【作者】 杨芳绒；

【导师】 马履一；

【作者基本信息】 北京林业大学 ， 森林培育， 2013， 博士

【摘要】 随着石油资源的日益枯竭,世界各国都已开始重视对可再生的生物质能源的研究。燃料型能源林是生物质能源的重要组成部分。刺槐(Robinia pseudoacacia L.)因其适应性强、生长快、易繁殖和耐燃烧,是一种传统而又具有良好开发前景的能源树种。本文以河南洛宁浅山丘陵区刺槐萌蘖林为研究对象,通过主要对冬季地上部分生长量的调查和对林木相关组成物质(灰分、挥发分)和元素(碳、氮、磷、钾)的测定,研究了刺槐能源林生物量、生物质当量热值和林分热值的变化特征及其影响因素。6年的持续调查研究得出以下主要结论：(1)刺槐能源林收获物热值变化有以下特征：矮林型生物质的当量热值高于乔林型。其中：1-5年生矮林型生物质当量热值随年龄增加而升高,在4-5年生时热值明显升高(P<0.05),变幅为18.76-19.16kj·g-1；8～39年生的乔林型当量热值随年龄增加而下降,变幅为18.50-19.06kj·g-1。不同器官的当量热值不同,其排列顺序为：叶>干>枝>皮；不同立地条件下的当量热值表现为阴坡大于阳坡；当量热值随枝条基径的增大而降低。(2)刺槐能源林生物量的变化有以下特征：1-5年生矮林型刺槐林基径和高度的年均生长量持续下降,连年生长量表现为波浪形下降,生物量平均值和连年增长量的变化都表现为上升的“V”型,5年生的连年生物量增长极为明显；8～39年生乔林型年均生物量的变化为8-22年为上升阶段,22年后为下降,34年时明显下降,22年生左右为转折点。(3)刺槐能源林不同形式收获物的特征为,生物量是标准煤量和发电量基础。其中矮林型生物质煤当量系数为0.6401～0.6538,乔林型为0.6313～0.6505。1度电耗标准煤为320g,以矮林型5年生林分为例,单位面积不同形式收获量分别为：生物量达32.1t·hm-2时,折合标准煤为20.6t·hm-2,可发电量约为64375度·hm-2；林分总热值的高低主要取决于林分生物量,当量热值影响较小(1.37%-1.92%)。煤质和电质收获量与生物质量有同样趋势和几乎一致的变化。(4)立地条件对乔林型和矮林型刺槐当量热值和生物质量有一致的影响,即阴坡高于阳坡,而且对矮林型的影响更明显,矮林型3年生后阴坡生物量超过阳坡1.98～2.23倍。(5)对矮林型2年生样地的抚育强度的试验表明,自然生长1年后,与对照相比,1/4抚育强度下生物量明显增加了20.64%,1/2抚育强度下生物量极明显,增加了30.25%。说明适时适当抚育对生物量增加是有效的。(6)影响矮林型刺槐能源林热值差异的原因之一是木纤维结构的差异。初步断定,刺槐树干木纤维壁厚与热值呈正相关,而长度与腔径对热值则有负向影响。木纤维结构与热值间明显相关性。(7)影响热值差异的另一个原因是不同的组成成分。刺槐不同器官粗灰分含量的变化为：树叶>树皮>树枝>树干；挥发分含量随基径的增大有下降的趋势；矮林型刺槐林木的碳含量顺序是为：2年生>4年生>3年生>1年生。粗灰分和挥发分含量与干重热当量值为负相关,林分的碳储量与总热值呈正相关。各因子综合相关性分析结果为：热值与灰分、全碳、氮、磷和钾等因子的相关性较高；全碳、灰分与其它因子的相关性很高。本研究系统分析了矮林型与乔林型刺槐能源林生物量和当量热值的变化特征,从热值与灰分、挥发分、养分以及碳含量等方面,揭示了影响刺槐热值的主要因子；将生物学、热力学的参数引入评价燃料能源林指标,为能源林理论研究与实践应用相结合提供一个新途径。更多还原

【Abstract】 Studies on renewable biomass resources have been emphasized in all the countries of the world with the exhaustion of the traditional resources. The fuel type energy forest is the major part of biomass resources. Locust, a traditional fuel energy tree species, has wonderful development prospect, because it has good features such as strong adaptability, fast growth, feeding nature and nectar with the large-scale cultivation in our country. Locust in the hilly region of Luoning County, Henan Province was researched from the perspectives of the biomass of locust energy forest, thermal equivalent, variation characteristics of the stand caloric values and their influencing factors by investigating the aboveground growth and biomass of locust and by determining and analyzing the matters (ash, volatile matter) and elements (carbon, nitrogen, phosphorus, potassium) of forest-related components for six years. Major conclusions are as follows.(1) Variation characteristics of the harvest thermal equivalent of the locust energy forest are as follows. The thermal equivalent of the coppice type was higher than that of the high forest type. The thermal equivalent value of the coppice type was obviously high at the ages of four to five with the amplitude of18.76～19.16kj·g-1, while the amplitude of the thermal equivalent of the high forest type was18.50～19.06kj·g-1; The thermal equivalent values of organs were different with the sequence of leaf> trunk> branch> bark; The thermal equivalent values of site conditions were also different, for the average value of the shady slope was higher than that of the sunny slope at the age of two or more; The thermal equivalent decreased as the branch diameter enlarged.(2) Variation characteristics of the biomass of the locust energy forest are as follows. The average annual biomass maximum of the high forest type was22years with obvious decrease at the age of34. During one to five years of locust shrub growth of the coppice working circle, the ground diameter and height declined continuously which was manifested as a declining pattern of "W". It was slightly different in these two wavy patterns, for the steepness of the height was larger than that of the diameter. The annual increment and continuous increment of biomass were both manifested as an increasing pattern of "V" and the continuous increment at the age of five was very obvious.(3) The total harvest volume of various species of the locust energy forest had different coefficient conversions on the basis of biomass. The coal equivalent coefficient of the coppice type biomass was0.6401～0.6538, while that of the high forest type was0.6313～0.6505. One kilowatt hour needed320g of standard coal. For example, as for the harvest volume of various species of the unit area of the five-year-old stand of the coppice type, when the biomass was32.1t·hm-2, the converted standard coal was20.6t·hm-2, which could produce about64375kilowatt hour·hm-2; the total thermal value of the stand mainly depended on the biomass of the stand, and the harvest volume and biomass of the coal quality and electric power had the same tendency and similar changes.(4) Site conditions had the same influence on the thermal equivalent value and biomass of the locust forests of the high forest type and coppice type, especially remarkably on the coppice type stand. The biomass of the coppice type in the shady slope was higher than that in the sunny slope at the age of two; the biomass in the shady slope was twice higher than that in the sunny slope at the age of three. The thermal equivalent value and coal equivalent coefficient were higher in the shady slope than those in the sunny slope except at the age of one, which indicated that the thermal equivalent value and biomass in the shady slope were both very high with the high total thermal equivalent value at the ages of four to five. (5)As was shown in the experiment of the tending intensity of the sample plot of the two-year-old coppice, biomass increased by20.64%(P<0.05) at the tending intensity of1/4and by30.25%(P<0.01) at the tending intensity of1/2, which suggested that the proper tending intensity was effective for the biomass increase.(6) The difference of wood fibre structure was one of the influencing factors of the difference of the thermal equivalent value of the coppice type of the locust energy forest. According to the initial judgment, fibre patterns and thickness of locust were positively correlated with the thermal value, while the length and size were negatively correlated.(7) Different comprehensive component was another reason for the difference of the thermal value. The tendency of shrub locust crude ash content was leaf> trunk> branch> bark; the volatile component decreased as the diameter increased; The sequence of shrub locust forest carbon density:2a>4a>3a>1a; crude ash and volatile component content were negatively correlated with the gross caloric value, while the carbon storage of a stand was positively correlated with the total caloric value. The comprehensive correlation analysis of all the factors showed that the thermal value had high correlation with the factors such as ash, pure carbide, nitrogen, phosphorus and potassium, while pure carbide and ash had high correlation with the other factors.The total harvest volume of various species of the locust energy forest, the variation characteristics and regular pattern of various forms such as biomass, coal quality and electric power were obtained, which provided a theoretical basis to make the measures of improving the harvest volume. The study of the short cutting period contributed a lot to the systematic study of the locust energy forest. The study showed that the biomass production and the short cutting period of the energy forest cultivation and the coppice management were of practical significance. The diameter class provided a theoretical basis for the classification of the harvest and a new method of combining theory with practice in the field of energy forests.更多还原