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  本文關(guān)鍵詞：秦嶺火地塘林區(qū)主要森林類型粗木質(zhì)殘體研究　出處：《西北農(nóng)林科技大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 秦嶺 粗木質(zhì)殘體 儲量 倒木分解 倒木呼吸 碳循環(huán)

【摘要】：本文以秦嶺火地塘林區(qū)銳齒櫟林、華山松林、油松林和華北落葉松林四種森林類型為研究對象,對其粗木質(zhì)殘體(Coarse woody debris,CWD)進(jìn)行了系統(tǒng)地研究。調(diào)查了四種森林類型的CWD基本特征,厘清了CWD的儲量及組成、腐爛等級組成、徑級組成;測定了四種森林類型的喬木層、灌木層、草本層、枯枝落葉層的生物量,揭示了CWD的儲量與森林生物量間的關(guān)系;計算了四種森林類型植物群落的α多樣性,分析了CWD的儲量與植物群落的α多樣性間的關(guān)系;測定了四種森林類型倒木的密度、含水量和溫度特征,采用單項指數(shù)衰減模型估測了倒木的分解速率,探討了影響倒木分解的因素,揭示了倒木形成的原因;測定了四種森林類型倒木及其土壤化學(xué)元素含量,明晰了倒木化學(xué)元素含量在腐爛過程的變化,闡明了倒木分解對土壤化學(xué)元素的影響;測定了四種森林類型的倒木呼吸、倒木溫度和倒木含水量,揭示了倒木呼吸與倒木溫度和倒木含水量間的關(guān)系,搞清了不同腐爛等級、不同樹種倒木呼吸的季節(jié)動態(tài);估算了四種森林類型的倒木呼吸年通量,比較了不同森林類型、不同腐爛等級倒木呼吸年通量,分析了倒木呼吸年通量的季節(jié)動態(tài)。主要研究結(jié)果如下:(1)2009~2014年的四個森林類型的CWD儲量變化范圍較大,但都逐年增加。倒木在銳齒櫟林、油松林和華北落葉松林所占比重最大,而華山松林的倒木和枯立木所占比例相當(dāng),根樁在四種森林類型的儲量最小。四種森林類型各腐爛等級的CWD儲量存在較大差異,銳齒櫟林中3級CWD儲量最大,華山松林以1級為主,油松林中2級最高,而華北落葉松林中1、2級最多。四種森林類型不同徑級的CWD儲量也存在較大差異,銳齒櫟林以30~40 cm倒木顯著占優(yōu)(P0.05),華山松林中20~30 cm倒木顯著最多(P0.05),油松林中30~40 cm倒木儲量最大,而華北落葉松林中主要是10~20 cm倒木。(2)2009~2014年的四個森林類型的總生物量逐年增加,年均總生物量和喬木層年均生物量都存在顯著差異(P0.05),銳齒櫟林顯著最高(P0.05),華北落葉松林顯著最低(P0.05);灌木層生物量在3種針葉林間沒有顯著差異(P0.05),但銳齒櫟林顯著最低(P0.05);草本層生物量,華北落葉松林顯著最高(P0.05),銳齒櫟林顯著最低(P0.05);而枯枝落葉層的生物量,銳齒櫟林和華山松林顯著高于油松林和華北落葉松林(P0.05);華山松林的CWD年均儲量顯著最高(P0.05),華北落葉松林顯著最低(P0.05)。喬木層的生物量在四種森林類型中都顯著最高(P0.05),其次為CWD的儲量。四種森林類型的CWD儲量與其立地總生物量間存在著極顯著的相關(guān)性(P0.0001),相關(guān)程度大小與森林類型及其物種組成有關(guān)。(3)四個森林類型的喬、灌、草層物種多樣性指數(shù)存在著不同程度的顯著性差異(P0.05),物種多樣性指數(shù)表現(xiàn)為:草本層灌木層喬木層的規(guī)律,但不同森林類型和多樣性指數(shù)間各有差異。各種α多樣性指數(shù)間均呈現(xiàn)出顯著的正相關(guān)(p0.05)。cwd儲量與群落物種多樣性間存在著不同程度的顯著正相關(guān)性(p0.05),其相關(guān)性與森林類型、植物生長型(喬木、灌木和草本)和不同的多樣性指數(shù)有關(guān)。該林區(qū)cwd儲量對植物群落物種豐富度指數(shù)的影響最大,而對pielou均勻度指數(shù)的影響很小,對草本層的物種多樣性影響較大,而對喬木層的影響較小。(4)四個樹種的倒木含水量和倒木溫度在2010年、2012年和2014年測定期間均呈現(xiàn)出月變化,但變化不一致。四個樹種的倒木含水量都隨著腐爛等級的增加,呈直線上升。而油松、華山松和華北落葉松的倒木溫度隨倒木腐爛呈現(xiàn)出先上升后下降的趨勢(43521),銳齒櫟倒木溫度則隨著倒木腐爛逐漸上升。另外,不同腐爛等級的倒木含水量與降雨量間都存在顯著相關(guān)性(p0.05),但不同腐爛等級倒木含水量與與空氣相對濕度間相關(guān)性不顯著(p0.05)。四個樹種的五個腐爛等級倒木溫度與氣溫和10cm地溫間均存在著顯著的線性正相關(guān)(p0.05),并且倒木溫度明顯滯后于氣溫和10cm地溫。相較于氣溫,倒木溫度與10cm地溫相關(guān)性更為密切,即相關(guān)系數(shù)更大。(5)四個樹種的倒木都隨著腐爛等級的增加,密度呈直線下降。通過單項指數(shù)衰減模型對該林區(qū)四個樹種倒木的密度與分解時間之間的關(guān)系進(jìn)行擬合表明,該林區(qū)四個樹種的曲線擬合都很好,r2值都很高,越到分解后期倒木腐爛越緩慢,分解所需時間越長。銳齒櫟倒木的分解常數(shù)最高,達(dá)到0.07064,而華北落葉松倒木的分解常數(shù)最低,僅有0.0316。油松分解掉50%和95%所需時間約為20年和86年,華山松分解掉50%和95%所需時間約為14年和60年,銳齒櫟分解掉50%和95%所需時間約為10年和42年,而華北落葉松分解掉50%和95%所需時間約為22年和95年。(6)四個樹種倒木分解過程中6種化學(xué)元素含量都存在著不同的差異,c在倒木化學(xué)元素含量中最高,其次為n。四個樹種倒木的c、k含量和c/n都隨著倒木的腐爛呈現(xiàn)出下降趨勢,而四個樹種倒木的n、p、ca、mg含量則隨著倒木的腐爛都呈現(xiàn)出上升的趨勢。另外,四個樹種倒木下3個土層的土壤c含量都隨著倒木的腐爛顯著遞增(p0.05),油松、華山松和華北落葉松倒木下3個土層的土壤n含量也都隨著倒木的腐爛顯著遞增(p0.05),但銳齒櫟倒木下3個土層的土壤n含量隨著倒木的腐爛呈現(xiàn)先增加接著下降而后趨于平穩(wěn)的趨勢。四個樹種倒木下3個土層的土壤p、k和ca含量隨著倒木的腐爛波動較大,但無明顯的變化規(guī)律。不同樹種的倒木下土壤m(xù)g含量在不同土層間隨著倒木的腐爛變化趨勢各不相同。四個樹種不同分解時間的倒木下土壤c、n和mg含量都隨著土層加深而顯著遞減(p0.05)。(7)四個樹種的倒木呼吸在2010、2012和2014年的測定期間均沒有顯著差異(p0.05),但不同腐爛等級間存在著顯著差異(p0.05),差異程度因樹種和分解等級而異。三個針葉樹種(華北落葉松、油松、華山松)的各腐爛等級倒木呼吸均呈現(xiàn)出:45321,而闊葉樹種(銳齒櫟)的各腐爛等級倒木呼吸則顯示出:54321。四個樹種的不同腐爛等級的倒木呼吸在2010、2012和2014年的測定期間均呈現(xiàn)出明顯的月變化,但變化幅度各有差異,5個腐爛等級的倒木呼吸最大值均出現(xiàn)在8月,而最低值均出現(xiàn)在10月。闊葉樹種(銳齒櫟)的倒木呼吸要高于針葉樹種(華北落葉松、油松、華山松),而華北落葉松的倒木呼吸最低。(8)倒木溫度驅(qū)動著倒木呼吸的變化,倒木溫度是影響倒木呼吸的主要環(huán)境因子。四個樹種的不同腐爛等級倒木呼吸與倒木溫度間均呈顯著的正相關(guān)(p0.05),并且都存在著極顯著的指數(shù)關(guān)系(P0.0001),倒木溫度解釋了66%以上的倒木呼吸變化。四個樹種的不同腐爛等級倒木呼吸Q10值變化范圍為1.82~3.55,不同樹種和不同腐爛等級間均存在著差異。四個樹種不同腐爛等級的倒木呼吸與倒木含水量間沒有顯著的相關(guān)性(P0.05)。(9)四個森林類型的倒木呼吸年通量都呈現(xiàn)出明顯的單峰趨勢,夏季倒木呼吸年通量最高,冬季最低,具有很明顯的季節(jié)變化。四個森林類型的不同腐爛等級倒木呼吸年通量變化范圍較大,但都隨時間呈增長的趨勢,2010年的倒木呼吸年通量最低,2014年最高。銳齒櫟林的平均倒木呼吸年通量顯著最高(P0.05,70.57±7.23 g C·m-2·a-1),其次為油松林(52.59±4.58 g C·m-2·a-1)和華山松林(51.75±4.34 g C·m-2·a-1),華北落葉松林顯著最低(P0.05,36.49±3.23 g C·m-2·a-1)。各分解等級的倒木呼吸年通量在不同森林類型間各有差異,銳齒櫟林的3、4、5級的平均倒木呼吸年通量占到其總量的88.86%;華山松林和油松林都以3級所占比重顯著最高(P0.05),分別占31.24%和30.80%;華北落葉松林在1、2、3和4級間沒有顯著性差異(P0.05),但5級顯著最低(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 闂寸殑鍏崇郴榪涜鎷熷悎琛ㄦ槑,璇ユ灄鍖哄洓涓爲(wèi)縐嶇殑鏇茬嚎鎷熷悎閮藉緢濂，

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