【作者】 陈志云；

【导师】 马祥庆； 彭龙福；

【作者基本信息】 福建农林大学 ， 林业， 2010， 硕士

【摘要】 杉木(Cunninghamia lanceolata)是我国南方特有的速生用材林树种之一,具有生长快、材质好、产量高、栽培面积广等优点。然而随着杉木人工林连栽代数和面积逐渐增加,杉木纯林地力衰退十分明显,林分稳定性下降,产量逐代递减。如何保持南方林区杉木人工林生态系统的持续生产力和稳定性已成为当前林业生产中急需解决的重大课题,而营造杉阔混交林则被认为是维持杉木人工林长期生产力的较好途径之一。米老排干形通直,材质较好,是水土保持、土壤改良、混交造林以及生物防火的优良树种。本文通过对16年生杉木纯林与杉木-米老排混交林的对比研究,从生物量、生产力、养分循环等方面进行系统全面的分析研究,探寻其混交林生态系统生产力及养分循环的特征与规律,为评价以杉木为主的林分可持续经营提供理论依据和实践经验。主要研究结果如下：1.杉木-米老排混交林与杉木纯林生长差异较大。两种林分胸径生长量的差异表现为,混交林中坡杉木胸径生长有较大优势,而杉木纯林下坡表现出更大的生长优势；树高方面,混交林杉木上、中、下坡分别比杉木纯林提高了14.1%、19.0%、9.1%；材积分别比纯林提高了29.3%、26.1%、1.9%；蓄积量分别为132.87 m3/hm2、191.83 m3/hm2、267.48m3/hm2,其中上、中坡分别比纯林提高了21.3%、17.3%,混交林中上坡和中坡蓄积量较杉木纯林有明显的优势。在同一林分不同坡位,两种林分各生长指标均表现为下坡>中坡>上坡的变化规律。2.杉木-米老排混交林与杉木纯林生物量存在明显差异。同一坡位杉木-米老排混交林总生物量比杉木纯林高;不同坡位两种林分总生物量均表现为：下坡>中坡>上坡。杉木-米老排混交林上坡和中坡各器官生物量的分配是干>根>枝>皮>叶,而下坡表现为干>根>枝>叶>皮；不同坡位杉木纯林各器官生物量分配顺序表现为,干生物量最大,叶、枝、根、皮的生物量差异不是很明显。3.杉木-米老排混交林与杉木纯林N、P、K养分总积累的差异表现为：同一坡位生长条件下,混交林上、中、下坡的N积累量分别比纯林高104.4%、93.4%、12.7%,P积累量分别比纯林高53.1%、37.7%、59.6%,K养分的积累在上坡和中坡比纯林高42.01%、99.47%,而在下坡则为纯林大于混交林；不同坡度同一林分养分总积累量均表现为下坡>中坡>上坡,这一变化规律与两种林分乔木层养分积累量的差异规律相同。4.杉木-米老排混交林与杉木纯林养分利用效率存在明显差异。混交林上坡、中坡、下坡的乔木层养分利用效率分别比杉木纯林高11.5%、9.5%、57.0%。不同坡位条件下,混交林乔木层养分利用效率呈现上坡>下坡>中坡的变化规律,杉木纯林则表现为上坡>中坡>下坡；混交林上、中、下坡的林下植被养分利用效率均高于杉木纯林,可见混交林能提高林分林下植被的养分利用效率。5.杉木-米老排混交林与杉木纯林凋落物年产量差异较大。同一坡位不同林分年凋落量表现为混交林>杉木纯林；同一林分不同坡位年凋落量均表现为下坡>中坡>上坡。混交林的凋落物组成大小排序：上坡为枝>叶>果>花,中坡和下坡为叶>枝>果>花,而杉木纯林则表现为枝>叶>果>花。6.杉木-米老排混交林与杉木纯林养分存留量、年归还量、年吸收量及归还比的差异均表现为：混交林>杉木纯林。其中混交林的中坡的养分循环能力对于杉木纯林有明显的优势。同一林分同一坡位生长条件下,两种林分养分年存留量、年吸收量均表现为N>K>P；而年归还量、归还比则表现为N>P>K。从养分归还比看,杉木纯林表现为下坡>上坡>中坡,而混交林则表现为中坡>下坡>上坡,说明混交林中坡坡位的地力条件有利于养分的循环。总之,与杉木纯林相比,杉木与米老排混交有利于杉木的生长。杉木-米老排混交林中的杉木平均树高、平均胸径、材积和蓄积量均大于杉木纯林。且混交林的生物量、养分积累量、养分的利用效率、养分的归还比等均呈现混交林大于杉木纯林的变化规律。可见,营造混交林较杉木纯林而言,有更高的生产力且养分循环能力也较强。更多还原

【Abstract】 Chinese fir is one of the rapid growing species in the south of china, with the advantages of fast growth, good material, high yield and widely cultivated area etc. However, with the increasing area of Chinese fir plantation, land capability and stability of stand of pure Chinese fir forestry significantly declined, so that the output diminished generationally in Chinese fir plantations. How to keep continued productivity and stability of the forestry production of Chinese fir plantation has become the major subject to resolve, while to build mixed forestry with Chinese fir forests is considered to be one of the methods to maintain long-term productivity of Chinese fir plantation. M. laosensis has straight form and good quality, which is a fine tree for soil and water conservation, soil improvement, afforestation and biological fireproof. This thesis compared the Chinese fir plantations and the mixed forest of Chinese fir and M. laosensis, it synthetically analyzed biomass, productivity and nutrient cycling to explore the features and regularity of the mixed forest ecosystem productivity and nutrient cycling. It provided the theory basis and practical experience for the evaluation of Chinese fir plantation to the sustainable management. The main results were as follows:1. There was great difference between the growth of the Chinese fir plantations and the mixed forest. The difference of DBH growth manifested as that of Chinese fir had obvious advantage in middle slope of the mixed forest, but it showed greater advantage in lower slope of the Chinese fir plantations. The growth of trees height in upper slope, middle slope and lower slope of the mixed forest was increased by 14.1%,19.0% and 9.1% respectively compared with that of the Chinese fir plantations. The volume was 132.87m3/hm2,191.83m3/hm2 and 267.48 m3/hm2 respectively, it improved 21.3% and 17.3% in upper slope and middle slope, which showed that there was great superiority in the upper slope and middle slope of the mixed forest. Compared with the same stand in the different slope positions, each index of the two stand were showed:lower slope>middle slope>upper slope.2. There was significant difference between the biomass of the Chinese fir plantations and the mixed forest. The total biomass of the mixed forest in the same slope position was higher than that in the Chinese fir plantations; The total biomass in the different slope positions of different stands showed that biomass of the lower slope was the highest, and the second was in the middle slope, while the third was in the upper slope. The distribution of the different organs’ biomass in upper slope and middle slope of the mixed forest was:stem>root> branch> skin> leaves, but biomass in lower slope was that:stem>root>branch>leaves> skin. The distribution of the different organs’ biomass in different slope positions of the Chinese fir plantations was that stem was the highest and the difference among the root, branch, skin and leaves was not obvious.3. The difference of N, P, K accumulated amount between Chinese fir plantations and the mixed forest showed that N accumulated amount in upper slope, middle slope and lower slope of the mixed forest was increased by 104.4%,93.4% and 12.7%, respectively, compared with that in the Chinese fir plantations under the growth condition of the same slope. P accumulated amount was increased by 53.1%,37.7% and 59.6%, respectively. K accumulated amount was 42.0% and 99.5%, respectively higher than that of the Chinese fir plantations. The total nutrient accumulation in the different slope positions of the same stand was that:lower slope>middle slope>upper slope, this variation was similar to the nutrient accumulation of tree layer in different stands.4. The difference of nutrient using efficiency between Chinese fir plantations and the mixed forest was evident. The nutrient use efficiency of tree layer in upper slope, middle slope and lower slope of the mixed forest was increased by 11.5%,9.5% and 57.0%,respectively, compared with that of the Chinese fir plantations and the nutrient use efficiency was increased by 40.8%,-13.0% and 33.0% respectively compared with that of Chinese fir plantations. Under the condition of different slope positions, the nutrient use efficiency of tree layer of mixed forestry was arranged in the order:upper slope>lower slope>middle slope, while nutrient use efficiency of pure Chinese fir was that:upper slope>middle slope>lower slope.5. The difference of litter’s annual output between Chinese fir plantations and the mixed forest was evident. The litter’s annual output in the same slope positions of different stands was:the mixed forest>the Chinese fir plantations. The litter’s annual output in different slope positions of the same stand was showed that:lower slope>middle slope>upper slope. The composition of litter of the mixed forest was:branch> leaves>fruit>flower in upper slope, compared with that leaves>branch>fruit>flower in lower slope and middle slope, while it showed:branch>leaves>fruit>flower in Chinese fir plantations.6. The difference of the nutrient’s remaining quantity, annually retained, annually uptake and return proportion between Chinese fir plantations and the mixed forest was all arranged in the order:the mixed forest>the Chinese fir plantations. The nutrient cycling ability in middle slope of the mixed forest had a distinct advantage over that of the Chinese fir plantations. The nutrient’s remaining quantity and annually uptake of N was all highest in the same slope position of the same stand, and the lowest was P. The highest of annually retained and return proportion was N, and the minimum was K. The nutrient’s return proportion of the Chinese fir plantations was arranged in the order:middle slope>lower slope>upper slope, it could be seen that the soil condition in the middle slope of mixed forest was in favor of the nutrient’s circulation.In short, compared with the Chinese fir plantations, mixed Chinese fir forestry with M. laosensis was in favor of the growth of Chinese fir. The average tree height, average DBH, volume of timber and volume of the mixed forest were all higher than that of the Chinese fir plantations. And the biomass, nutrient accumulation, nutrient using efficiency and the nutrient’s return proportion all showed the same rule. It showed that a mixed forest had higher productivity and nutrient cycling ability than that of Chinese fir plantations.更多还原