本文選題：興安落葉松　切入點：年輪寬度　出處：《沈陽農(nóng)業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：大興安嶺是我國氣候變暖的敏感地區(qū)。為了探究氣候變暖背景下溫度變化對不同區(qū)域興安落葉松(Larix gmelinii)徑向生長的抑制性,利用樹木年代學方法在大興安嶺主脈南段、中段和北段的15個地區(qū)進行樹木年輪取樣,建立了各點年輪寬度年表,根據(jù)取樣點地理位置、年表的主成分載荷系數(shù)、年表間相關(guān)分析對年表進行分類并合成南部、中部和北部各氣候分區(qū)的興安落葉松年輪指數(shù)。用相關(guān)函數(shù)剖析了興安落葉松徑向生長與溫度的關(guān)系,連系滑動響應分析和多元線性回歸模型探討溫度抑制興安落葉松徑向生長的根本原因,并展望未來氣候變暖背景下,興安落葉松林生態(tài)系統(tǒng)的分布變革。結(jié)果主要有:1.近百年來研究區(qū)溫度變化在20世紀20-30年代和70-80年代有兩個明顯的分界點,之后研究區(qū)進入了顯著的升溫期。自1960年以來,研究區(qū)氣候條件為半濕潤氣候,且自1984年以來,區(qū)域干濕狀況具有半濕潤轉(zhuǎn)化為半干旱的趨勢,暖干化趨勢呈中部南部北部。研究區(qū)自1901-2001年凍土類型均為不連續(xù)多年凍土,凍土退化在1925-1955年和1969-1999年最為嚴重,尤其南部地區(qū)在1988年后無多年凍土分布。區(qū)域干旱指數(shù)、冰凍指數(shù)下降趨勢在時間上與區(qū)域溫度升高趨勢相對應,因此,氣候變暖導致了研究區(qū)環(huán)境條件的明顯變動。2.胸高斷面積增量(BAI)指示的樹木生長量同期呈中部南部北部的趨勢,升溫過程中,南部、中部落葉松BAI趨勢下降,其中,中部落葉松的BAI在第二次升溫中下降趨勢最顯著。這種趨勢變化在時間上與區(qū)域溫度升高、環(huán)境條件變動一致,表明溫度升高對興安落葉松徑向生長具有抑制性,且抑制程度具有局地差異性。3.落葉松徑向生長對溫度的響應具備南北差別(中部北部南部):南部落葉松生長與上年11月-當年4月平均溫度顯著負相關(guān)(p0.05),中部落葉松生長與上年生長季、上年冬季、當年秋季平均溫度顯著負相關(guān)(p0.05),北部落葉松生長與當年4-5月(生長季前)平均溫度極顯著正相關(guān)(p0.01)。氣候變暖背景下,高溫引起的區(qū)域暖干化使土壤水分成為限制落葉松生長的主要因子,土壤干旱加劇使落葉松生長對溫度變化的響應增強。BAI指示的落葉松生產(chǎn)力經(jīng)歷了從響應低溫脅迫到響應高溫引起的水分脅迫的轉(zhuǎn)變。將來幾十年,若溫度持續(xù)升高,大興安嶺區(qū)域落葉松徑向生長量將呈南部和中部降低、北部升高的趨勢。然而,北部區(qū)域?qū)β淙~松徑向生長的天然保護作用并不穩(wěn)定,年輪指數(shù)與溫度的正響應系數(shù)的降低,預示了興安落葉松適宜分布區(qū)的北移,未來氣候變暖可能破壞興安落葉松林生態(tài)系統(tǒng)的平衡,并導致其被其它森林生態(tài)系統(tǒng)所取代。
[Abstract]:The Daxing'an Mountains is a sensitive region for climate warming in China. In order to study the inhibition of temperature change on the radial growth of Larix gmelinii in different regions under the background of climate warming, the tree chronology method was used in the southern segment of the main vein of the Daxing'an Mountains. Tree ring sampling was carried out in 15 areas in the middle and north segments, and the chronology of the width of each point ring was established. The chronological table was classified and synthesized according to the geographical location of the sampling point, the principal component load coefficient of the chronological table, and the correlation analysis between the chronological tables. The relationship between radial growth and temperature of Larix gmelinii in central and northern climatic regions was analyzed by correlation function. Coupled sliding response analysis and multivariate linear regression model were used to study the root causes of temperature inhibition on radial growth of Larix gmelini, and to look forward to the future climate warming. The main results are as follows: 1. In the last hundred years, the temperature variation of the study area has two distinct boundary points in 20th century, 20-30 's and 70-80 's, and then the research area has entered a significant warming period. Since 1960, the study area has entered a significant warming period. The climatic conditions in the study area are semi-humid, and since 1984, the dry and wet conditions in the study area have the tendency of converting from semi-humid to semi-arid, and the trend of warm drying is northern and central. The permafrost types in the study area from 1901-2001 are all discontinuous permafrost. The degradation of permafrost was most serious in 1925-1955 and 1969-1999, especially in the southern region, where there was no distribution of frozen soil for many years after 1988. The decreasing trend of regional drought index and freezing index corresponds to the increasing trend of regional temperature in time. Climate warming resulted in obvious changes of environmental conditions in the study area. 2. The tree growth indicated by the increment of sternal height and sectional area was the same as that of the northern part of the central part. During the heating process, the BAI trend of the south and central larch decreased, among which, The BAI of Larix gmelinii decreased most significantly in the second temperature rise, which was consistent with the regional temperature and environmental conditions, indicating that the radial growth of Larix gmelinii was inhibited by the rise of temperature. The response of radial growth of Larix gmelinii to temperature was significantly different from north to south (central and northern: southern larch growth was negatively correlated with the average temperature from November to April of last year), and the response of larch radial growth to temperature was significantly negatively correlated with that of middle tribe. The growth of Pinus tabulaeformis and the growth season of last year. In winter of last year, the average temperature in autumn was significantly negatively correlated with that of P0.05, and the growth of Larix gmelini was positively correlated with the average temperature of April / April (pre-season) of that year. Regional warming and drying caused by high temperature make soil moisture the main factor limiting the growth of larch. When soil drought intensifies, the response of larch growth to temperature changes is enhanced. The productivity of larch indicated by Bai has undergone a transition from response to low temperature stress to water stress caused by high temperature. The radial growth of Larix gmelinii in the Daxing'anling region will decrease in the south and the middle of the region, and increase in the north. However, the natural protective effect of the northern region on the radial growth of the larch is not stable, and the positive response coefficient of annual ring index and temperature is decreased. It indicates that the suitable distribution area of Larix gmelinii is moving northward, and the future climate warming may destroy the balance of forest ecosystem of Larix gmelini forest and lead to its replacement by other forest ecosystems.
【學位授予單位】：沈陽農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：S791.222
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本文編號：1617131