Several equations were selected using nonlinear regression analysis for setting up growth and yield modehe of Dahurian larch (Laris gmelinii Rupr.) plantations. Data of 405 stem analysis trees were collected from 336 ...Several equations were selected using nonlinear regression analysis for setting up growth and yield modehe of Dahurian larch (Laris gmelinii Rupr.) plantations. Data of 405 stem analysis trees were collected from 336 temporary plots throughout the Daxing’an Mountains. Results showed that the Richards equation was the best model for estimating tree height, stand mean height and stand dominant height by age, the Power equation was the fdiest model for predicting tree volume by DBH and tree height, and the Logarithmic stand vofume equation was good for predicting stand volume from age, mean height. basal area and other stand variables. These models can be used to construct volume tabIes, site index table and other forestry tables for Dahurian ghantations.展开更多
Community properties of dahurian larch (Larix gmelini) plantations at the Experimental Station of Laoshan were studied. Results show that under the different distributions of the combines of tree layer of dahurian lar...Community properties of dahurian larch (Larix gmelini) plantations at the Experimental Station of Laoshan were studied. Results show that under the different distributions of the combines of tree layer of dahurian larch plantations, stands have different community structure characteristics and biological productivities. From the result of the analysis of variance, it shows that there is the obvious difference among biomass of understory, herb layer and litter for four structure tpps.展开更多
The biornass and productivity for dahurian larch (Larix gmelini) plantations of four structure types were measured. The biomass of trees, understory' herb and litter was surveyed using methods of average standard ...The biornass and productivity for dahurian larch (Larix gmelini) plantations of four structure types were measured. The biomass of trees, understory' herb and litter was surveyed using methods of average standard tree and subsample yield respectively.The estimated total mean biomass for dahurian larch plantation communities of four structure types was 159. 445 t/hm2 and the net productivity was 12. 237 t/hm2. a.展开更多
This paper studies the characteristics of larch bark pyrolysis and analyzes factors that affect the pyrolysis and the liquid pyrolytic component. The results are as follows: TG curve shows that the pyrolysis can be di...This paper studies the characteristics of larch bark pyrolysis and analyzes factors that affect the pyrolysis and the liquid pyrolytic component. The results are as follows: TG curve shows that the pyrolysis can be divided into three parts: drying process, pyrolytic process, and carbonate and calcinated process. Both the size of grain and the temperature rising rate affect the shape of TG and DTG. Vinegar and sedimentary tar are main components of pyrolyzate products. GC-MS is applied to analyze vinegar. It is shown that the vinegar is a highly complex compound which is composed of phenol and its derivatives (45.620%), organic acid (13.851%), keto derivatives (9.754%), aldehydic derivatives (8.573%), alcoholic derivatives (1.794%), ester and its derivatives (0.205%).展开更多
Tree-ring samples from Dahurian Larch (Larix gmelinii (Rupr.) Rupr.) were collected at three sites in the northern Da Hinggan Mountains. Using samples measured by X-ray densitometry, measurements of tree-ring maximum ...Tree-ring samples from Dahurian Larch (Larix gmelinii (Rupr.) Rupr.) were collected at three sites in the northern Da Hinggan Mountains. Using samples measured by X-ray densitometry, measurements of tree-ring maximum latewood density chronologies of two sites were found to be significantly correlated with summer temperature. These two sites' tree-ring series were combined to form a single standard regional chronology. This was used to reconstruct the May-August monthly mean maximum temperature for the period 1855-2008 AD, and it explained 39.5% of the total temperature variance. In the past 154 years, there were 4 cold periods (1874-1893, 1927-1948, 1951-1960 and 1992-2002) and 4 warm periods (1855-1873, 1894-1916, 1961-1991 and 2003-2008). The summer temperature rose more obviously than that of winter in this region. Having been validated by other temperature reconstructions from the surrounding area, the reconstruction could indicate the summer temperature changes of large-scale regions.展开更多
文摘Several equations were selected using nonlinear regression analysis for setting up growth and yield modehe of Dahurian larch (Laris gmelinii Rupr.) plantations. Data of 405 stem analysis trees were collected from 336 temporary plots throughout the Daxing’an Mountains. Results showed that the Richards equation was the best model for estimating tree height, stand mean height and stand dominant height by age, the Power equation was the fdiest model for predicting tree volume by DBH and tree height, and the Logarithmic stand vofume equation was good for predicting stand volume from age, mean height. basal area and other stand variables. These models can be used to construct volume tabIes, site index table and other forestry tables for Dahurian ghantations.
文摘Community properties of dahurian larch (Larix gmelini) plantations at the Experimental Station of Laoshan were studied. Results show that under the different distributions of the combines of tree layer of dahurian larch plantations, stands have different community structure characteristics and biological productivities. From the result of the analysis of variance, it shows that there is the obvious difference among biomass of understory, herb layer and litter for four structure tpps.
文摘The biornass and productivity for dahurian larch (Larix gmelini) plantations of four structure types were measured. The biomass of trees, understory' herb and litter was surveyed using methods of average standard tree and subsample yield respectively.The estimated total mean biomass for dahurian larch plantation communities of four structure types was 159. 445 t/hm2 and the net productivity was 12. 237 t/hm2. a.
文摘This paper studies the characteristics of larch bark pyrolysis and analyzes factors that affect the pyrolysis and the liquid pyrolytic component. The results are as follows: TG curve shows that the pyrolysis can be divided into three parts: drying process, pyrolytic process, and carbonate and calcinated process. Both the size of grain and the temperature rising rate affect the shape of TG and DTG. Vinegar and sedimentary tar are main components of pyrolyzate products. GC-MS is applied to analyze vinegar. It is shown that the vinegar is a highly complex compound which is composed of phenol and its derivatives (45.620%), organic acid (13.851%), keto derivatives (9.754%), aldehydic derivatives (8.573%), alcoholic derivatives (1.794%), ester and its derivatives (0.205%).
基金supported by the National Natural Science Foundation of China (40871058)the Science and Technology Ministry Commonwealth Trade (Meteorology) Scientific Research Specialized Project (YHY200806011)the National Basic S&T Project of the Ministry of Science and Technology of China (2007FY220200)
文摘Tree-ring samples from Dahurian Larch (Larix gmelinii (Rupr.) Rupr.) were collected at three sites in the northern Da Hinggan Mountains. Using samples measured by X-ray densitometry, measurements of tree-ring maximum latewood density chronologies of two sites were found to be significantly correlated with summer temperature. These two sites' tree-ring series were combined to form a single standard regional chronology. This was used to reconstruct the May-August monthly mean maximum temperature for the period 1855-2008 AD, and it explained 39.5% of the total temperature variance. In the past 154 years, there were 4 cold periods (1874-1893, 1927-1948, 1951-1960 and 1992-2002) and 4 warm periods (1855-1873, 1894-1916, 1961-1991 and 2003-2008). The summer temperature rose more obviously than that of winter in this region. Having been validated by other temperature reconstructions from the surrounding area, the reconstruction could indicate the summer temperature changes of large-scale regions.
