Effect of nitrogen addition on DOC leaching and chemical exchanges on canopy leaves in Guangdong Province,China     

Taiki Mori  Kaijun Zhou  Senhao Wang  Wei Zhang  Jiangming Mo 《林业研究》2019,(5):1707-1713

The impact of nitrogen(N)deposition on dissolved organic carbon(DOC)fractions in throughfall is not well understood.We performed a laboratory experiment and compared DOC leaching from canopy leaves after dipping leaves in pure water(control)and NH4NO3 solution(N-treatment)for 18 h.Net changes of DOC,NH4^+,NO3^-,SO4^2-,K^+,Mg^2+,Ca^2+and H^+contents after dipping leaves were determined by comparing solutions with and without leaves.We recorded no differences of DOC leaching between control and N-treatment,implying that N deposition had minor impacts on canopy DOC production.This confirmed that previous experiments testing the effects of N addition on DOC dynamics without considering the effects of the canopy reaction successfully described the real situation.We also confirmed the previously-reported canopy exchange process in spite of a high background N deposition at our study site.N-treatment significantly increased base cation leaching,especially K^+,and the increase was positively correlated with foliar NH4?retention.Net leaching of H^+and SO4^2-was not affected by the N-treatment.  相似文献   

中国竹林认证现状及趋势     

周妍  张宏亮  郭帆  王琴 《世界林业研究》2019,32(2):78-82

中国是世界上竹子资源最丰富的国家,也是全球竹子资源开发利用最充分的国家。竹林认证是我国森林认证一个重要且有特色的领域。中国竹林认证自本世纪初在浙江的一些地区开始实践至今已经历了10多年的发展,目前总体呈现缓中有进的趋势,已在认证要求、操作程序、模式选择等方面取得了一定进展,为世界竹业发展提供了较好的示范。文中从认证竹林面积与分布、类型与特点以及审核中存在的不符合项等方面总结我国竹林认证现状,指出竹林认证的成效及在实施过程中面临的挑战,分析竹林认证的发展趋势并提出相应对策。  相似文献   

森林土壤动物生态功能研究进展     

潘菲  张燕林  黄彩凤  周垂帆 《世界林业研究》2020,33(2):37-42

森林土壤动物是森林土壤生态系统中不可分割的重要组成部分,对森林土壤生态系统的物质循环和能量流动起着重要作用。文中综述了近10年森林土壤动物生态功能的相关研究进展,包括森林土壤动物对土壤理化性质、微生物、植物的影响以及外来土壤动物入侵对土壤生态系统的影响等;展望了我国森林土壤动物的未来研究方向,未来研究应多关注森林土壤动物生态功能的作用机制、森林土壤动物对全球变化的响应、外来土壤动物入侵对森林生态系统的影响、森林土壤动物种类的研究范围以及新技术的应用,以期为我国森林土壤动物生态功能、土壤动物与生态系统、可持续利用土壤动物等领域研究提供科学参考。  相似文献   

我国喀斯特断陷盆地石漠化区植物群落构建机制研究     

李桂静  廖江华  吴斌  关颖慧  曹建华  周金星 《世界林业研究》2020,33(3):67-73

喀斯特断陷盆地是我国石漠化综合治理8大喀斯特类型中治理成效最低、治理难度最大的区域,面临石漠化严重、干旱频发、植被恢复难等突出问题。文中针对水分是影响喀斯特断陷盆地石漠化治理与植被恢复成效最关键的限制因素,综合分析了国内外水分梯度差异与植物群落构建机制研究动态与发展趋势;提出利用日趋成熟的水分脆弱性评价方法,通过建立基于耦合暴露度、敏感性及适应性的水资源脆弱性评价指标体系,以满足遥感影像分辨率和植物群落调查样地大小的评价单元进行水分脆弱性评估;在建立物种库—功能性状—生境特征数据库的基础上,提出基于功能性状差异进行喀斯特断陷盆地植物群落机制构建的研究方案。提出的研究方案有望解决喀斯特断陷盆地石漠化区水分梯度特征与分布格局、自然植物群落组配规律及其生境特征、水分梯度与生境要素对植物群落特征及功能性状组成的影响规律等关键科学问题,可为不同脆弱生态区植被恢复群落构建机制研究提供重要参考和借鉴。  相似文献   

脉动燃烧技术及其在林业中的应用     

汪东  刘键  陈青  蒋雪松  周宏平  许林云  茹煜 《世界林业研究》2020,33(5):47-52

脉动燃烧是指在一定声振条件下发生的一种周期性燃烧,其燃烧室内压力强度、气流速度、温度及热释放效率等参数随着时间呈周期性变化,是一种特殊的不稳定燃烧过程,具有燃烧效率高、燃料经济性好、运行环境友好等优点。研制基于脉动燃烧技术的林业作业装备对于提高林业生产效率、促进环保高效燃烧技术的发展具有重要意义。文中概述了脉动燃烧技术的工作原理、特点及发展现状,介绍了脉动燃烧技术在林业病虫害防治、木材干燥和土壤消毒中的应用,并在分析脉动燃烧技术的不足及其在林业作业应用中存在问题的基础上,提出脉动燃烧技术在林业作业应用中的发展方向。  相似文献   

不同地形条件下群落物种多样性与胸高断面积的差异分析   总被引：3，自引：2，他引：3  

汤孟平  周国模  施拥军  陈永刚  吴亚琪  赵明水 《林业科学》2007,43(6):27-31

以浙江天日山国家级自然保护区的常绿阔叶林为例,基于DEM在群落尺度上分析不同地形条件下群落物种多样性和胸高断面积的差异.对单一地形因子分析的结果表明:在常绿阔叶林群落中,坡度过大或过小均可引起常绿阔叶林物种多样性和胸高断面积下降,中等坡度时物种多样性和胸高断面积最高;胸高断面积随坡向的变化比物种多样性敏感,自东坡经南坡过渡到西坡,胸高断面积呈降低趋势,东坡的物种多样性和胸高断面积最高,西南坡最低;物种多样性和胸高断面积随地表粗糙度增加呈降低的趋势.对组合地形因子分析结果表明:坡向和坡度的不同组合,对物种多样性的影响不大,但与胸高断面积存在较大的相关性,各坡度级中,西南坡胸高断面积均最低;坡向和粗糙度的不同组合对物种多样性的影响不大,但与胸高断面积存在一定的相关性,在各粗糙度级中,西南坡均为最低;坡度和粗糙度组合对物种多样性和胸高断面积的影响均较大,同一粗糙度级中,物种数在各坡度级表现为坡度级2＞坡度级3＞坡度级1,除坡度级1外,各粗糙度级上的胸高断面积随坡度的增加而增加.  相似文献   

Characterization of the morphological,physical, and mechanical properties of seven nonwood plant fiber bundles     

Sasa Sofyan Munawar  Kenji Umemura  Shuichi Kawai 《Journal of Wood Science》2007,53(2):108-113

The morphological, physical, and mechanical properties of the nonwood plant fiber bundles of ramie, pineapple, sansevieria, kenaf, abaca, sisal, and coconut fiber bundles were investigated. All fibers except those of coconut fiber had noncircular cross-sectional shapes. The crosssectional area of the fiber bundles was evaluated by an improved method using scanning electron microscope images. The coefficient factor defined as the ratio of the cross-sectional area determined by diameter measurement, to the cross-sectional area determined by image analysis was between 0.92 and 0.96 for all fibers. This indicated that the area determined by diameter measurement was available. The densities of the fiber bundles decreased with increasing diameters. The diameters of each fiber species had small variation of around 3.4%-9.8% within a specimen. The tensile strength and Young’s modulus of ramie, pineapple, and sansevieria fiber bundles showed excellent values in comparison with the other fibers. The tensile strength and Young’s modulus showed a decreasing trend with increasing diameter of fiber bundles.  相似文献   

Storage of biomass and net primary productivity in desert shrubland of Artemisia ordosica on Ordos Plateau of Inner Mongolia, China     

Jin Zhao  Qi Yu-chun  Dong Yun-she 《林业研究》2007,18(4):298-300

Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.  相似文献   

Relationship between effective solar radiation and sap flow process during an entire growing season in Western Mountains of Beijing     

Xu Jun-liang Ma Lv-yi 《中国林学(英文版)》2007,9(4):251-255

In order to explore the relationship between the time processes of solar radiation and sap flow, sap flow velocity (SFV) of Platycladus orientalis and Pinus tabulaeformis, effective solar radiation (ESR) and other environmental factors were synchronously monitored for one year in the Beijing Western Mountains by using a thermal dissipation probe (TDP) system and an automatic weather station. Results showed significant differences between changes in diurnal characteristics of ESR and sap flow in sunny days during three seasons. Starting times of sap flow occurred generally 1.5–3 hours later than those of solar radiation and there were small differences between Platycladus orientalis and Pinus tabulaeformis. But peak times and stopping times of sap flow varied con-siderably with large contrasts in ESR. The duration of sap flow showed clear differences among the seasons owing to the variable rhythms of climate factors in Beijing. Fluctuation amplitude in the duration of sap flow remained relatively stable during the autumn but changed greatly during spring and summer. Changes in diurnal sap flow velocity of both Platycladus orientalis and Pinus tabu-laeformis were about 0–3 hours later than those of ESR but with the same configuration. The start of sap flow was mainly induced by the sudden intensification of ESR (sunrise effect). Seasonal models of SFV indicated that a cubic equation had the best fit. It was more practical to simulate seasonal water consumption models of trees with ESR. In further investigations, these models should be optimized.  相似文献   

Water absorption of boron-treated and heat-modified wood     

Saip Nami Kartal  Won-Joung Hwang  Yuji Imamura 《Journal of Wood Science》2007,53(5):454-457

Heat treatments change the chemical and physical properties of wood and dimensional stability and hygroscopicity are affected as a result of modifications of wood cell components. This study evaluated the water absorption of wood specimens treated with boron compounds followed by heat treatment. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or disodium octoborate tetrahydrate (DOT) solutions were heat-modified at either 180° or 220°C for 2 or 4 h. Carbohydrate composition and water absorption of the specimens were then measured and compared with those of untreated and unheated specimens. Wood carbohydrates were significantly degraded in the specimens after heat treatment. The heat treatment evidently decreased the water absorption and the heat-modified specimens absorbed less water than unheated specimens. The higher the treatment temperature and the longer the treatment time, the lower the amount of absorbed water. The boron-treated and heat-modified specimens, however, showed increased water absorption due to the hygroscopic properties of BA and DOT.  相似文献