Estimating Wind Damage in Forested Areas Due to Tornadoes
Research Highlights: Simulations of treefall patterns during tornado events have been conducted, enabling the coupled effects of tornado characteristics, tree properties and soil conditions to be assessed for the first time. Background and Objectives: Treefall patterns and forest damage assessed in...
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| Format: | Article |
| Language: | English |
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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/1999-4907/12/1/17 |
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| author | Mohamed A. Mansour Daniel M. Rhee Timothy Newson Chris Peterson Franklin T. Lombardo |
| author_facet | Mohamed A. Mansour Daniel M. Rhee Timothy Newson Chris Peterson Franklin T. Lombardo |
| author_sort | Mohamed A. Mansour |
| collection | DOAJ |
| description | Research Highlights: Simulations of treefall patterns during tornado events have been conducted, enabling the coupled effects of tornado characteristics, tree properties and soil conditions to be assessed for the first time. Background and Objectives: Treefall patterns and forest damage assessed in post-storm surveys are dependent on the interaction between topography, biology and meteorology, which makes identification of characteristic behavior challenging. Much of our knowledge of tree damage during extreme winds is based on synoptic storms. Better characterization of tree damage will provide more knowledge of tornado impacts on forests, as well as their ecological significance. Materials and Methods: a numerical method based on a Rankine vortex model coupled with two mechanistic tree models for critical wind velocity for stem break and windthrow was used to simulate tornadic tree damage. To calibrate the models, a treefall analysis of the Alonsa tornado was used. Parametric study was conducted to assess induced tornadic tree failure patterns for uprooting on saturated and unsaturated soils and stem break with different knot factors. Results: A power law relationship between failure bending moments and diameter at breast height (DBH) for the hardwood species provided the best correlation. Observed failure distributions of stem break and windthrow along the tornado track were fitted to lognormal distributions and the mean of the critical wind speeds for windthrow were found to be higher than that for stem break. Relationships between critical wind speed and tree size were negatively correlated for windthrow and positively correlated for stem break. Higher soil moisture contents and lower knot factors reduced the critical wind speeds. The simulations show varying tree fall patterns displaying forward and backward convergence, different tornado damage widths and asymmetry of the tracks. These variations were controlled by the relative magnitudes of radial and tangential tornado velocities, the ratio between translational speed and maximum rotational wind speed and the mode of failure of the trees. Conclusions: The results show the complexity of predicting tornadic damage in forests, and it is anticipated that this type of simulation will aid risk assessments for insurance companies, emergency managers and forest authorities. |
| first_indexed | 2024-03-10T13:47:02Z |
| format | Article |
| id | doaj.art-fafe297405d748a59b2f39975408ff69 |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T13:47:02Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-fafe297405d748a59b2f39975408ff692023-11-21T02:32:56ZengMDPI AGForests1999-49072020-12-011211710.3390/f12010017Estimating Wind Damage in Forested Areas Due to TornadoesMohamed A. Mansour0Daniel M. Rhee1Timothy Newson2Chris Peterson3Franklin T. Lombardo4Department of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, CanadaDepartment of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USADepartment of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, CanadaDepartment of Plant Biology, University of Georgia, Athens, GA 30602, USADepartment of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USAResearch Highlights: Simulations of treefall patterns during tornado events have been conducted, enabling the coupled effects of tornado characteristics, tree properties and soil conditions to be assessed for the first time. Background and Objectives: Treefall patterns and forest damage assessed in post-storm surveys are dependent on the interaction between topography, biology and meteorology, which makes identification of characteristic behavior challenging. Much of our knowledge of tree damage during extreme winds is based on synoptic storms. Better characterization of tree damage will provide more knowledge of tornado impacts on forests, as well as their ecological significance. Materials and Methods: a numerical method based on a Rankine vortex model coupled with two mechanistic tree models for critical wind velocity for stem break and windthrow was used to simulate tornadic tree damage. To calibrate the models, a treefall analysis of the Alonsa tornado was used. Parametric study was conducted to assess induced tornadic tree failure patterns for uprooting on saturated and unsaturated soils and stem break with different knot factors. Results: A power law relationship between failure bending moments and diameter at breast height (DBH) for the hardwood species provided the best correlation. Observed failure distributions of stem break and windthrow along the tornado track were fitted to lognormal distributions and the mean of the critical wind speeds for windthrow were found to be higher than that for stem break. Relationships between critical wind speed and tree size were negatively correlated for windthrow and positively correlated for stem break. Higher soil moisture contents and lower knot factors reduced the critical wind speeds. The simulations show varying tree fall patterns displaying forward and backward convergence, different tornado damage widths and asymmetry of the tracks. These variations were controlled by the relative magnitudes of radial and tangential tornado velocities, the ratio between translational speed and maximum rotational wind speed and the mode of failure of the trees. Conclusions: The results show the complexity of predicting tornadic damage in forests, and it is anticipated that this type of simulation will aid risk assessments for insurance companies, emergency managers and forest authorities.https://www.mdpi.com/1999-4907/12/1/17tornadotreefallvortexwind speedstreeroot |
| spellingShingle | Mohamed A. Mansour Daniel M. Rhee Timothy Newson Chris Peterson Franklin T. Lombardo Estimating Wind Damage in Forested Areas Due to Tornadoes Forests tornado treefall vortex wind speeds tree root |
| title | Estimating Wind Damage in Forested Areas Due to Tornadoes |
| title_full | Estimating Wind Damage in Forested Areas Due to Tornadoes |
| title_fullStr | Estimating Wind Damage in Forested Areas Due to Tornadoes |
| title_full_unstemmed | Estimating Wind Damage in Forested Areas Due to Tornadoes |
| title_short | Estimating Wind Damage in Forested Areas Due to Tornadoes |
| title_sort | estimating wind damage in forested areas due to tornadoes |
| topic | tornado treefall vortex wind speeds tree root |
| url | https://www.mdpi.com/1999-4907/12/1/17 |
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