【作者】 杨东；

【导师】 万福绪；

【作者基本信息】 南京林业大学 ， 水土保持与荒漠化防治， 2012， 博士

【摘要】 海岸防护林在改良土壤、降低风速、改善区域生态环境等方面发挥了重要作用，是沿海地区经济可持续发展的重要保障。国内外关于沿海防护林体系的林带结构、土壤改良、抵抗台风等方面进行了大量研究，取得了丰硕成果，积累了丰富的实践经验。但目前多数海岸防护林带林种单一，抵抗病虫害能力和稳定性较差，而可用于造林的树种类型较少。本文以长江三角洲地区的上海市和南通市海岸防护林带为研究对象，以选择适宜的造林树种和配置模式为目标，分别从海岸带植被类型分布、树种受水盐胁迫的反应、试验林树种综合评价、不同类型防护林肥力状况等方面入手进行研究。结果表明：（1）泥质海岸滩涂分布的主要植被群落为海三棱藨草、互花米草、芦苇等群落，内侧分布有狗尾草、白茅、加拿大一支黄花等草本群落，群落植被类型较为单一。土壤PH值和土壤含水率是影响滩涂植被群落物种多样性和植物分布的重要土壤因子，土壤PH值与三个多样性指数均呈显著负相关关系，相关系数分别为-0.912、-0.933、-0.905；土壤含水率与物种丰富度呈显著负相关，相关系数为-0.904，与其它两个多样性指数也有较高的负相关关系，相关系数分别为-0.722、-0.865；滩涂植被群落随土壤含水率的下降和PH值的降低，其物种多样性指数逐渐增加。（2）对4个防护林树种水盐胁迫下各项生理指标和生长情况的研究表明，初期低水盐浓度下可能刺激苗木根系的生长，但随着试验时间增加和水盐胁迫水平增高，水盐胁迫对不同树种的茎、叶、根系的生长和生物量的积累有明显抑制作用。（3）树木的生理指标中，质膜透性、叶绿素、可溶性蛋白含量等指标都与树木的耐水盐能力有关。但各个指标的变化趋势有很多不同，其受胁迫浓度、胁迫时间等影响较大，原因可能是各树种对水盐胁迫浓度都有一定的生理适应范围，且对胁迫的响应时间也有较大差异。因此用单一生理指标来分析树木的耐水盐能力，不确定性因素较多，评价难度较大。（4）通过主成分分析得到4个树种抵抗水盐胁迫能力大小顺序为乌桕>落羽杉>喜树>栾树，这与试验观测结果相符。由主成分分析因子载荷可以看出，苗高、地径、生物量与两个因子均为正相关，且载荷很大；质膜透性与两个因子均为负相关，载荷较大；游离脯氨酸含量对因子1载荷很大，但对因子2载荷很小；其它指标与两个因子的相关性不同。总之，评价树木的耐水盐能力，如选用生理指标，必须选择适合的胁迫压力和胁迫时间，且应结合多个生理指标进行综合分析。实际应用中，选择可以直接观测的形态指标如苗高、地径、生物量等形态指标，既方便操作，又比较可靠。（5）用层次分析法构建海岸带防护林树种选择评价指标体系，共涵盖了19个评价点，覆盖了生长适应性、生态功能、景观效应和经济价值等防护林树种选择的主要方面，采用定性与定量相结合的方法，对29个试验树种进行综合评价。根据评价结果推荐乔木树种12种，分别为苦楝、青桐、栾树、金丝垂柳、乌桕、黄连木、中山杉、喜树、墨西哥落羽杉、雪松、枫香、南酸枣，作为泥质海岸带防护林适宜造林树种。（6）海岸6种典型防护林带的林下土壤各种养分指标和除过氧化氢酶外几种主要的土壤酶活性在土层中的分布规律较为相似，一般随土层深度的增加而降低且差异显著，林地土壤养分和酶活性均高于滩地对照。水杉和杉木两种针叶树种林下土壤容重、含盐量均高于刺槐和杨树林等阔叶树种，非毛管孔隙度则低于后者；刺槐与杨树，杉木与杨树两种混交林土壤物理性状、养分含量及酶活性均好于纯林。（7）对防护林带的生长状况调查表明，刺槐与杨树，杉木与杨树混交林林木生长情况比纯林好,林木的平均树高、胸径均明显高于各自的纯林，林分郁闭度相对纯林明显增大。刺槐和杨树混交后，径高比分别为1：72.22和1：83.17，而刺槐和杨树纯林的径高比分别为1：70.90和1：80.86；杉木和杨树的混交林中杉木的径高比为1：89.97，而其纯林则为1：85.99，说明混交林中林木圆满度相对纯林大，树干尖削度变小，出材率增加。（8）用多元逐步回归方法对防护林草本层物种多样性指数与土壤肥力因子的关系研究表明：土壤PH值与草本层物种多样性指数呈显著负相关，且对三个物种多样性的解释能力分别达到84.6%、56.1%和59.1%，可见影响草本层物种多样性的主要因子是土壤PH值。其次是土壤全磷含量，它与草本层物种多样性指数呈正相关，对三个物种多样性的解释能力分别为11.3%、32.1%和31.9%。此外，土壤含水率、土壤有效磷含量、土壤容重、孔隙度和全氮含量也对草本层物种多样性有一定的影响。更多还原

【Abstract】 Coastal shelter forest had played an important role in the coastal economic sustainabledevelopment, and it could improve the soil, reduce the wind speed and improve the regionecological environment. Study on the forest structure, soil improvement, resistance typhoonability of coastal shelter forest system at home and abroad had been done and greatachievements had been made. But now most of the coast shelter belt species was single,resistance insect ability and forest stability was poor, and few tree species could be used forafforestation. This paper studied the coast of shelter belt by the Yangtze river delta region ofShanghai and Nantong, separately from the coastal vegetation type distribution, reaction of treespecies under water and salt stress, comprehensive evaluation of experimental forest treespecies, soil fertility status under different types of shelter forest, in order to choose moreappropriate afforestation tree species and better configuration mode.. The results showed that:（1）The main kinds of vegetation communities on coast beaches in ShangHai area wereScirpus mariqueter, Spartina alterniflora Loisel., Phragmites australis, inside were Setairaviridis(L.)Beauv, Imperata cylindrica (Linn.) Beauv. And Solidago canadensis L.. Soil PHvalue and soil moisture content were the important soil factors which effected vegetationspecies diversity and plant distribution. Soil PH value had a significant negative correlationwith three communities diversity indexes, and the correlation coefficient was respectively-0.912,-0.933,-0.905; Soil moisture content had significant negative correlation with speciesrichness, and the correlation coefficient was-0.904.it also had a high negative correlation withthe other two diversity indexes, and the correlation coefficient was respectively-0.722,-0.865.With soil moisture descended and PH value reduced, the species diversity index of communitieson coast beach increased gradually.（2）Researches about various physiological indexes and the growth of four shelter foresttree species under water and salt stress showed that in the early stages, lower water and saltconcentration might stimulate the growth of root seedlings, but with the test time passed and thelevels of salt and water stress increased, it had a significant inhibitory effect on the stem, leaf,root growth and biomass accumulation of different species.（3）In the physiological indexes, plasma membrane permeability, chlorophyll, solubleprotein content,etc were relevant to trees water and salt resistant ability. But the change trendof each index had many different, which was effected by the concentration and time of stress.The reason might be the tree species had a certain physiological range of stress, and theresponse time of various tree species also had a big difference. So using a single physiologicalindex to analysis the trees resistance ability to water and salt stress was uncertain and difficult. （4）The principal component analysis about the four species resistance ability to salt andwater stress showed that: Sapium sebiferum>Taxodium mucronatum> Camptotheca acuminata> Koelreuteria paniculata, which was in agreement with observation results. By principalcomponent analysis, seedling height, ground diameter, biomass had a positive correlation withtwo factors, and the factor loadings were big; Plasma membrane permeability had a negativecorrelation with two factors; Factor1loading of free proline content was big, but factor2loading was very small; Other indexes association with two factors was different. In short, ifchoose physiological indexes to analysis trees water and salt resistance ability, it must choosesuitable for pressure and intimidation of stress, and should combine with various physiologicalindexes. In practical application, the choice can be directly observable form indicators such asseedling height, ground diameter, and biomass, morphological index, which were moreconvenient and reliable for operation.（5）AHP was used to construct the coastal shelter forest tree species selection evaluationindex system, totally covering19ranking points, including the major aspects such as the growthadaptability, ecological function, landscape effect and economic value. With the qualitative andquantitative method, test tree species were comprehensive evaluated. According to theevaluation results, Melia azedarach Linn., Firmiana simplex(L.)W.F.Wight, Koelreuteriapaniculata,etc were recommended as suitable planting species to muddy coastal shelter forest.（6）Soil nutrient indexes except catalase under six typical coast forest of shelter belt had asimilar distribution, and generally reduced with the increasing of soil depth and had asignificant difference, while they were higher than the beach. Soil bulk density and salt contentof Metasequoia glyptostroboides and Cunninghamialanceolata（Lamb.）Hook. were higher thanthe locust and Poplars, while the capillary porosity were lower than the latter. Soil nutrientcontent and enzyme activity of two mixed forest were better than pure forest.（7）The growth condition of the trees showed that: the trees in two mixed forest werebetter than trees in pure forest, the average tree height, diameter at breast height and crowndensity were significantly higher than the pure forest. The diameter to height ratio of locust andpoplars in mixed forests was respectively1：72.22,1：83.17, while in pure forests wasrespectively1：70.90,1：80.86; Cunninghamialanceolata（Lamb.）Hook. in mixed forest was1：89.97, while in pure forest was1：85.99. So trees in mixed forests the Taper was smaller,while fullness and stand Outturn Tables ratio were bigger than in pure forests.（8）The results of stepwise regression about soil fertility properties affecting speciesdiversity in herb layer showed that the main factor affecting species diversity was soil PH, andit had an obvious negative correlation. For species richness of herb layer、Simpson index andShannon index its explanation ability respectively achieved84.6%、56.1%and59.1%. Thenwas the soil total phosphorus. and it was positively related with herb layer species, itsexplanation ability for the three species diversity index respectively achieved11.3%、32.1%and31.9%. In addition, the soil moisture content, soil phosphorus content, effective soil bulk density, porosity and total nitrogen content had a certain effect on the herb layer of speciesdiversity.更多还原