Publications

To accurately and non-destructively monitor the growth of spring wheat in the Hetao Irrigation Area, UAV remote sensing was employed during various fertility stages. Digital image indices from diverse fertilization treatments were calculated and compared with physiological indices to identify the most sensitive digital image indices corresponding to these indices. The study underscored the critical importance of the flowering stage in the growth of spring wheat, thus highlighting the necessity of focusing on this stage. This finding reiterated that the flowering stage was pivotal for spring wheat development in the Hetao Irrigation Area. Several digital image indices, such as GLA, R, G, INT, g, GRVI, MGRVI, RGBVI, EXG, and GRRI, exhibited a high frequency of significant correlations with physiological indices during the four primary reproductive stages of wheat. Consequently, these sensitive digital image indices during the flowering stage can more effectively characterize the physiological indices of spring wheat.

The regulation of stand density has been studied in specific aspects of plantations with different age categories. A clearer understanding is still required of the extent to which stand density impacts multiple plantation attributes such as tree growth, understory vegetation diversity, and soil properties in Korean pine (Pinus koraeinsis Sieb. et Zucc) plantations. This study utilized a 43-year-old middle-aged Korean pine plantation in Qingping Forest Farm in northeast China to answer the research question posed. Three stand density levels, low stand density (LSD, 716 trees/ha), medium stand density (MSD, 850 trees/ha), and high stand density (HSD, 916 trees/ha) were studied for their effects on plantation attributes enumerated above. The results revealed a significant (p < 0.05) effect of stand density on mean stand volume (m3). Medium stand density had the highest mean stand volume of 26.16 (±0.27) m3 while the lowest stand volume was recorded for the low stand density at 14.90 (±1.72) m3. Also, significant differences in total nitrogen, total potassium, available nitrogen, available potassium, and percentage soil moisture content were observed among stand density levels. Additionally, stand density was found to have significant effects on species richness, Shannon–Wiener, and Simpson’s diversity indexes for the shrub and herb layers of the plantation. This study shows that a medium stand density is the most optimal for promoting tree growth and understory biodiversity, as well as enhancing the status of certain soil nutrients. Thus, medium density achieves a balance between growth, nutrient availability, and biodiversity in middle-aged Korean pine plantations after a short period of thinning. These findings provide valuable knowledge for forest management, emphasizing the significance of continuous, long-term, and site-specific research.

Fraxinus chinensis subsp. rhynchophylla (Oleaceae), hereafter F. rhynchophylla, is an important timber species in northeast China; however, little is known about its seed dormancy and germination, which hinders regeneration of the species from seeds for reforestation and conservation. Our aim was to determine the class of seed dormancy and how to break it. Studies were conducted to determine the permeability of the seed coat to water, changes in embryo development during cold stratification and effects of cold stratification on germination over a range of temperatures. The seeds were water-permeable, and the embryo was fully developed and filled the embryonic cavity. Cold stratification at 5 °C for 8 weeks was effective in breaking dormancy; thus, we conclude that the seeds have nondeep physiological dormancy (PD). As cold stratification time was increased, the ability of seeds to germinate at low temperatures (e.g., 10 °C and 15 °C) increased, indicating the presence of Type 2 nondeep PD, in which the minimum temperature for germination decreases during dormancy-break. Nondormant seeds germinated to high percentages and rates at constant temperatures of 25 °C (germination percentage was 63%) and at alternating temperature regimes of 35 °C/25 °C, 30 °C/15 °C, 25 °C/20 °C and 20 °C/10 °C (germination percentage was 66%, 67%, 65% and 66%, respectively). To produce seedlings, we recommend 8 weeks of cold stratification at 5 °C before sowing the seeds at temperatures ranging from 15 °C to 30 °C.

To select excellent clones characterized by fast growth and high-quality wood of Catalpa fargesii Bur., growth traits, including height and diameter at breast height (DBH) at 1, 9, 11 and 13 years old, were collected and wood properties, including the Pilodyn value and elastic modulus at age 13 of 200 clones of C. fargesii from different ecological areas (four provinces), were measured. Genetic variation analysis and repeatability estimation were carried out. The correlation between the characteristics and the correlation between the characteristics and the geographical and climatic factors were analyzed. Excellent clones were selected by a comprehensive evaluation method combined with breeding values. The traits of C. fargesii were significantly different among the clones. The coefficient of variation (CV) ranged from 12.12% to 26.17%, and the repeatability (R) ranged from 0.79 to 0.97. The growth traits among ages of 9, 11 and 13 were significantly correlated, and the growth traits at ages of 9, 11 and 13 and Pilodyn values at the age of 13 were positively correlated with altitude and negatively correlated with longitude. Tree growth at ages of 11 and 13 showed a high negative correlation with wood properties. The suitable tree age for the early selection of clones with excellent growth and wood properties is 11 years old. Nine clones with excellent growth, six clones with high-quality wood and three clones with great growth and wood properties were selected, which laid a foundation for further optimization of C. fargesii clones. Additionally, C. fargesii clones in the western and high-altitude areas featured fast growth, while those in the eastern and low-altitude areas had better wood properties. This study serves as a reference for the selection of C. fargesii clones in different ecological areas.

Certain fluctuations were found when using the opening degree index to evaluate the effects of the adjacent broadleaved trees on the under-canopy target Korean pine (Pinus koraiensis Sieb. et Zucc.) trees in a mixed forest of planted Korean trees and natural broadleaved trees. The fluctuations were probably caused by the different positions and sizes of the adjacent broadleaved trees over the target Korean pine trees. For the purpose of clarifying this issue, the effect of the position and size (marked by height and diameter) of the neighborhood broadleaved trees on the height and diameter growth of Korean pine trees under the canopy in a secondary forest at different opening degree levels was studied. Generally, the mean DBH (diameter at breast height) and mean height of P. koraiensis trees under the canopy were higher when the adjacent broadleaved trees were located on the north or east sides of the target P. koraiensis trees than when they were located on the south or west sides. This was the case at all opening degree levels except the 0.5 opening degree level, where no significant difference was observed among the growth indexes of Korean pine trees based on the different positions of neighborhood trees. The mean DBH and height of P. koraiensis trees under the canopy decreased with the increase in the DBH and height of the adjacent broadleaved trees at all orientations and at all opening degree levels, but only those of the Korean pine trees with adjacent broadleaved trees on the south side in the 12.6–13.5 m height range and those with adjacent broadleaved trees on most sides in the 18.6–21.0 cm and 13.6–14.5 m height ranges at opening degree levels of K = 2.0, 1.5, and 1.0 reached a significant level of difference; whereas those of most Korean pine trees with adjacent broadleaved trees on the south and west sides in the height range of 11.6–12.5 m and DBH ranges of 13.6–16 cm and 16.1–18.5 cm, as well as the ones with adjacent broadleaved trees on most sides in the DBH range of 18.6–21.0 cm and the height range of 13.6–14.5 m at the opening degree level of K = 0.5, reached a significant level of difference, with a few exceptions. In conclusion, the broadleaved trees with a large diameter, great height, and a south or west orientation of the target P. koraiensis trees had a negative impact on their growth, but influence intensities changed at different opening degree levels.

Abstract With the introduction of ultra-low emission environmental protection policies in national and local coal-fired power plants, ultra-low emission transformation of coal-fired power plants is required to be carried out in an all-round way. Under this background, the first 600 MW supercritical circulating fluidized bed (SCCFB) boiler unit in the world have carried out the demonstration of the technical route of ultra-low emission transformation and the research of key technologies. By adopting limestone desulphurization and low nitrogen combustion in furnace, selective non-catalytic reduction (SNCR) technology outside furnace and the integrated desulfurization and dust removal process of flue gas circulating fluidized bed (CFB-FGD), the unit realizes the technical route of ultra-low emission, and has good investment and operation economy, which can adapt to the development trend of environmental protection in the future. The CFB-FGD and dust removal system can further improve the operation economy of the boiler by setting pre-electrostatic precipitator (pre-ESP), designing double-tower and optimizing the single-tower switching mode, optimizing the pressure margin of the induced draft fan, and adopting the coordinated desulphurization operation mode inside and outside the furnace. The research results can provide a reference for the selection of ultra-low emission transformation for 660MW ultra-supercritical CFB boiler unit.

The objective of this research was to study the differences in endogenous hormone levels and the genes related to reproductive development in Chinese pinenut (Pinus koraiensis) trees of different ages. The apical buds of P. koraiensis were collected from 2-, 5-, 10-, 15-, and 30-year-old plants and also from grafted plants. There were three replicates from each group used for transcriptome sequencing. After assembly and annotation, we identified the differentially expressed genes (DEGs) and performed enrichment analysis, pathway analysis, and expression analysis of the DEGs in each sample. The results showed that unigenes related to reproductive development, such as c64070.graph_c0 and c68641.graph_c0, were expressed at relatively low levels at young ages, and that the relative expression gradually increased with increasing plant age. In addition the highest expression levels were reached around 10 and 15 years of age, after which they gradually decreased. Moreover, some unigenes, such as c61855.graph_c0, were annotated as abscisic acid hydroxylase genes, and the expression of c61855.graph_c0 gradually declined with increasing age in P. koraiensis.