Modelling the time course of shade,temperature, and wood recovery in streams with riparian forest restoration     

Robert J. Davies‐Colley  Mark A. Meleason  Raeme M.J. Hall  J. Christopher Rutherford 《新西兰海洋与淡水研究杂志》2013,47(3):673-688

Action is increasingly being taken in New Zealand and elsewhere to restore ecological function to streams through planting of riparian zones. We used simulation modelling to explore the relative performance of three strategies to restore the riparian zone of a pastoral stream to native forest by: (1) passive regeneration; (2) planting then abandonment of a Pinus radiata plantation; and (3) active restoration by planting selected native trees. We linked the forest model LINKNZ with a shade and temperature model (sWAIORA), and a wood model (OSU_STREAMWOOD) to simulate recovery trajectories for key forest stream attributes in hypothetical streams (1.3–14.0 m channel width) in the central North Island, New Zealand. Both active restoration strategies outperformed passive regeneration in shade, temperature and stream wood volume for most of the simulation time (800 years). Although the abandoned pine plantation provided greatest shade initially (<100 years), active native planting provided the greatest benefits overall. In general, recovery of stream shade (and temperature) is expected within decades, is accelerated by deliberate planting, and is fastest in small streams in which thermal stress from sunlight exposure is greatest. However, full recovery of stream and riparian function may take centuries, being dependent on large trees providing wood to structure the channel.  相似文献   

2008年春季中国南方冰雪冻害林木物理折损典型样带分析   总被引：1，自引：0，他引：1  

邵全琴  黄麟  刘纪远  匡文惠  李佳 《山地学报》2009,27(2)

2008年春季我国南方发生了特大冰雪灾害,林木损害严重。选择江西省井冈山-吉泰盆地-于山山脉-武夷山支脉样带作为研究区,两次进行野外调查,结合收集的数据,进行综合分析,取得结论包括：（1）在研究样带内人工林的损毁程度为湿地松林〉马尾松林〉混交人工林〉杉木林,在受损样本中湿地松林的实际受损比例高达61．3％,其中不可自然恢复折损实际比例达43．2％,相对比例达70．4％,主要是因为湿地松是美国南部地区外来引进种,生长块、材质疏松,而且割脂活动较强;马尾松为乡土造林先锋树种,材质较为坚硬,但受割脂活动影响,在受损样本中实际受损受损比例也高达52．5％,其中不可自然恢复折损实际比例达31．8％,相对比例达60．9％;杉木是本地树种,实际受损比例46％,其中不可自然恢复受损实际仅14．9％,相对比例也仅32．5％,低于混交人工林。（2）调查样带自西向东,西部井冈山地区常绿阔叶林受损程度最轻,分布在700m左右的人工柳杉林受损严重,杉木林分布在700m以下的受损程度较轻,而分布在900m以上的则相对严重;中部吉泰盆地受损调查样点中,分布在低海拔的湿地松林和马尾松林,因割脂活动受损程度严重,杉木林受损最轻,长期封育的天然次生林落叶阔叶林,由于藤本植物的缠绕,导致大量冰挂积雪,受损十分严重;东部兴国和宁都县,分布在400m以下的人工飞播马尾松因个体小基本未受损,分布在400m以上的1960年代人工种植马尾松,因割脂活动,受损严重;而分布在500～900m的杉木林受损程度较轻。  相似文献   

鳞毛蕨天山云杉林粗死木质残体贮量及其分解动态   总被引：6，自引：0，他引：6  

刘翠玲  潘存德  梁瀛 《干旱区地理》2009,32(2)

为了丰富我国森林粗死木质残体研究的对象类型,并为探讨粗死木质残体在天山云杉天然更新中的生态作用奠定基础,借助粗死木质残体5级分类系统,采用临时标准调查法对西天山国家级自然保护区原始鳞毛蕨天山云杉纯林粗死木质残体的贮量、养分含量及其分解动态进行了研究.结果表明:(1)鳞毛蕨天山云杉林粗死木质残体体积贮量为337.61 m3/hm2,生物量为87.98mg/hm2;倒木树干是粗死木质残体的主体组成部分,占总体积的98.09%;(2)以基本密度(比重)为衡量指标,倒木腐朽等级越高,其密度越小,倒木分解符合单项指数衰减模型,分解常数为0.01174.5个不同腐朽等级倒木的平均滞留时间依次为4年、18年、38年、68年和92年.在自然状态下,倒木分解50%、90%和95%所需时间分别为59年、196年和255年;(3)倒木有机碳、全N、全P、全K、Na+的平均含量依次为55.93%±1.42%、0.34%±0.07%、0.12%±0.01%、0.06%±0.01%和0.03%±0.002%,Ca2+、Mg2+的平均含量分别为56.74±4.87 g/kg和34.89±3.66 g/kg,不同养分的变化趋势不同,但同一养分在不同腐朽等级倒木之间的差异不显著.  相似文献   

Wood distribution in neotropical forested headwater streams of La Selva,Costa Rica     

Daniel Cadol  Ellen Wohl  Jaime R. Goode  Kristin L. Jaeger 《地球表面变化过程与地形》2009,34(9):1198-1215

Surveys of wood along 30 forested headwater stream reaches in La Selva Biological Station in north‐eastern Costa Rica represent the first systematic data reported on wood loads in neotropical streams. For streams with drainage areas of 0·1–8·5 km² and gradients of 0·2–8%, wood load ranged from 3 to 34·7 m³ wood/100 m channel and 41–612 m³ wood/ha channel. These values are within the range reported for temperate streams. The variables wood diameter/flow depth, stream power, the presence of backflooding, and channel width/depth are consistently selected as significant predictors by statistical models for wood load. These variables explain half to two‐thirds of the variability in wood load. These results, along with the spatial distribution of wood with respect to the thalweg, suggest that transport processes exert a greater influence on wood loads than recruitment processes. Wood appears to be more geomorphically effective in altering bed elevations in gravel‐bed reaches than in reaches with coarser or finer substrate. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Large wood budget and transport dynamics on a large river using radio telemetry          下载免费PDF全文

Edward R. Schenk  Bertrand Moulin  Cliff R. Hupp  Jean M. Richter 《地球表面变化过程与地形》2014,39(4):487-498

Despite the abundance of large wood (LW) river studies there is still a lack of understanding of LW transport dynamics on large low gradient rivers. This study used 290 radio frequency identification tagged (RFID) LW and 54 metal (aluminum) tagged LW, to quantify the percent of in‐channel LW that moves per year and what variables play a role in LW transport dynamics. Aluminum tags were installed and monitored on LW in‐transit during the rising limb of a flood, the mean distance traveled by those pieces during the week was 13.3 river kilometers (km) with a maximum distance of 72 km. RFID tagged LW moved a mean of 11.9 km/yr with a maximum observed at 101.1 km/yr. Approximately 41% of LW low on the bank moves per year. The high rate of transport and distance traveled is likely due to the lack of interaction between LW floating in the channel and the channel boundaries, caused primarily by the width of the channel relative to length of the LW. Approximately 80% of the RFID tags moved past a fixed reader during the highest 20% of river stage per year. LW transport and logjam dynamics are complicated at high flows as pieces form temporary jams that continually expand and contract. Unlike most other studies, key members that create a logjam were defined more by stability than jam size or channel/hydrologic conditions. Finally, using an existing geomorphic database for the river, and data from this study, we were able to develop a comprehensive LW budget showing that 5% of the in‐channel LW population turns over each year (input from mass wasting and fluvial erosion equals burial, decomposition, and export out of system) and another 16% of the population moving within the system. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   

A flume experiment on wood storage and remobilization in braided river systems   总被引：1，自引：0，他引：1       下载免费PDF全文

Walter Bertoldi  Matilde Welber  Luca Mao  Sandra Zanella  Francesco Comiti 《地球表面变化过程与地形》2014,39(6):804-813

This work investigates wood dynamics in braided streams through physical modelling in a mobile bed laboratory flume, with the specific objective to characterize wood storage and turnover as a function of wood input rate and of wood element type. Three parallel channels (1.7 m wide, 10 m long) filled with uniform sand were used to reproduce braided networks with constant water discharge and sediment feeding. Wood dowels with and without simplified root wads were regularly added at the upstream end of each flume at different input rates, with a 1:2:3 ratio between the three flumes. Temporal evolution of wood deposition patterns and remobilization rates were monitored by a series of vertical images that permitted the recognition of individual logs. Results show that wood tends to disperse in generally small accumulations (< 5 logs), with higher spatial density on top of sediment bars, and is frequently remobilized due to the intense morphological changes. The amount of wood stored in the channel depends on log input rate through a non‐linear relationship, and input rates exceeding approximately 100 logs/hour determine a sharp change in wood dynamics, with higher storage volume and augmented formation of large jams (> 10 elements) that are less prone to remobilization. Presence of root wads seems to play a minor role in wood deposition, but it reduces the average travel distance of logs. Turnover rates of logs were similar in the three flumes, independently of wood input rate and largely resembling the turnover rate of exposed bars. For the simulated conditions, significant effects of wood on bed morphology were not observed, suggesting that interactions with fine sediments and living vegetation are crucial to form large, stable wood jams able to bring about relevant morphological changes. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Large in‐stream wood studies: a call for common metrics     

Ellen Wohl  Daniel A. Cenderelli  Kathleen A. Dwire  Sandra E. Ryan‐Burkett  Michael K. Young  Kurt D. Fausch 《地球表面变化过程与地形》2010,35(5):618-625

During the past decade, research on large in‐stream wood has expanded beyond North America's Pacific Northwest to diverse environments and has shifted toward increasingly holistic perspectives that incorporate processes of wood recruitment, retention, and loss at scales from channel segments to entire watersheds. Syntheses of this rapidly expanding literature can be facilitated by agreement on primary variables and methods of measurement. In this paper we address these issues by listing the variables that we consider fundamental to studies of in‐stream wood, discussing the sources of variability in their measurement, and suggesting more consistency in future studies. We recommend 23 variables for all studies of in‐stream wood, as well as another 12 variables that we suggest for studies with more specific objectives. Each of these variables relates either to the size and characteristics of in‐stream wood, to the geomorphic features of the channel and valley, or to the ecological characteristics of the riparian zone adjacent to the study reach. The variables were derived from an overview of those cited in the literature and from our collective field experiences. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

以ArcObjects开发树木景观模型   总被引：1，自引：0，他引：1  

周翠竹  向南平 《海洋测绘》2005,25(3):63-66

ArcObjects是一个功能强大的GIS组件库，利用ArcObjects提供的SceneViewerControl控件结合VisualBasic6.0开发工具，通过“贴图法”构建图像模型，较好地实现了树木景观的可视化建模，在视觉上取得了较好的效果。  相似文献   

Fossil coniferous wood from the Early Cretaceous Jehol Biota in western Liaoning,NE China: New material and palaeoclimate implications     

《Cretaceous Research》2016

The Early Cretaceous Jehol Biota, one of the most important Mesozoic lagerstätten in East Asia, is especially well-known for occurrences of fossil feathered dinosaurs and early angiosperms. However, the terrestrial biodiversity, especially the fossil wood record, is poorly known. In this study, several structurally preserved coniferous wood specimens from the Lower Cretaceous Yixian Formation are investigated, based on collections from the Heichengzi Basin in Beipiao of western Liaoning, Northeast China. Four species referred to four genera of fossil wood are described, including Taxodioxylon heichengziense sp. nov., Thujoxylon beipiaoense sp. nov., Sciadopityoxylon liaoningense Ding and Protocedroxylon shengjinbeigouense sp. nov. These new records enlarge the fossil wood diversity of the Yixian Formation up to 10 species in 9 genera, and provide further insights into the forest vegetation composition of the Early Cretaceous Jehol Biota. Systematic analysis of the floral constitution indicates that the petrified forests of the Yixian Formation are dominated by conifers, represented by Araucariaceae, Podocarpaceae, Sciadopityaceae, Pinaceae and Cupressaceae in the western Liaoning region. Palaeoclimatical analysis of the fossil wood assemblage implies that the western Liaoning region was dominated by a cool temperate, wet and seasonal climate with variable interannual water supply in the western Liaoning region during the Early Cretaceous.  相似文献   

Evidence of palaeo-wildfire from the upper Lower Cretaceous (Serra do Tucano Formation,Aptian–Albian) of Roraima (North Brazil)     

《Cretaceous Research》2016

Wood fossil charcoal is identified from the upper Lower Cretaceous (Serra do Tucano Formation, Aptian–Albian) of Roraima (North Brazil). The presence of charcoal demonstrates the occurrence of Early Cretaceous palaeo-wildfires for the first time in this region and only the third time for the entirety of South America. A gymnospermous taxonomic affinity can be established for the charred woods and a relationship with conifers is likely, thus providing additional evidence for the taxonomic composition of Early Cretaceous floras in this region.  相似文献