How roots of Picea abies and Fraxinus excelsior plantations contribute to soil strength and slope stability: evidence from a study case in the Hyrcanian Forest, Iran

Soil Research ◽  
2020 ◽  
Author(s):  
Marzieh Esmaiili ◽  
Ehsan Abdi ◽  
John L. Nieber ◽  
Mohammad Jafary ◽  
Baris Majnounian
Keyword(s):  
Picea Abies ◽  
Slope Stability ◽  
Soil Strength ◽  
Fraxinus Excelsior ◽  
Hyrcanian Forest ◽  
Study Case

Effects of two-year weather exposure on thermally modified Picea abies, Pinus sylvestris, and Fraxinus excelsior wood

2020 ◽  
Vol 50 (11) ◽  
pp. 1160-1171
Author(s):  
Chenyang Cai ◽  
Antti Haapala ◽  
Mohammad Habibur Rahman ◽  
Markku Tiitta ◽  
Valtteri Tiitta ◽  
...  
Keyword(s):  
Picea Abies ◽  
Pinus Sylvestris ◽  
Color Change ◽  
Exposure Period ◽  
Fraxinus Excelsior ◽  
Chemical Degradation ◽  
Surface Chemical ◽  
Exposure Test ◽  
Density Surface ◽  
Eastern Finland

The use of thermally modified timber (TMT) in outdoor applications is well established, but its performance against the stresses of outdoor conditions is not comprehensively understood. This study investigates the changes in density, surface chemical composition, color, equilibrium moisture content (EMC), checking, hardness, and cupping of thermally modified boards of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), and European ash (Fraxinus excelsior L.) during a two-year weather exposure test in Eastern Finland. Unmodified pine, spruce, and ash and copper salt impregnated pine boards were used as controls. The results show that a two-year weather exposure period causes degradation of hydrophobic lignin, and the leaching of the degraded compounds changed the color, increased the EMC, and decreased the hardness of specimens. Although the EMC of TMT specimens was lower compared with unmodified and impregnated ones during weathering, the changes were more obvious in TMT than in the controls. More checks occurred in the TMT specimens than in unmodified ones after the exposure. On the other hand, the TMT specimens had a lower degree of cupping. These findings also indicate that an increase in modification temperature induces more checks but improves the durability of all studied species by reducing the chemical degradation, color change, cupping, and hygroscopicity during weather exposure.

EFFECT OF CHEMICAL TREATMENTS ON THE GERMINATION OF FOREST TREE SEEDS

1946 ◽  
Vol 22 (1) ◽  
pp. 17-24 ◽  
Author(s):  
L. P. V. Johnson
Keyword(s):  
Picea Abies ◽  
Copper Oxide ◽  
Picea Glauca ◽  
Pinus Resinosa ◽  
Forest Tree ◽  
Potassium Nitrate ◽  
Larix Decidua ◽  
Fraxinus Excelsior ◽  
Betula Papyrifera ◽  
Betula Lenta

Chemical treatments were tested, in comparison with stratification and presoaking, for their effects on germination of forest tree seeds.Significant increases in percentage germination were obtained from potassium nitrate in Betula lenta, B. papyrifera, Fraxinus excelsior, Picea Abies, P. glauca, P. rubens and Pinus resinosa; from thiourea in Larix decidua, Picea Abies, P. glauca and P. rubens; from ethylene chlorhydrin in Betula lenta, B. papyrifera, Fraxinus excelsior, Larix decidua and Pinus resinosa; from red copper oxide in Pinus resinosa; from zinc oxide in Betula papyrifera, Picea glauca, Pinus Banksiana and P. resinosa; from stratifiaction in Acer saccharum, Betula lenta, B. lutea, B. papyrifera, B. populifolia, Fraxinus excelsior, Larix decidua, Picea glauca, Pinus resinosa and P. Strobus; and from presoaking in Betula papyrifera, Larix decidua and Picea Abies.The rate of germination was accelerated by potassium nitrate in Betula papyrifera, Picea Abies, P. glauca, P. rubens and Pinus Strobus; by thiourea in Betula lenta, Larix decidua, Picea glauca and P. rubens; by ethylene chlorhydrin in Larix decidua; by red copper oxide in Betula papyrifera; by stratification in practically all species; and by presoaking in Larix decidua and Picea Abies.The rate of seedling growth was increased by zinc oxide in Larix, Picea, Pinus and Thuja, and by red copper oxide in Pinus.

Slope Stability Integrate Analyses: The Study Case of Mount Falcone (Central Italy)

2015 ◽  
pp. 1371-1376
Author(s):  
Domenico Aringoli ◽  
Marco Materazzi ◽  
Bernardino Gentili ◽  
Gilberto Pambianchi ◽  
Nicola Sciarra
Keyword(s):  
Slope Stability ◽  
Central Italy ◽  
Study Case

scholarly journals Effect of Oriental beech root reinforcement on slope stability (Hyrcanian Forest, Iran)

2014 ◽  
Vol 60 (No. 4) ◽  
pp. 166-173 ◽  
Author(s):  
E. Abdi
Keyword(s):  
Tensile Strength ◽  
Slope Stability ◽  
Root Distribution ◽  
Factor Of Safety ◽  
Power Relationship ◽  
Strength Increase ◽  
Hyrcanian Forest ◽  
Reinforcement Effect ◽  
Root Reinforcement ◽  
Oriental Beech

Vegetation significantly affects hillslope mechanical properties related to shallow landslides and slope stability. The objective of this study was to investigate and quantify the effect of Oriental beech root reinforcement on slope stability. A part of Hyrcanian forest in northern Iran was selected for the study area. To do the research, the Wu model (WM) was used and data related to the distribution and tensile strength of Oriental beech roots were collected. Root distribution was assessed using the concept of the root area ratio and trenching method. Laboratory tensile tests were conducted on fresh roots for strength characteristics. The factor of safety was calculated for two different soil thicknesses (1 and 2 m) and slope gradients between 10 and 45&deg;. The results showed that the root distribution generally decreased with increasing soil depth and the mean root strength value was 38.23 &plusmn; 1.19 MPa for 0.35&ndash;5.60 mm diameter range. The results verified a power relationship between tensile strength and root diameter. The reinforcement effect (C<sub>r</sub>) decreased with depth and the strongest reinforcement effect was in the second soil layer (10&ndash;20 cm) which showed a shear strength increase of 1.47 kPa. The increased factor of safety due to the presence of roots in one- and two-metre soil thicknesses was 27&ndash;44% and 15&ndash;26%, respectively. The improvement effect of roots was increased with increasing slope gradient and shallower soil thicknesses. &nbsp; &nbsp;

Influence of Soft Clay on Slope Stability

2015 ◽  
Vol 754-755 ◽  
pp. 463-467
Author(s):  
Zuhayr Md Ghazaly ◽  
Mustaqqim Abdul Rahim ◽  
Nur Fitriah Isa ◽  
Liyana Ahmad Sofri ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Slope Stability ◽  
Soft Clay ◽  
Soil Strength ◽  
Soil Samples ◽  
Grain Size Analysis ◽  
Unit Weight ◽  
Size Analysis ◽  
Time Range ◽  
High Water Content ◽  
Major Disaster

Slope stability is very important on designing a safe slope. If this were to be taken lightly by the engineer, major disaster will occur that results in lost of lives. Each engineer is responsible to evaluate all aspects of design, especially when designing a slope gradient on the surface of soft clay. Soft clay containing high water content and if not planned properly, water from the soft clay will seep into the slope and causes reduction in soil strength. The purpose of this research was to investigate the effect of water absorption of soft clay on the stability of the slope. The objectives of this study were to analyze the soil strength when the soil were soaked in water to a set of different time range and to analyze slope stability on soft clay based on the infiltration of water from underground using PLAXIS software. In this study, soil samples were taken and laboratory experiments were carried out to obtain the unit weight, cohesion, and friction angle of the soil samples. The experiments involved were grain size analysis test and unconfined compression test. Data from the experiments will be used in PLAXIS software to obtain the factor of safety.

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