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不同混交度指数的比较分析 总被引：8，自引：0，他引：8
混交度是近年来提出的描述林分树种相互隔离程度的指数,包括简单混交度、树种多样性混交度和物种空间状态; 但现有混交度的指数对空间结构单元的树种隔离关系表达不完整,存在不同混交结构具有相同混交度的问题。本文在分析简单混交度、树种多样性混交度和物种空间状态及其存在问题的基础上,提出全混交度。以天目山常绿阔叶林数据为例,采用基于 GIS 的 Voronoi 图分析方法对不同混交度指数进行比较分析。结果表明: 由于树种多样性混交度、物种空间状态和全混交度都是对简单混交度的改进,所以各混交度既有区别又有联系,证明它们之间存在数学关系。全混交度增加考虑最近邻木相互之间的树种隔离关系,并引入生物多样性 Simpson 指数,可明显提高对不同混交结构的分辨能力。 相似文献
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通过对普洱江城苦丁茶场及西双版纳普文试验林场西南桦与高阿丁枫不同混交模式的生长量指标进行调查分析,结果表明,(1)10年生前,西南桦的胸径较高阿丁枫速生,林木的平均胸径西南桦大于高阿丁枫;11年生后,林木的平均胸径高阿丁枫大于西南桦;(2)10年生时,普文林场混交林的西南桦和高阿丁枫胸径生长一致(11.7 cm),西南桦树高超出高阿丁枫树高3.0 m。说明混交林中西南桦为早期速生树种;幼林阶段,西南桦和高阿丁枫胸径于不同的时期呈现错峰生长。同时,西南桦和高阿丁枫的地理分布、立地的生态适宜条件和林学特征等分析结果表明这2个树种在适宜的混交模式下属混交匹配的树种。建议采用非均匀密度控制混交,以实现2个树种的良好生长和长期混交。 相似文献
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泡桐混交林混交模式试验研究 总被引：1，自引：0，他引：1
根据树种的生物学特性和混交目的性,设计了泡桐与毛竹、泡桐与杉木、泡桐与茶叶、四种混交模式,并进行了15a的跟踪调查研究。试验表明,不同混交模式中的泡桐、混交伴生树种、经济作物的产量及质量均有较明显的差异,泡桐与板栗混交、泡桐与毛竹混交这两种混交模式值得推广。 相似文献
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退耕还林工程营造混交林，在确定主要树种后，怎样选择适宜的混交树种，至关重要。因为选择的混交树种即要与主要树种在生长特点和生态要求等方面一致，又要考虑混交树种本身的适应性，达到营造混交林的预期目的。因此，混交树种的选择应具有如下具体条件：1.混交树种应具有良好的辅佐、护土和改土作用或其他效能，给主要树种创造有利的生长环境，以提高林分的稳定性。2.混交树种最好与主要树种之间的矛盾不太大。较理想的混交树种应生长较缓慢，较耐荫，其根型以及对养分、水分的要求与主要树种有一定的差别。3.混交树种与主要树种没有共同… 相似文献
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本研究以昆明市近郊的昆明西山林场为试验地,构建云南松-旱冬瓜-麻栎、云南松-旱冬瓜-滇青冈、云南松-滇青冈-麻栎三种混交模式,并以云南松、旱冬瓜、麻栎和滇青冈纯林作为对照,跟踪调查混交试验下各树种幼树生长情况及土壤养分元素变化情况。研究表明:(1)在不同混交模式下各树种生长表现不一,且生长差异多不显著。(2)云南松纯林的土壤有机质及全氮、全磷、全钾呈现减小的趋势,而对阔叶树种纯林及含阔叶树种的混交模式而言,尤其是落叶树种的混交模式及落叶树种纯林而言,其有机质、全氮、全磷及全钾略有上升。因此,在云南松林地土壤肥力本身比较贫瘠的情况下,适当补植阔叶树种,尤其是落叶阔叶树种,对于提高土壤肥力具有重要意义。 相似文献
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冷杉 (Abiesfabri(Mast)Ciaib)、落叶松 (Larixkaempferi(Lamb)分别是我国西南高海拔地区和北方的主要用材林栽培树种。过去 ,冷杉都是纯林栽植 ,或与云杉 (PiceaaxprataeMast)混交。美姑县洪溪林场从 1989年开始 ,利用冷杉与日本落叶松混交栽植 ,取得了成功。通过 15年的观察研究 ,我们发现冷杉与落叶松混交 ,林木生长的各项指标均优于冷杉纯林和日本落叶松纯林。冷杉与落叶松混交林下的物种多样性和生物多样性 ,也比冷杉纯林和冷云杉混交林增加了。该项技术成果具有一定的推广价值。现将调查研究结果介绍如下 :1 试验地区的自然概况试… 相似文献
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马尾松、固氮树种混交造林探讨 总被引：1，自引：0，他引：1
选用固氮树种与马尾松混交,对促进马尾松生长作用十分显著,并可不断增加林地土壤肥力,保持地力资源的永续利用。树种搭配模式主要有:马尾松×杨梅、胡枝子,马尾松×南岭黄檀、胡枝子,马尾松×江南桤木、胡枝子。 相似文献
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薪炭林经营与其他林种经营的区别在于寻求能量的最大产出,林分总能量的输出取决于组成树木的热值及其生物量。通过生物量和能量的研究,可以了解薪炭林分生物量和能量的积累动态,为林分的物质循环和能量流动以及林分的开发和利用提供基础资料。 中国桉树人工林面积近40万ha,遍布南方16个省(区)的600多个县,在华南地区的林业生产和人民群众的日常生活中占着非常重要的地位。但桉树纯林多代连续经营(尤其以短轮伐期连续经营)引起地力衰退,导致林分生产力下降以及其他不良的生态后果已为长期的生产实践和科学研究所证实。为此,我们自1982年始在海南岛琼海、三亚、屯昌等县 相似文献
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Xiaoxiang Liu Qiubo Chen Zhenhui Wang Longlian Xie Zhi Xu 《Frontiers of Forestry in China》2008,3(2):232-236
This study on the allelopathic effects and chemical components of the essential oi l from Eucalyptus grandis × E. urophylla shows that the leaf oil emulsion of E. grandis × E. urophylla can inhibit the proliferation of pathogenic fungi Fusarium oxysporum, Pyriculerie grisea, Glorosprium musa rum and Phytophthora capsici. Pupation and feeding of the pest insects Spodopteralitura Fabricius and Helicoverpa armigera Hubner are shown to be affected with restraining effects which increase with the increasing levels of oil concentration.
A GC/MS analysis of the leaf oil indicated that the main components, with a relative content of ⩾3%, were alloocimene (43.22%),
α-pinene (13.63%), γ-terpinene (5.49%), (E)-3,7-dimethyl-2,6-octadien-1-ol (3.58%), β-fenchyl alcohol (4.58%), and 2-amino-3,5-dicyano-6-(4-methoxyphenoxy)-pyridine (3.67%). Terpenes played an important role
in the inhibitory effects of E. grandis × E. urophylla essential oil on pathogenic fungi and pest insects. Poor biodiversity of eucalyptus plantations is a function of allelopathy.
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Translated from Chinese Journal of Ecology, 2007, 26(6): 835–839 [译自: 生态学杂志] 相似文献
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Reforestation is one of the most effective ways to reduce the impacts of desertification. Caragana microphylla Lam. and Pinus sylvestris var. mongolica Litrin have been widely used to stabilize shifting sands in the Horqin sandy land area since the 1980s. However, soil water
depletion has been of major concern in C. microphylla and P. ongolica plantations and in many places current soil moisture cannot meet the demand of growing plants. To determine the water budget
of C. microphylla and P. mongolica plantations, we studied the effect of plantations on soil moisture and assessed the evapotranspiration in plantations of
both species. Investigations were conducted at a fenced plot at Wulanaodu (42°29′N, 119°30′E, 479 m a. s. l), located at the
western edge of the Horqin Sandy Land area in Inner Mongolia, northern China. Five year old C. microphylla and seven year old P. mongolica plants were selected from the plantations and transplanted to iron boxes (400 cm×200 cm×120 cm) which can drain extra water.
Plant spacing of 1 m×1 m was applied to P. mongolica, and two plant spacings of 1 m×1 m and 1 m×2 m to C. microphylla. The transplanted plants grew for two years in the boxes. Soil moisture from soil surface to a depth 80 cm were measured
at 20 cm intervals in boxes every 10 d (2004) or 3 d (2005) during the growing season with a TDR water meter. The evapotranspiration
was estimated from a mathematical formula and the characteristics of soil water consumption and evapotranspiration of these
two plantations were analyzed. The soil water of P. mongolica was more than that of C. microphylla at the same 1 m×1m spacing. The soil water of C. microphylla with the 1 m×2 m spacing was more than that of the 1 m×1 m spacing. The evapotranspiration ranged from high to low as follows:
C. microphylla (1 m×1 m), C. microphylla (1 m×2 m) and P. mongolica (1 m×1 m) during the growing seasons. The evapotranspiration of individual plants ranging from high to low was C. microphylla (1 m×2 m), C. microphylla (1 m×1 m), and P. mongolica (1 m×1 m) during the growing season. C. microphylla grown for five year consumed more water than P. mongolica grown for seven years at the same spacing.
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Translated from Acta Ecological Sinica, 2008, 28(5): 1981–1990 [译自: 生态学报] 相似文献
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Tree row spacing affected agronomic and economic performance of Eucalyptus-based agroforestry in Andhra Pradesh, Southern India 总被引：1，自引：1，他引：0
J. V. N. S. Prasad G. R. Korwar K. V. Rao U. K. Mandal C. A. R. Rao G. R. Rao Y. S. Ramakrishna B. Venkateswarlu S. N. Rao H. D. Kulkarni M. R. Rao 《Agroforestry Systems》2010,78(3):253-267
The 3 × 2 m spacing currently used for eucalyptus plantations in the state of Andhra Pradesh, southern India does not permit intercropping from the second year. This discourages small landholders who need regular income from taking up eucalyptus plantations and benefiting from the expanding market for pulpwood. Therefore, on-farm experiments were conducted near Bhadrachalam, Khammam district (Andhra Pradesh) for over 4 years from August 2001 to November 2005 to examine whether wide-row planting and grouping of certain tree rows will facilitate extended intercropping without sacrificing wood yield. Eucalyptus planted in five-spatial arrangements in agroforestry [3 × 2 m (farmers’ practice), 6 × 1 m, 7 × 1.5 m paired rows (7 × 1.5 PR), 11 × 1 m paired rows (11 × 1 PR) and 10 × 1.5 m triple rows (10 × 1.5 TR)] was compared with sole tree stands at a constant density of 1,666 trees ha?1. Cowpea (Vigna unguiculata) was intercropped during the post-rainy seasons from 2001 to 2004, and fodder grasses (Panicum maximum and Brachiaria ruziziensis) were intercropped during both the seasons of 2005. At 51 months after planting, different spatial arrangements did not significantly affect height and diameter at breast height (dbh). Total dry biomass of eucalyptus in different spatial arrangements ranged between 59.5 and 52.9 Mg ha?1, the highest being with 6 × 1 m and the lowest with 10 × 1.5 TR, but treatment differences were not significant. The widely spaced paired row (11 × 1 PR) and triple row (10 × 1.5 TR) arrangements produced 62–73% of sole cowpea yield in 2003, 59–66% of sole cowpea yield in 2004, and 79–94% of sole fodder in 2005. In contrast, the 3 × 2 m spacing allowed only 17–45% of sole crop yields in these years. The better performance of intercrops in widely spaced eucalyptus was likely because of limited competition from trees for light and water. Intercropping of eucalyptus in these wider rows gave 14% greater net returns compared with intercropping in eucalyptus spaced at 3 × 2 m, 19% greater returns compared with that from sole tree woodlot and 263% greater returns compared with that from sole crops. Therefore, in regions where annual rainfall is around 1,000 mm and soils are fairly good, eucalyptus at a density of 1,666 plants per ha can be planted in uniformly spaced wide-rows (6 m) or paired rows at an inter-pair spacing of 7–11 m for improving intercrop performance without sacrificing wood production. 相似文献
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对广西宁明县相似立地条件下1年生尾巨桉(DH32-29)和雷林1号桉幼林的生物量和5种营养元素(N、P、K、Ca 和 Mg)积累量及其分配特征进行了研究。结果表明：1年生尾巨桉和雷林1号人工幼林林分生物量分别为13.70和12.06 t·hm–2,不同器官生物量均以树干最大,树叶或树根最小。两种桉树不同器官中营养元素含量均以树叶最高,其次是树皮、树枝和树根,树干最低,林木不同器官中营养元素含量均以 N 最高,其次是 K 和 Ca,Mg 和 P最低。1年生尾巨桉幼林营养元素积累量为124.84 kg·hm–2,略低于雷林1号桉幼林(132.76 kg·hm–2),5种营养元素积累量在尾巨桉人工林的分配为树叶＞树枝＞干皮＞干材＞树根,在雷林1号桉的分配为树枝＞树叶＞干材＞干皮＞树根。尾巨桉幼林营养元素利用效率略高于雷林1号桉幼林。 相似文献
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两种桉树与厚荚相思混交的生长效应研究 总被引：5，自引：0，他引：5
对尾叶桉和雷林１号桉与厚荚相思的两种混交方式混交林的生长、抗风力进行了研究,结果表明：以桉树为主要目的树种的混交林,所选用桉树的生长量大于相思时,其增产效应显著,尾叶桉与厚荚相思带状混交能明显提高尾叶桉的生长量,以４行带效果最好,适宜在风害不严重的地区采用。尾叶桉与厚荚相思行间混交能降低厚荚相思的风害率并能明显增加混交林单位面积的木材产量,在沿海台风多发地区是有推广价值的一种混交方式。 相似文献
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J. V. N. S. Prasad G. R. Korwar K. V. Rao K. Srinivas Ch. Srinivasarao B. Pedababu B. Venkateswarlu S. N. Rao H. D. Kulkarni 《New Forests》2011,42(1):51-61
On-farm experiments were conducted in Khammam district of Andhra Pradesh from 2001 to 2006 to evaluate the biomass productivity,
intercrop yields and profitability of Eucalyptus tereticornis clonal and Leucaena leucocephala variety K-636 based systems. Trees were planted at a spacing of 3 × 2 m and evaluated at three locations. Height growth was
significantly higher in leucaena during the 4 year where as difference in diameter growth was not significant. Biomass partitioning to the bole was high in case of leucaena, ranged from 83% in 2.5–5 cm diameter at breast height (DBH)
trees to 89% in 12.5–15 cm DBH trees and in eucalyptus clones the corresponding values were 71% in 2.5–5 cm DBH trees and
83% in 12.5–15 cm DBH trees. Marketable biomass productivity was higher with leucaena (95 Mg ha−1) in comparison to eucalyptus (87 Mg ha−1). Competition effects of trees on intercrops were observed from the 2 year (2002 post-rainy season). Intercrop yields were
45% of the sole crop in eucalyptus system and 36% in leucaena system during the 2 year. Sole eucalyptus and leucaena plantations
and intercropping systems recorded higher gross and net returns over arable cropping. Therefore, it can be concluded that
leucaena variety K636 and eucalyptus clonal based agroforestry systems are profitable alternatives to arable cropping under
rainfed conditions. 相似文献
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Multipurpose tree species （MPTs） were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2 m × 2 m （2500 stems·hm^-2） could have the potentiality to meet the timber/fuelwood requirement due to its high wood production of 635 m^3·hm^-2 with mean annual increment （MAI） of 2.54×10^-2 m^3.treel.a^-1 in a short rotation period of 10 years. Thus, A. auriculiformis is a short rotation forest tree species suitable to grow in subtropical humid climate. On the other hand, at 16 years of age, Eucalyptus hybrid and Michelia champaca in spacing of 3 m × 3 m （1111 stems.hm^2） produced appreciably high timber volume of 315 m^3.hm^-2 and 165 m^3.hm^-2 with MAI of 1.77×10^-2 m^3.tree^-1·a^-1 and 0.92×10.2 m^3.tree^-1.a^-1, respectively. At 16 years of age, Gmelina arborea produced a timber volume of 147 m^3.hm^-2 with MAI of 1.47×10^-2 m^3.tree^-1.a^-1 followed by Samania saman （140 m^3.hm^-2）, Albizziaprocera （113 m^3·hm^-2） and Tectona grandis （79 m3.hm^-2） with MAI of 1.40, 1.13 and 0.78 × 10^-2 m^3 .tree^-1a^-1, respectively in 4 m × 4 m spacing （625 stems.hm^-2）. Gliricidia maculata and Leucaena leucocephala could be used as live fences around the farm boundary to supply their N-rich leaves for mulch as well as manure to crops. In agroforestry arboretum, direct seeded upland rice （Oryza sativa - variety, AR-11）, groundnut （Arachis hypogaea - variety, JL-24） and sesamum （Sesamum indicum - variety, B-67） were grown during the initial period upto 8 years of tree establishment. Under other MPTs, there was a reduction in crop productivity as compared to open space. After 8 years of tree establishment, horti-silvi and silvi-pastoral systems were developed and pineapple （Ananas comosus - variety Queen）, turmeric （Curcuma longa -variety RCT -1） and cowpea （Vigna sinensis - variety Pusa Barsati） as forage crop were raised. The productivity of p 相似文献
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A dramatic decline in forest cover in eastern Africa along with a growing population means that timber and poles for building
and fuelwood are in short supply. To overcome this shortage, the region is increasingly turning to eucalyptus. But eucalyptus
raises environmental concerns of its own. Fears that it will deplete water supply, affect wildlife and reduce associated crop
yields have caused many countries in the region to discourage farmers from planting this exotic. This paper is part of a series
of investigations on the growth and water use efficiency of faster growing eucalyptus hybrids, which was introduced from South
Africa to Kenya. The hypothesis is that the new hybrids are more efficient in using water and more suitable for the semi-arid
tropics than existing eucalyptus and two popular agroforestry species. Gas exchange characteristics of juvenile Eucalyptus grandis (W. Hill ex Maiden), two eucalyptus hybrids (E. grandis × Eucalyptus camaldulensis Dehnh.), Grevillea robusta (A. Cunn) and Cordia africana (Lam) was studied under field and pot conditions using an infrared gas analyzer was used to measure photosynthetic active
radiation (PAR), net photosynthetic rate (A), stomatal conductance (g
s) and transpiration rate (E) at CO2 concentrations of 360 μmol mol−1 and ambient humidity and temperature. A, E and g
s varied between species, being highest in eucalyptus hybrid GC 15 (24.6 μmol m−2 s−1) compared to eucalyptus hybrid GC 584 (21.0 μmol m−2 s−1), E. grandis (19.2 μmol m−2 s−1), C. africana (17.7 μmol m−2 s−1) and G. robusta (11.1 μmol m−2 s−1). C. africana exhibited high E values (7.0 mmol m−2 s−1) at optimal soil moisture contents than G. robusta (3.9 mmol m−2 s−1) and eucalyptus (5.3 mmol m−2 s−1) in field experiment and G. robusta (3.2 mmol m−2 s−1) and eucalyptus (4.2 mmol m−2 s−1) in pot-grown trees. At very low soil moisture content, extremely small g
s values were recorded in GC 15 and E. grandis (8 mmol m−2 s−1) and G. robusta (14 mmol m−2 s−1) compared to GC 584 (46.9 mmol m−2 s−1) and C. africana (90.0 mmol m−2 s−1) indicating strong stomatal control by the species. Instantaneous water use efficiency ranged between 3 and 5 μmol mmol−1 and generally decreased with decline in soil moisture in pot-grown trees but increased with declining soil moisture in field-grown
trees. 相似文献