广西东门不同林龄巨尾桉人工林的生物生产力及经济效益分析

发布时间：2018-07-08 17:34

本文选题：桉树人工林 + 生物量　；参考：《广西大学》2017年硕士论文

【摘要】：桉树人工林发展关系国家木材安全和国土生态安全,因此,备受社会和学术界的广泛关注。本研究以广西国有东门林场不同林龄(短周期:7a;中周期:13a;长周期:21a)的巨尾桉人工林为研究对象,采用野外调查和室内分析相结合的方法,对不同林龄的巨尾桉人工林的生物量、生产力、碳储量、林分蓄积量和经济效益进行了比较研究,旨在揭示不同林龄巨尾桉人工林生长量与经济效益的特征及变化规律,为科学、合理确定经营周期提供参考资料。研究取得的主要结果如下:1.不同林龄林分生物量存在显著的差异,7a的短周期林分生物量为133.54±5.62 t/hm2,13a的中周期林分生物量为 335.16±33.57 t/hm2,21a的长周期林分生物量相应为383.20±38.03 t/hm2,表明随着经营周期的延长,巨尾桉林分的生物量逐渐增加,但由短周期到中周期林分生物量增加明显,增幅达150.98%,由中周期到长周期的增幅较小,仅为14.33%。2.不同林龄巨尾桉人工林乔木层各组分生物量的分配规律一致,各组分生物量所占比例的大小顺序均表现为树干树根树皮树枝树叶,不同组分的大小随经营周期延长的变化规律有所不同,树干生物量占总生物量的比例呈现先增加后降低,而树枝和树根生物量则相反,为先降低后增加趋势;树皮生物量的比例为持续增加,而叶的生物量比例为持续递减。3.不同林龄巨尾桉林分林下植被的生物量随着经营周期的延长而递增,由短周期林分的14.97 t/hm2、中周期林分23.97 t/hm2增至长周期林分的24.53 t/hm2。显然,中周期后林下植被的生物量增长缓慢。灌木层生物量占林下植被生物量的54.34-77.76%,草本层生物量只占22.24-45.66%。4.不同林龄巨尾桉林分乔木层生产力存在显著差异,7a的短周期林分生产力为19.08±0.80 t/hm2·a,13a的中周期林分相应为25.78±2.58 t/hm2 · a,21a的长周期林分为18.25± 1.81 t/hm2 · a,表明随着经营周期的延长,巨尾桉林分生产力呈先增加后减小的趋势,以中周期经营的林分生产力最高。5.不同林龄巨尾桉人工林生态系统碳储量,7a林分为165.81±5.39 t · C/hm2,13a时增大到 265.53±19.59 t · C/hm2,增长了 99.72 t·C/hm2,21a时微弱增长,为266.71±16.59 t·C/hm2。生物量碳储量随着经营周期的延长而增加,相反,土壤碳储量则随着经营周期的延长而减少。7年生的短周期林分地上部分碳储量占生态系统碳储量的39.38%,地下部分占60.62%;13年生的中周期林分地上和地下碳储量的比例分别是61.28%和38.72%;21年生的长周期林分分别为63.10%和36.90%。6.林分蓄积量随着经营周期的延长而显著增加,由7a、13a的144.95 m3/hm2、13a的346.97 m3/hm2,增至21a的553.69 m3/hm2。随着经营周期的延长,净现值不断增加,7a时为17239.86元/hm2,到12a时达到最高值(30297.61元/hm2),之后逐渐降低,到21a时为22008.59元/hm2,而内部收益率于13年生时开始趋近峰值(53.32%),收益明显高于短周期林分(7a),与长周期林分无显著差异。7.从生产力和经济效益两个维度来看,本研究认为,在现有的经营水平下,东门林场巨尾桉人工林的经营周期以13a左右为佳。
[Abstract]:The development of Eucalyptus plantation is related to national wood safety and land ecological security. Therefore, it is widely concerned by the social and academic circles. This study takes the different Lin Ling (short cycle: 7a; 13A; long period, 21a) of Eucalyptus Plantations in the state-owned East Gate forest farm of Guangxi as the study of the elephant, the combination of field investigation and indoor analysis, and the method of combining the field investigation and the indoor analysis. A comparative study of biomass, productivity, carbon reserves, forest stock volume and economic benefits of Eucalyptus grandis Plantation with forest age was carried out to reveal the characteristics and change rules of growth and economic benefits of different forest age eucalyptus plantations, and to provide reference materials for scientific and rational management cycle. The main results are as follows: 1. There was a significant difference between the biomass and the forest age. The biomass of the short cycle stand biomass of 133.54 + 5.62 t/hm2,13a was 335.16 + 33.57 t/hm2,21a, and the biomass of the long period stand was 383.20 + 38.03 t/hm2, indicating that the biomass of the stand of Eucalyptus grandis increased gradually with the extension of the operating period, but it was from short period. The increase of biomass in the middle period was 150.98%, and the increase from middle to long period was small. It was only the same distribution law of the biomass of each component in the tree layer of Eucalyptus grandis Plantation with different forest age. The order of the proportion of the biomass of each component was all the tree root bark branches and leaves of the tree trunk, and the size of the different components was large. The proportion of tree stem biomass to total biomass increased first and then decreased, while the biomass of branches and roots decreased first and then increased, and the proportion of bark biomass increased continuously, while the biomass ratio of leaves was continuously decreasing in.3. different forest age of Eucalyptus Plantations under different forest age. The biomass increased with the extension of the operating cycle, from 14.97 t/hm2 of short period stand and 23.97 t/hm2 to 24.53 t/hm2. of long period forest. The biomass of undergrowth vegetation was slow after middle period. The biomass of shrub layer accounted for 54.34-77.76% of the biomass of vegetation under forest, and the biomass of herbaceous layer was only 22.24-45.66%.4 The productivity of the tree layer of Eucalyptus grandis stand with different forest age was significantly different. The short cycle stand productivity of 7a was 19.08 + 0.80 t/hm2. A, and the middle period stand of 13A was 25.78 + 2.58 t/hm2. A, and the long period forest of 21a was 18.25 + 1.81 t/hm2. A, indicating that the productivity of Eucalyptus grandis stand increased and then decreased with the extension of the operating period. The trend, the highest forest productivity in the middle period is.5. of the different forest age of Eucalyptus urophylla plantation ecosystem. The 7a stand increased to 265.53 + 19.59 t. C/hm2 when the stand was 165.81 + 5.39 t. C/hm2,13a. It grew weak at 99.72 t. C/hm2,21a, and the biomass carbon reserves of 266.71 + 16.59 t C/hm2. extended with the operation period. On the contrary, on the contrary, the carbon reserves of soil carbon reserves in the short period forest of.7 years are 39.38% and 60.62% in the underground, and the proportion of the upper and underground carbon reserves in the 13 year period forest is 61.28% and 38.72% respectively, and the 21 year long period forest is 63.10%, respectively. And 36.90%.6. stand volume increased significantly with the extension of the operating cycle, from 7a, 13a 144.95 m3/hm2,13a 346.97 m3/hm2, to 21a 553.69 m3/hm2., as the operation period extended, the net present value continued to increase, 7a at 17239.86 yuan /hm2, to 12a reached the maximum value (30297.61 yuan /hm2), then gradually reduced to 22008.59 to 22008.59 Yuan /hm2, and the internal rate of return began to reach the peak value (53.32%) when 13 years old, and the income was obviously higher than the short cycle stand (7a). There was no significant difference from the long cycle stand..7. from the two dimensions of productivity and economic benefit, this study believed that under the existing management level, the operation cycle of the plantation of Eucalyptus giant Eucalyptus Plantations in the East Gate forest was about 13A.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：F326.27;S718.5

【参考文献】