林芝云杉林粗木质残体持水特性研究

粗木质残体(CWD)是森林生态系统的重要组成部分，在水土保育、维持生物多样性和生态平衡等方面起着重要作用。林芝云杉(Picea likiangensis var.linzhiensis)是藏东南亚高山暗针叶林的主要建群树种之一，为了解藏东南亚高山森林中粗木质残体的持水特性，以岗乡自然保护区原始林芝云杉林为研究对象，采用浸泡模拟法研究粗木质残体的分解程度、密度与持水性能的关系。结果表明：CWD密度随着分解程度加深而减小；吸水率随浸泡时间增加而增加，可用方程y=clnx-d拟合；吸水速率随分解等级加深而减小，可用方程y=ax^-b进行拟合；标准地内CWD最大持水量为41.25t·hm^-2,相当于降雨4.12mm,有效持水为33.93t·hm^-2,相当于降雨3.39mm。林芝云杉林内不同分解等级粗木质残体持水性能差异明显，其中Ⅴ级密度最小，持水量最高，证实了CWD分解程度对森林生态系统粗木质残体储水能力和吸收能力的影响，该研究有利于后续开展林芝云杉粗木质残体的生态功能研究。     

元谋干热河谷典型植被枯落物持水能力研究

选取元谋干热河谷3种植被恢复典型人工纯林(印楝、新银合欢、桉树),通过对林下枯落物蓄积量的实地调查和室内持水过程试验,测定枯落物的持水能力和持水过程。结果表明:1)3种林分单位面积枯落物蓄积量由大到小依次为:新银合欢(5.751t/hm2)桉树(3.328t/hm2)印楝(2.041t/hm2)。2)3种林分枯落物持水能力存在显著差异。最大持水量、蓄水量、最大拦蓄量和有效拦蓄量大小依次为新银合欢桉树印楝;自然持水量、自然持水率和最大持水率大小依次为印楝新银合欢桉树。3)将3种林分枯落物持水过程分析得出:枯落物持水量和吸水速率分别与浸水时间呈显著的对数关系和幂函数关系,枯落物在1h内持水量和吸水速率迅速增加,随着时间的延长,吸水速率逐渐下降,24h后基本达到饱和。     

塔里木沙漠公路防护林凋落物的持水特性

采用野外典型抽样和室内浸水的方法,对4种定植年限不同的塔里木沙漠公路防护林带内凋落物的储量、持水量和吸水速率进行研究。结果表明：① 不同定植年限防护林内凋落物储量依次为：13 a林带 (42.3 t•hm^-2) >6 a林带 (39.6 t•hm^-2) > 10 a林带 (39.1 t•hm^-2) > 7 a林带 (16.2 t•hm^-2)。② 沙漠公路防护林的林下未分解层凋落物持水量的排序为：梭梭 >柽柳>沙拐枣;而半分解层凋落物持水量的排序是：柽柳>梭梭>沙拐枣,且防护林内凋落物最大持水量半分解层均大于未分解层。③ 各林龄不同树种不同分解程度的凋落物持水量与浸水时间之间呈对数关系,最佳拟合关系式为W=b+a lg t,吸水速率与浸水时间之间呈幂函数关系,关系式为：V=ktⁿ,凋落物吸水速率在0～1 h内急剧下降,4 h以后下降平稳,其吸水作用逐渐减小。     

典型草原不同放牧强度凋落物的持水能力

探讨草地凋落物对草地水文功能的影响,在内蒙古典型草原对不同放牧强度的草地凋落物的持水能力进行了测定。结果表明:随着放牧强度的增加,草地凋落物的持水量呈现先增加后降低的趋势,重度放牧下草地凋落物的持水量仅为108g/kg,比中度放牧区的持水量1971.57g/kg降低了95%,这是凋落物组成成分差异的结果,凋落物的吸水速率和浸泡时间的回归分析表明,二者之间具有明显的相关性,回归方程分别为:对照区:Y=738.1X-0.656;轻度放牧区:Y=1569.3X-0.665;中度放牧区:Y=2650X-0.715;重度放牧区:Y=162.38X-0.563。     

保水剂与氮肥混施对土壤持水特性的影响

测定聚丙烯酰胺(PAM)、凹凸棒/聚丙烯酸(WT)和聚丙烯酸钠(HM)3种保水剂在浓度分别为2‰、5‰8、‰的NaCl、MgCl2、CaCl2、FeCl3、尿素、硝酸钾、氯化铵等7种溶液中的吸水倍率;用离心机法测定保水剂与氮肥混施条件下土壤的持水特性。结果表明:与去离子水比较,保水剂在盐溶液中的吸水倍率显著下降,且随着溶液浓度升高,保水剂的吸水倍率明显下降,对于同一盐溶液浓度,离子类型对保水剂吸水倍率的影响表现为:Na+Mg2+Ca2+Fe3+,WT保水剂表现出较强的抗离子特性;保水剂在不同氮肥溶液中的吸水倍率有较大差异,氮肥类型对保水剂吸水倍率的影响表现为:尿素硝酸钾氯化铵;保水剂与氮肥混合施入土壤能提高土壤的持水能力,但施入氮肥降低了保水剂的性能;推荐保水剂与氮肥混合使用时,施氮量不超过0.50 gN/kg干土,保水剂用量不超过6‰。     

油页岩有机碳矿化特征及在栽培基质中应用可行性分析

探讨油页岩有机碳矿化分解过程、有机碳组分变化特征以及环境因素作用规律可为评价油页岩在栽培基质中应用的可行性提供科学依据.试验在室内控制温度和水分条件下,分析了洗盐和未洗盐油页岩有机碳矿化动态变化特征.结果表明:油页岩基质在60 d培养期间,温度升高10℃使未洗盐基质总矿化量分别增加2%～28%(100%田间持水量)、2%～22%(80%田间持水量)和1%～15%(60%田间持水量);洗盐基质则分别增加2%～17%(100%田间持水量)、1%～5%(80%田间持水量)和7%～14%(60%田间持水量).将第60 d基质中活性有机碳含量进行回归分析,发现两种不同供试油页岩活性有机碳含量与温度和水分之间均呈正相关关系;未洗盐油页岩活性有机碳含量与温度和水分间相关性不显著,而洗盐后油页岩活性有机碳含量与温度和水分之间相关性显著(P=0.0214).用一级动力学方程拟合油页岩基质有机碳矿化动态得到未洗盐基质分解速率常数最大达1.2×10-3/d,洗盐基质其分解速率常数介于0.5×10-3～0.7×10-3/d.油页岩在长达60 d的培养过程中表现为有机碳持续分解、活性有机碳递增,证实其在基质栽培中的应用将对养分持续供给和维护作物根系生理活性发挥重要作用.     

大兴安岭北部兴安落叶松原始林倒木研究

倒木是森林生态系统的重要组成部分之一,在森林生态系统中发挥着许多重要、独特的生态功能。对大兴安岭北部兴安落叶松原始林倒木进行研究,发现平均每块样地共有兴安落叶松和白桦倒木32株,总材积为14.92m3,大约165m3/hm2,兴安落叶松占78%。研究认为,在大兴安岭兴安落叶松林生态系统,兴安落叶松的浅根性生理特征是影响倒木输入的内在原因;风和多年冻土是影响倒木输入的重要生态因子。由于大兴安岭林区低温高湿的环境,倒木分解非常慢,其中Ⅱ、Ⅲ级腐烂级倒木的现存量最多,兴安落叶松倒木的分解常数是0.0136/a(R2=0.9557),白桦为0.3508/a(R2=0.8789)。倒木的产生为森林经营管理提出了警示,预示达到成熟年龄的林分要及时进行抚育渐伐,避免树木心腐而浪费资源;同时,倒木的发生及其分解产生了很多重要作用和病虫害以及森林火灾隐患,应进行合理地管理利用。     

内蒙古扎兰屯市典型森林枯落物、土壤水源涵养功能研究

对扎兰屯林区3种典型(天然兴安落叶松、天然白桦、人工兴安落叶松)林分不同郁闭度等级林下枯落物及土壤水文特性进行了研究。结果表明:1)森林枯落物储量为24.81~82.32t/hm2,天然林枯落物的储量明显高于人工林。天然白桦林枯落物持水量最大(270.25t/hm2),人工落叶松纯林最小(88.25t/hm2)。枯落物对水分的有效拦蓄量为天然落叶松林(122.36t/hm2)天然白桦林(94.49t/hm2)人工落叶松林(67.99t/hm2)。2)土壤最大持水量为2958.51~3723.39t/hm2,其总孔隙度、最大持水量均表现为天然落叶松林天然白桦林人工落叶松林。土壤有效持水量天然白桦林(1033.23t/hm2)天然落叶松林(946.37t/hm2)人工落叶松林(833.34t/hm2)。3)天然落叶松林和人工落叶松林当郁闭度处于85%以上,天然白桦林郁闭度处于55%以下时,其枯落物量和最大持水量最大;天然落叶松林在郁闭度65.2~67%,天然白桦林郁闭度40.07~54.52%,人工落叶松林郁闭度85.66~100%时,枯落物对水分有效拦蓄量最大。4)天然落叶松林郁闭度73.49~96%,天然白桦林郁闭度为56.07~65.37%,人工落叶松林郁闭度为46.72~67.29%时,其土壤有效持水量最大。     

保水剂对土壤持水特性的作用机理研究

分别将B1(北京华瑞祥科技有限公司高吸水树脂保水剂)、B2(广东东莞市安信保水有限公司农林保水剂)、B3(唐山博亚科技工业开发有限责任公司的高能抗旱保水剂)3种保水剂以不同用量(0.05%、0.10%和0.50%)施入无团聚体孔隙的风沙土中,测定各处理土壤在不同吸力时的含水量,并用V-G模型拟合各土壤水分特性曲线,获得各处理土壤的水分特性曲线参数和主要水分常数等结果,以期揭示使用保水剂在改善土壤持水性方面的作用特征和机理。结果表明:1使用保水剂后,除土壤无效水部分无显著变化外,各处理土壤饱和含水量、田间持水量、重力水和有效水部分均显著增加,保水剂用量为0.50%时处理土壤的田间持水量比对照高3~4.7倍,使用保水剂显著改善了土壤中、低水吸力段的持水容量,即土壤的"孔隙"持水部分。2各处理土壤的水分特征曲线右移,各吸力段的持水容量明显增加,n值均小于对照,表明使用保水剂显著增大了在失水过程中土壤的持水能力。3使用保水剂后,各处理土壤增加的吸水量主要来源于重力水和有效水,保水剂用量为0.05%时,各处理土壤重力水所占比重高于60%,随着保水剂用量增加,重力水所占比重下降,有效水分所占比重提高,表明保水剂对土壤持水特性的作用机理主要体现为增加了土壤的"毛管孔隙"持水比例,即在低使用量时显著改善土壤重力水部分,随着保水剂使用量的增加则显著增加土壤有效水部分。4综合比较保水剂类型和对土壤持水能力的改善作用,B3型保水剂在使用量为0.5%时的改善效果最好。由此得出,化学保水剂尽管是一种具有很强分子吸水能力的基质,却在土壤中能够极大地改变土壤"孔隙"持水性,增加土壤有效水贮量,应当受到应有的重视和广泛使用。     

氮肥对保水剂吸水保肥性能的影响

测定保水剂在不同氮肥(尿素、碳酸氢铵、硝酸铵、硫酸铵、氯化铵)溶液中的吸水倍率和对肥料养分的吸持量,分析不同氮肥对保水剂吸水、保肥性能的影响。结果表明:保水剂在各种氮肥溶液中吸水倍率显著下降,并随肥料浓度的增加下降幅度增加;受影响程度聚丙烯酸钠盐型保水剂大于聚丙烯酰胺-丙烯酸盐型保水剂;不同氮肥对保水剂吸水倍率的影响按尿素、碳酸氢铵、硝酸铵、硫酸铵、氯化铵顺序递增。保水剂在大量吸水的同时,也对溶液中的肥料分子或者离子有吸持作用,吸持量均随肥料浓度的增加而增加;保水剂和肥料品种不同,吸持量也不同;除尿素外,保水剂对肥料的吸持率随肥料浓度的增加而降低,最高浓度下,吸持率按硝酸铵、碳酸氢铵、氯化铵、硫酸铵、尿素次序依次增大。     

天山中部不同林龄天然云杉林地表土壤入渗性能研究

通过对天山中部不同林龄天山云杉(Picea schrenkiana var.tianschanica(Rupr.)Chen et Fu)地表土壤和林外草地土壤进行实验室人工降雨模拟渗透试验,初步探讨了天山云杉林地土壤的入渗性能.结果表明:1)累积渗透量、入渗速率与入渗时间均呈幂指数相关关系.稳渗速率最高为近熟林1.91...     

Spatial distribution pattern of Picea schrenkiana population in the Middle Tianshan Mountains and the relationship with topographic attributes

The spatial distribution of plant populations is an important feature of population structure and it determines the population's ecological preferences,biological characteristics and relationships with...     

西天山雪岭云杉林分密度对森林生物量分配格局和异速生长的影响

雪岭云杉林是新疆天山北坡山地森林中广泛分布的优势种,探讨林分密度对天山雪岭云杉林器官生物量分配格局和树高-胸径异速生长的影响,对于阐明雪岭云杉林生物量在不同环境中的适应具有重要意义。通过分析在不同林分密度(≤300株·hm^-2、300~450株·hm^-2、450~600株·hm^-2、>600株·hm^-2)下雪岭云杉林(Picea schren?kiana)的生长特性,研究林分密度对雪岭云杉林器官生物量分配格局及树高-胸径异速生长的影响。结果表明,随着林分密度增加,雪岭云杉林各器官平均生物量均降低;树干和树根生物量占比增加,树枝生物量占比减少,树叶和树皮生物量占比变化不显著;雪岭云杉林树高和胸径均随林分密度的增加而降低。此外,雪岭云杉林树高(H)和胸径(D)间具有显著的异速生长关系,其中树高-胸径(H-D)的最优异速生长方程为:y=2.312×x^0.900(R²=0.761,P<0.01);随着林分密度增加,雪岭云杉林lgH-lgD呈现出复杂非线性异速生长关系,该关系的显著性受林分密度变化呈现逐渐降低的趋势,这表明林分密度通过雪岭云杉林对生长资源的竞争影响各器官的生长发育。研究结果可为雪岭云杉林的可持续经营与管理提供理论依据和数据支撑。     

天山雪岭云杉（Picea schrenkiana）林净化空气功能研究

通过对天山北坡森林中降尘量、总悬浮颗粒物（TSP）浓度的动态监测,以及对不同海拔梯度树叶中硫含量的测定,分析天山雪岭云杉对空气中主要污染物吸附、过滤作用,以此来评价天山北坡森林的空气净化功能。研究结果表明：①在6～7月,郁闭度0.8的林地降尘量最多可达14.04 g/（m2.30 d）,较对照空旷地滞尘量增加4.88g...     

天山不同海拔雪岭云杉径向生长对气候变化的响应

为研究不同海拔雪岭云杉(Picea schrenkiana)径向生长对气候要素的响应关系,分别在新疆伊犁尼勒克喀什河流域森林低、中、高海拔采集雪岭云杉树芯样本,建立不同海拔雪岭云杉树轮宽度年表。树轮年表与气象资料相关分析结果显示:影响3个采样点树木径向生长的气候因子主要是平均气温和相对湿度,对降水响应微弱。高、低海拔树轮径向生长对气温和相对湿度的响应相同,均对气温正响应,与相对湿度负响应,中海拔则与高低海拔相反。自1991年研究区气候突变后,雪岭云杉径向生长发生“生长分异”,高、低海拔树轮宽度指数呈显著下降,而中海拔呈显著上升。气候突变点前后,树木径向生长主要对气温和相对湿度响应关系不稳定,中海拔对5—9月的气温的正相关和对相对湿度的负相关显著增强,而低、高海拔主要与7—8月的气温转为显著负相关,与1—2月、7—8月相对湿度的正相关显著加强。根据雪岭云杉对气候要素的响应模式,气温的快速升温会加快水分蒸发,相对湿度随之下降,从而引起的干旱加剧对低、高海拔林区雪岭云杉生长产生负面影响,而适宜的增温可能对森林中部雪岭云杉生长具有促进作用。     

Altitudinal patterns of stand structure and herb layer diversity of Picea schrenkiana forests in the central Tianshan Mountains,Northwest China

Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental factors.In this study,the altitude patterns of forest stand structure and species diversity were analyzed across 20 plots in the Tianchi Nature Reserve,Northwest China.The results showed that mean stem height(Hm),maximum stem height(Hmax) and mean stem diameter at breast height(Dm) of Picea schrenkiana trees all decreased significantly with increasing altitude.Potential tree height(H*) decreased while stem taper increased significantly as altitude increased,suggesting remarkable altitudinal changes in biomass allocation between the diameter and height growth of Picea schrenkiana.Understory herbaceous richness increased significantly with increasing altitude,or with decreasing total basal area(TBA),Hm and stand volume(Volume).High light availability for understory herbs might account for the higher species richness at high altitude.Sorensen Index decreased significantly with the increase in altitude intervals,while the Cody Index demonstrated a converse pattern,suggesting greater differences in species composition with larger distances.     

天山北坡天山云杉的种群结构特征和空间分布格局

从径级结构、静态生命表、存活曲线和个体空间分布格局等方面研究新疆天山北坡天山云杉的种群结构特征与空间分布规律。研究结果表明:1)种群年龄结构中幼苗幼树(Ⅰ级)比例最大(82.11%),中树(Ⅲ-Ⅵ级)和大树(Ⅶ-Ⅹ级)比例次之,小树(Ⅱ级)比例最小(0.26%)的规律;2)种群死亡率在Ⅰ径级最高(99.70%),随着径级的增加,死亡率呈现"高-低-高"模式,种群生命期望呈现"低-高-低"的模式;3)天山云杉种群的存活曲线接近于DeeveyⅢ型,即Ⅰ径级存活指数最高(6.91),Ⅱ径级(1.16)急剧下降,Ⅱ-Ⅴ径级逐渐上升,随后逐渐下降;4)种群格局随取样尺度由25-400m2增加,聚集强度逐渐降低,其中,在取样规模为25和150m2尺度上聚集分布强度较大;5)随着种群年龄增加,分布格局由聚集型向随机型过渡,聚集强度减弱。幼苗幼树在取样规模为25和150m2尺度上聚集分布强度较大;中树在50m2和150m2尺度上较大;而小树和大树聚集强度不受取样面积影响。因此,天山北坡的天山云杉天然林应适当间伐以促进更新,种群更新的最适林隙面积为25m2。     

The relationship between soil,climate and forest development in the mid-mountain zone of the Sangong River watershed in the northern Tianshan Mountains,China

The mountainous forests in arid regions, being sensitive to climate change, are one of the key research topics related to the mechanism of interaction between climate and the terrestrial ecosystem. In this study, the spatial distribution of a mid-mountain forest and its environmental factors were investigated by using a combination of remote sensing technology, field survey, climate indices and soil nutrient analysis in the Sangong River watershed of the northern Tianshan Mountains. The forest(Picea schrenkiana) was distributed between 1,510 and 2,720 m asl. Tree height and diameter at breast height(DBH) exhibited a bi-modal pattern with increasing elevation, and rested at 2,450 and 2,250 m asl, respectively. The two maxima of DBH appeared at 2,000 and 2,550 m asl, and the taller trees were observed at 2,100 and 2,600 m asl. For the annual mean temperature, the difference was approximately 5.8°C between the lowest and the highest limits of the forest, and the average decreasing rates per hundred meters were 0.49°C and 0.55°C with increasing altitude between 1,500 and 2,000 m asl and above 2,000 m asl, respectively. The annual precipitation in the forest zone first increased and then decreased with the increase of altitude, and the maximum value was at 2,000 m asl. For per hundred meters, the annual precipitation increased with the rate of 31 mm between 1,500 and 2,000 m asl and decreased by 7.8 mm above 2,000 m asl. The SOM, TN and TP were high between 2,000 and 2,700 m asl and low at the lower and upper forest limits. The minimum Ca CO3 concentration, p H value and EC coincided with the maximum precipitation belt at 2,000 m asl. The SOM, TN and TP were high in the topsoil(0–10 cm) and differed significantly from the values observed in the deep soil layers(10 cm). The soil nutrients exhibited spatial heterogeneity and higher aggregation in the topsoil. In conclusion, soil and climate are closely related to each other, working synergistically to determine the development and spatial distribution of the mid-mountain forest in the study area. The order of the importance of environmental factors to forest development in this study is as follows: soil nutrientsprecipitationelevationtemperature.     

Environmental factors influencing snowfall and snowfall prediction in the Tianshan Mountains,Northwest China

Snowfall is one of the dominant water resources in the mountainous regions and is closely related to the development of the local ecosystem and economy. Snowfall predication plays a critical role in understanding hydrological processes and forecasting natural disasters in the Tianshan Mountains, where meteorological stations are limited. Based on climatic, geographical and topographic variables at 27 meteorological stations during the cold season(October to April) from 1980 to 2015 in the Tianshan Mountains located in Xinjiang of Northwest China, we explored the potential influence of these variables on snowfall and predicted snowfall using two methods: multiple linear regression(MLR) model(a conventional measuring method) and random forest(RF) model(a non-parametric and non-linear machine learning algorithm). We identified the primary influencing factors of snowfall by ranking the importance of eight selected predictor variables based on the relative contribution of each variable in the two models. Model simulations were compared using different performance indices and the results showed that the RF model performed better than the MLR model, with a much higher R~2 value(R~2=0.74; R~2, coefficient of determination) and a lower bias error(RSR=0.51; RSR, the ratio of root mean square error to standard deviation of observed dataset). This indicates that the non-linear trend is more applicable for explaining the relationship between the selected predictor variables and snowfall. Relative humidity, temperature and longitude were identified as three of the most important variables influencing snowfall and snowfall prediction in both models, while elevation, aspect and latitude were of secondary importance, followed by slope and wind speed. These results will be beneficial to understand hydrological modeling and improve management and prediction of water resources in the Tianshan Mountains.