. formosana significantly increased with the increase of fine root orders in the two modes, while specific root length (SRL) and root length density (RLD) significantly decreased (P<0.05). As compared with pure plantation of A. formosana, the mixture with L. multiflorum reduced fine root diameter while increased specific root length in soil surface (0-10 cm) and subsurface (10-20 cm), but there was only significant effect of the mixture on specific root length of the first two order roots (P<0.05). Mixture with L. multiflorum significantly increased root length density and biomass of the first two order roots in surface soil layer (P<0.05), however, the last three order roots were in reverse. Mixture with L. multiflorum significantly increased root length density and biomass of the first five order roots in subsurface soil layer (P<0.05). Fine root biomass of A. formosana decreased significantly with soil depth in the two modes (P<0.05). Fine root biomass, diameter, specific root length and root length density were to some extent related with water content, temperature, organic matter content, total nitrogen content and hydrolytic nitrogen content in soil, and the effects of soil organic matter content, total nitrogen content and hydrolytic nitrogen content on fine roots were more significant than other factors.

In this paper, two-years-old seedlings of Quercus variabilis and Platycladus orientalis were subjected to the following treatments: full sunlight+wind; full sunlight without wind; shading+wind; shading without wind, to segregate irradiation from wind effect on growth and morphogenesis of the seedlings. After two-month treatment, wind blowing significantly inhibited height growth of the two species. However irradiation itself did not change their height growth. Diameter growth of P. orientalis was promoted by irradiation, but not related to wind blowing. Both irradiation and wind increased taper of P. orientalis stem, while they did not change taper of Q. variabilis stem. Irradiation with wind enhanced root growth of P. orientalis, but the two environmental factors did not change the root/shoot ratio. In general, wind, but not irradiation, inhibited height growth of the two species. The two species had differential responses of growth and morphogenesis to irradiation and wind. Wind blowing had relatively more significant inhibition to Q. variabilis growth, not only height growth but also assimilation, stomatal conductance, diameter and root growth. In contrast, wind did not significantly change the above processes of P. orientalis except for its height growth. Irradiation promoted diameter growth of P. orientalis, and along with wind increased root growth. However irradiation did not vary the processes of Q. variabilis.