ABSTRACT Increasing attention is being given to climate technologies on the international climate... more ABSTRACT Increasing attention is being given to climate technologies on the international climate change agenda, not least in the agricultural sector and water sectors, and to technologies for adaptation. However investments in technology-based adaptation (seeds, dams, irrigation, etc.) are complicated by the fact that it remains difficult to predict future climate change impacts, especially on a local scale. In addition, evidence for the costs and benefits of implementing adaptation technologies is relatively limited. The analysis presented in this paper shows that there is a large potential for integrating adaptation technologies into the planning and implementation of on-going and future projects. Based on local-level data from a technology needs assessment project in Lebanon, this paper presents two examples of the economic feasibility of implementing adaptation technologies in the agricultural and water sectors. The results show that the technologies can be applied at low cost and with relatively little effort.
* Simple models of light interception are useful to identify the key structural parameters involv... more * Simple models of light interception are useful to identify the key structural parameters involved in light capture. We developed such models for isolated trees and tested them with virtual experiments. Light interception was decomposed into the projection of the crown envelope and the crown porosity. The latter was related to tree structure parameters. * Virtual experiments were conducted with three-dimensional (3-D) digitized apple trees grown in Lebanon and Switzerland, with different cultivars and training. The digitized trees allowed actual values of canopy structure (total leaf area, crown volume, foliage inclination angle, variance of leaf area density) and light interception properties (projected leaf area, silhouette to total area ratio, porosity, dispersion parameters) to be computed, and relationships between structure and interception variables to be derived. * The projected envelope area was related to crown volume with a power function of exponent 2/3. Crown porosity was a negative exponential function of mean optical density, that is, the ratio between total leaf area and the projected envelope area. The leaf dispersion parameter was a negative linear function of the relative variance of leaf area density in the crown volume. * The resulting models were expressed as two single equations. After calibration, model outputs were very close to values computed from the 3-D digitized databases.
This study contributes in listing and understanding the distribution of riparian species accordin... more This study contributes in listing and understanding the distribution of riparian species according to environmental and anthropogenic factors, recognizing the impact of these factors on biodiversity and tree growth and conducting an easy method for the assessment of habitat quality in a typical riparian ecosystem in the Eastern Mediterranean Basin. The methodology involved field assessment and the evaluation of riparian habitat quality by giving scores to different criteria, composing the habitat quality index. The results showed that river channel deviation is the most significant factor affecting riparian habitat quality. Non disturbed sites have significant higher scores, yet they are not classified as in natural conditions due to the effect of intrinsic environmental factors on habitat quality, namely bioclimatic conditions and river flow regime. An increase of biodiversity was recorded when habitat quality improved. Higher riparian habitat quality resulted in the presence of old growth trees, and climax species. This study allowed us to assess the requirements of major riparian species in terms of habitat quality, and to classify them based on their functional adaptation, in order to adopt appropriate ecosystem restoration and conservation plans.
The taxonomy of oaks in Lebanon relies on the works of Mouterde (1966). Since half a centrury, th... more The taxonomy of oaks in Lebanon relies on the works of Mouterde (1966). Since half a centrury, there were no taxonomic revision for these species, namely for Quercus pinnatifida Gmelin, which is no more in use worldwide after successive nomenclature revisions. This name was replaced by Quercus pubescens Willd. subsp. pubescens which has never been recorded in Lebanon. However, Quercus kotschyana O. Schwarz is cited as an en-demic species of Lebanon, but it was never mentioned by Mouterde works, nor by the literature that followed (i.e. Abi Saleh, 1976, 1996; Menitsky, 2005; Tohme & Tohme, 2014). This work aims at revealing the taxonomy of an endemic oak of Lebanon, and clarify the existing confusion in the nomenclature of species. The comparison of collected plant material from different sites, with the holotype of Quercus kotschyana, and the botanical description and drawings found in the literature, allowed us to conclude that Quercus pinnatifida Gmel. was wrongly attributed to the taxon found in Lebanon, and that the actual present species is Quercus kotschyana O. Schwarz.
ABSTRACT Increasing attention is being given to climate technologies on the international climate... more ABSTRACT Increasing attention is being given to climate technologies on the international climate change agenda, not least in the agricultural sector and water sectors, and to technologies for adaptation. However investments in technology-based adaptation (seeds, dams, irrigation, etc.) are complicated by the fact that it remains difficult to predict future climate change impacts, especially on a local scale. In addition, evidence for the costs and benefits of implementing adaptation technologies is relatively limited. The analysis presented in this paper shows that there is a large potential for integrating adaptation technologies into the planning and implementation of on-going and future projects. Based on local-level data from a technology needs assessment project in Lebanon, this paper presents two examples of the economic feasibility of implementing adaptation technologies in the agricultural and water sectors. The results show that the technologies can be applied at low cost and with relatively little effort.
* Simple models of light interception are useful to identify the key structural parameters involv... more * Simple models of light interception are useful to identify the key structural parameters involved in light capture. We developed such models for isolated trees and tested them with virtual experiments. Light interception was decomposed into the projection of the crown envelope and the crown porosity. The latter was related to tree structure parameters. * Virtual experiments were conducted with three-dimensional (3-D) digitized apple trees grown in Lebanon and Switzerland, with different cultivars and training. The digitized trees allowed actual values of canopy structure (total leaf area, crown volume, foliage inclination angle, variance of leaf area density) and light interception properties (projected leaf area, silhouette to total area ratio, porosity, dispersion parameters) to be computed, and relationships between structure and interception variables to be derived. * The projected envelope area was related to crown volume with a power function of exponent 2/3. Crown porosity was a negative exponential function of mean optical density, that is, the ratio between total leaf area and the projected envelope area. The leaf dispersion parameter was a negative linear function of the relative variance of leaf area density in the crown volume. * The resulting models were expressed as two single equations. After calibration, model outputs were very close to values computed from the 3-D digitized databases.
This study contributes in listing and understanding the distribution of riparian species accordin... more This study contributes in listing and understanding the distribution of riparian species according to environmental and anthropogenic factors, recognizing the impact of these factors on biodiversity and tree growth and conducting an easy method for the assessment of habitat quality in a typical riparian ecosystem in the Eastern Mediterranean Basin. The methodology involved field assessment and the evaluation of riparian habitat quality by giving scores to different criteria, composing the habitat quality index. The results showed that river channel deviation is the most significant factor affecting riparian habitat quality. Non disturbed sites have significant higher scores, yet they are not classified as in natural conditions due to the effect of intrinsic environmental factors on habitat quality, namely bioclimatic conditions and river flow regime. An increase of biodiversity was recorded when habitat quality improved. Higher riparian habitat quality resulted in the presence of old growth trees, and climax species. This study allowed us to assess the requirements of major riparian species in terms of habitat quality, and to classify them based on their functional adaptation, in order to adopt appropriate ecosystem restoration and conservation plans.
The taxonomy of oaks in Lebanon relies on the works of Mouterde (1966). Since half a centrury, th... more The taxonomy of oaks in Lebanon relies on the works of Mouterde (1966). Since half a centrury, there were no taxonomic revision for these species, namely for Quercus pinnatifida Gmelin, which is no more in use worldwide after successive nomenclature revisions. This name was replaced by Quercus pubescens Willd. subsp. pubescens which has never been recorded in Lebanon. However, Quercus kotschyana O. Schwarz is cited as an en-demic species of Lebanon, but it was never mentioned by Mouterde works, nor by the literature that followed (i.e. Abi Saleh, 1976, 1996; Menitsky, 2005; Tohme & Tohme, 2014). This work aims at revealing the taxonomy of an endemic oak of Lebanon, and clarify the existing confusion in the nomenclature of species. The comparison of collected plant material from different sites, with the holotype of Quercus kotschyana, and the botanical description and drawings found in the literature, allowed us to conclude that Quercus pinnatifida Gmel. was wrongly attributed to the taxon found in Lebanon, and that the actual present species is Quercus kotschyana O. Schwarz.
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Papers by Jean Stephan