[Objective] Study of the effects of thinning and climate factors on the variation of tree ring width will help further deepen our understanding of the factors driving Larix olgensis tree ring width during climatic change.[Method] In this study, radial width profiles from breast height of L. olgensis trees were analyzed using a nonlinear mixed modeling approach. Radial width profiles were sampled from 20 permanent plots (surveyed from 1987 to 2012) in northeast China within semi-natural larch-spruce-fir forests in which thinning was conducted. Each ring width was measured by Lintab 6 tree-ring width measuring instrument before cross dated by the COFECHA software, a total of 231 radial width profiles were used for modeling. The climate data was linearly interpolated from the data of neighboring weather stations since 1964 to 2010. Combining the overlapping periods of each part of the data, the data selected from 1987 to 2010 were used for modeling.[Result] The results showed that cambial age, stand density, competition, thinning and climatic factors had significant effects on tree-ring width of L. olgensis. Thinning was applied on the plots twice in 1987 and 1993, respectively. The first thinning was carried out at stand age of 20, we found that the positive effect of heavy thinning (40%) was stronger than that of the moderate thinning (30%) on ring width, while light thinning (20%) was found not significant. After the first thinning, the growth rate of ring width was accelerated which lasted 4 years and reached its peak at the 2^nd-3^rd year. For the second thinning, only moderate and light thinning intensity were adopted, the effects of both were found to be significant on ring width. However, the positive effect of the light thinning was identified stronger than moderate thinning on ring width. Similarly, the growth rate of ring width was accelerated after second thinning which lasted 15 years and reached its peak at the 4^th-5^th year. Seven climatic factors were found to be directly related to ring width. Varied effects of the climatic factors were found on ring width, the greatest effect was found of the highest temperature in July and the accumulative temperature higher than 5℃ in growing season. The summer hot and humid index was shown less impact, while minimum but significant effects were found in winter precipitation, the lowest temperature in September, the average temperature in April and precipitation in May. The determination coefficient of model was significantly improved from 0.37 to 0.73 by introducing a random effect of model intercept at the plot and the individual levels.[Conclusion]The heavy and moderate thinning can significantly improve the growth of L. olgensis in mixed stands within 4 years following the thinning. Significant climatic effects were identified on the growth of L. olgensis at low-altitudes of northeast China. The highest temperature in July and accumulative temperature higher than 5℃ in growing season were found to be the main limiting factors on the growth. Our results indicate that the climatic effects should be considered in order to accurately model the growth of L. olgensis under current climate scenario.

[Objective] The objective of this study was to determine the construction mechanism of typical mid-subtropical natural broad-leaved forest community by studying spatial pattern and association based on natural stratification of arbor-layer.[Method] Five plots in size of 50 m×50 m set up at a location where the forest is nearly old-growth forest community in Wanmulin Nature Reserve in Fujian Province were investigated. The arbor layers of the plots were divided into sub-layers using the maximum light receiving plane (MLRP) method. The spatial pattern of each sub-layer and association of paired sub-layers therefore could be tested based on the spatial point pattern analysis.[Result] The arbor layer of each plot could be divided into light receiving layer (sub-layer Ⅰ) and none-light receiving layer (sub-layer Ⅱ). Arbor trees in each sub-layer of each plot are mainly in random pattern in the small spatial scale of 0-25 m. Only at a few scales trees of sub-layers deviated from the null model of complete spatial random, among them, trees of sub-layer Ⅰ tended to have a uniform dispersion because of strong competition and almost equivalent competitive power, but trees of sub-layer Ⅱ displayed a cluster pattern because of aggregation growth of some species in that sub-layer. Sub-layers Ⅰ and Ⅱ displayed overall non-significant association, most paired sub-layers displayed the null model at almost all scales indicating an equilibrium between total positive effects and total negative effects derived from various ecological processes.[Conclusion] The studied typical mid-subtropical natural broad-leaved forest communities are structured by neutral factors. The communities are stable and can be maintained for a long time because various ecological processes in the communities are at equilibrium.

[Objective] It is critical to examine the characteristics of hydrogen (δD) and oxygen (δ¹⁸O) stable isotopes in the precipitation as well as the source and migration process of regional atmospheric precipitation in Anqing that help reveal the mechanism of the hydrological cycle in the forest ecosystem of Anhui Province along the Yangtze River in response to climate change.[Method]Using a stable isotope technique, we analyzed the compositions of δD and δ¹⁸O in 155 precipitation samples between June 2015 and June 2017 in Anqing, and examined the local meteoric water line. To analyze whether and how the climatic factor affects the compositions of δD and δ¹⁸O in the precipitation, we established the relationships of δD (δ¹⁸O) to the precipitation and temperature. We traced the sources of atmospheric water in Anqing by calculating the D-excess (d) in the precipitation, and verified the results of the sources through HYSPLIT model.[Result]The relationship between δD and δ¹⁸O in the precipitation in Anqing was δD=(8.08 ±0.06)δ¹⁸O+(10.84±0.48) (R²=0.99, n=155). The stable isotopes δD and δ¹⁸O were significantly negatively associated with temperature (P<0.01), while no significant correlation was found between the stable isotopes and the precipitation (P>0.05). The D-excess(d) was close to the global average (10‰), suggesting that the precipitation in the area was mainly affected by the ocean monsoon. The results of air mass back trajectories of the precipitation were calculated by the HYSPLIT model and showed that there were different sources of atmospheric vapor in Anqing. In spring, the atmospheric vapor was affected by the local evaporation and continental air mass from north and south China, and was likely influenced by the Pacific southeast monsoon when rainfall was heavy. In other seasons, atmospheric vapor sources were mainly impacted by the South China Sea air mass, Pacific southeast monsoon, and southwest monsoon of India Ocean.[Conclusion]In this study, the precipitation in Anqing was primarily influenced by atmospheric vapor from the ocean. Differing from the traditional stable isotopes theory of temperature effect, a opposite temperature effect was found in the precipitation in Anqing, this is probably attributable to the latitudes of Anqing, suggesting that different geographical locations probably influenced the composition of δD and δ¹⁸O in the precipitation. Therefore, further studies understand the influences are needed.

[Objective]The objective of the present study was to reveal the relationship between sugar accumulation and the activity of sucrose-metabolizing enzymes in different Jujube cultivars and different parts of fruits at different developmental stages so as to provide a basis for further improving the sugar accumulation theory in jujube fruits.[Method] The fruits from three different cultivars, Ziziphus jujuba ‘Hupingzao’, Z. jujuba ‘Popozao’, and Z. jujuba ‘Pozao’, were used to determine the content of sucrose, fructose, glucose, starch and the relevant metabolizing enzyme activities in the shoulder and top part of jujube dates at different developmental stages with High Performance Liquid Chromatography (HPLC).[Result] 1) The sugar accumulation started a little earlier in shoulder part than in top part of dates of all three jujube cultivars. The content of soluble sugar in the fruit shoulder was significantly higher than that in the fruit top in all three jujube cultivars (P<0.05). Both fructose and glucose were mainly accumulated at early stage of fruit development, and the content of sucrose was very low in all tested cultivars. Cultivar ‘Hupingzao’ firstly began to accumulate sucrose, and the content of sucrose reached to 3-4 times greater than that of fructose and glucose at maturity. As for cultivar ‘Popozao’, the sugar accumulation pattern was similar to that of ‘Hupingzao’, while the sucrose accumulation in ‘Pozao’ was lastly occurred, and the content of fructose and glucose was much higher than that of sucrose. The soluble sugar content of ‘Popozao’ was significantly higher than ‘Hupingzao’ and ‘Pozao’ at fruit ripening stage(P<0.01). 2) The starch content of jujube fruits in all three cultivars was low over the whole developmental stage(the highest value was 6.78 mg·g^-1FW), and it was lower in shoulder than in top part. The activity of amylase in three cultivars showed opposite trend to that of starch accumulation throughout the process. 3) The metabolizing enzymes of sugar in stem end showed similar activities to that in calyx end in all three cultivars. The acid invertase(AI) activity was always higher than that of neutral invertase (NI). Highly active invertase promoted the metabolism of sucrose at the early stage of fruit development. The activity variation of sucrose phosphate synthase (SPS) was consistent with the change of sucrose accumulation in all varieties. The activities of sucrose synthase in direction of synthetic (SSs) in ‘Popozao’ and ‘Hupingzao’ were significantly higher than ‘Pozao’. The sucrose synthase activity in direction of cleavage (SSd) in three cultivars was low, and no significant difference was detected among different cultivars.[Conclusion]The jujubes of ‘Hupingzao’ and ‘Popozao’ were typically sucrose accumulated fruits, while ‘Pozao’ jujube was hexose-prevalent type. SPS regulated sugar accumulation in ‘Popozao’ fruits, and was also the common key enzyme to control fruit sucrose accumulation of all three cultivars, therefore it could be the main factor of different content of soluble sugar in different cultivars. The sucrose synthase (SSs) enzyme played a key role mainly in the synthetic direction during the course of fruit development. The fruit sugar accumulation of ‘Hupingzao’ was regulated comprehensively by sucrose metabolizing enzymes. Sugar accumulation in ‘Pozao’ fruit was regulated by both SSd and SPS, and amylase played an important role in the starch accumulation in jujube fruits for all three cultivars.

[Objective] Exogenous hormones, penetrant, sugar, coagulant and culture model that have impacts on somatic embryogenesis of nematode-resistant Pinus densiflora were studied.[Method] On the basis of investigation and analysis against nematode-resistant P. densiflora germplasm resources database, two clones 22^#-1 and 13^#-1 of nematode-resistant P. densiflora that the induction and proliferation of somatic embryos at a good state were tested. Somatic embryogenesis was determined by comparative tests of different culture methods and different culture media. The optimum medium and method for somatic embryogenesis and germination and plantlet regeneration were screened. SPSS17.0 and other software were used to analyze the somatic embryos.[Result] The number of normal somatic embryos reached 171 embryo·g^-1, higher than other treatments on the LP medium added with 15 mg·L^-1ABA+140 g·L^-1 PEG8000. Regarding the penetrant, the number of normal somatic embryos of nematode-resistant P. densiflora was up to 179 embryo·g^-1, higher than other treatments on 8 g·L^-1 inositol concentration. Embryogenic callus was directly placed on the maturation medium adding inositol. Embryogenic callus was not cultured on the middle medium. Therefore, the culture time could be shortened by 2-3 weeks. Mature cotyledon embryos were formed around 8 weeks. Regarding the carbon source, cultured on LP medium with 60 g·L^-1 maltose, the number of normal somatic embryos reached 235 embryo·g^-1, higher than other treatments; For the coagulant, when plant gel concentration was 3 g·L^-1, solidification of medium displayed a moderate hardness and cotyledon embryo grew well. Supplemented with polyethylene glycol (PEG) and adding coagulant agar concentration from 6 g·L^-1 to 12 g·L^-1, the medium was not solidified. Callus was unable to grow and no cotyledon embryos were formed. Regarding the culture model, after 11-12 weeks the embryogenic callus developed into mature somatic embryos on liquid-solid proliferation-solid maturation. The number of normal somatic embryos of 22^#-1 was up to 239 embryo·g^-1, higher than other treatments. The somatic embryo germination rate was 67.2% and plantlet conversion rate from the germinated somatic embryos was 46.5%. Up to 32.7% of the transplanted plantlets were successfully survived three months in soil.[Conclusion] Embryogenic callus of nematode-resistant P. densiflora was on the LP medium with 15.0 mg·L^-1 ABA +140 g·L^-1 PEG8000+ 8 g·L^-1 inositol+60 g·L^-1 maltose+3 g·L^-1 plant gel. The culture method was liquid-solid proliferation-solid maturation culture. Normal mature somatic embryos were successfully obtained and regenerated plantlets were transplanted to survive. At the same time, the culture duration could be shortened by 2-3 weeks, and the process of somatic embryogenesis of nematode-resistant P. densiflora was speeded up. Regenerated plants survived through transplanting. This study provides a feasible technique for large-scale propagation and mass production of nematode-resistant P. densiflora.

[Objective] The SBP family genes encode a class of transcription factors which recognize and bind to the promoter of the MADS-box gene SQUAMOSA (SQUA), and regulate plant growth and reproductive growth. Systematic identification and analysis of Phyllostachys edulis SBP family genes can help to understand the role of them in vegetative growth and reproductive growth of P. edulis, and lay a foundation for gene functional analysis of SBP family genes in P. edulis.[Method] The SBP family genes were identified by bioinformatics methods using published P. edulis genomic data. The basic biological information of P. edulis SBP family genes was analyzed by using MEGA 6.0,DNAMAN, psRNATarget and other bioinformatics software. The expression patterns of P. edulis SBP family genes were studied by using the quantitative real-time fluorescence PCR (qPCR) in different tissues including leaf, root and stem, during floral development and under high salt stress.[Result] A total of 18 SBP family genes were identified in the genome of P. edulis, and these genes had a single and highly conserved SBP domain, of which 10 SBP family genes had miR156 target sites. There are 74 amino acid residues in the SBP domain of P. edulis, including two zinc finger domains and one NLS domain. The SBP transcription factors with close evolutionary relationship have similar motif distribution pattern and gene structure. The phylogenetic analysis of the SBP family gene of different species showed that the SBP family genes of P. edulis were closely related to the SBP family in rice. The qPCR result showed that, the relative expression levels of PeSBP11 and PeSBP16 were the highest in stems and roots, respectively. There were six genes (PeSBP1, PeSBP2, PeSBP3, PeSBP7, PeSBP15 and PeSBP17) with relatively low expression levels and no obvious change of expression abundances at P1-P4 stages (early in the formation of inflorescence (P1), the differentiation of spikelet (P2), the differentiation of floret (P3), the growth of spikelet (P4)) during the development of inflorescences. And seven genes (PeSBP5, PeSBP9, PeSBP10, PeSBP12, PeSBP14, PeSBP16 and PeSBP18) expression level increased in the P1-P2, of which high expression level of PeSBP10 and PeSBP14 continued to P3 phase. Seven genes (PeSBP6, PeSBP8, PeSBP9, PeSBP10, PeSBP14, PeSBP16 and PeSBP18) had a higher expression level than other genes in P3. Five genes (PeSBP4, PeSBP5, PeSBP9, PeSBP13 and PeSBP16) had the higher expression value than other genes at stage P4. The relative expression levels of PeSBP2, PeSBP3, PeSBP4, PeSBP8, PeSBP10, PeSBP11, PeSBP12 and PeSBP14 increased gradually with the prolonging of treatment time under high salt stress.[Conclusion] P. edulis SBP family genes were relatively conserved in evolution, and there is not novel SBP genes found in P. edulis genome. qPCR analysis showed that the SBP family genes of P. edulis were involved in the growth of vegetative organs of P. edulis, and played an important role in the flowering process of P. edulis. Under the high salt stress, the expression of four SBP family genes were significantly increased, which were involved in the response to high salt stress.

[Objective] By comparing the GLAS data denoising algorithm based on different window functions and the accuracy of different inversion models of forest crowns, the waveform denoising algorithm is optimized and the inversion model with high estimation accuracy is obtained, which can lay the foundation for the study of forest biomass estimation.[Method] Firstly, the GLAS data are denoised by the Blackman window function and the Gaussian window function, and the effects of two kinds of waveform denoising method is quantitatively compared with the root mean square error(RMSE)and the signal to noise ratio(SNR). Then, the waveform data denoised by the window function that produced a better denoising effect were used to extract waveform data parameters. Four forest types (coniferous forests, broadleaf forests, mixed coniferous and broadleaf forests, and all forests)were included in this study. The linear regression method was used to develop a waveform-parameter model with the waveform length and a topographic-index model with the waveform length and the topographic-index. A full-parameter model was based on the topographic-index model with the height of median energy, the waveform leading edge, and the waveform trailing edge. Finally, the result of the crown height estimations of these three models were compared.[Result] The result show that the Gaussian window function gave a lower RMSE and a higher SNR than the Blackman window function. This indicates that use of the Gaussian window function for denoising provided more accurate data. For all forest types, the predictions of crown height given by the full-parameter model were more accurate than those given by other two models. The predictions of crown height for the coniferous forest given by the topographic-index model(R²=0.853, RMSE=2.519 7 m) were more accurate than the predictions of that model for other forest types. The predictions given for the mixed coniferous and broadleaf forest by the full-parameter model(R²=0.972,RMSE=1.001 4 m)were more accurate than the predictions of that model for other forest types.[Conclusion] In conclusion, the Gaussian window function performed better than the Blackman window function in denoising the GLAS waveform data. For the waveforms reflected from complex terrain, when the new multiple linear regression model was developed that included several waveform data parameters and the topographic-index, the performance of the model in interpreting the maximum crown height was significantly improved. This makes our model overcome the difficulty of interpreting the maximum crown height of forest on the highly sloping terrain, and thus an accurate estimation of forest crown height on complex terrains can be achieved.

[Objective] The effects of different segmentation scales on the object-oriented tree species classification based on high spatial resolution remote sensing image and spaceborne polarimetric SAR data collaborated were studied, and the suitability of tree species classification based on the two kinds of data collaborated was also evaluated in this research.[Method] QuickBird remote sensing image and Radarsat-2 data are used as the experimental data. 3 segmentation schemes, using QuickBird remote sensing image only, using Radarsat-2 data only, and using QuickBird and Radarsat-2 together,are applied in the object-oriented classification. In every segmentation scheme, 10 segmentation scales (25-250, step 25) are adopted, and the modified Euclidean distance 3 (ED3_modified) is used to to evaluate the segmentation quality. In the 3 segmentation schemes, the respective characteristics and the common characteristics are applied separately in support vector machine classifier to carry on object-oriented tree species classification.[Result] On the 10 segmentation scales, the values of ED3_modified of segmentation with QuickBird and Radarsat-2 collaborated and QuickBird only are significantly lower than those with Radarsat-2 only. The best segmentation (ED3_modified=0.34) is gotten at scale 100 with QuickBird and Radarsat-2 collaborated. On the 10 segmentation scales, the OA of 3 segmentation-classification schemes are low at the small scales. The OA improves as the scale becomes bigger, and reaches the maximum at a scale. Then the OA reduces with the scale increasing. The segmentation-classification using QuickBird and Radarsat-2 together gets the best accuracy at scale 100 (OA=85.55%; Kappa=0.86), and the scheme using QuickBird remote sensing image alone gets the best accuracy at 150(OA=81.11%; Kappa=0.82), the scheme using Radarsat-2 data alone gets the best accuracy at 125(OA=66.67%; Kappa=0.68), OA and ED3_modified are highly correlated(R²=0.73).[Conclusion] At all scales(25-250), the segmentation quality and accuracy of using QuickBird and Radardat-2 together are better than any other segmentation result and accuracies of using only one source of data, and has obvious advantages compared to only use Radarsat-2 data. Segmentation scale plays an important role in tree species classification. Good matching segmentation and reference objects can get higher classification accuracies. At the same time, the classification results are not obviously influenced by slightly over segmentation or insufficient segmentation.

[Objective] Arbuscular mycorrhizal (AM) fungi, forming the symbiosis with the majority of terrestrial plants, can facilitate host plants to absorb nutrients from soils and thus improve plant growth. This study aimed to investigate the relationships among AM fungi, plants and soil physical-chemical properties, and to determine the factors affecting the different-aged black locust (Robinia pseudoacacia) growth on the Loess Plateau of China. These result could provide a scientific basis for managing black locust plantation and further reveal their important role in environmental protection.[Method] This study was conducted in Wangdonggou watershed region at Changwu County, Shaanxi Province, China. Soil, shoot and root samples were collected in a chronosequence of black locust plantations including stands 0 (grassland), 11, 23, 35 and 46 years old stands. Soil physical-chemical properties, shoot and root nutrient contents, easily extracted glomalin contents, arbuscular mycorrhizal (AM) fungal colonization rate and spore density were measured.[Result] 1) Along the chronosequence, AM fungal colonization rate firstly increased and then maintained stability, and AM fungal spore density increased linearly; 2) Stand age was significantly correlated with the nutrients status of black locust roots and shoots such as contents of K, Zn, Fe, Mn in roots and N, Cu, Zn, K, Mn, Ca, Mg in shoots; 3) With the increasing stand age, soil available K increased, soil NO₃^--N firstly increased, then decreased and finally increased, and easily extracted glomalin content decreased linearly; 4) In general, black locust growth was synthetically affected by soil physical-chemical properties, AM fungi and plant nutrient status, whereas the factors positively affecting black locust growth varied with stand age. Specially, the growth of 11 and 23 years old black locust was positively correlated with contents of shoot K, Mn, Ca, Mg, Fe and Zn; the 35 years old black locust was positively correlated with contents of soil available K, shoot N and Cu, AM fungal colonization rate and spore density; the 46 years old black locust was positively correlated with AM fungal spore density and contents of root K and Fe, soil available K and NO₃^--N.[Conclusion] 1) Soil physical-chemical properties, AM fungal attributes and plant nutrients varied along the chronosequence of black locust. 2) The influencing factors of black locust growth changed as black locust aged. More specially, the growth of young black locust (11-23 years) mainly depended on shoot nutrient status, while, the growth of mature black locust (35-46 years) was synthetically affected by shoot and root nutrient status, AM fungal attributes and soil N and K content.

[Objective] Myrtenal can be derived by selective oxidation of α-pinene, which is renewable and abundant in China.Myrtenal has been found to exhibit various biological activities. The compounds containing thiazole orhydrazone moieties have been found to show a wide range of biological activities, and have been widely used as blocks for designing bioactive molecules. Therefore,a series of novel myrtenal-based thiazole-hydrazone bioactive compounds can be synthesized by incorporating both thiazole and hydrazone active blocks into the myrtenal skeleton with an attempt to provide a new pathway for the modification and high-value utilization of α-pinene which is a natural and preponderant forest resource in China.[Method] Myrtenal was prepared by the selectively allylic oxidation of α-pinene. Then, myrtenal-based thiosemicarbazone was prepared by the condensation reaction of myrtenal with thiosemicarbazide, followed by the reaction of myrtenal-based thiosemicarbazone with a series of substituted α-bromoacetophenones to yield sixteen myrtenal-based thiazole-hydrazone compounds 4a-4p which have not been reported in the literature. The molecular structures of the target compounds were confirmed by FT-IR,¹H-NMR,¹³C-NMR, and ESI-MS, and antifungal activity of the target products was evaluated by agar dilution method.[Result] Sixteen novel myrtenal-based thiazole-hydrazone target compounds were synthesized.At 50 mg·L^-1, the antifungal activity test showed that all the target compounds exhibited to certain degree antifungal activity against Rhizoctonia solani,Fusarium oxysporum f. sp. cucumerinum,Cercospora arachidicola,Helminthosporium maydis, Physalospora piricola,Colleetotrichum lagenarium,Alternaria solani, and Gibberella zeae. In total, the target compounds displayed the best antifungal activity against P.piricola,and there were twelve compounds with an inhibition rate of more than 60%, in particular, compound 4n (R=4-NO₂)presented the best inhibition rate of 90.6% (A-class activity level).[Conclusion] A series of novel myrtenal-based thiazole-hydrazone compounds were synthesized. These compounds exhibited to certain degree antifungal activity, and among them compound 4n (R=4-NO₂) was a leading compound worthy of deep research.

[Objective] The nano-Ag/TiO₂ wood-based composite materials were prepared by ultrasound assisted impregnation, and the chemical structure and microstructure were analyzed in this study, with the aim to provide a theoretical basis for the new type of nano mildew wood composite research.[Method] With six sodium hexametaphosphate and KH560 as dispersant, the Pinus sylvestris var. mongolica was reacted with nano Ag/TiO₂ to propagate nano-Ag/TiO₂ wood-based composite materials by ultrasonic assisted impregnation. The effects of ultrasonic power, time and nano Ag/TiO₂ concentration on the loading amount and leach-resistance of nano-Ag/TiO₂ wood-based composite materials were studied, and the performance of the crystalline, axial distribution, chemical structure, thermal stability and microcosmic structure of nano-Ag/TiO₂ wood-based composite materials were also investigated.[Result] 1) With the increase of ultrasonic power, the loading amount increased and then decreased. The loading amount of the 75 W ultrasonic wave treated samples increased by 31.5%. With the increase of ultrasonic power, the leach-resistance continued to increase. The leach-resistance of the 300 W ultrasonic wave treated samples increased by 7%. 2) Ultrasonic treatment time has little effect on the loading amount. With the increase of ultrasonic time, the leach-resistance increased and then decreased. The leach-resistance were reached the peak value of 77.73% at 30 min. 3) With the increase of nano-Ag/TiO₂ concentration, the loading amount continued to rise. When the concentration was 2%, the drug loading amount was 3.363 kg·m^-3. The leach-resistance was decreased with the increase of nano-Ag/TiO₂ concentration. When the concentration was 0.5%, the leach-resistance was 78.33%. 4) After ultrasonic assisted impregnation, nano Ag/TiO₂ successfully entered the interior of the wood and attached to the cell wall, the agglomeration phenomenon was reduced and the dispersion and immersion depth were significantly enhanced. 5) The modified nano-particles predicted in the tracheid and attached to the cell walls through hydroxyl hydrogen bond association. KH560 coupling agent grafting not only in TiO₂, and reacted with the hydroxyl groups of wood cellulose. 6) After penetrating into wood specimens, the nano-Ag/TiO₂ retained characteristic structures of anatase TiO₂ and thus retained photocatalytic activity. The decreased intensity of cellulose was due to the addition of nanoparticles having reduced the cellulose content in the specimen. 7) The thermal stability of nano-Ag/TiO₂ wood-based composite materials enhanced and the maximum degradation temperature increased by 11.8℃.[Conclusion] 1) Ultrasonic assisted treatment significantly increased the loading amount and the leach-resistance, and the ultrasonic power had a significant effect on the leach-resistance. 2) After ultrasonic assisted impregnation, nano-Ag/TiO₂ successfully entered the interior of the wood and attached to the cell wall, some of nano-Ag/TiO₂ reacted with the hydroxyl groups of the wood, and the others were connected with wood by KH560. 3) The thermal stability of nano-Ag/TiO₂ wood-based composite materials was improved.

[Objective] Aiming at cutting oak by laser, the influences of single and multiple cutting technology parameters on cutting seam width and depth were investigated, in order to provide theoretical basis to quickly determine the reasonable technical parameters according to the cutting effect requirements for production processing professionals.[Method] The technical parameters of laser cutting machine were used as influence factors, and the depth and width of cutting seam were set as the target of cutting effect. The longitudinal and horizontal comparison method were applied to observe the regularity of data change and proceed experimental data handling.[Result] The results showed that, in the case of single cutting, when lens height was F=3 mm, the seam width was about 0.2 mm; if F=7 mm, the width was about 0.1 mm; if F=11 mm, the width was about 0.3 mm. In the case of secondary cutting, if F=3 mm, the width was about 0.2-0.3 mm; if F=7 mm, the width was about 0.1-0.2 mm; if F=11 mm, the width was about 0.3-0.4 mm. In the case of three times cutting, if F=3 mm, the width was about 0.3 mm; if F=7 mm, the width was about 0.2 mm; if F=11 mm, the width was about 0.4 mm. It was observed that seam width was gradually reduced when lens height increased from 3 to 7 mm, but if the lens height was greater than 7 mm, the seam width began to increase, and the faster increasing rate was found. With the increase of cutting frequency, the seam depth increment became very small when the lens height was the same. Under the same conditions, the more the cutting frequency, the higher the absolute value of seam depth, and the increment of seam depth varied in each cutting. When the cutting speed v ≤ 100 mm·s^-1 and the light intensity was lower than 40%, the seam depth increment decreased with the increase of cutting frequency, i.e. the seam depth became smaller and smaller in each cutting. When the cutting speed v ≥ 100 mm·s^-1 and light intensity was more than 60%, with the increase of cutting frequency, the seam depth increment became bigger but the degree of increasing was relatively smaller.[Conclusion] The extremely significant factor that affecting the seam width was lens height F, when F was around 7 mm, the seam width was minimum, just about 0.1 mm. The seam width was increased when lens height was too large or small, and the growth rate increased quickly if the lens height was too large. Repeatedly cutting would lead the increase of seam width, but it would no longer change when achieved a certain degree. The seam depth increased with the cutting times, but the increasing degree reduced gradually at low and middle speed. The first reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 60% light intensity,the lens height is 7 mm. The second reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 40% light intensity, the lens height is 7 mm.The third reasonable cutting plan is that we can use 50 mm·s^-1 feeding speed, 60% light intensity, the lens height is 4 mm.When large seam depth was obtained by cutting repeatedly instead of adjusting the lens height, the initial height of lens was F=5-6 mm, the light intensity was 50%-60%, and the cutting speed was less than 50 mm·s^-1. In order to obtain big seam depth,the multiple cutting technology with the lens height reducing gradually showed better quality and higher security in comparison with the single cutting method with low speed and high light intensity.

[Objective] The hydrolysis of cured urea-formaldehyde resin(UF resin) plays an important role on long-term formaldehyde emission from UF resin-bonded panels. The crystallinity of cured UF resin also have an effect on the hydrolysis stability. The influence of pH condition during UF resin curing on the hydrolysis stability and crystallinity of cured UF resin was studied.[Method] Four kinds of UF resin with different F/U mole ratios (0.95,1.20,1.35 and 1.50) were synthesized in the lab.The UF resin was cured on different pH (3.5, 4.0, 4.5, 5.0 and 7.5) conditions. The crystallinity of the cured UF resin was measured by XRD. The hydrolysis stability of cured UF resin was characterized by the mass loss and liberated formaldehyde content of cured UF resin in HCl solution(0.1 mol·L^-1).[Result] The hydrolysis stability of cured UF resin with F/U mole ratio of 0.95 increased with the decreasing of pH (from 7.5 to 4.0),then decreased with the decreasing pH (from 4.0 to 3.5),and there was the same trend of crystallinity of cured UF resin in the same pH range. The hydrolysis stability and crystallinity were exhibited the maximum at pH 4.0.The hydrolysis stability of cured UF resin with F/U mole ratio of 1.50 increased with the decreasing pH (from 7.5 to 3.5),and the crystallinity of cured UF resin with F/U mole ratio of 1.50 was much less than 0.95 and decreased with the decreasing pH value(from 5.0 to 3.5).The hydrolysis stability of cured UF resin with different F/U mole ratio under the same pH condition decreased with the decreasing of F/U mole ratio(from 1.50 to 1.20),and then showed an increasing trend (F/U mole ratio changed from 1.20 to 0.95).The crystallinity of cured UF resin increased with the decreasing F/U mole ratio(from 1.50 to 0.95). The hydrolysis stability of cured UF resin with F/U mole ratio of 1.20 and 0.95 was the worst and is the best,respectively.[Conclusion] The hydrolysis stability of cured UF resin with F/U mole ratio of more than 1.20 was mainly affected by condensation degree of cured UF resin. In other words, decreasing pH value was good for improving the hydrolysis stability, but not in favor of crystalline of cured UF resin. The hydrolysis stability of cured UF resin with F/U mole ratio of less than 1.20 was affected by not only condensation degree but also crystallinity of cured UF resin,and the condensation degree affects the hydrolysis stability by means of the crystallinity. The hydrolysis stability and crystallinity of cured UF resin increased with the decreasing pH value, but decreased when pH value was less than 4.0. The hydrolysis stability of cured UF resin with F/U mole ratio of 1.20 was the worst.

[Objective] Aiming at the measurement error and biased decomposition in existing researches, this paper adopts a new estimation method, recalculates 2004-2015 Chinese forestry technical efficiency and total factor productivity (TFP) growth, with a view to understand and evaluate correctly the development model of Chinese forestry industry and the quality of economic growth.[Method] Based on the "one-step" stochastic frontier approach (SFA) and provincial panel dataset (2004-2015), this paper analyses the regional disparity of technical efficiency in China forestry industry and its influence factors. On this basis, the TFP growth and their components in each province and region are measured by the SFA-Malmquist index method. Finally, by dividing the change of TFP into changes in technology and in technical efficiency, the sources of TFP growth in each province and region are analyzed.[Result] The result show that:1) There were widespread inefficiency in China forestry production, and the average technical efficiency is only 0.546 during 2004-2015, still has much room for improvement. 2) In all factors, annual precipitation, the controlled areas of forest pest and the amount of forestry professional technical personnel have a significant positive effect on the forestry technical efficiency, while the occurred areas of forest pest has the opposite effect, and the forest fire disaster area influence is also negative, but not significant. 3) Over the period of 2004-2015, China's forestry annual growth rate of TFP is 16.48%, but this growth is mainly driven by the frontier technology progress, and the technical efficiency improvements had played a side effect. 4) Almost all provinces had got a positive growth in forestry TFP growth, but there was over half of provinces' TFP growth showed deviates from technology progress and technical efficiency improvements.[Conclusion] In the past decades, the growth of TFP in China forestry industry was achieved predominantly by technological progress rather than technical efficiency improvements, the latter has weaken and even dragged the growth of TFP in some provinces. According to the comparison of each province and four regions, almost all the provinces spending a positive TFP growth rate, but there are significantly regional variations in growth rate and there are also regional differences in growth momentum. Therefore, in order to sustain TFP growth of China forestry industry, apart from the continued efforts in increasing the technology innovation investment and promoting technology progress, it is equally important to strengthen the absorption and utilization of existing technologies, and reduce the loss of technical efficiency. The government should adopt the corresponding forestry development policies according to the growth characteristics of TFP in different regions.

Wood rheology is studied mainly focusing on the deformation law and mechanisms of wood under the conditions of stress/strain, temperature, humidity and other circumstances,and its main research field is wood viscoelasticity. The real load-bearing structure of wood is the cell wall, and the structure and chemical composition of cell wall have a significant influence on its viscoelastic behavior. Therefore, having a good comprehension on cell wall structure and viscoelastic properties is of great significance to realize the high efficiency design of wood fiber/plastic composites and pulp and paper manufacturing process. In this paper, the cell wall structure was described from the cell wall S₂ layer and the chemical composition. This paper summarized the influence of S₂ layer microfibril angle and chemical composition on wood cell wall viscoelastic behavior, and the mechanisms of action were explained at the molecular level. In addition, this paper summarized the application of dynamic mechanical analysis (DMA) and nanoindentation techniques on the studies of the relationships between the wood cell wall layer structure and the viscoelasticity. The viscoelasticity of wood cell wall is influenced by the complexity of cell wall structure, diversity of chemical composition and external environmental conditions and other factors, and there are also some interactions among these factors. Therefore, suggestions for future research should be focused on the following aspects:1) To clarify the molecular mechanisms of microfibril orientation and proportion of cellulose crystalline and amorphous region during the growth of wood cells. 2) To illuminate spatial organization arrangement of Matrix in the S\-2 layer of wood cell wall and the expression of the mechanical behavior of the interaction between microfibril and Matrix. 3) To reveal the influence mechanism of content and types of hemicellulose and lignin on cell wall viscoelasticity. At the same time, the external environmental factors (temperature, humidity) and load types (static/dynamic, tension/compression/bending) were brought into the research system to interpret mechano-sorptive creep behavior law and its responsive mechanisms of cell wall, which is under the combined action of "thermo-hydro-mechanical". 4) To utilize various testing techniques, and to introduce the research method and theoretical models of the related disciplines, such as the finite element method and the research method of the composite materials, with the aims to build physical and mathematical models which can explain the viscoelastic properties of wood cell wall.

Megaxyela parki Shinohara is recorded for the first time in China,and it was collected in Tianshui District,Tianshui city, Ganshu province. The species has been recorded only from South Korea. Megaxyela parki differs from its congeners by the black body with antennae entirely reddish brown; thorax, abdomen and legs with distinct reddish brown maculae. The specimen examined here is deposited in the Insect Museum of Central South University of Forestry and Technology.

[Objective] This study investigated the flight parameters and control effects against Fall Webworm (Hyphantria cunea) by using UAV in poplar plantation. The results would provide a new way to control Fall Webworm.[Method]In this study, the droplets drifting distance, deposition density, penetrability and distribution of aerial spray by using UAV (YM-V6) for controlling Fall Webworm in the forest were investigated with water-based staining tracing method.[Result]The result showed that when the UAV was 2.5-3.5 m from the top of the canopy(relative flight height), and the flight speed of the UAV was within 1.5-3 m·s^-1, the droplets drift distance was limited in 2-3 m, spray penetration could reach 10 m, and the density and homogeneity of droplets were well, and as a result, the applying pesticide effect was well. Analyzing the droplets deposition effect in upper, middle and lower of the target showed that when the UAV flight speed was in 2.5 m·s^-1, and the relative flight height was 3.0 m in the plantation, the diameter of droplets in the upper part of forest was bigger, the homogeneity was lower; the diameter of droplets in middle and lower of forest was smaller, and the homogeneity was higher. The deposition density of droplets in up, middle, and lower part was significant different.[Conclusion]The applying pesticide effect was well when the UAV was 2.5-3.5 m from the top of the canopy,and the flight speed was within 1.5-3 m·s^-1. In spraying insecticides of Abamectin and Emamectin-benzoate by the UAV to prevent and control Fall Webworm, we surveyed the insecticides effect after 24, 48 and 72 h, the corrected mortality was about 30%,50% and 70%. The control effect of the single dose of Emamectin-benzoate was better than the single dose of Abamectin slightly.

[Objective] This study investigated the surface fuel loads of Tianshan spruce (Picea schrenkiana) forests in the central Tianshan Mountains,analyzed their relationship with terrain and stand factors, and compared the differences in surface fuel loads among stands at different canopy density levels. The result would provide scientific data and guidance for Tianshan spruce forests fuel management.[Method] Totally 48 plots were set up along an altitudinal gradient in the central Tianshan. The surface fuel loads of 1, 10 and 100 h time-lags and the terrain and stand factors of Tianshan spruce forests were measured. The correlations between fuel loads and the terrain and stand factors were analyzed and a fuel load estimation model was established using multiple linear regression method.[Result] The surface fuel loads of 1 h, 10 h and 100 h time-lags and the total fuel loads were 1.49±1.00, 2.69±1.05, 2.06±0.29 and 6.24±1.21 t·hm^-2, respectively. The total fuel loads in high, medium and low canopy densityies were 12.09±3.13, 4.29±2.35, and 2.34±0.83 t·hm^-2, respectively. The fuel loads with 1 h time-lag were correlated negatively with elevation and positively with slope or canopy density (P<0.05). The fuel loads with 10 h time-lag were correlated negatively with elevation (P<0.05) and positively with tree height or canopy density (P<0.01). The fuel loads with 100 h time-lag were correlated positively with canopy density (P<0.01) and tree height (P<0.05). The total fuel loads were correlated positively with canopy density (P<0.01) and tree height (P<0.05).[Conclusion] The elevation, slope, tree height and canopy density have to a certain degree influence on the surface fuel loads of Tianshan spruce forests in the central Tianshan Mountains, of which the canopy density has the most significant impact on the fuel loads. The canopy density is positively correlated with the fuel loads. The fuel loads were highest in the stand with the high canopy density, followed by the stand with the medium canopy density. Because it is dry in the forest and the litter is not easily decomposed,thus a large amount of surface fuel is accumulated. The higher fuel loads with 1h time-lag in stand increased the possibility of forest fire. From the quantity and composition of the surface fuel load, it can be concluded that the Tianshan spruce forests in the central Tianshan Mountains have the material basis for the occurrence of forest fires.