【作者】 孙楠；

【导师】 李凤日； 李梦；

【作者基本信息】 东北林业大学 ， 森林经理学， 2012， 博士

【摘要】 本研究是黑龙江省科技重大攻关项目“优质木结构用材原料林良种选育及定向培育技术研究”的部分研究内容(GA09B202-02)。杂种落叶松是黑龙江省林业科学研究所经过30多年研究出的新树种,其生长速度,抗病虫害能力及抗寒性都较长白落叶松有绝对优势,目前黑龙江省正在推广该树种的大面积栽植,这就需要建立一套相应的、比较完善的栽培模式来指导杂种落叶松的经营,而栽培模式中最重要的部分就是造林密度的研究。本研究选取的试验地是我国目前最大的一片杂种落叶松人工林,面积20hm2,林龄为14年。2004年按照四种造林密度(2500株/hm2、3300株/hm2、4400株/hm2、6600株/hm2)设置固定标准地48块,连续观测至今。期间,对不同造林密度下杂种落叶松的生物量,凋落量,凋落物的分解及林地的土壤情况进行了调查,为杂种落叶松人工林造林密度的研究积累了丰富的第一手资料,研究结果具有较强的说服力,可以为杂种落叶松栽培模式的完善提供很好的补充。本研究采用方差分析,多重比较,数学模型等方法,对四种造林密度下杂种落叶松的生长规律、生物量及碳储量、凋落物及其分解、林地土壤理化性质和微生物等进行了研究与分析,得到的主要结果有：造林密度对杂种落叶松单株生长指标都有显著影响,造林密度越大,其林分的胸径、单木材积和冠幅就越小,综合生长,干形,出材率等指标后,得出3300株/hm2林分的林木生长较好,干形相对较为饱满,出材率最大。造林密度对杂种落叶松单株生物量及其分配都有显著影响,3300株/hm2的林分,单株生物量最大为23.65kg,其中树枝与树叶所占比例较大,达到35.43%;4400株/hm2的林分单株生物量最小,只有21.78kg,但干材与树皮所占比例最大,达到69.28%。根据不同的造林密度建立了杂种落叶松单株生物量的回归模型,拟合精度较高,为今后杂种落叶松生物量和碳储量的估算提供更精确的科学依据。造林密度影响杂种落叶松凋落物的分解速率,林分密度越大,枯枝落叶的分解周期越长,最长超过17年(2500株/hm2),最短只有13年多一点(6600株/hm2),在改变林内微生境后,2500株/hm2林分的分解周转期最短,只需不到4年的时间。枯枝落叶中各养分元素含量减少较快的是造林密度为3300株/hm2和4400株/hm2的林分,说明这两种造林密度下杂种落叶松枯枝落叶养分元素的归还较快。从造林密度对林地土壤中水解氮、有效磷、速效钾、全氮、全磷、钙、镁等养分的含量及微生物数量的影响来看,3300株/hm2和4400株/hm2的林分,土壤结构较好,养分元素充足,较另两种密度更适合微生物的繁衍增殖。对以上研究进行综合的评价与分析,得出3300株/hm2和4400株/hm2是杂种落叶松人工林生长、干形及养分循环较好的造林密度。3300株/hm2的造林密度在培育中小径材时不需进行抚育间伐,而4400株/hm2的杂种落叶松在培育中径材或大径材时要进行1-2次的间伐。本研究是对杂种落叶松优化经营模式的一个重要补充,为杂种落叶松人工林在黑龙江省的大面积推广提供科学的指导和依据。更多还原

【Abstract】 This research is part of the "Study on the improved variety and directed breeding technology of the high quality wood construction material forest" of the significant research project of Heilongjiang Province science and technology (GA09B202-02).Hybrid larch is a new species for forestry research institute of Heilongjiang province to study after30years, whose growth rate, disease and pest resistance ability and hardiness were more excellent than Larix Olgensis. A corresponding, more perfect cultivation pattern will be established for Hybrid Larch was extended in Heilongjiang province large area at present, and the important part of the pattern is the study on the planting density. The experimental field was established in the biggest area of Hybrid Larch in our country, which is14years old and the area is20hm3.48fixed standards were observed continuously that were setted in four afforestation densities(2500N/hm2,3300N/hm2,4400N/hm2,6600N/hm2) in2004.The first-hand material of the study on afforestation density were accumulated from the data of the biomass, litterfall, litter decomposition and soil conditions of Hybrid Larch in different afforestation density were investigated, so the results has strong persuasion and can provide very good supplement for Larch hybrids cultivation pattern.The growth law, biomass and carbon storage, litter and its decomposition, soil physical and chemical properties and microorganisms were studied with variance analysis, multiple comparison, mathematical models and other methods, the main result are:The effect of afforestation density on plant growth index of Hybrid Larch were remarkable. The afforestation density bigger, the diameter, singleplant volumn and crown width of Hybrid Larch smaller.3300N/hm2is the best afforestation density for the better growth, stem form relatively full, large yield.The effect of afforestation density on the singleplant biomass and stand biomass of Hybrid Larch were significant. The singleplant biomass in3300N/hm2was biggest (23.65kg) and the proportion of branch and leaves were larger(35.43%). The singleplant biomass in4400N/hm2was lowest(21.78kg) and the proportion of trunk and bark were larger(69.28%). The fitting precision of individual biomass regression model in different density which can provide more accurate scientific basis for biomass and carbon storage of Hybrid Larch were higher.The decomposition rate of Hybrid Larch litter was effected by afforestation density, the density bigger, the decomposition cycle longer, the longest time was more than17years(2500N/hm2) and the shortest was only a little more than13years (6600N/hm2). The decomposition cycle was only less than4years in2500N/hm2after the microhabitat altered. The content of nutrient elements of litter in3300N/hm2and4400N/hm2decreased faster and it showed that the nutrient elements in these two afforestation densities returned faster.3300N/hm2and4400N/hm2were the more suitable afforestation density for better soil structure, nutrient adequacy and microbe propagate according by the effect of the content of hydrolyzable nitrogen, available phosphorus, available potassium, total nitrogen, total phosp N horus, total potassium, calcium, magnesium and the quantity of soil microbes3300N/hm2and4400N/hm2were the the better afforestation density for Hybrid Larch on growth, stem form and nutrient cycle from the analysis and evaluation of the above research. Thinning was not needed to cultivate middle diameter timber and small diameter timber in the stand the afforestation density was3300N/hm2, and1or2times thinning in the stand the afforestation density was4400N/hm2to cultivate middle diameter timber and large diameter timber.This research was an important supplement for the optimization management of Hybrid Larch, and it can provide scientific guidance and basis for Hybrid Larch to extension in Heilongjiang Province.更多还原