Objective: This study aimed to screen and identify efficient phosphate solubilizing bacteria from Chinese fir, We investigated its phosphate solubilizing characteristics, and explored ecological adaptability, so as to provide bacterial resources and culture conditions for the development of microbial fertilizer for Chinese fir. Method: Phosphate solubilizing bacteria were isolated from soil and Chinese fir plant by PVK inorganic phosphorus medium, and identified by physiological and biochemical tests as well as 16S rDNA gene sequence. A single factor test was used to analyze the phosphate solubilizing characteristics of phosphate solubilizing bacteria under different pH, temperature, carbon source, nitrogen source and phosphorus source. Result: 1) A total of 20 strains of phosphate solubilizing bacteria were isolated and screened, and the three strains with the strongest phosphate solubilizing capacity were P5, RP2 and RP22 (195.61, 109.20 and 78.86 mg·L^-1, respectively). 2) Strain P5 was identified as Burkholderia ubonensis, RP2 as Pseudomonas frederiksbergensis and RP22 as Pseudomonas grimontii by physiological and biochemical tests, combined with 16S rDNA sequence analysis and phylogenetic tree construction. 3) The results of single factor experiment showed that the P5 strain had the strongest phosphate solubilizing ability when the pH was 5, the temperature was 30℃, the carbon source was sucrose, the nitrogen source was ammonium chloride, and the phosphorus source was calcium phosphate. RP2 showed the strongest phosphate solubilizing ability when pH7, 30℃, the carbon source was glucose, the nitrogen source was potassium nitrate, and the phosphorus source was calcium phosphate. RP22 showed the strongest phosphate solubilizing ability when the pH7, 25℃, the carbon source was glucose, the nitrogen source was potassium nitrate, and the phosphorus source was calcium phosphate. Conclusion: The screened bacteria have high phosphate solubilizing ability among which strain P5 has an efficient phosphate solubilizing ability under acidic and high temperature conditions, which has great potential for the development of microbial fertilizers.

Objective: This study reveals the phytolith and phytolith occuluded carbon (PhytOC) storage in the aboveground organ of Pinus massoniana plantations at different stand ages in subtropical China, and measures the PhytOC sequestration potential in P. massoniana plantations, and provides a scientific basis for long-term carbon sequestration research in P. massoniana plantations. Method: We used a chronosequence approach to examine the effect of stand age on the above-ground part of plant PhytOC storage by sampling 15, 24, 36, 55, and 63 a P. massoniana stands. Phytoliths were extracted by microwave digestion method, and the C concentration in phytoliths was determined. Result: The distribution of phytolith and PhytOC concentrations in above-ground biomass of P. massoniana varied among different organs of the pine trees (P < 0.05). Phytolith concentration decreased in the order of leaf (1.829 g·kg^-1) > branch (0.771 g·kg^-1) > trunk (0.452 g·kg^-1). PhytOC concentration decreased in the order of leaf (0.357 g·kg^-1) > branch (0.172 g·kg^-1) > trunk (0.104 g·kg^-1). Both phytolith and PhytOC concentrations in leaves and branches were affected by age (P < 0.05), while no differences were observed for C in per unit of phytolith in the above-ground biomass (P>0.05). Phytolith concentration in leaves differed with stand age in the order:55 a (2.358 g·kg^-1) > 63 a (1.923 g·kg^-1) > 36 a (1.719 g·kg^-1) > 24 a (1.655 g·kg^-1) > 15 a (1.489 g·kg^-1). Leaf phytolith concentrations were negatively correlated with concentrations of available silicon (R²=0.27, P < 0.05) and pH (R²=0.45, P < 0.05) in the 0-10 cm soil layer. PhytOC storage in branches and trunks accounted for 20.7% and 69.2% of the total storage, respectively. PhytOC storage in above-ground biomass was affected by age and decreased in the order of 55 a (15.97 kg·hm^-2) > 63 a (15.54 kg·hm^-2) > 36 a (10.63 kg·hm^-2) > 15 a (10.46 kg·hm^-2) > 24 a (10.13 kg·hm^-2). The annual PhytOC sequestration rate in the above-ground part of Masson pine stands was affected by age, decreasing in the order as follows:15 a (10.94 kgCO₂·hm^-2a^-1) > 24 a (9.97 kgCO₂·hm^-2a^-1) > 36 a (7.20 kgCO₂·hm^-2a^-1) > 55 a (5.10 kgCO₂·hm^-2a^-1) > 63 a (4.76 kgCO₂·hm^-2a^-1). Conclusion: Both plant organ and age significantly affected the phytolith and PhytOC concentrations (P < 0.05). Taking the area of 1.20×10⁷ hm² of P. massoniana stands in subtropical China and the mean PhytOC production flux of 7.58 kgCO₂·hm^-2a^-1, it was estimated approximately 91 000 t CO₂·a^-1 being sequestered in P. massoniana phytoliths.

Objective: A method of non-destructive detection for the spatial structure of underground bamboo rhizomes in moso bamboo forest by using ground penetrating radar(GPR) was developed, in order to solve the problem that the spatial structure and underground biomass could not be accurately predicted due to the deep underground and inconvenient observation of moso bamboo rhizomes, providing a new idea for the study of underground bamboo rhizomes in moso bamboo forest. Method: The GPR was used to detect the bamboo rhizomes in the sample plots of moso bamboo forest. The information of bamboo rhizomes was extracted after radar data pretreatment. At the same time, the diameters of bamboo rhizomes were estimated based on hyperbolic model, and the biomass of bamboo rhizomes was fitted by diameter (D) and length (L). Then the measured values were used to test the model. Finally, the vertical and horizontal spatial structure of bamboo rhizomes was analyzed. Result: The GPR could effectively detect the position of the underground bamboo rhizomes. The error range of the hyperbolic model for the diameter and length of the bamboo rhizomes were -14.45%-20.66% and 0.53%-8.51%. The estimated error range of the space position in X, Y and Z directions were 0.13%-6.65%, 1.23%-6.55%, and 2.42%-7.41%, respectively. The estimated values were close to the measured values. As for biomass, polynomial model and exponential model using DL and D²L as variables had the best fitting results. The coefficient of determination (R²) ranged from 0.93 to 0.95, and the root mean square error (RMSE) was from 18.3 to 22.4 kg·hm^-2. The simulated results of the exponential and polynomial models with D²L as variables were significantly better than that of the exponential and polynomial models with D, D² and DL as variables. Generally, the exponential model with D²L as the variable was the best fitting model of bamboo rhizomes biomass(BR), while the specific expression was BR=65.17e^0.002D2L. Analysis of bamboo rhizomes spatial structure showed that the vertical distribution of bamboo rhizomes was mainly in 0-40 cm soil layer, in which the number of rhizomes accounts for 91% of the total, while the length and biomass of bamboo rhizomes account for 95% and 93% of the total respectively, and the diameter of bamboo rhizomes in the lower soil (>20 cm) was significantly larger than that in the surface soil (0-20 cm). The underground rhizomes were tortuous, and the spatial distribution was relatively uniform. There was little difference in the diameter of the same rhizomes, but there were significantly differences in the diameter of different rhizomes (P < 0.01). The length and biomass of the rhizomes per unit area in the sample plot were 54 080 m·hm^-2 and 1 001.17 kg·hm^-2 respectively. Conclusion: The results showed that GPR could successfully detect the position information of the underground bamboo rhizomes and obtain the vertical and horizontal spatial structure of the bamboo rhizomes. At the same time, the bamboo rhizomes diameter model and the biomass model also produced the good prediction results, indicating that GPR technology could provide technical support for the study of bamboo rhizomes structure and dynamics and the relationship with above-ground standing bamboo.

Objective: The study was intended to explore the response of radial growth of Abies forrestii and Picea likiangensis to climate factors in the central Hengduan Mountains. In order to provide some basic data for further reconstruction of the history of climate change in Southwest China and to provide a theoretical basis for modelling species distribution and conservation of A. forrestii and P. likiangensis in the context of global climate change. Method: Based on dendroclimatological methods, we established standard chronologies of A. forrestii and P. likiangensis, which are dominant species in the Small Zhongdian area in Shangri-La County of Yunnan Province. Relationship between the two standard chronologies and climatic factors in the central Hengduan Mountains, Southwest China was analyzed. Result: The responses of the two tree species to climate factors were different, and A. forrestii was more sensitive, and hence more suitable for dendroclimatological studies; Response function coefficients indicated that air temperature had a significantly stronger restraining effect on A. forrestii than on P. likiangensis; The radial growth of A. forrestii positively correlated with the mean air temperatures in the previous November and current August (P < 0.05), positively correlated with the maximum air temperature in the previous November and current April (P < 0.05), positively correlated with the minimum air temperature in the previous May (P < 0.05), positively correlated with precipitation in the current March (P < 0.05); Spatial correlation analysis revealed that variations in standard chronology of A. forrestii could reflect the change of the minimum air temperature in the previous November, and the highest correlation with climate factors occurred in the vicinity of the study area; In the future, global warming will promote the radial growth of the two species; Meanwhile, the coupling effects of large-scale atmospheric-oceanic-land variability may affect the radial growth of A. forrestii and P. likiangensis in the central Hengduan Mountains. Conclusion: At the high altitudes in the middle of the central Hengduan Mountains, air temperature is the main climate factor limiting the radial growth of A. forrestii and P. likiangensis, and the response of radial growth of the two tree species to climate factors shows some differences, which also shows that it has great potential to study the population growth dynamics and its response to climate change by using tree-rings.

Objective: To provide reference for tree species selection in Horqin sandy land, the distribution rules of nonstructural carbohydrate (NSC, including soluble sugars and starch in the study, accounting for more than 90% of the total) in main tree species of shelterbelt forests were studied, and the distribution patterns in NSC of different tree species were clarified. Method: The contents of soluble sugars and starch in different organs (leaves, branches, trunks and roots) of the main shelterbelt tree species (Pinus tabulaeformis, Pinus densiflora, Pinus sylvestris var. mongolica, Ulmus pumila and Populus×xiaozhuanica) in Horqin sandy land were measured. The two-way ANOVA was used to analyze the effects of tree species, organs and their interactions on NSC. One-way ANOVA was used to analyze the differences of soluble sugars, starch and NSC among different tree species, and the effects of the different leaf ages and branch ages on the distribution of NSC in conifers (P. tabulaeformis, P. densiflora and P. sylvestris var. mongolica). Result: There were no significant differences in the content of NSC in leaves among the five tree species. However, the soluble sugars contents in the branches and roots of coniferous species were significantly higher than those of broad-leaved tree species (U. pumila and P.×xiaozhuanica), while the values in the trunks were lower in coniferous species than those in broad-leaved tree species. The starch contents in leaves and branches of U. pumila were significantly higher than those of other tree species, while it was higher in roots of broad-leaved tree species than coniferous species. Meanwhile, the contents of soluble sugars and NSC were significantly greater in the leaves and branches than in the trunks and roots over the five tree species. The starch content was higher in the trunks of P. tabulaeformis and P. densiflora, but it was higher in the leaves of P. sylvestris var. mongolica, U. pumila and P.×xiaozhuanica. The contents of soluble sugars and NSC were higher in two-year-old than current year and one-year-old needles of P. tabulaeformis and P. densiflora, but the values were greater in one-year-old than current year and two-year-old needles of P. sylvestris var. mongolica. The starch content was the lowest in one-year-old needles among all age needles of P. tabulaeformis and P. densiflora, whereas it was the highest in one-year-old needles of P. sylvestris var. mongolica. The soluble sugars, starch and NSC contents decreased with increasing branch age of P. tabulaeformis and P. densiflora, while the soluble sugar content was greater in two-year-old than one-year-old branches of P. sylvestris var. mongolica. Conclusion: The results indicate that the NSC contents are relatively low in shelterbelt main tree species in Horqin sandy land. Soluble sugars allocate in different organs following nearer distance, and it is different in allocation pattern of starch in various organs of different tree species. NSC distribution in different organs is more beneficial for water absorption through roots for coniferous species, while it is more beneficial for water transport over long distances in stems for broad-leaved species. As for NSC distribution in different leaf ages of coniferous species, the one-year-old needles of P. sylvestris var. mongolica and the two-year-old needles of P. tabulaeformis and P. densiflora are the main organs. In different branch ages, NSC distribution decreases with increasing branch ages for P. tabulaeformis and P. densiflora, but one-year-old branches are distributed less for P. sylvestris var. mongolica.

Objective: Global warming leads to increased intensity and higher frequency of drought. The difference of the hydraulic functions and xylem structure between branches and roots of three Taxodiaceae species in the humid area, as well as the quantitative relationship between the structure and the hydraulic function of xylem, was studied to understand the mechanism of adaptation to drought of plants in the humid area and to provide data support for the relative predictability of tree death risk in humid area in time and space. Method: Taxodium distichum var. imbricatum, Taxodium distichum and Sequoia sempervirens in humid region were investigated to determine the hydraulic conductivity and vulnerability curve of branches and roots. Paraffin sections were made to observe the xylem anatomical structure, and parameters of the tracheids and pit structural properties were calculated. Result: P₂₀, P₅₀ and P₈₈(the xylem water potential corresponding to the water loss of 20%, 50% and 88% represents the embolism resistance of branches and roots) of roots were all smaller than those of branches. The correlation coefficient between specific conductivity and P₅₀of branches and roots was close to 0 (R²=0.01, P=0.62). Correlation analysis of xylem anatomical structure and functional traits showed that:tracheid diameter was positively correlated with specific conductivity (r=0.82, P=0.001), and tracheid density was negatively correlated with specific conductivity (r=-0.68, P=0.01). The pit torus area was positively correlated with P₅₀ (r=0.4, P=0.19). Redundancy analysis revealed that:tracheid diameter had a significant effect on the specific conductivity and the interpretation degree was up to 80.1% (P=0.004). The pit torus area had a great influence on P₅₀ and the interpretation degree was up to 70.1% (P=0.18). Conclusion: The embolism resistance of the roots of three Taxodiaceae species is weaker than that of branches. Tracheid diameter determines the specific conductivity of hydraulic efficiency. The pit torus area determines the embolism resistance to P₅₀. There is no efficiency-safety trade-off in xylem hydraulic conducting system of branches and roots, as the material basis for this trade-off does not exist. Moreover, water conducting system for three species are of low efficiency and safety.

Objective: The paper focused on studying and developing the additive model systems of stem taper and bark thickness of dahurian larch(Larix gmelinii), which was expected to provide the bases for consistent estimation of the stem and bark volume of dahurian larch. Method: The equations of diameter outside bark (DOB), diameter inside bark (DIB) and bark thickness (BT) of dahurian larch were developed based on Kozak (2004) model and multiple regression technique, and they were compared with former models of taper and bark thickness. In addition, the five methods and the developed individual models were combined to construct the optimal additive taper and bark thickness model systems, respectively. Five methods included the single model estimation, total amount control and two of its logistic transformation, and total decomposition methods. All additive model systems were fitted by the PROC MODEL of SAS packages with the seemingly unrelated regression (SUR) method. Four indexes of Akaike information criterion(AIC), Bayesian information criterion(BIC), root mean square error(RMSE) and adjusted coefficient of determination(R_a²) were used to evaluate different additivity methods. Mean error (ME), mean absolute error (MAE), total relative error (TRE) and mean absolute percentage error (MAPE) were employed to evaluate the prediction precision of different model systems. Result: 1) The developed single models Kozak (2004) of DOB, DIB and BT were better than the other selected taper and bark thickness models, and the condition number (CN) values were all less than 30. It was generally believed that if the CN value is less than 30, there is no multicollinearity existed in the models, so they were used to establish the optimal system. 2) The fitting results of the five additive models showed that in general, four indexes of the total amount control performed better than the rest, and the results of validation were in accordance with the fitting results. Conclusion: The fitting and validation results, and the residual graphics of additive equation systems of DOB, DIB and BT with the total amount control showed consistent performances, therefore, the total amount control was selected as consistent prediction model system of stem and bark volume of dahurian larch in Daxing'anling.

Objective: To build a preliminary evaluation model of resistance to the damages of Curculio chinensis for Camellia oleifera based on fruit properties (capsule shape index, pericarp thickness, tea saponin content) of 8 Changlin clones of C. oleifera and C. chinensis's damage rate at four crucial stages (oviposition period, incubation period of larvae, developmental period of larvae and maturation period of larvae) to provide a theoretical basis for resistance breeding of C. oleifera. Method: The capsule shape index and pericarp thickness of 8 Changlin clones were measured during the peak of oviposition period. The accumulation of tea saponin was determined at four key periods. Finally the damage rate of each clone was counted. StepAIC() function in MASS package in R language was used to construct multiple linear regression model by using various measurements of the fruit properties as variables and the damage rate as dependent variables. Result: There were significant differences in capsule shape index between the 8 clones at the oviposition stage (P < 0.05), with a range of 0.5-1.2. Changlin No. 166 was long and elliptical, and the capsule shape index ranged from 0.5 to 0.7. Among the 8 clones, the pericarp thickness was between 3-6 mm, and the pericarp thickness of Changlin No. 53 was (5.03 ±0.08) mm which was higher than others. The pericarp thickness of all the clones was within the damage range of C. chinensis. The accumulation of tea saponin in the 8 clones at the four key stages showed to be different, and the tea saponin contents were obviously divided into three clusters. Based on the multivariate regression analysis of the 6 variables, the multivariate linear model with damage rate of C. chinensis (Y) as the dependent variable was preliminarily constructed:Y=0.531 6-0.301X₂-0.436 57X₄ + 0.059 526X₅-0.019 4X₆ (X₂:pericarp thickness; X₄:tea saponin content in incubation period of larvae; X₅:tea saponin content in developmental period of larvae; X₆:tea saponin content in maturation period of larvae). The regression model fitted well (P < 0.01, R²=0.773 7). Conclusion: The fruit properties (capsule shape index, pericarp thickness, tea saponin content) of C. oleifera were determined and analyzed. A multiple linear regression model was used to analyze the correlation between C. oleifera fruit properties and damage rate of C. chinensis in the four key periods. A preliminary evaluation model for the resistance to C. chinensis for C. oleifera was established. The establishment of the model is crucial for exploiting plant defensive traits in C. oleifera breeding to manage insect pests.

Objective: This study aimed to understand the correlation between the physical structure of poplar leaves and their rust resistance, and the corresponding morphological indexes were put forward for judging the Melampsora rust-resistance in the poplar breeding. Method: The uredinial density of 29 poplar clones was investigated in Forest Experimental Station of Northwest A&F University in late autumn. The mature leaves of the lower canopy were collected. The difference of anatomical structure of poplar leaves were analyzed by light microscopy, transmission electron microscopy and scanning electron microscopy and the correlation of 12 leaf histological indexes, such as cuticle thickness, epidermis thickness, palisade tissue thickness and so on, were studied. Result: Based on the Squared Euclidean Distance of uredinial density, 29 poplar clones were divided into three groups. In terms of the poplar section classification, Sect. Leuces were the non-hosts of M. larici-populina, Sect. Aigeiros were the resistant hosts, and Sect. Tacamahaca were the susceptible hosts. The first generation hybrids of P. deltoides cv. Lux female and P. cathayana male showed susceptibility to rust, and the rust resistance of hybrids poplars displayed a paternal transmission style. The abaxial epidermis, sponge tissue and the total leaf thickness of the host poplar were significantly thicker than those of the non-host poplars. However, palisade thickness, stomatal adjacent distance and the cell density of sponge tissue in host poplars were significantly lower than those of the non-host poplars. Among host poplars, the upper epidermis thickness of susceptible groups were significantly lower than stronger resistant groups. A stable positive correlation between the rust resistance of different poplars and the cuticle thickness, as well as the epidermal cell wall thickness of leaves was found by correlation analysis. Conclusion: There are significant differences in the rust resistance of different poplars. Cuticle thickness and upper epidermal cell wall thickness can be used as two morphological indicators in practice of the rust-resistant poplar breeding.

Objective: In order to avoid planting Pinus densiflora(Japanese red pine, JRP) in the woodland which is potentially seriously damaged by JRP blight(Pestalotiopsis funerea), the disease based index(DBI)-site factors evaluation system was established to quantitatively predict the degree of potential pathogen infection of JRP needle blight in the forest land to be planted. Methods: The disease based index of each sample plot was found based on the DBI curve group graph of JRP needle blight. Through correlation analysis, the key site factors were selected, the relationship equations between DBI-all site factors and DBI-key site factors of JRP needle blight were established by using the quantificative theory I. Results: 1) Correlation analysis showed that elevation, soil texture and humus depth had an extremely significant influence on disease based index(P < 0.01), slope aspect had significant influence on disease based index(P < 0.05), and the order of contribution to disease based index was slope aspect < soil texture < elevation < humus depth. 2) The multiple linear regression model of all site factors, key site factors and disease based index reached the extremely significant level statistically(P < 0.01), and the determination coefficient(R²) was 0.710 0 and 0.678 0, respectively, indicating that the model had a good fitting effect, and 4 key site factors could be used to replace all site factors as the independent variables of the equation. 3) A field test on model (2) (DBI-key site factors) showed that the average estimation error(MPE) was 8.73%, indicating that the estimation accuracy is above 91.27%. the TRE value is close to 0, thus the model is reliable. Conclusion: Disease based index-site factors evaluation system can quantitatively predict potential infection of JRP needle blight, which can provide theoretical basis for optimum planting and prevention of JRP needle blight.

Objective: Since the larvae of forest trunk borers live inside the trunk, it is difficult to identify the species. In order to quickly and accurately recognize the species of longicorn larvae and carry out biological control, a novel method was proposed to detect and analyze the vibration signals of longicorn larvae feeding in trees. With the method, the behavioral characteristics extraction and species identification of longicorn larvae were performed by means of wood boring vibration signal processing. Method: The vibration signals were obtained when the longicorn larvae were moving in the feeding channel. The signal waveform and relative amplitude were analyzed, then the time domain characteristics, such as waveform and vibration duration were extracted. Firstly, variational mode decomposition (VMD) was used for signal denoising, and then the denoised signal was decomposed by wavelet packet. The energy of each node in frequency domain was calculated. The characteristic frequency and energy ratio of each node were employed as the frequency domain characteristics. The time-domain and frequency-domain features were used to identify the longicorn species. Result: The duration of Batocera horsfieldi boring wood vibration signal was about 11.1 ms, and there was a distinct concave in middle of the waveform. The characteristic frequency was about 550 Hz, and the energy of wavelet packet was mainly distributed at 2, 3, 4 nodes, which is different from that of Anoplophora glabripennis. The duration of Anoplophora glabripennis boring wood vibration signal was about 8.2 ms. There were two concaves in the middle and real of the waveform separately. Compared with those of Batocera horsfieldi, there was no 550 Hz frequency component, but a 2 500 Hz component in the spectrum of A. glabripennis boring wood vibration signal. The duration time of Aromia bungii (in Prunus cerasifera) boring wood vibration was about 6.4 ms without concave in the waveform. Two frequency components above 2 000 Hz were found in spectrum. The vibration duration of A. bungii (in Malus micromalus) boring wood was about 19.8 ms. There was no concave but a convex in the rear of the waveform. Low frequency component near 100 Hz was found in the spectrum. Conclusion: The longicorn larvae can be detected and identified by wood boring vibration signal analysis. It is of great importance to early recognize trunk borer and select appropriate control measures.

Objective: It is of great significance to reveal the characteristics of non-methane hydrocarbons (NMHCs) emitted from the combustion of different tree species in order to calculate the total emissions of NMHCs in the process of different types of forest fires and to evaluate the impact on the atmospheric environment and human health. Method: The branch, leaves and bark of the typical tree species of Larix gmelinii, Pinus sylvestris var. mongolica, Quercus mongolica, Betula platyphylla and Populus davidiana in the Daxing'anling Mountains were used as objects. A biomass simulation combustion device was used to measure and analyze the emission factors and characteristics of NMHCs released by five tree species under different combustion conditions. The flue gas is collected by ASP-DC-1.2 electric sampler. NMHCs was determined by Entech 7100 preconcentration system and Agilent 7890A/5975 chromatography-mass spectrometry (GC-MS). The standard gas was a mixture of 57 kinds of non-methanes from Spectra Gases Inc., USA. Result: 1) A total of 48 NMHCs were detected, of which 19 were alkanes, 15 were alkenes, and 14 were aromatics. The 10 compounds with the largest emission factors accounted for 80.86% of the total NMHCs emission factors, among which i-Butane had the highest emission factor, accounting for more than 1/3 of the total NMHCs emission factor; 2) The emission factors (mg·kg^-1) of various compounds ranged from 359.88±101.43 alkanes of Pinus sylvestris var. mongolica to 756.54±205.47 alkanes of Quercus mongolica, and from 285.02±71.19 alkenes of Betula platyphylla to 358.72±92.60 alkenes of Larix gmelinii, and from 133.24±33.96 aromatics of Pinus sylvestris var. mongolica to 183.48±48.10 aromatics of Populus davidiana; 3) The average emission factor (mg·kg^-1) of NMHCs in the five tree species was 739.81±214.54 in the flaming state, and 1 284.91±405.72 in the smoldering state; 4) The average emission factors (mg·kg^-1) of leaves, branch and bark were 1 089.26±451.94, 918.44±237.80, and 1 029.39±413.84, respectively; 5)The emission factors (mg·kg^-1) of Quercus mongolica, Larix gmelinii, Populus davidiana, Betula platyphylla and Pinus sylvestris var. mongolica, and were 1 259.18±331.49, 1 111.56±248.53, 1 019.17±270.76, 889.05±235.58, 782.86±309.07, respectively; 6) The average ozone forming potential of the five tree species was 3.678 g·kg^-1. The ozone forming potential of alkanes, alkenes and aromatics accounted for 16%, 73% and 11% of the total, respectively. Conclusion: In the Daxing'anling Mountains, five typical arbor species emit three types of total non-methane hydrocarbons (alkanes, alkenes, and aromatics) when burning. Among them, i-Butane has the highest emission factor, and alkenes have the highest ozone forming potential. The total non-methane hydrocarbon release is related to combustion status. The overall combustion efficiency is low under smoldering condition, and the NMHCs emission factor is significantly higher than that of flaming combustion; There is no significant difference in carbon content among different biomass, so NMHCs emission factors do not show extremely significant differences. However, there are many influencing factors of NMHCs emission factors, leading to different average emission factors of non-methane total hydrocarbons by combustion in different tree species, the order is Quercus mongolica > Larix gmelinii > Populus davidiana > Betula platyphylla > Pinus sylvestris var. mongolica; the average emission factors of NMHCs in leaves and bark are slightly larger than those in branch.

Objective: The main purpose of this paper was to explore the spatial-temporal changes of forestry and fruit industry land in Luntai artificial oasis in the watershed of Dina River, Xinjiang Uygur Autonomous Region, hoping to evaluate the development of forestry and fruit industry and provide basic data and theoretical basis for the further research of forestry and fruit industry sustainable development in small watershed. Method: The land use information of forestry and fruit industry was extracted from the remote sensing images (obtained in August 1992, August 1998, September 2007 and August 2018) and unmanned aerial vehicle data (obtained in July and August 2018 in the field survey) by means of visual interpretation supported by RS and GIS, and the spatial-temporal changes within 26 years of forestry and fruit industry were further analyzed via mathematical statistic, dynamic degree, transfer matrix and gravity center model. Result: 1) The area of forestry and fruit industry increased in the past 26 years from 2 138 hm² in 1992 to 7 626 hm² in 2018. In 1992, 10% of artificial oasis was occupied by forestry and fruit industry, this rate increased to 14% in 1998 and 18% in 2007, but followed by a decrease to 12% in 2018.2) From 1992 to 2007, the annual average growth rate of forestry and fruit industry (11%) was higher than that of artificial oasis (4%-5%) in area. From 2007 to 2018, the situation reversed that the annual average growth rate of forestry and fruit industry (1%) was much less than that of artificial oasis (7%) in area. 3) In the past 26 years, the land that transferred into forestry and fruit industry (6 645 hm²) was far more than the land that transferred out of forestry and fruit industry (1 362 hm²). Farm land (2 671 hm²), unused land inside artificial oasis (2 345 hm²) and land outside artificial oasis (1 421 hm²) were the main sources supporting the expansion of forest and fruit industry. The land that transferred out of forestry and fruit industry was mainly farmland (918 hm²). 4) The distribution center as well as radiation distance for forestry and fruit industry changed little over the 26 years. Conclusion: In the past 26 years, the forestry and fruit industry in Luntai artificial oasis in the watershed of Dina River developed rapidly and experienced 3 stages:the rapid development stage(1992-1998), the leapfrog development stage(1998-2007) and the stable development stage(2007-2018). The forestry and fruit industry was mainly influenced by policy and its trend was the same as that in its located place, Xinjiang Uygur Autonomous Region. The expansion of the artificial oasis was mainly due to the expansion of farmland rather than the development of forestry and fruit industry. Most of the expansion area of forestry and fruit industry was generated from farmland and unused land inside the artificial oasis, and a small amount came from gobi desert area outside the artificial area. Compared with sandy desert, gobi desert was more appropriate for forestry and fruit industry development.

Objective: For the purposes of playing full value of wood, increasing the timber yield and improving the automatic level of wood processing industry, a new method for automatic optimizing cross-cut saw based on deep learning algorithm was proposed in this paper. Method: Pretrained defect detection network (Net.1) and grade classification network (Net.2) were obtained based on enough samples. Images of timber were captured by the vision sensor, the defect position on image could be confirmed based on Net. 1, while the grade position could be confirmed based on Net. 2. Final physical position could be determined based on the homography relationships between image plane and physical plane. Cutting list could also be obtained. Result: The experiment in our detailed conditions showed that the time of defect detection was 123 ms (per image), while the accuracy was 95.8% (per image). The time of grade classification was 55 ms (per image), while the accuracy was 97.1% (per image). The average time of detection was 86 ms (per image), while the average accuracy was 96.5% (per image). Conclusion: Our new method presented many advantages, such as a high operation speed, a high recognition efficiency and a strong robustness. The algorithm could improve the traditional optimizing cross-cut saw with a high automation and could also meet the requirements of real-time and accurate detection in wood processing.

Objective: In this paper, the Chinese fir (Cunninghamia lanceolata) and radiata pine (Pinus radiata) lumber with 40 mm thickness were subjected as materials. During high temperature kiln drying, formaldehyde concentration was analyzed as effected by temperature and moisture content of lumber, and was compared to that of conventional kiln drying radiata pine lumber. Method: During the lumber drying, according to the temperature in kiln and moisture content distribution of lumber, as for high temperature drying, the discharged gas of Chinese fir and radiata pine lumber were sampled 7 and 9 times, respectively; while for conventional drying, the discharged gas of radiata pine lumber was sampled 10 times. The extraction speed was 1.0 L·min^-1 and the time was 30 min. Referring to EPA method 0011, two 200 mL gas washing bottles with 40 mL distilled water were put in series in ice bath to make aldehydes fully dissolved in the water. Then the formaldehyde concentration was measured by acetyl acetone method. Result: As for Chinese fir and radiata pine lumber in high temperature ranged from 90℃ to 120℃, the minimum and maximum formaldehyde concentrations were 4.21 mg·m^-3 and 11.43 mg·m^-3, 3.66 mg·m^-3 and 12.71 mg·m^-3, respectively, which were all higher than the requirement limit of the non-organized emission standard that formaldehyde concentration didn't beyond 0.20 mg·m^-3. The drying temperature was linear with the released formaldehyde concentration in the temperature range of 90-120℃, and the determination coefficients (R²) were 0.668 and 0.934, respectively. When the drying temperature was 105℃, the concentration of formaldehyde increased gradually with the decrease of moisture content of radiata pine, they were negatively linear relationships, and the determination coefficients (R²) was 0.885. However, the drying temperature was the most important factor affecting the weight of formaldehyde release. During the conventional kiln drying, when the temperature of kiln did not beyond 90℃ and the moisture content of radiata pine lumber decreased gradually, the released formaldehyde concentration was almost constant with (0.19±0.03) mg·m^-3, and was less than the requirement limit of the non-organized emission standard of formaldehyde concentration. Conclusion: When the drying temperature is higher than 90℃, the gas discharged during drying should be recycled to avoid environmental pollution.

Objective: This study was conducted to evaluate the mechanical properties of the tensile joints of a paralleled string truss connected by self-tapping screws which were screwed from different angles, in order to provide basic scientific data for its practical engineering applications and improve the code for design timber structures. Method: The test pieces of the truss tensile joint were made by the imported SPF dimension lumber and self-tapping screws. By changing the angle between the axial direction of the screw and the grain direction of the web of the truss, the pull-out test was conducted on the 7 groups of tensile joints with angles of 0°, 15°, 30°, 45°, 60°, 75°, and 90°. The test was conducted according to the American specification ASTM D1761-12. Each specimen was pulled out at a constant rate of 2.54 mm·min^-1. The destructive form record, the failure mode analysis and, the comparison of the load-displacement curves, ultimate load-carrying capacity, yield load and stiffness of each group of specimens were implemented. Result: There were 2 types of failure modes:head pulled through the member and the screw pulled out from the tensile joint. When the angle were 0° and 15°, the failure of the test piece was mainly due to the fact that the compressive strength radical to the grain of the wood was less than the characteristic withdrawal strength of the screw, and the screw finally pulled through the chord of the specimen; when the angle was 30°-90°, the cause of failure of specimens was that the shear force formed by the embedment strength reached the yield load of the screw. When the angle were 0° and 15°, the load-displacement curves of specimens kept very well near the maximum load; when the angle ranged from 30° to 60°, the load-displacement curves decreased slowly; when the angle were 75° and 90°, the load-displacement curves all had a significant yield stage. The bearing capacity of the joint was affected by the yield strength of the screw and the compression strength perpendicular to the grain of the wood. When the angle was 60°, the average load-carrying capacity of the specimens was the highest, reaching 7.423 kN, and the yield load was the highest when the angle was 0°, which was 4.859 kN. The stiffness of the joints decreased when the angle between screw axis and grain direction increased. Conclusion: The mechanic behavior of the tensile joint might be the best when the inclined angle is between 45° and 60°. Specimens with an angle of inclination of 0° could be suitable for use in buildings where stiffness is critical.

Objective: In-depth exploration of the relationship between forest quality(FQ)and economic growth from a spatial perspective, and analysis of the differences between forest areas under regional heterogeneity conditions, and prediction of the time path of future evolution in different regions. Method: Drawing on the analytical framework of environmental Kuznets curve(EKC), the spatial econometric model is established between forest quality and economic growth based on interprovincial panel data from 2003 to 2016 in China. Result: 1) The promotion of economic growth to forest quality improvement is a long-term process, and the EKC hypothesis is validated by the U-shaped variation between forest quality and economic growth at present stage. 2) There are significant differences between different forest regions. The northeast China and north China are characterized by inverted N-type, northwest China is characterized by U-type while southwest China is linear of negative, however, there is no EKC relationship in south and southeast China. At present, the forest quality in northeast China and north China has not crossed the second inflection point. Conclusion: The econometric test can provide a more differentiated explanation consider heterogeneity conditions of different forest areas. So the existence of spatial spillover effects makes it necessary for neighboring regions to establish a complete cooperation mechanism for forest management and protection, forestry industry guarantee and factor flow mechanism, and in combination with their own endowment conditions to seek a equilibrium point for the coordinated development of forest quality improvement, ecological protection and economic growth.

Objective: Vitex rotundifolia, sandy plant and halophyte, naturally grows on the sandy beach coast front with arid and barren soil. In order to adapt to the adverse environment of strong wind and sea immersion, the seeds of V. rotundifolia have developed a deep dormancy. This study aimed to explore the dormancy characteristics of V. rotundifolia seed and the methods of breaking the seed dormancy, so as to provide theoretical basis to the propagation from seeds and large-scale production. Method: In this study, water absorption of the fruit and seed was measured. The sites and types of endogenous germination inhibitors were biologically identified, the mechanical barrier of the seed coat was broken with physical means (concentrated H₂SO₄, cutting peel), and the inhibitor concentration was reduced by low temperature stratification and GA₃ treatment to study the possible types of and cause for dormancy, and methods of breaking dormancy of V. rotundifolia. Result: The results showed that:1) Vitex rotundifolia had a thick pericarp, and the endocarp had a completely corked stone cell layer with a seed empty shell rate of 26%. The peel had obvious mechanical hindrance to the water absorption, and the seed had no water absorption barrier. 2) The water extract and methanol extract of the peel were able to significant inhibit the seed germination and seedling growth of Chinese cabbage. The inhibitory effect of water extract on the seed germination and seedling growth of Chinese cabbage was more obvious than that of methanol extract under the same concentration, that is, the activity of the water-soluble germination inhibitor is greater than that of the alcohol-soluble germination inhibitor. The GA₃ treatment of peel water extract and methanol extract could significantly improve the seed germination rate, root length and seedling height of Chinese cabbage. The water extract and methanol extract of the seeds did not significantly inhibit the seed germination and seedling growth of Chinese cabbage, indicating that the presence of water-soluble and alcohol-soluble germination inhibitors in the pericarp of V. rotundifolia is the main cause of seed dormancy. 3) Seed dormancy was able to be broken down by low temperature stratification for 90 d, GA₃, GA₃+concentrated H₂SO₄, GA₃+cutting peel, GA₃+low temperature stratification for 30 d, GA₃+low temperature stratification for 60 d and GA₃+low temperature stratification for 90 d. The seed germination time under GA₃+concentrated H₂SO₄ treatment was the shortest(14 days), and the germination rate was the highest(44%). Conclusion: The mechanical barrier and the endogenous inhibitor of the peel are the main factors affecting the dormancy of Vitex rotundifolia. Treatment with 500 mg·L^-1GA₃+concentrated H₂SO₄ can effectively release seed dormancy and increase germination rate.

Objective: Reporter gene is a gene encoding protein or enzyme which can be detected easily. DsRED, a fluorescent reporter gene, has been widely expressed in eukaryotic cells including animals, plants and yeast. At present, DsRED gene has been transformed into walnut(Juglans regia) somatic embryos as a reporter gene successfully. The growth and proliferation of transformed somatic embryos, tissue-cultured plantlets and 3-year-old green-house regenerated plants are growing well. The research detected the expression of DsRED gene in somatic embryos and regenerated plants of walnut to explore whether the expression of DsRED as a reporter gene was stable in the regenerated walnut plants and whether it had influence on the subsequent growth and development of regenerated plants, and to provide evidence for further broadening the application scope of DsRED as a reporter gene. Method: Detection of fluorescence expression in somatic embryos, tissue-cultured plantlets and 3-year-old plants of walnut by fluorescence microscopy. The expression of DsRED gene and protein in walnut somatic embryos and tissue-cultured plantlets were detected by PCR, qRT-PCR and Western Blot. Moreover, to confirm the reliability and stability of DsRED expression, the morphological indices of tissue-cultured plantlets and 3-year-old plants were measured as well. Result: The appearance of DsRED somatic embryos were pink-to-red under white light while they showed bright red under fluorescent light. Compared to the control, transformed DsRED somatic embryos exhibited globular, heart-shaped, torpedo and cotyledonary embryo development stages with normal morphology. The appearance of DsRED tissue-cultured plantlets and 3-year-old plants showed bright red and control showed totally dark under fluorescent field while they are similar under the bright field. The difference of growth parameters of stems and leaves between DsRED and control were not significant. The microscopy detection showed that DsRED gene was expressed highly in the vascular bundles of vegetative organs in DsRED tissue-cultured plantlets and 3-year-old plants. DsRED gene expression of somatic embryos and tissue-cultured plantlets were identified by PCR, qRT-PCR and Western Blot. The results showed that the expected band size (681 bp) was obtained from DsRED somatic embryos and tissue-cultured plantlets. There was no significant difference in the expression of DsRED mRNA between DsRED somatic embryos and tissue-cultured plantlets, while the DsRED mRNA expression level in control was zero. Western Blot analysis showed that there were strong positive bands at 26 kDa in DsRED somatic embryos and tissue-cultured plantlets, while no specific bands in the control. The analysis on the gray scale of the Western Blot bands indicated that the relative expressions had no significant differences between the DsRED somatic embryos and tissue-cultured plantlets, while the expression of the control was zero. Conclusion: DsRED gene can be expressed and translated stably in walnut somatic embryos, tissue-cultured plantlets and 3-year-old plants. The DsRED is an ideal genetic transformation report gene of walnut. This study provides a basis for the application of DsRED as a reporter gene in fruit crops.

Objective: Logging used to be one of the main human disturbance activities in the Daxing'anling Mountains. This study aimed to provide a basis for maintaining the forest soil fauna ecosystem stability by investigating the effects of severe harvest cutting on the ground-dwelling arthropod community in coniferous and broadleaf mixed forests in the Daxing'anling Mountains. Method: In the beginning of June and the end of August, 2017, we investigated the response of ground-dwelling arthropods to cutting disturbance by pitfall traps in natural secondary Larix gmelinii-Betula platyphylla mixed forests (referred to as CK), the deforested land where the forest was cut about 10 to 15 years ago (referred to as A), and the deforested land that was logged more than 30 years ago (referred to as B) in Songling Forest Station, the eastern part of the Daxing'anling Mountains. Result: During the study period, a total of 78 924 individual arthropods were captured with 1 458 pitfalls in the early of June and the end of August 2017, belonging to 109 groups of 70 families, 16 orders, 6 classes, 94 genera, and 1 unidentified. The dominant groups were Tetramorium, Onychiurus, Hypogastrura, and Sminthurinus. Compared to CK, the number of fungivorous group of ground-dwelling arthropods were significantly decreased due to severe deforestation disturbance, and they were significantly more in June than August (P < 0.05). The number of omnivorous group was also decreased in severe deforestation plots (P < 0.05), and there was no significant difference between June and August (P>0.05). The data analysis showed that the number of macro ground-dwelling arthropods and the groups of meso- and micro-sized arthropods were significantly decreased under harvesting stress (P < 0.05), which was significantly affected by sampling time (P < 0.05). The Shannon-Wiener index(H'), Pielou index(J_s) of macro arthropods in A and B were significantly higher than that in CK (P < 0.05), and the H', J_s of meso and micro arthropods in June were significantly higher than August (P < 0.05). The Jaccard index analysis indicated that the community of A was most similar to B, and there was a low similarity between B and CK. Besides, the Petraitis niche overlap index of ground-dwelling arthropods was increased on account of deforestation, indicating that the utilization of resources by ground-dwelling arthropods had become abundant, but there was no significant difference (P>0.05). Principal coordinate analysis (PCoA) based on Bray-Curtis similarity coefficient showed that harvesting caused apparent differentiation of ground-dwelling arthropods community composition, and the community composition of soil arthropods community in logged area had high similarity, and that greatly differed from natural secondary area, indicating that the variation of ground-dwelling arthropods community between deforestation and natural secondary forest could be persisted for a long time. Partial redundancy analysis (pRDA) suggested that the community was mainly affected by the thickness of litter, ground temperature, and humidity. Conclusion: The composition and diversity of ground-dwelling arthropods community are affected by deforestation. Compared to the natural secondary forests (CK), the groups of ground-dwelling arthropods are significantly decreased with the increase of harvesting years, and the indexes of H', J_s are both significantly increased. The niche breadth of partial common group has changed due to harvesting stress, and the variation of niche overlap index of partial group is considerable, but the common niche overlap index is still low. The composition of ground-dwelling arthropods community in logged area greatly differs from natural secondary area, and there is no significant difference of soil arthropod communities diversity between the two logged areas, indicating that the effect of logging on soil arthropod communities is long standing. The ground-dwelling arthropods community is mainly affected by litter thickness, ground temperature, and humidity.