秦岭火地塘林区主要森林类型粗木质残体研究

发布时间：2018-01-01 02:13

  本文关键词：秦岭火地塘林区主要森林类型粗木质残体研究　出处：《西北农林科技大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 秦岭 粗木质残体 储量 倒木分解 倒木呼吸 碳循环

【摘要】：本文以秦岭火地塘林区锐齿栎林、华山松林、油松林和华北落叶松林四种森林类型为研究对象,对其粗木质残体(Coarse woody debris,CWD)进行了系统地研究。调查了四种森林类型的CWD基本特征,厘清了CWD的储量及组成、腐烂等级组成、径级组成;测定了四种森林类型的乔木层、灌木层、草本层、枯枝落叶层的生物量,揭示了CWD的储量与森林生物量间的关系;计算了四种森林类型植物群落的α多样性,分析了CWD的储量与植物群落的α多样性间的关系;测定了四种森林类型倒木的密度、含水量和温度特征,采用单项指数衰减模型估测了倒木的分解速率,探讨了影响倒木分解的因素,揭示了倒木形成的原因;测定了四种森林类型倒木及其土壤化学元素含量,明晰了倒木化学元素含量在腐烂过程的变化,阐明了倒木分解对土壤化学元素的影响;测定了四种森林类型的倒木呼吸、倒木温度和倒木含水量,揭示了倒木呼吸与倒木温度和倒木含水量间的关系,搞清了不同腐烂等级、不同树种倒木呼吸的季节动态;估算了四种森林类型的倒木呼吸年通量,比较了不同森林类型、不同腐烂等级倒木呼吸年通量,分析了倒木呼吸年通量的季节动态。主要研究结果如下:(1)2009~2014年的四个森林类型的CWD储量变化范围较大,但都逐年增加。倒木在锐齿栎林、油松林和华北落叶松林所占比重最大,而华山松林的倒木和枯立木所占比例相当,根桩在四种森林类型的储量最小。四种森林类型各腐烂等级的CWD储量存在较大差异,锐齿栎林中3级CWD储量最大,华山松林以1级为主,油松林中2级最高,而华北落叶松林中1、2级最多。四种森林类型不同径级的CWD储量也存在较大差异,锐齿栎林以30~40 cm倒木显著占优(P0.05),华山松林中20~30 cm倒木显著最多(P0.05),油松林中30~40 cm倒木储量最大,而华北落叶松林中主要是10~20 cm倒木。(2)2009~2014年的四个森林类型的总生物量逐年增加,年均总生物量和乔木层年均生物量都存在显著差异(P0.05),锐齿栎林显著最高(P0.05),华北落叶松林显著最低(P0.05);灌木层生物量在3种针叶林间没有显著差异(P0.05),但锐齿栎林显著最低(P0.05);草本层生物量,华北落叶松林显著最高(P0.05),锐齿栎林显著最低(P0.05);而枯枝落叶层的生物量,锐齿栎林和华山松林显著高于油松林和华北落叶松林(P0.05);华山松林的CWD年均储量显著最高(P0.05),华北落叶松林显著最低(P0.05)。乔木层的生物量在四种森林类型中都显著最高(P0.05),其次为CWD的储量。四种森林类型的CWD储量与其立地总生物量间存在着极显著的相关性(P0.0001),相关程度大小与森林类型及其物种组成有关。(3)四个森林类型的乔、灌、草层物种多样性指数存在着不同程度的显著性差异(P0.05),物种多样性指数表现为:草本层灌木层乔木层的规律,但不同森林类型和多样性指数间各有差异。各种α多样性指数间均呈现出显著的正相关(p0.05)。cwd储量与群落物种多样性间存在着不同程度的显著正相关性(p0.05),其相关性与森林类型、植物生长型(乔木、灌木和草本)和不同的多样性指数有关。该林区cwd储量对植物群落物种丰富度指数的影响最大,而对pielou均匀度指数的影响很小,对草本层的物种多样性影响较大,而对乔木层的影响较小。(4)四个树种的倒木含水量和倒木温度在2010年、2012年和2014年测定期间均呈现出月变化,但变化不一致。四个树种的倒木含水量都随着腐烂等级的增加,呈直线上升。而油松、华山松和华北落叶松的倒木温度随倒木腐烂呈现出先上升后下降的趋势(43521),锐齿栎倒木温度则随着倒木腐烂逐渐上升。另外,不同腐烂等级的倒木含水量与降雨量间都存在显著相关性(p0.05),但不同腐烂等级倒木含水量与与空气相对湿度间相关性不显著(p0.05)。四个树种的五个腐烂等级倒木温度与气温和10cm地温间均存在着显著的线性正相关(p0.05),并且倒木温度明显滞后于气温和10cm地温。相较于气温,倒木温度与10cm地温相关性更为密切,即相关系数更大。(5)四个树种的倒木都随着腐烂等级的增加,密度呈直线下降。通过单项指数衰减模型对该林区四个树种倒木的密度与分解时间之间的关系进行拟合表明,该林区四个树种的曲线拟合都很好,r2值都很高,越到分解后期倒木腐烂越缓慢,分解所需时间越长。锐齿栎倒木的分解常数最高,达到0.07064,而华北落叶松倒木的分解常数最低,仅有0.0316。油松分解掉50%和95%所需时间约为20年和86年,华山松分解掉50%和95%所需时间约为14年和60年,锐齿栎分解掉50%和95%所需时间约为10年和42年,而华北落叶松分解掉50%和95%所需时间约为22年和95年。(6)四个树种倒木分解过程中6种化学元素含量都存在着不同的差异,c在倒木化学元素含量中最高,其次为n。四个树种倒木的c、k含量和c/n都随着倒木的腐烂呈现出下降趋势,而四个树种倒木的n、p、ca、mg含量则随着倒木的腐烂都呈现出上升的趋势。另外,四个树种倒木下3个土层的土壤c含量都随着倒木的腐烂显著递增(p0.05),油松、华山松和华北落叶松倒木下3个土层的土壤n含量也都随着倒木的腐烂显著递增(p0.05),但锐齿栎倒木下3个土层的土壤n含量随着倒木的腐烂呈现先增加接着下降而后趋于平稳的趋势。四个树种倒木下3个土层的土壤p、k和ca含量随着倒木的腐烂波动较大,但无明显的变化规律。不同树种的倒木下土壤mg含量在不同土层间随着倒木的腐烂变化趋势各不相同。四个树种不同分解时间的倒木下土壤c、n和mg含量都随着土层加深而显著递减(p0.05)。(7)四个树种的倒木呼吸在2010、2012和2014年的测定期间均没有显著差异(p0.05),但不同腐烂等级间存在着显著差异(p0.05),差异程度因树种和分解等级而异。三个针叶树种(华北落叶松、油松、华山松)的各腐烂等级倒木呼吸均呈现出:45321,而阔叶树种(锐齿栎)的各腐烂等级倒木呼吸则显示出:54321。四个树种的不同腐烂等级的倒木呼吸在2010、2012和2014年的测定期间均呈现出明显的月变化,但变化幅度各有差异,5个腐烂等级的倒木呼吸最大值均出现在8月,而最低值均出现在10月。阔叶树种(锐齿栎)的倒木呼吸要高于针叶树种(华北落叶松、油松、华山松),而华北落叶松的倒木呼吸最低。(8)倒木温度驱动着倒木呼吸的变化,倒木温度是影响倒木呼吸的主要环境因子。四个树种的不同腐烂等级倒木呼吸与倒木温度间均呈显著的正相关(p0.05),并且都存在着极显著的指数关系(P0.0001),倒木温度解释了66%以上的倒木呼吸变化。四个树种的不同腐烂等级倒木呼吸Q10值变化范围为1.82~3.55,不同树种和不同腐烂等级间均存在着差异。四个树种不同腐烂等级的倒木呼吸与倒木含水量间没有显著的相关性(P0.05)。(9)四个森林类型的倒木呼吸年通量都呈现出明显的单峰趋势,夏季倒木呼吸年通量最高,冬季最低,具有很明显的季节变化。四个森林类型的不同腐烂等级倒木呼吸年通量变化范围较大,但都随时间呈增长的趋势,2010年的倒木呼吸年通量最低,2014年最高。锐齿栎林的平均倒木呼吸年通量显著最高(P0.05,70.57±7.23 g C·m-2·a-1),其次为油松林(52.59±4.58 g C·m-2·a-1)和华山松林(51.75±4.34 g C·m-2·a-1),华北落叶松林显著最低(P0.05,36.49±3.23 g C·m-2·a-1)。各分解等级的倒木呼吸年通量在不同森林类型间各有差异,锐齿栎林的3、4、5级的平均倒木呼吸年通量占到其总量的88.86%;华山松林和油松林都以3级所占比重显著最高(P0.05),分别占31.24%和30.80%;华北落叶松林在1、2、3和4级间没有显著性差异(P0.05),但5级显著最低(P0.05),只占到11.85%。
[Abstract]:This paper takes Qinling Mountains Huoditang Forest of Quercus acutidentata forest, Huashan pine forest, pine forest and larch forest four forest types as the research object, the coarse woody debris (Coarse woody, debris, CWD) were systematically studied. The investigation of the CWD basic characteristics of four kinds of forest types, clarify the CWD reserves and composition, decay class composition, size composition; Determination of the tree layer, four forest types of the shrub layer, herb layer biomass, litter layer, reveal the relationship between the amount of reserves and forest biomass between CWD; calculation of the four types of forest plant community diversity, analyzes the relationship between reserves and CWD of the plant community diversity among four forest types; pour wood density, moisture content and temperature characteristics, attenuation model estimates the decomposition rate of logs with single index, factors that affect the decomposition of fallen trees, reveals the formation of fallen wood Reason; four types of forest wood and chemical element contents in soil were determined, clear down the content of chemical elements in the change of decay, the wood effect on soil chemical elements decomposition; four types of forest respiration were measured, wood temperature and wood moisture content, revealing the relationship respiration and wood temperature and wood moisture content between different decay classes, find out, the seasonal dynamics of different tree species in respiration; estimation of four forest types in respiration flux, comparison of different forest types, different decay classes in respiration flux, analyzed the seasonal dynamics of wood in the respiratory flux. The main results are as follows: (1) four forest types CWD reserves range 2009~2014 years, but are increasing year by year. Wood in the Sharptooth oak forest, pine forest and larch forest accounted for the largest proportion, and Huashan Pine logs and snags proportion, reserves of piles in the four forest types. The minimum of four forest types in each decay class CWD reserves are different, 3 grade CWD reserves of Quercus acutidentata forest in Huashan pine forest, mainly at level 1, the 2 highest level in Chinese pine forest, and the leaves in North China in the pines 1,2 grade most. Four forest types of different size class CWD reserves are quite different, with 30~40 cm acuteserrata forest wood was dominant (P0.05), 20~30 cm in Huashan pine wood was the most (P0.05), 30~40 cm in Pinus tabulaeformis forest wood and the largest reserves, North China Larch Forest in 10~20 is the main cm wood. (2) the total biomass of four forest types in 2009~2014 increased year by year, the annual average total biomass and average biomass of arbor layer had significant difference (P0.05), Quercus aliena was the highest (P0.05), larch forest was the lowest (P0.05); shrub layer biomass There was no significant difference in the 3 species of coniferous forest (P0.05), but the acuteserrata forest was lowest (P0.05); herb layer biomass of larch was highest (P0.05), Quercus aliena was the lowest (P0.05); and litter biomass of Quercus acutidentata forest and pine forest and pine forest was significantly higher than that of Huashan Larch (P0.05); Huashan pine forest reserves significantly the highest average CWD (P0.05), larch forest was the lowest (P0.05). The biomass of tree layer in the four forest types are significantly highest (P0.05), followed by CWD reserves. The amount of CWD reserves and site total biomass of four forest types there is a significant correlation between the degree of correlation (P0.0001), the composition and size of forest types and species. (3) of four forest types Joe, irrigation, with significant differences in grass species diversity index (P0.05), the species diversity index of performance: The herb layer and shrub layer of tree layer in different forest types and rules, but the diversity index varies. Diversity index showed significant positive correlation (P0.05) diversity.Cwd reserves and species have significant positive correlation in different degree (P0.05), its relationship with forest type. Type of plant growth (trees, shrubs and herbs) and diversity index of different effects. The forest reserves of CWD plant species richness is the largest, but has little influence on the uniformity of the Pielou index, a greater impact on the species diversity of herb layer, but it has little effect on the tree layer (4). The four species of wood moisture content and wood temperature in 2010, 2012 and 2014 during the determination showed monthly changes, but the changes are not consistent. The four species of wood moisture content increase with the decay level, a straight line rise. And Pinus tabulaeformis, China Mountain pine and larch logs with wood rot showed the temperature increased first and then decreased (43521), acuteserrata wood temperature with wood decay gradually increased. In addition, different decay classes of wood containing all significant correlation exists between rainfall and water (P0.05), but different decay classes down wood moisture content and relative humidity of air and no significant correlation between (P0.05). Four species of the five decay classes of wood and air temperature and 10cm temperature were significant linear correlation (P0.05), and wood temperature lagged behind the temperature and 10cm temperature. Compared to temperature, temperature logs 10cm and temperature correlation more closely, the correlation coefficient is greater. (5) the four species of wood were increased with the decay class, the density decreased linearly. By the single exponential decay model of the forest of four tree species wood density and decomposition time 闂寸殑鍏崇郴杩涜�屾嫙鍚堣〃鏄�,璇ユ灄鍖哄洓涓�鏍戠�嶇殑鏇茬嚎鎷熷悎閮藉緢濂，

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