Effect Of Decay On Carbon Sequestration Of Wood And Its Mechanism

Wood is an ecological material,but in the process of storage and use,it is easy to be decayed.This not only causes the wood to color changed,reduces its value,can also make wood structure damaged and increase the security risk during use.And in the process of decay,a lot of the carbon trapped in the wood are released.This phenomenon reduces the advantage of biological carbon sequestratio aCurrently,there are few reports on the inpact of decay on wood carbon emissions,and corresponding quantitative data are lack.So this research choose typical broadleaf wood and soft wood tree species(poplars and Korean pine)as the research object.In order to provide basic data and theoretical basis for wood carbon sequestration and wood preservation,the brown rot fungi(Gloeophyllum trabeum,G.t)and white-rot fungi(Coriolus versicolor,C.v)were used to rotten wood processing.The weight toss rate,carbon fixation and chemical conpositions of both healthy wood and decayed wood were measured,and the effects of decay tire on carbon fixation and chemical compositions were systematically analyzed.Then based on the changes of each chemical composition,the mechanism of change in carbon fixation was elucidated.The main research contents of this paper include:1)Characterization of wood decay degree.The mass loss rate and the compressive strength of the white poplar and red pine specimens treated with different brown rot and white rot were measured to characterize the degree of decay.2)The effect of decay on the chemical content of the test piece.The chemical conposition of the specimens with different degrees of deeay was measured,and the relative values of the components were calculated by the mass loss rate,and the relative values of the corrponents were studied.3)The effect ofdecay on the amount of carbon sequestered by wood.The carbon sequestration of various test pieces and the carbon content of each chemical corrponert were measured,and the internal mechanism of the effect of decay on the carbon sequestration of wood was analyzed.4)Establish a regression model of wood decay and carbon sequestratioa The main conclusions are as follows:(1)The brown rot treatment has a significant effect on the wood quality loss rate and the conpressive strength of the grain,and its efFect is far stronger than that of the white rot fungus.The effect of white rot treatment on the corrpressive strength of wood grain is similar to that of brown rot?which increases first and then decreases.However,white rot has a much weaker effect on wood quality loss rate and compressive strength than brown rot(2)With the increase of brown rot time,the absolute content and proportion of lignin in wood sanroles increased slightly,and the absolute content and proportion of hemicellulose(including a-cellulose and hemicellulose)decreased significantly.With the extension of white rot time,the absolute content and relative content of lignin in wood sanples increased slightly and then slowly decreased.(3)With the increase of brown rot time,the absolute carbon fixation of wood did not decrease,but increased slightly,and the relative carbon fixation decreased significantly.With the extension of white rot,the absolute carbon fixation and relative carbon fixation of wood increased first.Afterwards,the law of continuous decline began,which indicates that decay has a significant effect on the change of wood carbon sequestration.Sisce the carbon content of unit mass lignin is 64.08%higher than that of hemicellulose,the absolute carbon content in the wood is not reduced.In short,the change of lignin specific gravity during decay is the decisive factor affecting the change of absolute carbon sequestration of wood.The mass toss rate is the decisive factor affecting the change of relative carbon sequestration of wood.