Ramzi Touchan
Biographic Data
| ID | 5598788 |
|---|---|
| NAME | Ramzi Touchan |
| GIVEN NAMES | Ramzi |
| FAMILY NAME | Touchan |
| SIGNATURE | TOUCHAN R |
| AFFILIATIONS | University of Arizona |
| ORCID | 0000-0003-1263-3692 |
| VERIFIED | Yes |
| TOTAL WORKS | 24 |
| TOTAL CITATIONS | 10 |
| AUTHOR COUNT | 24 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1999 |
| LATEST PUBLICATION YEAR | 2024 |
| H-INDEX | 3 |
Precipitation Reconstruction Using Tree-Ring Chronologies from Jordan and the Eastern Mediterranean Region
An international summer course in dendrochronology, “Tree Rings, Climate, Natural Resources, and Human Interaction”, was held in Amman, Jordan, in summer 2023. Drs. Ramzi Touchan and David M. Meko from the University of Arizona Laboratory of Tree-Ring Research were course instructors. The course, with 10 students from Jordan, Algeria, Tunisia, Pakistan, Greece, and the USA, included training in core-sample collection, sample preparation, crossdat…
Analysis of the Climate Signal in Subannual Width Measurements of Pinus nigra Tree Rings in Kastamonu Province, Turkey
Black pine (Pinus nigra) is a widely distributed tree species across southern Europe and Asia Minor. This article summarizes a dendroclimatological study of subannual P. nigra ring width conducted during an international summer course “Tree Rings, Climate, Natural Resources, and Human Interaction” in 2022. Increment cores were collected from 15 young (oldest 105 years) P. nigra trees in the Araç Forest District in Kastamonu Province, Turkey. Site…
PDSI Reconstruction from Tree Rings in Central Siberia (Russia)
This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Cheriomushki, Russia, in the summer of 2018. The course was attended by 12 participants from six countries (Belgium, India, Lebanon, Poland, Russia, and South Africa) and instructors from the USA and included basic training in dendrochronology skills and dendroclimatology and dendroecology projects. This report focuses on…
Oceanic Influence on Chiricahua Mountains Drought Observed in a 383-Year Douglas-Fir Reconstruction
Drought in the North American Southwest is a recurring phenomenon. The knowledge of drought recurrence and severity is crucial for sustainable water resource management in the region. Tree-ring reconstructions of climate variables provide valuable indirect evidence of climate variability and elucidate the relationship between large-scale circulation anomalies and the climate in the region. Here we have developed a May–July Palmer Drought Severity…
A multi-century Sierra Nevada snowpack reconstruction modeled using upper-elevation coniferous tree rings (California, USA)
Snowpack in the Sierra Nevada Mountains accounts for around one-third of California’s water supply. Melting snow provides water into dry summer months characteristic of the region’s Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response is critical in this region of agricultural, recreational, and ecological value. Here we investigated the relationships between tree rings of montane conife…
Two Reconstructions of August–july Precipitation for Central Northern Arizona From Tree Rings
This study reports two multi-century regional reconstructions of annual precipitation based on Pinus ponderosa and P. edulis from four sites in central northern Arizona. It compares standard regional and time-nested methods to generate reconstructions from 1581–2016 C.E. and 1529–2016 C.E., respectively. The strongest climate relationship is a positive correlation between total ring width and 12-month total precipitation ending in July of the gro…
Tree growth and vegetation activity at the ecosystem-scale in the eastern Mediterranean
Linking annual tree growth with remotely-sensed terrestrial vegetation indices provides a basis for using tree rings as proxies for ecosystem primary productivity over large spatial and long temporal scales. In contrast with most previous tree ring/remote sensing studies that have focused on temperature-limited boreal and taiga environments, here we compare the normalized difference vegetation index (NDVI) with a network of Pinus brutia tree ring…
Climate controls on tree growth in the Western Mediterranean
The first large-scale network of tree-ring chronologies from the western Mediterranean (WM; 32°N–43°N, 10°W–17°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation and rotated empirical orthogonal function analyses are applied to 85 tree-ring series and corresponding gridded climate data to assess the climate signal embedded in the network. Chronologies range in length from 80 to 1129 …
Precipitation reconstruction for the Khakassia region, Siberia, from tree rings
A nested July–June precipitation reconstruction for the period AD 1777–2012 was developed from multi-century tree-ring records of Pinus sylvestris L. (Scots pine) for the Republic of Khakassia in Siberia, Russia. Calibration and verification statistics for the period 1948–2012 show a high level of skill and account for a significant portion of the observed variance (>50%) irrespective of which period is used to develop or verify the regression mo…
Elevation-layered dendroclimatic signal in eastern Mediterranean tree rings
Networks of tree-ring data are commonly applied in statistical reconstruction of spatial fields of climate variables. The importance of elevation to the climatic interpretation of tree-ring networks is addressed using 281 station precipitation records, and a network of 79 tree-ring chronologies from different species and a range of elevations in the eastern Mediterranean. Cluster analysis of chronologies identifies 6 tree-ring groups, delineated …
August to July Precipitation from Tree Rings in the Forest-Steppe Zone of Central Siberia (Russia)
The goal of this research report is to describe annual precipitation reconstruction from Pinus sylvestris trees on three sites in the Abakan region, located in the Minusinsk Depression, at the confluence of the Yenisei and Abakan Rivers, Russia. The study was performed during the 4th annual international summer course “Tree Rings, Climate, Natural Resources and Human Interaction” held in Abakan, 5-19 August 2013. The reconstruction, for the 12-mo…
Old World megadroughts and pluvials during the Common Era
An atlas of megadroughts in Europe and in the Mediterranean Basin during the Common Era provides insights into climate variability.
Alternative standardization approaches to improving streamflow reconstructions with ring-width indices of riparian trees
Old, multi-aged populations of riparian trees provide an opportunity to improve reconstructions of streamflow. Here, ring widths of 394 plains cottonwood ( Populus deltoides, ssp. monilifera) trees in the North Unit of Theodore Roosevelt National Park, North Dakota, are used to reconstruct streamflow along the Little Missouri River (LMR), North Dakota, US. Different versions of the cottonwood chronology are developed by (1) age-curve standardizat…
Spatial patterns of eastern Mediterranean climate influence on tree growth
The first large-scale network of 79 tree-ring chronologies in the Eastern Mediterranean and Near East (EMNE; 33°N–42°N, 21°E–43°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation analysis and cluster analysis are applied to tree-ring data and gridded climate data to assess the climate signal embedded in the network in preparation for climate field reconstructions and formal proxy/mod…
Dendroclimatology in the Eastern Mediterranean
Dendroclimatology in the Eastern Mediterranean (EM) region has made important contributions to the understanding of climate variability on timescales of decades to centuries. These contributions, beginning in the mid-20th century, have value for resource management, archaeology, and climatology. A gradually expanding tree-ring network developed by the first author over the past 15 years has been the framework for some of the most important recent…
Dendrochronology Course In Valsaín Forest, Segovia, Spain
This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Valsaín, Spain, in summer of 2012. The course, with 14 participants from three countries (Spain, Algeria, and Russia), included basic training in dendrochronology skills as well as applied projects in dendroclimatology, dendroecology and dendrogeomorphology.
Monsoon precipitation reconstructed from tree rings in the southwestern United States
Fire History In European Black Pine (Pinus nigra Arn.) Forests of the Valia Kalda, Pindus Mountains, Greece
The past fire regime of European black pine (Pinus nigra Arn.) forests in Valia Kalda in Greece was investigated by standard dendrochronology methods. The sampled trees contained a record of fires from the early 14th Century through the late 19th Century with the last fire recorded in 1891. Evidence of non-lethal surface fires over the past seven centuries suggests that in addition to its destructive power, fire also plays a role in ecological fu…
Latewood Chronology Development for Summer-Moisture Reconstruction In the US Southwest
Tree-ring studies have demonstrated that conifer latewood measurements contain information on long-term North American monsoon (NAM) variability, a hydroclimatic feature of great importance to plants, animals, and human society in the US Southwest. This paper explores data-treatment options for developing latewood chronologies aimed at NAM reconstruction. Archived wood samples for five Douglas-fir (Pseudotsuga menziesii, Mirb. Franco) sites in so…
The North American monsoon in the U.S. Southwest
Towards a reconstruction of Blue Nile baseflow from Ethiopian tree rings
Most of the water in the River Nile originates from monsoonal rainfall over the Ethiopian Highlands. Despite warnings of future climate change, little is known about the historical variability in this supply, particularly at annual resolution. Development of tree-ring records in this region has been limited by the occurrence of bi- or multimodal rainfall regimes, causing the development of multiple growth rings that cannot be dated with confidenc…
May–June precipitation reconstruction of southwestern anatolia, Turkey during the last 900 years from tree rings
A May–June precipitation reconstruction (AD 1097–2000) has been developed for southwestern Anatolia in Turkey, the longest reported to date in this region. The reconstruction was derived from a regional Juniperus excelsa chronology that was built from material sampled at four sites in the Antalya and Mersin Districts. The regional tree-ring chronology accounts for 51% of the variance of instrumentally observed May–June precipitation. The years AD…
Exploratory Temperature and Precipitation Reconstructions from the Qinling Mountains, North-Central China
February–April (FMA) temperature at Foping (1879–1989) and July–August (JA) precipitation at Xian (1895–1988) have been reconstructed using total ring width (TRW) and maximum latewood density (MXD) from trees in the Qinling Mountains, at the northern limit of the East Asian monsoon, in central China. The Xian JA precipitation reconstruction, albeit short, represents the first well-replicated, crossdated dendroclimatic reconstruction of summer mon…
Twentieth-century summer warmth in northern Yakutia in a 600-year context
We report unusual twentieth-century early-summer warmth recorded by larch tree-rings at the north ern tree-line in far northeastern Eurasia (Yakutia). The tree-ring series are strongly replicated and well suited to the detection of fluctuations on interannual to century timescales. They are strongly correlated with local instrumental temperature data. Mean early-summer temperature in the twentieth century significantly exceeds that of any period …
Spatial patterns of eastern Mediterranean climate influence on tree growth
The first large-scale network of 79 tree-ring chronologies in the Eastern Mediterranean and Near East (EMNE; 33°N–42°N, 21°E–43°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation analysis and cluster analysis are applied to tree-ring data and gridded climate data to assess the climate signal embedded in the network in preparation for climate field reconstructions and formal proxy/mod…
Towards a reconstruction of Blue Nile baseflow from Ethiopian tree rings
Most of the water in the River Nile originates from monsoonal rainfall over the Ethiopian Highlands. Despite warnings of future climate change, little is known about the historical variability in this supply, particularly at annual resolution. Development of tree-ring records in this region has been limited by the occurrence of bi- or multimodal rainfall regimes, causing the development of multiple growth rings that cannot be dated with confidenc…
Twentieth-century summer warmth in northern Yakutia in a 600-year context
We report unusual twentieth-century early-summer warmth recorded by larch tree-rings at the north ern tree-line in far northeastern Eurasia (Yakutia). The tree-ring series are strongly replicated and well suited to the detection of fluctuations on interannual to century timescales. They are strongly correlated with local instrumental temperature data. Mean early-summer temperature in the twentieth century significantly exceeds that of any period …
A multi-century Sierra Nevada snowpack reconstruction modeled using upper-elevation coniferous tree rings (California, USA)
Snowpack in the Sierra Nevada Mountains accounts for around one-third of California’s water supply. Melting snow provides water into dry summer months characteristic of the region’s Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response is critical in this region of agricultural, recreational, and ecological value. Here we investigated the relationships between tree rings of montane conife…
Twentieth-century summer warmth in northern Yakutia in a 600-year context
We report unusual twentieth-century early-summer warmth recorded by larch tree-rings at the north ern tree-line in far northeastern Eurasia (Yakutia). The tree-ring series are strongly replicated and well suited to the detection of fluctuations on interannual to century timescales. They are strongly correlated with local instrumental temperature data. Mean early-summer temperature in the twentieth century significantly exceeds that of any period …
Exploratory Temperature and Precipitation Reconstructions from the Qinling Mountains, North-Central China
February–April (FMA) temperature at Foping (1879–1989) and July–August (JA) precipitation at Xian (1895–1988) have been reconstructed using total ring width (TRW) and maximum latewood density (MXD) from trees in the Qinling Mountains, at the northern limit of the East Asian monsoon, in central China. The Xian JA precipitation reconstruction, albeit short, represents the first well-replicated, crossdated dendroclimatic reconstruction of summer mon…
May–June precipitation reconstruction of southwestern anatolia, Turkey during the last 900 years from tree rings
A May–June precipitation reconstruction (AD 1097–2000) has been developed for southwestern Anatolia in Turkey, the longest reported to date in this region. The reconstruction was derived from a regional Juniperus excelsa chronology that was built from material sampled at four sites in the Antalya and Mersin Districts. The regional tree-ring chronology accounts for 51% of the variance of instrumentally observed May–June precipitation. The years AD…
The North American monsoon in the U.S. Southwest
Towards a reconstruction of Blue Nile baseflow from Ethiopian tree rings
Most of the water in the River Nile originates from monsoonal rainfall over the Ethiopian Highlands. Despite warnings of future climate change, little is known about the historical variability in this supply, particularly at annual resolution. Development of tree-ring records in this region has been limited by the occurrence of bi- or multimodal rainfall regimes, causing the development of multiple growth rings that cannot be dated with confidenc…
Latewood Chronology Development for Summer-Moisture Reconstruction In the US Southwest
Tree-ring studies have demonstrated that conifer latewood measurements contain information on long-term North American monsoon (NAM) variability, a hydroclimatic feature of great importance to plants, animals, and human society in the US Southwest. This paper explores data-treatment options for developing latewood chronologies aimed at NAM reconstruction. Archived wood samples for five Douglas-fir (Pseudotsuga menziesii, Mirb. Franco) sites in so…
Fire History In European Black Pine (Pinus nigra Arn.) Forests of the Valia Kalda, Pindus Mountains, Greece
The past fire regime of European black pine (Pinus nigra Arn.) forests in Valia Kalda in Greece was investigated by standard dendrochronology methods. The sampled trees contained a record of fires from the early 14th Century through the late 19th Century with the last fire recorded in 1891. Evidence of non-lethal surface fires over the past seven centuries suggests that in addition to its destructive power, fire also plays a role in ecological fu…
Dendrochronology Course In Valsaín Forest, Segovia, Spain
This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Valsaín, Spain, in summer of 2012. The course, with 14 participants from three countries (Spain, Algeria, and Russia), included basic training in dendrochronology skills as well as applied projects in dendroclimatology, dendroecology and dendrogeomorphology.
Monsoon precipitation reconstructed from tree rings in the southwestern United States
Spatial patterns of eastern Mediterranean climate influence on tree growth
The first large-scale network of 79 tree-ring chronologies in the Eastern Mediterranean and Near East (EMNE; 33°N–42°N, 21°E–43°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation analysis and cluster analysis are applied to tree-ring data and gridded climate data to assess the climate signal embedded in the network in preparation for climate field reconstructions and formal proxy/mod…
Dendroclimatology in the Eastern Mediterranean
Dendroclimatology in the Eastern Mediterranean (EM) region has made important contributions to the understanding of climate variability on timescales of decades to centuries. These contributions, beginning in the mid-20th century, have value for resource management, archaeology, and climatology. A gradually expanding tree-ring network developed by the first author over the past 15 years has been the framework for some of the most important recent…
August to July Precipitation from Tree Rings in the Forest-Steppe Zone of Central Siberia (Russia)
The goal of this research report is to describe annual precipitation reconstruction from Pinus sylvestris trees on three sites in the Abakan region, located in the Minusinsk Depression, at the confluence of the Yenisei and Abakan Rivers, Russia. The study was performed during the 4th annual international summer course “Tree Rings, Climate, Natural Resources and Human Interaction” held in Abakan, 5-19 August 2013. The reconstruction, for the 12-mo…
Old World megadroughts and pluvials during the Common Era
An atlas of megadroughts in Europe and in the Mediterranean Basin during the Common Era provides insights into climate variability.
Alternative standardization approaches to improving streamflow reconstructions with ring-width indices of riparian trees
Old, multi-aged populations of riparian trees provide an opportunity to improve reconstructions of streamflow. Here, ring widths of 394 plains cottonwood ( Populus deltoides, ssp. monilifera) trees in the North Unit of Theodore Roosevelt National Park, North Dakota, are used to reconstruct streamflow along the Little Missouri River (LMR), North Dakota, US. Different versions of the cottonwood chronology are developed by (1) age-curve standardizat…
Elevation-layered dendroclimatic signal in eastern Mediterranean tree rings
Networks of tree-ring data are commonly applied in statistical reconstruction of spatial fields of climate variables. The importance of elevation to the climatic interpretation of tree-ring networks is addressed using 281 station precipitation records, and a network of 79 tree-ring chronologies from different species and a range of elevations in the eastern Mediterranean. Cluster analysis of chronologies identifies 6 tree-ring groups, delineated …
Tree growth and vegetation activity at the ecosystem-scale in the eastern Mediterranean
Linking annual tree growth with remotely-sensed terrestrial vegetation indices provides a basis for using tree rings as proxies for ecosystem primary productivity over large spatial and long temporal scales. In contrast with most previous tree ring/remote sensing studies that have focused on temperature-limited boreal and taiga environments, here we compare the normalized difference vegetation index (NDVI) with a network of Pinus brutia tree ring…
Climate controls on tree growth in the Western Mediterranean
The first large-scale network of tree-ring chronologies from the western Mediterranean (WM; 32°N–43°N, 10°W–17°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation and rotated empirical orthogonal function analyses are applied to 85 tree-ring series and corresponding gridded climate data to assess the climate signal embedded in the network. Chronologies range in length from 80 to 1129 …
Precipitation reconstruction for the Khakassia region, Siberia, from tree rings
A nested July–June precipitation reconstruction for the period AD 1777–2012 was developed from multi-century tree-ring records of Pinus sylvestris L. (Scots pine) for the Republic of Khakassia in Siberia, Russia. Calibration and verification statistics for the period 1948–2012 show a high level of skill and account for a significant portion of the observed variance (>50%) irrespective of which period is used to develop or verify the regression mo…
Two Reconstructions of August–july Precipitation for Central Northern Arizona From Tree Rings
This study reports two multi-century regional reconstructions of annual precipitation based on Pinus ponderosa and P. edulis from four sites in central northern Arizona. It compares standard regional and time-nested methods to generate reconstructions from 1581–2016 C.E. and 1529–2016 C.E., respectively. The strongest climate relationship is a positive correlation between total ring width and 12-month total precipitation ending in July of the gro…
A multi-century Sierra Nevada snowpack reconstruction modeled using upper-elevation coniferous tree rings (California, USA)
Snowpack in the Sierra Nevada Mountains accounts for around one-third of California’s water supply. Melting snow provides water into dry summer months characteristic of the region’s Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response is critical in this region of agricultural, recreational, and ecological value. Here we investigated the relationships between tree rings of montane conife…
Oceanic Influence on Chiricahua Mountains Drought Observed in a 383-Year Douglas-Fir Reconstruction
Drought in the North American Southwest is a recurring phenomenon. The knowledge of drought recurrence and severity is crucial for sustainable water resource management in the region. Tree-ring reconstructions of climate variables provide valuable indirect evidence of climate variability and elucidate the relationship between large-scale circulation anomalies and the climate in the region. Here we have developed a May–July Palmer Drought Severity…
PDSI Reconstruction from Tree Rings in Central Siberia (Russia)
This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Cheriomushki, Russia, in the summer of 2018. The course was attended by 12 participants from six countries (Belgium, India, Lebanon, Poland, Russia, and South Africa) and instructors from the USA and included basic training in dendrochronology skills and dendroclimatology and dendroecology projects. This report focuses on…
Analysis of the Climate Signal in Subannual Width Measurements of Pinus nigra Tree Rings in Kastamonu Province, Turkey
Black pine (Pinus nigra) is a widely distributed tree species across southern Europe and Asia Minor. This article summarizes a dendroclimatological study of subannual P. nigra ring width conducted during an international summer course “Tree Rings, Climate, Natural Resources, and Human Interaction” in 2022. Increment cores were collected from 15 young (oldest 105 years) P. nigra trees in the Araç Forest District in Kastamonu Province, Turkey. Site…
Precipitation Reconstruction Using Tree-Ring Chronologies from Jordan and the Eastern Mediterranean Region
An international summer course in dendrochronology, “Tree Rings, Climate, Natural Resources, and Human Interaction”, was held in Amman, Jordan, in summer 2023. Drs. Ramzi Touchan and David M. Meko from the University of Arizona Laboratory of Tree-Ring Research were course instructors. The course, with 10 students from Jordan, Algeria, Tunisia, Pakistan, Greece, and the USA, included training in core-sample collection, sample preparation, crossdat…
Geography (24 works) · Tree-ring climate responses (23 works) · Dendrochronology (22 works) · Plant Water Relations and Carbon Dynamics (22 works) · Physical geography (19 works) · Climatology (18 works) · Dendroclimatology (16 works) · Meteorology (14 works) · Archaeology (13 works) · Environmental Science (13 works)