【作者】 林红叶；

【导师】 叶功富；

【作者基本信息】 福建农林大学 ， 水土保持与荒漠化防治， 2010， 硕士

【摘要】 自二十世纪50年代东南沿海地区从国外引进木麻黄(Casuarina equisetfolia)以来,由于其具有耐旱、抗贫瘠、耐盐碱和抗风沙等特性,成为海岸带主要防护林树种,在防风固沙、改善沿海地区生态环境、提供用材、保障人民生活与经济发展等方面发挥着难以替代的巨大作用。本研究选择位于福建省东山县赤山林场不同连栽代数的木麻黄纯林以及木麻黄不同混交模式的林分为研究对象,调查对比其不同林分的环境效应,并结合数学分析方法,筛选一系列木麻黄防护林可持续经营指标,对其经营是否可持续进行量化判断。最后,综合调查和分析,总结得出一套囊括风口沙荒地、基干林带到农田防护林网,再到后沿片林的木麻黄防护林可持续经营配套措施。主要结论如下:(1)沿海木麻黄防护林不同经营模式下,对比8a、15a、46a生木麻黄林(分别为3代、2代、1代木麻黄纯林),随着纯林连栽代数的增加,土壤肥力逐年降低,随着代数增加,2代林、3代林下土壤有机质、全氮、水解氮较之1代林(全氮为0.879 g/kg,水解氮为28.56 mg/kg)均有所降低,2代林、3代林下土壤全钾含量比1代林都有所下降,不同代数林分下的林分土壤的pH值均偏酸性,随着土层深度变化,pH值没有呈现明显的变化规律。随着林地的连栽,木麻黄林地土壤容重逐渐变大,总孔隙度渐小,其中毛管孔隙度也呈现下降的趋势。不同混交比例模式下的木麻黄混交林中,木麻黄与湿地松的混交林表现出了较其他混交林更多的优势,混交林的经营模式较纯林连栽有效的改善了立地状况,土层0～20cm的养分含量对比中发现,木麻黄与马占相思混交的林地有机质远高于其他混交模式,且全氮及水解氮含量也高于其他混交模式的林地土壤。木麻黄与厚荚相思的混交林地土壤表层全磷含量较高于其他混交模式,木麻黄与柠檬桉混交林地的pH均值高于其他林地。湿地松与木麻黄混交模式下的林地土壤最大持水量和田间土壤持水量状态都优于其他混交模式,湿地松与木麻黄混交模式下的林地土壤容重数值也低于其他三种混交模式,总孔隙度大小排列上湿地松>柠檬桉>厚荚相思>马占相思,在毛管孔隙状况中,马占相思>厚荚相思>湿地松>柠檬桉。林下套种的混交模式较纯林连栽也有一定的优势。不同套种模式下林分蓄积量分别是:套竹(4591.69m3/hm2)>套木(3303.14m3/hm2)>单层林(1073.57m3/hm2)。单层林(木麻黄纯林)与木麻黄林下套种丛生竹与继续套种更新木麻黄两种形式,最大持水量、毛管持水量和田间持水量的值随土层渐深,普遍逐渐呈现下降趋势,且最大持水量最高值(0.31g/kg)出现在丛生竹与林麻黄套种中,单层林的土壤持水量状态也优于林下继续套种木麻黄。木麻黄防护林的防风效能和林分的疏密结构有着直接的关系,其中疏透结构的林带防风效能最强,都在70%以上,而紧密与通风结构的防风效能较差。(2)在科学性、层次性、独立性和完整性、可操作性原则的指导下,以木麻黄防护林总体可持续经营为目标,在生态可持续、社会可持续以及经济可持续的状态指导下,筛选出15个三级指标,通过综合评分法,计算得出以福建省东山县为例的木麻黄防护林总体可持续经营能力0.6089的综合指数值,处于弱可持续性状态值区间,为弱可持续经营。从总体可持续经营能力的三个方向标的指数值中可以看到,生态可持续指数值高于社会和经济可持续指数值,说明在木麻黄防护林体系可持续经营中,生态效能的发挥还是比较稳定的。但由于防护效能是其作为防护林的首要重责,所以相应的社会、经济效能维持能力并不是很完善,使其可持续性尚未完全实现。(3)结合分析木麻黄防护林可持续经营影响因素,依据木麻黄防护林作用的不可替代性及资源的递减性,提出景观水平和林分水平上的可持续经营技术模式,其中景观水平的可持续经营重点是严格控制原有木麻黄林的转型,在保持现有面积及分布格局的基础上,尽可能的通过优良抗逆性无性系的选育更新增强原木麻黄林地的扩散能力,进而扩大其斑块范围和面积。林分水平的可持续经营是在景观水平可持续经营的要求下进行,通过长期保持林分的健康活力、更新能力及多样性,提高林分生产力。林分水平可持续经营技术模式是一套囊括风口沙荒地、基干林带到农田防护林网,再到后沿片林的木麻黄防护林可持续经营配套措施,即分别从适合不同海岸带情况的最优造林密度、造林措施、造林密度以及林带更新方式、林带结构,营造以混交林为主的配置模式。更多还原

【Abstract】 Since 1950s people in the Southeast coastal area adopted Casuarina equisetfolia from abroad, it has become the main tree that makes shelter-forest in coastal area because of the drought enduring, leanness enduring, salt toleration and anti-sandstorm abilities, and it has played a very important part in improving the soil and water conservation ability, improving the ecological environment of coastal area, supplying wood materials and ensuring the people’s livelihood and the development of the economy. The research was based on the object of the pure forest with different continuous generations and the forest with different mixed patterns in Chishan forest farm of Fujian Dongshan country. The environmental effects of different forests have been investigated and compared, and a serious of indexes of sustainable management of Casuarina equisetfolia were chosen combined the analysis methods of mathematics to judge the sustainability of the management quantized. At last, to synthesize the investigation and analysis, some supporting measures were summarized including from the sustainable management of sandy bare land in the wind and the main forest belts to shelter-forest network for fields.Under the comparison of different management modes of Casuarina equisetfolia shelter forests with the age of 8a, 15a and 46a in the coastal area which were third, second and first generation individually, the soil fertility was studied. The results showed that the soil fertility was decreased gradually with the increase of the generation number. The organic matter, whole nitrogen and hydrolysable nitrogen contents in the soil of the second and third generations were lower than those of the first generation. The pH value of different forests with a different generation all presented faintly acid, and the pH value didn’t show an obvious variation law with the change of the depth in the soil. With the increase of CPR, the soil bulk density of Casuarina equisetfolia increased gradually and the total porosity decreased gently, and the capillary porosity also had the trend of decreasing.In the mixed forests of capillary porosity with different mixed ratio modes, the mixed forest of Pinus elliottii and Casuarina equisetfolia showed more advantages than other forests with different mixed modes. The site condition of mixed forests with continuous plantation was improved well compared with the pure forest. From the comparison of nutrient contents in 0～20cm,it presented that the organic matters content of the mixed forest with Casuarina equisetfolia and Acaciamangium was higher than that in the soil of other kind mixed forests, and the Total-N and hydrolysable nitrogen content also showed the same rule. The Total-P content in the surface soil of the mixed forest of Casuarina equisetfolia and Acacia crassicarpa was higher than that in other mixed modes, and the average pH value of Casuarina equisetfolia and Eucalyptus Citriodora mixed forest was also higher than other mixed modes. The full water capacity and field water capacity of the soil in the mixed forest of Pinus elliottii and Casuarina equisetfolia were superior than other mixed modes, and the soil bulk density in that mixed mode forest was lower than the forests of other mixed modes. The ranking order of soil total-porosity was: Pinus elliottii>Eucalyptus citriodora >Acacia crassicarpa>Acaciamangium, and the order of capillary porosity was: Acaciamangium> Acacia crassicarpa>Pinus elliottii>Eucalyptus citriodora.The mixed mode of understory intercropping had some superiority than pure forest in CPR. the forest stock of different interplant modes were: bamboo intercropping (4591.69 m3/hm2)> Casuarina equisetfolia intercropping(3303.14m3/hm2)>monolayer forest(1073.57m3/hm2).The maximum water holding capacity and capillary moisture and field water capacity of pure forest of Casuarina equisetfolia and its bamboo interplant or the renewed Casuarina equisetfolia seeding interplant modes all showed a decrease trend generally with the depth of soil increasing. The maximum value of maximum water holding capacity(0.31g/kg) existed in the forest of bamboo and Casuarina equisetfolia interplant mode, and the moisture-holding capacity of monolayer forest was also better than that in Casuarina equisetfolia intercropping mode. There was a close relationship between the wind preventing effects and the wood density, and the tree belt with a draught mesh structure had the strongest windbreaking effects which were above 70% on the whole, while the forest belts with a tight and ventilating structure had a relatively poor effect.Under the instruction of scientific, understanding hierarchy, independence, integrity and maneuverability disciplines, aimed at the sustainable management of Casuarina equisetfolia, 15 three class indexes were chosen under the theory of ecological sustainability, social sustainability and economy sustainability. The comprehensive value of the sustainable management ability of Casuarina equisetfolia shelter forest in Dongshan country was 0.6089 which belonged to weak sustainable management level. From the three indexes value of whole sustainable management ability we can see that the ecological sustainability value was higher than social and economical sustainability value which indicated that the ecological effect of Casuarina equisetfolia shelter forest’s sustainable management was relatively stable. While the preventing effect of shelter forests was the most important duty, the sustainability of the shelter forests was not realized completely.Due to the non-substitutable function and the decrease of resources by degrees of Casuarina equisetfolia shelter-forests, the technological modes of the sustainable management were proposed in the landscape level and the standing forest level combined with the analysis of the affecting factors for the sustainable management of Casuarina equisetfolia shelter-forests. The key point of the sustainable management in landscape level was strictly controlling the transformation of the original Casuarina equisetfolia shelter-forests. Using the renew methods of the excellent resistance clone breeding, strengthened the spread ability and then enlarged the plaque area on the basis of keeping the present area and the spatial distribution patterns. The sustainable management in standing forest level was under the request of that in landscape level, and improved the productivity of the forest from keeping the long-term health, vitality, renewing ability and species diversity. The sustainable management mode in standing forest level was a set of strategies including from the sustainable management of sandy bare land in the wind and the main forest belts to shelter-forest network for fields which was mainly the configuration mode of mixed forests from best planting density, the best planting strategies, the best renew modes, and the best forest belt structure according to the different situations of coastal areas.Combined the influence factors of the sustainable management of Casuarina equisetfolia shelter forest, under the instruction of the results above, to synthesize the investigation and analysis, some supporting measures were summarized including from the sustainable management of sandy bare land in the wind and the main forest belts to shelter-forest network for fields.更多还原