【摘要】：桉樹(Eucalyptus)是聯(lián)合國糧農(nóng)組織推薦的三大類速生造林樹種之一,已經(jīng)成為我國南方速生豐產(chǎn)林的戰(zhàn)略性樹種。熱帶海南島的中西部地區(qū)為重要的桉樹人工林分布區(qū),這里屬于半濕潤、半干旱區(qū);連片種植桉樹林產(chǎn)生了較好的經(jīng)濟(jì)效益,但也引起了一系列的生態(tài)問題,其中水生態(tài)問題尤為突出。本研究以海南儋州林場桉樹林為研究對象,利用莖流測量系統(tǒng)長期監(jiān)測4~5a桉樹樹干液流速率,并同步監(jiān)測光合有效輻射、大氣溫度、相對濕度、降水、土壤水分等環(huán)境因子,分析桉樹人工林液流速率在時、日、月等不同時間尺度上的變化規(guī)律,揭示不同時間尺度上桉樹液流速率與環(huán)境因子的相關(guān)關(guān)系,探討不同時間尺度桉樹液流的主要影響因素,并測算桉樹群落年耗水量,為桉樹人工林的水分管理、合理經(jīng)營提供理論依據(jù)和實(shí)踐指導(dǎo)。研究結(jié)果表明:(1)時、日和月時間尺度上,光合有效輻射、氣溫、相對濕度變化顯著;降水和土壤水分在月尺度上有明顯變化,不同深度土層的土壤水分變化幅度不同,但存在極顯著相關(guān)和顯著差異,且受光合有效輻射的影響較大。(2)桉樹不同方位樹干液流實(shí)時監(jiān)測結(jié)果表明:晴、陰、雨天桉樹不同方位樹干液流速率日變化規(guī)律相似,晴天呈單峰型曲線,陰天和雨天呈多峰型或無峰型曲線;樹干東、南方位液流啟動與到達(dá)峰值時間分別較西、北方位要早20分鐘左右;晴、陰、雨天桉樹各方位液流速率均呈極顯著正相關(guān),且存在顯著或極顯著差異;晴天東、南、西、北側(cè)較低液流速率比較高液流速率低13.7%,陰天低34.4%,雨天低9.4%。晴天北側(cè)的液流速率與均值最為接近,陰、雨天北側(cè)的液流經(jīng)過校正可以減少整樹蒸騰測算誤差。(3)在時尺度上,桉樹液流速率呈現(xiàn)晝高夜低的變化;晴、陰、雨天桉樹液流速率日變化曲線有差異,晴天以單峰曲線為主,陰天以單峰或多峰為主,雨天變化特征不明顯;晴、陰、雨天桉樹液流全天日均值分別是5.58 mL·cm-2·h-1、3.97 mL·cm-2·h-1、1.41mL·cm-2·h-1。在日尺度上,桉樹液流速率變化幅度較大,變化范圍為4.86~145.12mL·cm-2·d-1;即使是相鄰兩天,液流速率差異也可很大,外界環(huán)境因子是影響其差異的主要原因。在月尺度上,桉樹樹干液流速率大小依次為:7月、6月、9月、8月、5月、10月、4月、11月、12月、3月、2月、1月;雨季(5~10月)樹干液流顯著高于旱季(1~4月和11~12月),前者月均值為2.82 L·cm-2·month-1,后者為1.47 L·cm-2·month-1。(4)在時尺度上,旱季,光合有效輻射對晴天與陰天的桉樹液流速率影響最大,空氣相對濕度影響次之,晴天光合有效輻射對桉樹液流速率的影響較陰天更大;雨天,空氣相對濕度和光合有效輻射對桉樹液流速率影響較大,空氣相對濕度的影響更大一些;氣溫與土壤水分對桉樹晴、陰、雨天的液流速率影響都較小。雨季,晴、陰、雨天桉樹液流速率均受光合有效輻射、空氣相對濕度和氣溫的影響,以光合有效輻射影響最大;氣溫與土壤水分對桉樹液流速率影響都較小。在日尺度上,旱季光合有效輻射是桉樹液流速率的主要影響因子;雨季氣溫和光合有效輻射是日尺度上桉樹液流速率的主要影響因子。在月尺度上,光合有效輻射是全年各月桉樹液流速率變化的最主要影響因子,30-60cm土壤水分是液流速率變化的重要因子。(5)桉樹液流日累積量因天氣、胸徑不同而不同。晴天最多,雨天最少;胸徑越大,日累積量越大。不同徑階標(biāo)準(zhǔn)木月耗水量有相似的月變化特征,但桉樹徑階越大,單木月蒸騰耗水量差異越大;雨季,7.51cm、9.39cm、12.45cm徑階的桉樹單木蒸騰耗水量為223.86L、766.31L、2164.6L;分別占全年的61.72%、66.26%、65.95%。2016年4~5a桉樹人工林群落蒸騰耗水3137543.78L·hm-2,約占當(dāng)?shù)囟嗄杲邓?6.15~39.2%,日均蒸騰耗水0.86 mm,旱季日均蒸騰耗水0.61 mm;雨季日均蒸騰耗水1.1 mm。
[Abstract]:Eucalyptus is one of the three fast-growing afforestation species recommended by FAO and has become a strategic tree species for fast-growing and High-yielding forests in southern China. In this study, Eucalyptus plantation in Hainan Yanzhou Forest Farm was selected as the research object, and the sap flow rate of Eucalyptus trunk was monitored by stem flow measurement system for a long period of 4 to 5 years, and the environmental factors such as photosynthetic active radiation, atmospheric temperature, relative humidity, precipitation and soil moisture were monitored synchronously. The relationship between Eucalyptus sap flow rate and environmental factors at different time scales was revealed. The main influencing factors of Eucalyptus sap flow at different time scales were discussed. The annual water consumption of Eucalyptus community was calculated to provide water management and rational management of Eucalyptus plantation. The results show that: (1) on the time scale of day and month, the changes of PAR, air temperature and relative humidity are significant; on the monthly scale, the precipitation and soil moisture have obvious changes, and the variation range of soil moisture in different depths is different, but there are extremely significant correlations and significant differences, and they are subject to PAR. (2) Real-time monitoring results of Eucalyptus trunk sap flow in different directions showed that the diurnal variation of sap flow rate in different directions of Eucalyptus trunk was similar in sunny, cloudy and rainy days, with a unimodal curve in sunny days and a multi-modal or non-modal curve in cloudy and rainy days. On sunny days, the sap flow rate on the north side is 13.7%, 34.4% on cloudy days and 9.4% on rainy days. On sunny days, the sap flow rate on the north side is the closest to the mean value. On cloudy and rainy days, the sap flow on the north side passes through correction. (3) On the time scale, the sap flow rate of Eucalyptus presents the change of day-high and night-low; on sunny, cloudy and rainy days, the diurnal variation curves of sap flow rate of Eucalyptus are different; on sunny days, single peak curves are dominant; on cloudy days, single or multi-peak curves are dominant; on rainy days, the variation characteristics of sap flow of Eucalyptus are not obvious; on sunny, cloudy and rainy days, the diurnal mean values of sap flow of Eucalyptus are respectively 5.58 mL.cm-2.h-1,3.97 mL.cm-2.h-1,1.41 mL.cm-2.h-1.On the diurnal scale, the sap flow rate of Eucalyptus varied greatly, ranging from 4.86 mL.cm-2.d-1 to 145.12 mL.cm-2.d-1.Even in the adjacent two days, the sap flow rate varied greatly, and the main reason for the difference was the environmental factors. In the rainy season (May-October), the trunk sap flow was significantly higher than that in the dry season (January-April and November-December), the monthly mean value of the former was 2.82 L.cm-2.month-1, and the latter was 1.47 L.cm-2.month-1. (4) On the time scale, in the dry season, the shading rate of PAR on sunny and cloudy days was significantly higher than that in the dry season (January-April and November-December). On rainy days, the relative humidity of air and the photosynthetic active radiation have a greater impact on the sap flow rate of eucalyptus, and the influence of air temperature and soil moisture on the sap flow rate of Eucalyptus is greater. In rainy season, sunny, cloudy and rainy days, the sap flow rate of Eucalyptus was affected by PAR, air relative humidity and air temperature, and PAR was the most important factor. The influence of air temperature and soil moisture on sap flow rate of Eucalyptus was small. Photosynthetically active radiation (PAR) is the main influencing factor of Eucalyptus sap flow rate on a daily scale. On a monthly scale, PAR is the most important influencing factor of Eucalyptus sap flow rate on a monthly scale, and 30-60 cm soil moisture is an important factor of sap flow rate. (5) Daily accumulation of sap flow varies with weather and DBH. The monthly water consumption of standard trees with different diameter scales had similar monthly variation characteristics, but the monthly water consumption of individual trees with larger diameter scales had greater differences; the monthly water consumption of individual trees with 7.51 cm, 9.39 cm and 12.45 cm diameter scales in rainy season was 223.86 L, 766.31 L and 2164.6 L, accounting for 61.72%, 66.26% and 65.95% respectively. Eucalyptus plantation community transpiration consumed 3137543.78 L HM 2, accounting for 26.15 39.2% of local precipitation, 0.86 mm of daily transpiration, 0.61 mm of daily transpiration in dry season and 1.1 mm of daily transpiration in rainy season.
【學(xué)位授予單位】：海南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：S792.39

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