Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China
The degree of mechanical reinforcement provided by plants depends upon its roots distribution in the soil and mechanical properties of the roots. The mechanical properties and distribution of root traits (root diameter and number) in the soil of the standing forest depends on the tree stem diameter....
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| Format: | Article |
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MDPI AG
2020-12-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/12/1/33 |
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| author | Alam Mehtab Yuan-Jun Jiang Li-Jun Su Sadiq Shamsher Jia-Jia Li Rahman Mahfuzur |
| author_facet | Alam Mehtab Yuan-Jun Jiang Li-Jun Su Sadiq Shamsher Jia-Jia Li Rahman Mahfuzur |
| author_sort | Alam Mehtab |
| collection | DOAJ |
| description | The degree of mechanical reinforcement provided by plants depends upon its roots distribution in the soil and mechanical properties of the roots. The mechanical properties and distribution of root traits (root diameter and number) in the soil of the standing forest depends on the tree stem diameter. This variation of root traits with tree stem diameter is rarely investigated. Therefore, this research presents the effect of tree stem diameter on the distribution of roots within the standing forest of <i>Cunninghamia</i> in the Longchi forest area, Sichuan province, China. In this area, shallow landslides take place frequently. We investigated the root traits distribution for trees with different stem diameters, i.e., 220 mm, 320 mm, 450 mm, and 468 mm, to show the variation of roots distribution in the soil with stem diameter. The root architecture of the selected trees was studied by step excavation method of the root zone accompanied by measurement of roots physical parameters (roots number and roots diameter) and indices (roots area ratio (RAR), roots biomass (RB), and roots distribution (RD)). We measured the root’s maximum tensile strength by performing root tensile tests in the laboratory. The field and laboratory-measured data were used to estimate the root cohesion by both the commonly used model Wu and Waldron Model (WWM) and Fiber Bundle Model (FBM). The results indicate that the tree stem diameter correlates with both the root distribution and the tensile strength. The roots indices and root cohesion increase with an increase in the diameter of the tree. Further, RAR decreases with depth and lateral distance from the tree stem, while the maximum values were observed in 10 cm depth. The relationship between roots diameter and roots tensile strength is established through power function. The average root cohesion estimated for a tree with stem diameter 220 mm is 23 kPa, 29 kPa for 320 mm, 54 kPa for 450 mm, and 63 kPa for 460 mm. This effect of stem diameter on the increase of soil shear resistance should be considered while evaluating the stability of slopes in standing forests. The comparison between WWM and FBM for investigated species suggests that WWM estimates the cohesion values greater than FBM by 65%. |
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| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T13:41:37Z |
| publishDate | 2020-12-01 |
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| series | Forests |
| spelling | doaj.art-630c55cf1e5143aea01e750423f08ff42023-11-21T03:00:57ZengMDPI AGForests1999-49072020-12-011213310.3390/f12010033Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest ChinaAlam Mehtab0Yuan-Jun Jiang1Li-Jun Su2Sadiq Shamsher3Jia-Jia Li4Rahman Mahfuzur5Key Lab. of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, ChinaKey Lab. of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, ChinaKey Lab. of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, ChinaGhulam Ishaq Khan Institute of Engineering Sciences and Technology (GIKI) Topi, Swabi 23640, KPK, PakistanKey Lab. of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, ChinaKey Lab. of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, ChinaThe degree of mechanical reinforcement provided by plants depends upon its roots distribution in the soil and mechanical properties of the roots. The mechanical properties and distribution of root traits (root diameter and number) in the soil of the standing forest depends on the tree stem diameter. This variation of root traits with tree stem diameter is rarely investigated. Therefore, this research presents the effect of tree stem diameter on the distribution of roots within the standing forest of <i>Cunninghamia</i> in the Longchi forest area, Sichuan province, China. In this area, shallow landslides take place frequently. We investigated the root traits distribution for trees with different stem diameters, i.e., 220 mm, 320 mm, 450 mm, and 468 mm, to show the variation of roots distribution in the soil with stem diameter. The root architecture of the selected trees was studied by step excavation method of the root zone accompanied by measurement of roots physical parameters (roots number and roots diameter) and indices (roots area ratio (RAR), roots biomass (RB), and roots distribution (RD)). We measured the root’s maximum tensile strength by performing root tensile tests in the laboratory. The field and laboratory-measured data were used to estimate the root cohesion by both the commonly used model Wu and Waldron Model (WWM) and Fiber Bundle Model (FBM). The results indicate that the tree stem diameter correlates with both the root distribution and the tensile strength. The roots indices and root cohesion increase with an increase in the diameter of the tree. Further, RAR decreases with depth and lateral distance from the tree stem, while the maximum values were observed in 10 cm depth. The relationship between roots diameter and roots tensile strength is established through power function. The average root cohesion estimated for a tree with stem diameter 220 mm is 23 kPa, 29 kPa for 320 mm, 54 kPa for 450 mm, and 63 kPa for 460 mm. This effect of stem diameter on the increase of soil shear resistance should be considered while evaluating the stability of slopes in standing forests. The comparison between WWM and FBM for investigated species suggests that WWM estimates the cohesion values greater than FBM by 65%.https://www.mdpi.com/1999-4907/12/1/33standing forest treesslope stabilitylandslidetree stem diameterroot cohesionroot tensile strength |
| spellingShingle | Alam Mehtab Yuan-Jun Jiang Li-Jun Su Sadiq Shamsher Jia-Jia Li Rahman Mahfuzur Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China Forests standing forest trees slope stability landslide tree stem diameter root cohesion root tensile strength |
| title | Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China |
| title_full | Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China |
| title_fullStr | Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China |
| title_full_unstemmed | Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China |
| title_short | Scaling the Roots Mechanical Reinforcement in Plantation of <i>Cunninghamia</i> R. Br in Southwest China |
| title_sort | scaling the roots mechanical reinforcement in plantation of i cunninghamia i r br in southwest china |
| topic | standing forest trees slope stability landslide tree stem diameter root cohesion root tensile strength |
| url | https://www.mdpi.com/1999-4907/12/1/33 |
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