TREE RINGS OF CEDRUS LIBANI AT THE NORTHERN BOUNDARY OF ITS NATURAL DISTRIBUTION

IAWA Journal ◽  
2003 ◽  
Vol 24 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Ünal Akkemik
Keyword(s):  
Tree Rings ◽  
Steep Slope ◽  
Limiting Factor ◽  
Response Functions ◽  
Natural Distribution ◽  
Northern Boundary ◽  
Valley Bottom ◽  
Cedrus Libani ◽  
Steep Slopes ◽  
Low Precipitation

The present study was carried out taking a total of 41 increment cores from three sites located in the northern boundary of Cedrus libani and three site chronologies were constructed. Three response functions were computed and a higher correlation with climate was found in the trees on the steep slopes. The low precipitation was an important limiting factor for growth. At the valley bottom site, neither precipitation, except for December, nor temperature, except for February were a limiting factor. The radial diameters of tracheids were measured, and the tracheid numbers representing the last seven years, from 1994 to 2000, were counted. Although the radial diameters were almost similar in all sites, the numbers of tracheids were greatest at the valley bottom site and lowest at the steep slope site.

Slope threshold in rill flow resistance

2021 ◽  
Author(s):  
Alessio Nicosia ◽  
Vito Ferro
Keyword(s):  
Friction Factor ◽  
Flow Resistance ◽  
Sediment Load ◽  
Steep Slope ◽  
Limiting Factor ◽  
Rill Erosion ◽  
Hydraulic Characteristics ◽  
Transport Capacity ◽  
Steep Slopes ◽  
Rill Flow

<p>Rills are small, steep sloping and ephemeral channels, shaped in soils, in which shallow flows move. Rill erosion strictly depends on hydraulic characteristics of the rill flow and for this reason flow discharge <em>Q</em>, rill width <em>w</em>, water depth <em>h</em>, mean flow velocity <em>V</em>, and friction factor are required to model the rill erosion process.</p><p>Erosive phenomena strictly depend on the attitude of the soil particles to be detached (<em>detachability</em>) and to be transported (<em>transportability</em>). These properties are affected by soil texture and influence the sediment load <em>G</em> to be transported by flow. The actual sediment load depends on the transport capacity <em>T<sub>c</sub></em> of the flow, which is the maximum amount of sediment, with given sizes and specific weight, that can be transported by a flow of known hydraulic characteristics.</p><p>According to Jiang et al. (2018) the hydraulic mechanisms of soil erosion for steep slopes are different from those for gentle slopes. Recent research on <em>T<sub>c </sub></em>equations exploring slopes steeper than 18% (Ali et al., 2013; Zhang et al., 2009; Wu et al., 2016) established that <em>T<sub>c</sub></em> relationships designed for gentle slopes (<18%) are unsuitable to be applied to steep slopes (17–47%). Also Peng et al. (2015) noticed that <<<em>there has been little research concerning rill flow on steep slopes (e.g. slope gradients higher than 10°)</em>>>. In other words, the slope of 18% could be used to distinguish between the “gentle slope” and the “steep slope” case for the recognized difference in hydraulic and sediment transport variables.</p><p>The applicability of a theoretical rill flow resistance equation, based on the integration of a power velocity distribution (Barenblatt, 1979; 1987), was tested using measurements carried out in mobile rills shaped on plots having different slopes (9, 14, 15, 18, 22, 24, 25 and 26%) and soil textures (clay fractions ranging from 32.7% to 73% and silt of 19.9% – 30.9%), and measurements available in literature (Jiang et al. (2018), Huang et al. (2020) and Yang et al. (2020)).</p><p>The Darcy-Weisbach friction factor resulted dependent on slope, Froude number, Reynolds number and <em>CLAY</em> and <em>SILT</em> percentages, which represent soil transportability and detachability, respectively. This theoretical approach was applied to two different databases distinguished by the slope threshold of 18%. The results showed that, for gentle slopes (< 18%), the Darcy-Weisbach friction factor increases with slope, <em>CLAY</em> and <em>SILT</em> content. Taking into account that for gentle slopes the hydraulic characteristics limit the transport capacity, for this condition <em>T<sub>c</sub></em> and the sediment load <em>G</em> are both limiting factors.</p><p>For steep slopes (> 18%), the flow resistance increases with slope and the ratio between <em>SILT</em> and <em>CLAY</em> percentage. Steep slopes determine high values of the transport capacity, which is consequently not a limiting factor. Thus, in this condition the actual sediment load is determined exclusively by the ratio between <em>SILT</em> and <em>CLAY</em> percentage. In other words, the only limiting factor for a steep slope condition is the sediment which can be transported (i.e. the sediment load <em>G</em>), affected by its soil detachability and transportability.</p>

scholarly journals PHYSICO-GEOGRAPHICAL OBSERVATIONS OF THE COASTAL ZONE OF THE NORTHEASTERN PART OF ISLAND RHODES

2018 ◽  
Vol 36 (2) ◽  
pp. 958 ◽  
Author(s):  
Ε. Βερυκίου-Παπασπυριδάκου ◽  
Γ. Μπαθρέλλος ◽  
Χ. Σκυλοδήμου
Keyword(s):  
Coastal Zone ◽  
Coastal Dunes ◽  
Steep Slope ◽  
Human Intervention ◽  
Alluvial Deposits ◽  
Study Region ◽  
Middle Slope ◽  
Steep Slopes ◽  
Geological Formations ◽  
Tectonic Movements

Rhodes is the biggest island of the Dodecanese complex; its geology is very interesting for the researchers because it h located onto the eastern end of the Aegean arcade. This paper involves the physico-geographical features of the coastal zone of the NE part of Rhodes. Specifically, the major geological formations of the region were studied and classified, according to their morphology and lithology. In addition, the human interventions that have affected the region were also recorded. The geological formations met in the study region are the following: Mesozoic limestones, Oligocene flysch, Pliocene - Pleistocene marls, calcarenites, and Holocene deposits. Steep slopes and cliffs basically characterize the limestone coasts. Some mirror faults, indicate the intense tectonic movements whereas, some coastlines witness the former sea level. The flysch coasts have mainly steep slope. The coasts, which are developed on marls and calcarenites have got various morphological slopes. This has resulted to the formation of steep costs with cliffs and middle slope costs that are characterized by smooth relief. The coasts developed onto alluvial deposits have mainly gentle slope bearing the bulk of the beaches. They are featured by several geoforms such as coastal dunes, while the human intervention is significant.

scholarly journals The cost disadvantage of steep slope viticulture and strategies for its preservation

OENO One ◽  
2021 ◽  
Vol 55 (1) ◽  
pp. 49-68
Author(s):  
Larissa Strub ◽  
Simone Mueller Loose
Keyword(s):  
Net Present Value ◽  
Univariate Analysis ◽  
Steep Slope ◽  
Production Costs ◽  
Pricing Policy ◽  
Fixed And Random Effects ◽  
Option Strategies ◽  
The Cost ◽  
Steep Slopes ◽  
The Impact

The falling fallow of steep slope vineyards is caused by cost disadvantages that have not been analysed so far. This study quantified the production costs of different types of steep slopes, identified cost drivers within viticultural processes and assessed the impact of grape yield on the production cost for vertical shoot positioning (VSP) systems. It also examined under what conditions the reshaping of steep slope vineyards into transversal terraces (TTs) is economically viable. Costs were derived from a dataset of 2321 working time records for labour and machine hours from five German wine estates over three years. The costs for standard viticultural processes were compared across five site types with different mechanisation intensities by univariate analysis of variance with fixed and random effects. The net present value (NPV) of reshaping slopes into horizontal terraces was also assessed. Manual management of steep slopes was determined to be 2.6 times more costly than standard flat terrain viticulture. The cost disadvantage of steep slopes mainly stems from viticultural processes with limited mechanisability that require specialised equipment and many repetitions. Current subsidies fall short of covering the economic disadvantage of manual and rope-assisted steep slopes. Climate change-related drought and yield losses further increase the economic unsustainability of steep slopes. Under certain conditions, the transformation of manual steep slope sites into TTs can be a viable economic option. Strategies to reduce the cost disadvantage are outlined. The estimated cost benchmarks provide critical input for steep slope wine growers’ cost-based pricing policy. These benchmarks also give agricultural policy reliable indicators of the subsidies required for preserving steep slope landscapes and of the support needed to transform manual steep slope sites into TTs.

The Design and Construction of the Chinipas Slope Pipeline Crossing

2016 ◽  
Author(s):  
Agostino Napolitano ◽  
Guido Guidotti ◽  
Andrea Marsili ◽  
Alessandro Fabbri ◽  
Marco Menichetti ◽  
...  
Keyword(s):  
Environmental Science ◽  
Three Dimensional ◽  
Steep Slope ◽  
The State ◽  
Mountain Range ◽  
Natural Gas Pipeline ◽  
Dimensional Reconstruction ◽  
Pipeline Project ◽  
The University ◽  
Steep Slopes

SAIPEM has been awarded the engineering, procurement and construction of “El Encino - Topolobampo” Natural Gas Pipeline Project in Mexico. The 30” pipeline begins in El Encino, in the state of Chihuahua, and terminates in Topolobampo, in the state of Sinaloa. It runs in a West-South West direction perpendicularly crossing the “Sierra Madre Occidental”, a mountain range characterized by uneven morphology with deep and narrow valleys and steep slopes. Near the village of Santa Matilde, before reaching the Chinipas River, the pipeline route has to overcome a 150 meters high steep slope on the left side of the valley of Chinipas. This slope features a sub vertical rocky cliff with a 55 meters drop in the upper section. A trenchless crossing of the slope was designed and executed to safely cross the steep slope by means of raise borer and tunnel. Since the area was nearly inaccessible, SAIPEM, for the first time in the design of a trenchless crossing of slopes, has performed the geomechanical study using a remote sensing process based on the Structure from Motion (SfM) technique for a three-dimensional reconstruction of the outcrop of the cliff. The activity has been carried out in collaboration with the Department of Earth, Life and Environmental Science of the University of Urbino. The results of the study led to the optimization of the trenchless geometry maintaining the raise bore into the competent rock avoiding frequent lithological variations critical during the drilling and identifying a suitable tunnel entrance location.

Optimizing cable harvesting layout when using variable-length cable roads in central Europe

2014 ◽  
Vol 44 (8) ◽  
pp. 949-960 ◽  
Author(s):  
Leo Bont ◽  
Hans Rudolf Heinimann ◽  
Richard L. Church
Keyword(s):  
Forest Management ◽  
Central Europe ◽  
Layout Optimization ◽  
Steep Slope ◽  
Variable Length ◽  
Alternative Models ◽  
Option Model ◽  
Points Of View ◽  
Steep Slopes

One of the classic operations problems in forest management is the layout of a harvesting system. This paper addresses the design of a harvesting system in areas characterized by steep slopes requiring cable-based harvesting. Layout optimization often involves numerous potential cable alignments and a small number of potential landings. In this paper we develop a model that addresses steep slope conditions found in central Europe that involve a large number of potential landings and cable alignments. In addition we extend existing work by considering variable-length alternatives for each feasible cable alignment. We construct three models, one for single-length cable options and two for variable-length alternatives and test their efficacy in solving 18 different harvesting area problems. We show that one of the variable-length alternative models can be solved in computer times that are competitive with the single-length option model. Overall, the savings that can be attributed to variable-length options are modest, but the alignments found by the variable-length options models are more realistic from forest engineers’ points of view, which will aid in its use and adoption.

Ecology and biogeography of Cassia brewsteri: assessment of potential sites for cultivation

2002 ◽  
Vol 42 (8) ◽  
pp. 1071 ◽  
Author(s):  
D. C. Cunningham ◽  
E. R. Anderson ◽  
K. B. Walsh
Keyword(s):  
Field Studies ◽  
Soil Conditions ◽  
Limiting Factor ◽  
Climate Modelling ◽  
High Survival ◽  
Vegetation Types ◽  
Natural Distribution ◽  
Potential Source ◽  
Survival And Growth ◽  
Ecological Parameters

Cassia brewsteri (F. Muell.) F. Muell. ex Benth. has been identified as a potential multipurpose agroforestry species, and also as a potential source of seed galactomannans (industrial gums). In this study, the natural and cultivated distributions of C. brewsteri were used as a basis for predicting potential sites for cultivation of the tree, using the climate modelling software ANUCLIM. The natural distribution was determined by compilation of data from herbaria and from field studies. The ecological parameters of natural occurrences were characterised in terms of soil and vegetation types by sampling 113 sites throughout the natural distribution in Queensland (18.583–26.150°S, 144.750–152.750°N). In addition to the natural occurrences, a further 11 sites were identified where the tree has been grown successfully in cultivation. Failures of the tree in agroforestry trials in Thailand may be explained by high temperature as a limiting factor in the distribution of the species. Failures of the species in trials in Australia, Zimbabwe and Malawi could not be attributed to climate or soil conditions at the trial sites, indicating that further research on culture of the tree is required to achieve high survival and growth rates.

Environmental determinants of a restricted cycad in central Australia, Macrozamia macdonnellii

2007 ◽  
Vol 55 (6) ◽  
pp. 601 ◽  
Author(s):  
Luke D. Preece ◽  
Angus W. Duguid ◽  
David E. Albrecht
Keyword(s):  
Current Distribution ◽  
Environmental Variables ◽  
Field Data ◽  
Information Criterion ◽  
Maximum Temperature ◽  
Limiting Factor ◽  
Environmental Determinants ◽  
Central Australia ◽  
Gis Software ◽  
Steep Slopes

Macrozamia macdonnellii (F.Muell. ex miq.) A.DC. (Zamiaceae) is a cycad restricted to the MacDonnell and surrounding ranges of central Australia. Although it is a conspicuous, iconic and reasonably abundant plant of these ranges, there has been little previous documentation of the factors that limit current distribution. The distribution is distinctively patchy with some observed preference for gullies, gorges and relatively shady slopes. Anecdotal evidence suggests this species may be a relict that had more widespread distributions during previous cooler and more mesic climates. In the present study, field data were collected at 143 sites within 13 locations to test the environmental determinants of its current distribution, using logistic regression. A regression model was created to model the presence of M. macdonnellii in relation to the field-collected environmental variables and GIS software was used to create a second model for derived environmental variables and collated known locations of M. macdonnellii. Variables included in the models were selected by using Akaike’s information criterion. The results suggest that M. macdonnellii is more likely to be present in environments that provide relatively low radiation (high shade), low maximum temperature, an optimum minimum temperature, steep slopes, high wetness, short distances to drainage lines and skeletal soils. Fire and rockiness indices were poor predictors of the presence of M. macdonnellii. Microclimate, determined by some of the variables, was found to be the primary limiting factor for the distribution of M. macdonnellii, which supports the possibility that this species is a climatic relict.

scholarly journals Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France)

2016 ◽  
Author(s):  
V. Breton ◽  
Y. Crosaz ◽  
F. Rey
Keyword(s):  
Plant Species ◽  
Seedling Emergence ◽  
Wood Chip ◽  
Water Erosion ◽  
Steep Slope ◽  
Wood Chips ◽  
Growing Seasons ◽  
Steep Slopes ◽  
Positive Effect ◽  
Soil Fertility Improvement

Abstract. The establishment of plant species can limit soil erosion dynamics in degraded lands. In marly areas in the Southern French Alps, both harsh water erosion and drought conditions in summer due to the Mediterranean mountainous climate prevent the natural implementation and rege neration of vegetation. Soil fertility improvement is sometimes necessary. With the purpose of revegetating such areas, we aimed to evaluate the effects of wood chip amendments on the revegetation performance of different native or sub-spontaneous plant species. We conducted two experiments on steep slopes over three growing seasons (2012–2014). The first consisted of planting seedlings (ten species), the second consisted of seeding (nine species including six used in the first experiment). First we noted that wood chips were able to remain in place even in steep slope conditions. The planting of seedlings showed both an impact of wood chip amendment and differences between species. A positive effect of wood chips was shown with overall improvement of plant survival (increasing by 11% on average, by up to 50% for some species). In the seeding experiment, no plants survived after three growing seasons. However, intermediate results for the 1st and 2nd years showed a positive effect of wood chips on seedling emergence: seeds of four species only sprouted on wood chips, and for the five other species the average emergence rate increased by 50%.

scholarly journals Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France)

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 599-610 ◽  
Author(s):  
Vincent Breton ◽  
Yves Crosaz ◽  
Freddy Rey
Keyword(s):  
Plant Species ◽  
Seedling Emergence ◽  
Wood Chip ◽  
Water Erosion ◽  
Steep Slope ◽  
Wood Chips ◽  
Growing Seasons ◽  
Steep Slopes ◽  
Positive Effect ◽  
Soil Fertility Improvement

Abstract. The establishment of plant species can limit soil erosion dynamics in degraded lands. In marly areas in the Southern French Alps, both harsh water erosion and drought conditions in summer due to the Mediterranean mountainous climate prevent the natural implementation and regeneration of vegetation. Soil fertility improvement is sometimes necessary. With the purpose of revegetating such areas, we aimed to evaluate the effects of wood chip amendments on the revegetation performance of different native or sub-spontaneous plant species. We conducted two experiments on steep slopes over three growing seasons (2012–2014). The first consisted of planting seedlings (10 species), and the second consisted of seeding (nine species including six used in the first experiment). First we noted that wood chips were able to remain in place even in steep slope conditions. The planting of seedlings showed both an impact of wood chip amendment and differences between species. A positive effect of wood chips was shown with overall improvement of plant survival (increasing by 11 % on average, by up to 50 % for some species). In the seeding experiment, no plants survived after three growing seasons. However, intermediate results for the first and second years showed a positive effect of wood chips on seedling emergence: seeds of four species only sprouted on wood chips, and for the five other species the average emergence rate increased by 50 %.

scholarly journals Improved Vulnerability Assessment Table for Retaining Walls and Embankments from a Working-Level Perspective in Korea

2021 ◽  
Vol 13 (3) ◽  
pp. 1088
Author(s):  
Jaejoon Lee ◽  
Hyunji Lee ◽  
Hongsik Yun ◽  
Chol Kang ◽  
Moonsoo Song
Keyword(s):  
Evaluation Criteria ◽  
Retaining Walls ◽  
Reinforced Soil ◽  
Steep Slope ◽  
Ease Of Use ◽  
Global Evaluation ◽  
Analytic Hierarchy ◽  
Inadequate Knowledge ◽  
Slope Collapse ◽  
Steep Slopes

Climate change can lead to unpredictable slope collapse, which causes human casualties. Therefore, Korea has devoted significant effort to the management of slope disasters. The Ministry of the Interior and Safety of Korea, which oversees the safety of the nation’s people, has allocated a four-year budget of $557 million to investigate, assess, and maintain steep slope sites. However, there have been fatalities caused by steep slope site evaluations based on inadequate knowledge and a single retaining walls and embankments (RW&E) assessment table. Therefore, the assessment table for RW&E-type steep slopes needs to be improved in terms of its accuracy, simplicity, and ease of use. In this study, domestic and global evaluation methods were reviewed, problems associated with the existing RW&E assessment table were identified, and a focus group interview was conducted. The RW&E assessment table was improved through an indicator feasibility survey and analytic hierarchy processing. The improved assessment table was categorized from one to four classifications to reduce the ambiguity of the evaluation: concrete, reinforced soil-retaining walls, stone embankments, and gabions. This study will provide the sustainability of slope safety and serve as a reference for classification and evaluation criteria across all national institutions that conduct RW&E evaluations.

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