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在海南半干早丘陵台地区,对窿缘桉、大叶相思、木麻黄、新银合欢、银合欢、刚果12号桉和雷林1号桉进行了筛选试验,结果表明:刚果12号桉、雷林1号桉、窿缘桉和大叶相思适应性强,生长快,生物量高,燃烧性能好,经济效益高,是适于当地生长和发展的优良薪材树种。 相似文献
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尾叶桉、细叶桉、赤桉、粗皮桉、巨桉（简称桉树类，下同）和马占相思、粗果相思及薄果相思（简称相思类，下同）等８个树种，在水土严重流失的贫瘠丘陵地经７年的生长试验，结果表明：除巨桉和细叶桉在该立地生长较缓慢外，其余６个树种生长快，产量较高。尤其是尾叶桉和马占相思，７年生胸径年均生长量在１．０ｃｍ以上，单位面积生物量（地上部分鲜重，下同）为５２．６９ｔ／ｈｍ２和４３．６７ｔ／ｈｍ２。不同树种的生长比较：桉树类树种（除巨桉外）４年生以前胸径、树高和生物量生长均比相思类树种生长快，４年后相思类树种逐渐赶上或超过桉树类树种。性状生长高峰期分别为：胸径桉树类为２年生（细叶桉１年生）、相思类为３～４年生，树高桉树和相思类均为１年生，生物量桉树类为２～３年生、相思类为４～６年生。 相似文献
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通过对１０个树种１－４年生的保存率、风害状况、林木生长表面的对比研究，运用模糊综合评判，选择的胶园防护林树种。初步结果表明，赤桉、细叶桉、刚果１２号桉适宜作为园防护林更新树种，山地木麻黄和大叶相思亦较适宜，其余树种均不适宜。 相似文献
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以杂交相思(Acacia mangium×A.auriculiformis)、黑木相思(Acacia melanoxylon)、大花序桉(Eucalyptus cloeziana)、台湾桤木(Alnus formosana)、红锥(Castanopsis hystrix)、巨尾桉广林9号(Eucalyptus grandis×E.urophylla‘GLGU9’)6种阔叶速生树种为研究对象,设计相同密度进行造林,对6种阔叶树种进行12个月的生长比较分析,旨在为优良速生阔叶树种的选择提供科学依据。结果表明,在相同造林密度下,各树种株高、胸径、材积增长迅速,且各生长指标差异显著,其中年株高增量最大为黑木相思(3.8 m),年胸径增量最大为大花序桉(4 cm),年均单株材积增量最大为巨尾桉广林9号(0.058 8 m~3/株),红锥各生长指标均为最小。造林密度对不同树种的生长有一定影响,短周期速生成材造林阔叶树种可优先选择巨尾桉广林9号、大花序桉和黑木相思。 相似文献
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本文主要阐明十年来先后在海南省４个试点和广东省花都试点所进行的７９个国内外树种（包括引进种、乡土及乡土化树种）的筛选试验结果。选出了尾叶桉马占相思、大叶相思、肯氏相思、斑皮桉、刚果１２桉、粗皮桉、赤桉、细叶桉、柠檬桉、雷林１号接及窿缘桉等１２个适应性强、生长快、产量高、效益快、抗性强、热值高及易繁殖的薪炭材树种，４年生年均材积和生物量生长分别为７０～５４ｍ３／ｈａ和１０～７０ｔ／ｈａ之间。同时，对部分树种进行简单的经济效益比较表明，经营优良薪炭材树种每公顷平均年收入在１０００元以上，投入产出比１：１、４～１：２０之间。 相似文献
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为了改善贫瘠地区的生态环境和解决群众的烧柴问题,中国林科院热带林业研究所于1984年开始承担国家攻关项目“薪炭林选种引种及栽培经营技术”的《热带优良速生薪材树种选择及薪材林栽培技术》的课题,在海南省内四个不同气候区和立地类型区进行多点试验研究。从29个参试树种中选出了刚果12号桉、尾叶桉、细叶桉、斑皮桉、赤桉、马占相思、大叶相思和雷林一号桉、窿缘桉等9个适应性强,生长快(年均径2.0 cm、高2.5m以上),产量高(材积20—25m~3/ha·a,生物量25—58t/ha·a),抗性(抗风及抗病虫害)强,燃烧性能 相似文献
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试验结果表明：尾叶桉和大叶相思或肯氏相思施行行间辊交是可行的３年生尾叶桉混交林林分蓄积量和生物量比尾叶桉纯林分别增长１８．７％～２３．３％和１６％～２４．３％，且以两行尾叶桉加一行大叶相思混交效果较好，其次为一行尾叶桉加一行大叶相思或肯氏相思。通过混交不仅能促进木木生长而且能提高尾叶桉干材生物量所占的比重，能改良土壤，提高林地有机质的含量。 相似文献
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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，所选用桉树地生长量大于相思时，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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在四川盆地通过引进国内外薪材树种和选择乡土薪材树种,进行栽植密度、始伐年龄、轮伐期等试验研究,结果表明:从引进的8个新材树种中,选择出任豆为适宜生长的树种,新银合欢、黑荆、荆为为适宜部分地区生长的树种;从13个乡土薪材树(草)种中筛选出桤木、刺槐、麻栎、栓皮栎、马桑、卵花甜茅等为比较优良的薪材树(草)种。桤木、刺槐、马桑等薪炭林的合理造林密度为10000株(丛)/ha;麻栎、栓皮栎为6000～7000株(丛)/ha;印花甜茅以行距1m为宜。桤木、刺槐、麻栎、栓皮栎等薪炭林,始伐年龄不超过5年,轮供期3～6年;马桑薪炭林始伐年龄为3～4年,轮伐期2～3年、印花甜茅栽植1年后平茬,以后每年采收。合理的造林密度、始伐年龄、轮伐期,能使选择的几个树种提高生物产量1.0～2.5倍。 相似文献
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本文对桤木人工薪炭林群落学特征做了分析,桤木薪炭林是人工造林配置的树种,故群落简单。对估测桤木人工薪炭林乔木层生物量建立了多个数学模型,选用W_(树干)=147.1914D~(2.0616)、W_(枝条)=37.5577D~(2.3962)、W_(叶)=31.0578(D~2H)~(0.7776)和W_(地上部分)=258.6222D~(2.0622)幂函数方程,分别获得各器官的生物量,树干重8895.720kg/ha,枝条重3657.651kg/ha,叶重3345.324kg/ha,乔木层地上部分总重量15898.696kg/ha。对林下灌木和草本植物采用收割法测定,灌木地上部分生物量为2265kg/ha,草本植物地上部分生物量为459kg/ha。所以桤木人工薪炭林的地上部分生物量为18622.696kg/ha。 相似文献
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Shanti Shrestha Bhaskar Singh Karky Anup Gurung Rajesh Bista Ole Reidar Vetaas 《Small-Scale Forestry》2013,12(4):507-517
This study assessed the net above-ground carbon stock in six community forests in the Dolakha district, Nepal. A survey was conducted of above-ground timber species, using random sampling. A tree-ring chronology for Pinus roxburghii was created to construct a growth model representative of the various mainly-pine species. The allometric model combined with tree ring analysis was used to estimate carbon stock and annual growth in the above-ground tree biomass. The out-take of forest biomass for construction material and fuelwood was estimated on the basis of interviews and official records of community forest user groups. The average annual carbon increment of the community forests was 2.19 ton/ha, and the average annual carbon out-take of timber and fuelwood was 0.25 ton/ha. The net average carbon balance of 1.94 ton/ha was equivalent to 117.44 tons of carbon per community forest annually. All the community forests were actively managed leading to a sustainable forest institution, which acts as a carbon sink. It is concluded that community forests have the potential to reduce emissions by avoiding deforestation and forest degradation, enhance forest carbon sink and improve livelihoods for local communities. 相似文献
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本文调查了桉树人工林和邻近天然林内土著的木本植物多样性、密度和物种组成。桉树人工林和邻近天然林内分别圈画出20个20m×20m样地,记录下每块样地内的物种名称、物种丰富度、植株直径和高度以及采集亚样方(4m2)内幼苗数目。本试验中,记录人工林内木本植物46种,邻近天然林内52种,分别来自36个科。人工林内,物种多样性(H’)为2.19,林下木本植物密度为3842株/hm2,幼苗密度为4151株/hm2;而天然林内的物种多样性、林下树木密度和幼苗密度分别为2.74,4122株/hm2和8101株/hm2。两种林分的木本植物物种组成相似性较高。研究还表明,桉树人工林适合于Millitia ferruginia和小果咖啡生长和再生,而对下层木本则不适合。 相似文献
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通过在涪江卵石河滩、“四旁”和紫色石骨子荒坡营造铁杆芭茅,连续5年观测其生长量和生物量,结果表明,铁杆芭茅具有较高的产薪量,第5茬的产柴量,紫色石骨子荒坡13154kg/ha,卵石河滩16039kg/ha。裸露石骨子地以人工爆破整地和1m行距,用3根种条一起埋入土中,能获得较高的生物产量。 相似文献
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The fuelwood potential of indigenous (Acacia nilotica, Azadirachta indica, Casuarina equisetifolia, Dalbergia sissoo, Prosopis cineraria andZizyphus mauritiana) and exotics (Acacia auriculiformis, A. tortilis, Eucalyptus camaldulensis andE. tereticornis) trees were studied. Calorific value variations for components, such as, stump, main stem, treetop, branches, foliage and bark, were determined. Tree components differed highly significantly (P<0.01) among groups (indigenous and exotics) and within species. The calorific means ranged from 18.7 to 20.8 MJ/kg for indigenous tree species and 17.3 to 19.3 MJ/kg for exotics. Besides calorific values, other fuelwood characteristics, such as, density, ash, biomass/ash ratio, moisture and nitrogen content were also studied. It was observed that indigenous tree species are better suited as fuelwood species as they contain high density wood, low ash content and low N percentage. The fuelwood value index (FVI) was found to be high of indigenous tree species and was maximum forCasuarina equisetifolia (2815). The most promising tree species were in the order ofC. equisetifolia, A. nilotica andZ. mauritiana. 相似文献
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Fuelwood is the main energy source for households in rural Africa, but its supply is rapidly declining especially in the densely
populated areas. Short duration planted tree fallows, an agroforestry technology widely promoted in sub-Sahara Africa for
soil fertility improvement may offer some remedy. Our objective was to determine the fuelwood production potential of 6, 12
and 18 months (the common fallow rotation periods) old Crotalaria grahamiana, Crotalaria paulina, Tephrosia vogelli and Tephrosia candida fallows under farmer-managed conditions in western Kenya. Based on plot-level yields, we estimated the extent to which these
tree fallows would meet household and sub-national fuelwood needs if farmers planted at least 0.25 hectares, the proportion
of land that is typically left under natural fallows by farmers in the region. Fuelwood yield was affected significantly (P < 0.05) by the interaction between species and fallow duration. Among the 6-month-old fallows, T. candida produced the highest fuelwood (8.9 t ha−1), compared with the rest that produced between 5.6 and 6.2 t ha−1. Twelve months old T. candida and C. paulina also produced significantly higher fuelwood yield (average, 9.6 t ha−1) than T. vogelli and C. grahamiana of the same age. Between the fallow durations, the 18-month fallows produced the most fuelwood among the species evaluated,
averaging 14.7 t ha−1. This was 2–3 times higher than the average yields of 6 and 12-month-old fallows whose yields were not significantly different.
The actual fuelwood harvested from the plots that were planted to improved fallows (which ranged from 0.01 to 0.08 ha) would
last a typical household between 11.8 and 124.8 days depending on the species and fallow duration. This would increase to
268.5 (0.7 years) and 1173.7 days (0.7–3.2 years) if farmers were to increase area planted to 0.25 ha. Farmers typically planted
the fallows at high stand densities (over 100,000 plants ha−1 on average) in order to maximize their benefits of improving soil fertility and providing fuelwood at the same time. This
potential could be increased if more land (which fortunately exists) was planted to the fallows within the farms in the region.
The research and development needs for this to happen at the desired scale are highlighted in the paper. 相似文献
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Diversity, density and species composition of naturally regenerated woody plants under Eucalyptus grandis plantation and the adjacent natural forest were investigated and compared. Twenty plots, with an area of 20 m × 20 m for
each, were established in both of E. grandis plantation and adjacent natural forest, independently. In each plot, species name, abundance, diameter and height were recorded.
Numbers of seedling were collected in five sub-plots (4 m2) within each major plot. A total of 46 species in the plantation, and 52 species in the natural forest, which belongs to
36 families were recorded. The diversity of species (H′) is 2.19 in the plantation and 2.74 in the natural forest. The density of understory woody plant was 3842 stems/ha in the
plantation and 4122 stems/ha in the natural forest. The densities of seedlings in the natural forest and the plantation were
8101 stems/ha and 4151 stems/ha, respectively. High similarity of woody species composition was found between the natural
forest and the plantation. The E. grandis plantation was found favoring the regeneration and growth of Millitia ferruginia and Coffea arabica in a much better way than other underneath woody species. 相似文献