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1.
以湖南省会同县马尾松次生林、马尾松阔叶树混交林和常绿阔叶林分类型为研究对象,探讨了生态系统随不同演替阶段进行的乔木层碳储量及空间分布特征。结果表明:不同演替阶段森林类型乔木层各器官平均有机碳含量为马尾松林针阔混交林常绿阔叶林的趋势。乔木层碳储量以常绿阔叶林最高,为129.34t·hm~(-2),其次为针阔混交林,为95.83 t·hm~(-2),最小是马尾松林,为85.27 t·hm~(-2)。各林分类型乔木层各器官碳储量为干根枝叶皮。乔木层碳储量主要集中于树干,其占乔木层碳储量比例由马尾松林向常绿阔叶林降低,而树根碳储量比例由马尾松林向常绿阔叶林增加。马尾松林、针阔混交林和常绿阔叶林20cm径级以上径级的个体占乔木层碳储量的大部分。 相似文献
2.
以中亚热带湖南省会同县处于演替早期的马尾松次生林、中期的马尾松阔叶树混交林和后期的常绿阔叶林分类型为研究对象,探讨了生态系统随不同演替阶段进行的乔木层生物量及空间分布特征。结果表明:乔木层生物量以常绿阔叶林最高,为292.51 t/hm~2,其次为针阔混交林,为206.87 t/hm~2,最小是马尾松林,为171.76 t/hm~2。乔木层生物量主要集中于树干,其占乔木层生物量比例由马尾松林向常绿阔叶林降低,而树根生物量所占比例由马尾松林向常绿阔叶林增加。马尾松林、针阔混交林和常绿阔叶林20 cm以上径级的生物量所占总生物量比例较大。 相似文献
3.
浙江省江山市不同森林类型枯落物持水性能 总被引：2，自引：0，他引：2
《浙江林业科技》2019,(6)
2017年10月,选取浙江省江山市典型地段的阔叶林、毛竹Phyllostachys edulis林、杉木Cunninghamia lanceolata林、马尾松Pinus massoniana林、针阔混交林、灌木林设立标准样地,研究不同森林类型枯落物持水性能。结果表明,6种不同森林类型枯落物储量为7.86～25.64 t·hm~(-2),由大到小依次为针阔混交林阔叶林马尾松林杉木林毛竹林灌木林,且枯落物厚度和储量大小排序一致;最大持水量变化在11.19～33.42 t·hm~(-2),有效拦蓄率范围为87.37%～126.41%,有效拦蓄量由大到小依次为针阔混交林阔叶林杉木林马尾松林毛竹林灌木林,含阔叶树种的森林枯落物的持水能力优于针叶林;枯落物持水量与浸泡时间呈对数函数关系,吸水速率与浸泡时间呈幂函数关系。 相似文献
4.
以白龙江林业管理局2010年森林资源规划设计调查(以下简称二类调查)为基础更新至2015年的资源数据,采用国家权威机构公布的社会公共数据,按照《中国森林植被生物量与碳储量评估》,参考白龙江森林生态站的观测数据,评估了白龙江林区森林植被生物量、碳储量与碳汇价值。结果表明:(1)森林植被生物量总量为10 939.65万t,总碳储量为5 528.47万t,单位面积生物量为143.32 t/hm~2,碳密度为72.43 t/hm~2,碳交易的潜在价值为324 336.91万美元(JI)或490 559.61万美元(CDM);(2)不同林分类型生物量总量、碳储量总量排序一致,排序为冷杉林云杉林针阔混交林油松林桦木林针叶混交林其他灌木林阔叶混交林铁杉柏木林国家特灌林华山松林落叶松林栎类林硬阔类林杨类林软阔类林疏林经济林;(3)不同林分类型单位面积生物量、碳密度排序一致,排序为软阔类油松林冷杉林硬阔类林针叶混交林阔叶混交林铁杉柏木林针阔混交林云杉林落叶松林桦木林栎类林杨类林华山松林经济林疏林、国特灌木林、其它灌木林。 相似文献
5.
《内蒙古林业调查设计》2017,(4):78-81
基于内蒙古大兴安岭林区2013年森林资源档案数据,运用生物量扩展因子法,量化内蒙古大兴安岭林区植被碳储量和碳密度。结果表明:内蒙古大兴安岭林区植被碳库总量41709.83×104t,平均碳密度为47.59±8.93 t C·hm-2;有林地乔木层在碳封存中占主导地位,其碳储量与面积近乎成正比,按龄组划分依次为中龄林成熟林近熟林过熟林幼龄林;按林分类型为针叶林针阔混交林阔叶林阔叶混交林针叶混交林;按林分起源为天然林人工林。有林地乔木层碳密度在不同龄组及不同林分起源间存在显著差异,在不同林分类型间无显著差异,其碳密度大小按龄组依次为成熟林近熟林过熟林中龄林幼龄林;按林分类型为阔叶林阔叶混交林针叶林针阔混交林针叶混交林;按林分起源为天然林人工林。 相似文献
6.
基于安徽省第九次全国森林资源清查数据,利用生物量—蓄积量转换模型,从不同森林类型、起源、龄组、优势树种(组)等方面进行分析,运用生物量换算因子连续函数法,对安徽省森林碳储量及碳密度进行估算。结果表明,安徽省森林碳储总量为11 843.59×10~4t,平均碳密度29.93 t/hm~2,其中乔木林碳储量为9 790.17×10~4t,占森林总碳储量的82.66%,乔木林平均碳密度为31.72t/hm~2,碳密度大小排序为:阔叶林针阔混针叶林,经济林、竹林碳储量为2 053.42×10~4t。乔木林中,天然林的面积、碳储量略小于人工林,但天然乔木林各龄组碳密度均大于人工林;阔叶混交林、杨树、马尾松、杉木、针阔混交林、栎类、针叶混交林的面积、碳储量占优势,其中又以阔叶混交林为最大,面积、碳储量均超过乔木林的28%。文章指出安徽省乔木林碳密度水平仍然不高,今后在增加森林面积的同时,仍需采取合理经营管理措施,促使森林质量和碳汇水平不断提高。 相似文献
7.
8.
不同森林类型土壤肥力状况研究 总被引：1，自引：0，他引：1
利用贵州天保工程效益监测网络设置在9个监测县和2个自然保护区的101个固定样地土壤分析结果,按常绿落叶阔叶林、常绿阔叶林、落叶阔叶林、针阔混交林、针叶林、针叶混交林、灌木林、竹林等8种不同森林植被类型在不同基岩发育的森林土壤中营养元素含量,对不同森林土壤的综合肥力进行分析评价。结果显示,不同森林植被类型的森林土壤的A层土中有机质、水解性氮、有效磷、速效钾等各项指标含量与森林植被类型呈正相关趋势且高于B层,B层土随不同基岩不同而有所变化,显示不同森林植被类型对土壤综合肥力的影响大于基岩;不同森林植被类型土壤的综合肥力大小顺序依次为:常绿落叶阔叶林>常绿阔叶林>针针混交林>落叶阔叶林>灌木林>针阔混交林>针叶林>竹类。 相似文献
9.
《浙江林业科技》2014,(1)
通过380个浙江省生态公益林中常绿阔叶林、针阔混交林、松林、杉木林4种主要森林群落的典型样地调查,对不同群落类型物种多样性的时空格局进行研究,结果表明:在空间格局上不同群落类型物种多样性存在较大差异,乔木层多样性指数以针阔混交林和常绿阔叶林为最高;针阔混交林的下木层物种数最高,其次是常绿阔叶林,但下木层各指数在各林型间均无显著差异;杉木林下草本层物种数指数最高,松林草本层各项指数都最低。从时间格局分析,不同群落类型的多样性指数随年龄变化各不相同,常绿阔叶林和针阔混交林乔木层物种数在幼龄-中龄-近熟阶段趋势一致,均为先大幅增加然后略有下降,两种针叶林型的物种数都相对稳定;4种主要群落类型的乔木层Simpson生态优势度指数D,常绿阔叶林和针阔混交林随时间变化趋势一致,均为先增加后略有下降再增加,且显著高于同年龄级的针叶林;常绿阔叶林和针阔混交林乔木层Shannon-Wiener多样性指数H′随时间各异,但都极显著高于同年龄级针叶林的指数。常绿阔叶林和针阔混交林群落物种组成丰富、多样性指数高,是浙江省生态公益林的理想群落与目的群落。 相似文献
10.
中亚热带常绿阔叶林不同演替阶段木质残体碳密度特征 总被引：1，自引：0，他引：1
为了更好地了解常绿阔叶林恢复演替过程中木质残体(WD)碳储量的变化特征,对鹰嘴界马尾松林、针阔混交林、常绿阔叶林进行了调查取样,结果表明:鹰嘴界常绿阔叶林演替阶段各林分中木质残体的现存量较低,在1.26~8.82 Mg/hm2之间,大小顺序为马尾松林针阔混交林常绿阔叶林,随演替进程呈逐渐增加趋势;演替阶段粗木质残体(CWD)碳含量因树种及其分解等级而异,随着CWD分解等级的提高,其碳含量逐渐降低;马尾松林、针阔混交林和常绿阔叶林的木质残体碳密度分别为0.62,1.75,3.78 Mg/hm2,分别相当于各林分乔木层碳密度的0.73%、1.83%和2.92%。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
13.
Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
15.
Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional
data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral
contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising
germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal
diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties
to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations. 相似文献
16.
《Wood material science & engineering》2013,8(2):76-84
Abstract Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists. 相似文献
17.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
19.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献
20.
本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献