Papers by Keyword: Plantation

Abstract: Liquefactions have been carried out on plantation fir scrap, with allylimidazolium ionic liquids as liquefaction agent. The primary component of plantation fir was analyzed, fir scrap properties were tested in contrast to peeled fir. Single-factor experiments were employed to discuss the influential factors liquefying plantation fir scrap by ionic liquids. The results showed that the appropriate conditions of liquefaction were 80°C, 30min, and the ratio of wood to liquor was 7:1, in these conditions, the liquefaction is nearly complete.

Abstract: Abstract: Xiaojiang drainage basin is one of the regions suffering from serious erosion and ecological degeneration due to the climate, geological and geomorphological conditions and the heavy human activities. Reforestation, which has been done since 1980s in the region, is an effective measure for the ecological restoration. Four types of plantations, i.e., Eucalyptus spp., Acacia mearnsii, Leucaena leucocephala and Pinus yunnanensis are investigated in the sample plots. Development processes and community structures of the tree layers, shrub layers and grass layers are studied with the “ergodic hypothesis” method and the index of species richness, coverage, importance value and Shannon_Wiener index et al, and erosion control abilities of the four types of plantations are compared in this paper. The result shows that the plantations of Acacia mearnsii and Leucaena leucocephala grow faster, which have higher crown coverages and stronger erosion control abilities than that of Pinus yunnanensis and Eucalyptus spp.. The Pinus yunnanensis plantation has a higher secondary understory biodiversity, the Eucalyptus spp. plantation has a high secondary understory biodiversity, but the plantations of Acacia mearnsii and Leucaena leucocephala have low secondary understory biodiversities. Study in this paper shows that the four types of plantation have distinct effects in promoting plant diversity and have different erosion control abilities. So plantation species selection and association mode should be considered in the process of reforestation for ecological restoration.

Abstract: The dynamics of the litter and soil organic matter content of four densities (A: 2500/hm²，B:3300/hm²，C:4400/hm²，D:6600/hm²) of hybrid Larch plantations were studied in Jiangshanjiao forest farm of Heilongjiang province of China. (1) The annual litter stock under the hybrid Larch plantation was 4634.6 ~ 5453.4 kg/hm², and the decreased order of the annual litter stock was under density of 4400, 3300 2500and 6600 trees per hectare. The decrease order of the litter stock no matter undecomposition and decomposition litter was under density of 3300, 4400, 2500 and 6600 trees per hectare, and the rate of the undecomposition litter stock to total litter stock was bigger than 50 %. (2) The seasonal dynamic of the soil organic matter under different densities of plantations basically had the same principle. In 0~10 cm soil layer, the soil organic matter was higher in June and August, was lower in May and July, and was flat or increased slightly in September, but was decreased in September under the plantations with density 4400 and 3300 trees per hectare. The soil organic matter in 10~20 cm and 20~40 cm layer had the same change principle, but the change range was flat and smooth. For the same density of plantation, the difference of the organic matter in the same soil layer between the different months was significantly (P < 0.05). (3) The difference of the soil organic matter content in the same soil layer under different densities of hybrid Larch plantation was significantly, and the decreased order of the soil organic matter in average was under density 4400, 3300, 6600 and 2500 trees per hectare. The results would provide the theories basis for manage the hybrid Larch plantations.

Abstract: The soil physical and chemical properties of four densities (A:2500/hm²，B:3300/hm²，C:4400/hm²，D:6600/hm2) of hybrid Larch plantations, Larix olgensis plantation(E) and Quercus mandsurica forest(F) were studied in Jiangshanjiao forest farm of Heilongjiang province of China. Soil bulk density, soil porosity, total N, total P, available N and available P were affected significantly by plantation density in hybrid Larch plantations. The lowest surface soil bulk density was in density 2500/hm². Soil porosity of density 2500/hm² and 3300/hm² was bigger than that of density 4400/hm² and density 6600/hm². Total N, total P and available N of density 4400/hm² and 3300/hm² were higher than that of density 6600/hm² and density 2500/hm². Total N, total P, available N and available P of hybrid Larch plantations were not lower than that of Larix olgensis plantation. The results of the soil physical and chemical properties under different densities of hybrid Larch plantations and different types of forest seems to confirm that hybrid Larch plantation did not decreased the soil fertility, and the hybrid Larch plantation with densities of 3300/hm² and 4400/hm² could be conductive to improving the soil quality. The results would provide the theories basis for manage the hybrid Larch plantations.

Abstract: The effects of four management measures (A: All broad-leaved trees and shrubs were cut, B: All broad-leaved trees were cut, C: All shrubs were cut, D: Partial upper broad-leaved trees were cut uniform.) of Pinus koraiensis plantations on the soil properties were studied in National Natural Reserve located in Lesser Xingan Mountains. Litter mass, soil organic matter mass, soil physical properties, soil chemical properties and microbial characteristics were affected significantly by management activities in the Pinus koraiensis plantations no matter what kind of management measures. The rate of undecomposed layer was bigger than 50% in measure A and measure B, and smaller than 50% in measure C and measure D. The lowest surface soil bulk density was in measure C and D. Soil organic matter mass of measure C and D was bigger than that of measure A and B. In the upper soil layer, the nutrient of measure C and D was higher than that of measure A and B. The totoal number of bacterium, fungi and actinomycetes was the bigger in measure C and D, and the smaller in measure A and B. The rusults of the soil properties under different management measures seems to confirm that increasing the degree of close-to-nature forest management could be conductive to improve the soil quality of Pinus koraiensis plantation.

Abstract: Chinese fir (Cunninghamia Lanceolata) is a unique fast growing merchantable timber species in China with good materials, and is a major fast growing timber species in provinces of southern China. With the increase in Chinese fir plantation areas and the improvement in the degree of pure forests, the diseases of Chinese fir are increasing and their damages are getting worse, which have caused great losses and affected the sustainable, rapid and healthy development of forestry in China. This article gives a description of pathogenies, symptoms and occurrence regularities of four important diseases of Chinese fir, including Glomerella cingulata, Pestalotia Sp., Pseudomonas cunninghamiae and Chlorosis, and puts forward the corresponding control measures of these diseases, which provides an important basis for disease control of Chinese fir plantations.