Pub Date : 2019-08-08DOI: 10.3959/1536-1098-75.2.152
R. D. Manzanedo, N. Pederson
ABSTRACT The use of tree-ring methods to study ecological processes, known as dendroecology, has been booming over the last decade. We believe that the incredible methodological strides in this subdiscipline over the last half century will be further advanced by purposefully integrating with other ecological subdisciplines and broadening the scope of dendroecology both in terms of methods and theory. Simultaneously, these efforts will greatly benefit a broad range of ecological disciplines through the incorporation of one of the greatest strengths of dendrochronology: highly-resolved ecological data that spans from seasons to centuries. Because these data are still alarmingly scarce in ecology but are crucial to understand the ecology of long-living organisms, we believe better integrating dendroecology and mainstream ecology will benefit both disciplines. We discuss five actions that can be readily embraced by the dendrochronological community to further advance the field while also making it more open for non-dendroecologists. These actions include: (i) promoting diverse or multi-discipline scientific collaborations and partnerships, (ii) diversifying dendroecological data sources, (iii) incorporating inference-based and hierarchical models to the dendroecological toolbox, (iv) improving and updating the global tree-ring databases, and (v) increasing the focus on ecological and evolutionary mechanisms in tree-ring-driven papers. We believe these actions will help facilitate a broad discussion on how to better integrate tree-ring-based ecology within mainstream ecology. We believe this has the potential to trigger major advancements in dendroecology, help resolve long-standing ecological questions and, ultimately, bring a new perspective and scale to ecological theory.
{"title":"TOWARDS A MORE ECOLOGICAL DENDROECOLOGY","authors":"R. D. Manzanedo, N. Pederson","doi":"10.3959/1536-1098-75.2.152","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.152","url":null,"abstract":"ABSTRACT The use of tree-ring methods to study ecological processes, known as dendroecology, has been booming over the last decade. We believe that the incredible methodological strides in this subdiscipline over the last half century will be further advanced by purposefully integrating with other ecological subdisciplines and broadening the scope of dendroecology both in terms of methods and theory. Simultaneously, these efforts will greatly benefit a broad range of ecological disciplines through the incorporation of one of the greatest strengths of dendrochronology: highly-resolved ecological data that spans from seasons to centuries. Because these data are still alarmingly scarce in ecology but are crucial to understand the ecology of long-living organisms, we believe better integrating dendroecology and mainstream ecology will benefit both disciplines. We discuss five actions that can be readily embraced by the dendrochronological community to further advance the field while also making it more open for non-dendroecologists. These actions include: (i) promoting diverse or multi-discipline scientific collaborations and partnerships, (ii) diversifying dendroecological data sources, (iii) incorporating inference-based and hierarchical models to the dendroecological toolbox, (iv) improving and updating the global tree-ring databases, and (v) increasing the focus on ecological and evolutionary mechanisms in tree-ring-driven papers. We believe these actions will help facilitate a broad discussion on how to better integrate tree-ring-based ecology within mainstream ecology. We believe this has the potential to trigger major advancements in dendroecology, help resolve long-standing ecological questions and, ultimately, bring a new perspective and scale to ecological theory.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"152 - 159"},"PeriodicalIF":1.6,"publicationDate":"2019-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43738104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-08DOI: 10.3959/1536-1098-75.2.101
A. Barbosa, D. Stahle, D. Burnette, M. Torbenson, E. Cook, Matthew J. Bunkers, G. Garfin, R. Villalba
ABSTRACT The meteorological factors involved in the formation of earlywood frost rings in Rocky Mountain bristlecone pine (Pinus aristata) have not been described in detail. This study used 51 tree-ring dated Rocky Mountain bristlecone pine trees growing at ca. 3500 m a.s.l. on Mt. Goliath, Colorado, to develop earlywood and latewood frost ring chronologies dating from 1930 to 2010 for investigation of the regional and large-scale weather anomalies responsible for these unusual growing season freeze events. The high-elevation meteorological station at Niwot Ridge, Colorado, was used to document the daily temperature anomalies most likely associated with these frost-damaged rings. NCEP-NCAR Reanalysis data were used to examine the synoptic meteorological conditions that tend to prevail during these unusual growing season temperature conditions. Earlywood frost rings occur during anomalous late-May and June freeze events in the Colorado Rockies associated with unseasonal mid-latitude circulation, including the penetration of a deep upper-level low pressure system and cold surface air temperatures into the west-central United States. The three latewood frost rings all occurred during September freeze events also associated with unseasonal and highly amplified mid-latitude circulation. The chronology of these early and late growing season freeze events may provide a useful independent check on daily temperature minima estimated with reanalysis techniques, and they can be extended into the pre-instrumental era thanks to the great age of Rocky Mountain bristlecone pine. Frost damage in Mt. Goliath bristlecone pine appears to be most frequent and severe in young trees found in the depressed tree line below a large cirque subject to intense cold air drainage. The development of the most detailed tree-ring records of past freeze events may therefore benefit from site selection in these cold air drainages, along with age-stratified tree sampling to ensure that the young and most frost susceptible age classes are well represented throughout the chronology.
{"title":"METEOROLOGICAL FACTORS ASSOCIATED WITH FROST RINGS IN ROCKY MOUNTAIN BRISTLECONE PINE AT MT. GOLIATH, COLORADO","authors":"A. Barbosa, D. Stahle, D. Burnette, M. Torbenson, E. Cook, Matthew J. Bunkers, G. Garfin, R. Villalba","doi":"10.3959/1536-1098-75.2.101","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.101","url":null,"abstract":"ABSTRACT The meteorological factors involved in the formation of earlywood frost rings in Rocky Mountain bristlecone pine (Pinus aristata) have not been described in detail. This study used 51 tree-ring dated Rocky Mountain bristlecone pine trees growing at ca. 3500 m a.s.l. on Mt. Goliath, Colorado, to develop earlywood and latewood frost ring chronologies dating from 1930 to 2010 for investigation of the regional and large-scale weather anomalies responsible for these unusual growing season freeze events. The high-elevation meteorological station at Niwot Ridge, Colorado, was used to document the daily temperature anomalies most likely associated with these frost-damaged rings. NCEP-NCAR Reanalysis data were used to examine the synoptic meteorological conditions that tend to prevail during these unusual growing season temperature conditions. Earlywood frost rings occur during anomalous late-May and June freeze events in the Colorado Rockies associated with unseasonal mid-latitude circulation, including the penetration of a deep upper-level low pressure system and cold surface air temperatures into the west-central United States. The three latewood frost rings all occurred during September freeze events also associated with unseasonal and highly amplified mid-latitude circulation. The chronology of these early and late growing season freeze events may provide a useful independent check on daily temperature minima estimated with reanalysis techniques, and they can be extended into the pre-instrumental era thanks to the great age of Rocky Mountain bristlecone pine. Frost damage in Mt. Goliath bristlecone pine appears to be most frequent and severe in young trees found in the depressed tree line below a large cirque subject to intense cold air drainage. The development of the most detailed tree-ring records of past freeze events may therefore benefit from site selection in these cold air drainages, along with age-stratified tree sampling to ensure that the young and most frost susceptible age classes are well represented throughout the chronology.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"101 - 115"},"PeriodicalIF":1.6,"publicationDate":"2019-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48535551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-08DOI: 10.3959/1536-1098-75.2.167
S. Leavitt, E. Cook, M. Hughes
Harold C. Fritts [known to many as “Hal”] passed away at his home in Tucson, Arizona, on January 10, 2019, at the age of 90. Hal was born December 17, 1928, in Rochester, New York, and was raised in the town of Pittsford where he developed a growing interest in nature. He attended Pittsford High School where he graduated as class salutatorian in 1947. Hal then enrolled at Oberlin College in Ohio where he earned his B.A. degree in 1951. Hal went on to graduate school at Ohio State University in Columbus, where he was awarded his M.Sc. in 1953 (Thesis:Radial Growth of Beech Trees in a Central Ohio Forest during 1952) and Ph.D. in 1956 (Dissertation: Relations of Radial Growth of Beech (Fagus grandifolia Ehrh.) to Some Environmental Factors in a Central Ohio Forest during 1954-55), both in botany. The primary instrument of his dissertation research was the “dendrograph” [named the Fritts-Dendrograph], developed with the help of his father, an engineer. One year before completing his Ph.D. Hal married his first wife Barbara June Smith. Hal took his first academic post as Assistant Professor at Eastern Illinois University in 1956. In 1960, he was appointed Assistant Professor of Dendrochronology at the University of Arizona, Laboratory of Tree-Ring Research (LTRR). His hire followed not long after the untimely death of LTRR Prof. Edmund Schulman in 1958. His early work examined intraand inter-annual treering growth of western conifers, aided by his dendrographs and cambial sampling. Moreover, he developed conceptual models of how various environmental factors could influence cell formation, maturation, and ring size, and eventually he began developing computer models of growth. This culminated in an advanced process model, TREERING, developed with Russian colleagues. These collective activities are tied to one of Hal’s enduring contributions to dendrochronology, namely that he injected scientific and computational rigor into the field and provided convincing quantitative validation to the underpinnings of dendrochronological principles. To this end, Hal also introduced
{"title":"In MemoriamHarold Clark Fritts 1928–2019","authors":"S. Leavitt, E. Cook, M. Hughes","doi":"10.3959/1536-1098-75.2.167","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.167","url":null,"abstract":"Harold C. Fritts [known to many as “Hal”] passed away at his home in Tucson, Arizona, on January 10, 2019, at the age of 90. Hal was born December 17, 1928, in Rochester, New York, and was raised in the town of Pittsford where he developed a growing interest in nature. He attended Pittsford High School where he graduated as class salutatorian in 1947. Hal then enrolled at Oberlin College in Ohio where he earned his B.A. degree in 1951. Hal went on to graduate school at Ohio State University in Columbus, where he was awarded his M.Sc. in 1953 (Thesis:Radial Growth of Beech Trees in a Central Ohio Forest during 1952) and Ph.D. in 1956 (Dissertation: Relations of Radial Growth of Beech (Fagus grandifolia Ehrh.) to Some Environmental Factors in a Central Ohio Forest during 1954-55), both in botany. The primary instrument of his dissertation research was the “dendrograph” [named the Fritts-Dendrograph], developed with the help of his father, an engineer. One year before completing his Ph.D. Hal married his first wife Barbara June Smith. Hal took his first academic post as Assistant Professor at Eastern Illinois University in 1956. In 1960, he was appointed Assistant Professor of Dendrochronology at the University of Arizona, Laboratory of Tree-Ring Research (LTRR). His hire followed not long after the untimely death of LTRR Prof. Edmund Schulman in 1958. His early work examined intraand inter-annual treering growth of western conifers, aided by his dendrographs and cambial sampling. Moreover, he developed conceptual models of how various environmental factors could influence cell formation, maturation, and ring size, and eventually he began developing computer models of growth. This culminated in an advanced process model, TREERING, developed with Russian colleagues. These collective activities are tied to one of Hal’s enduring contributions to dendrochronology, namely that he injected scientific and computational rigor into the field and provided convincing quantitative validation to the underpinnings of dendrochronological principles. To this end, Hal also introduced","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"167 - 169"},"PeriodicalIF":1.6,"publicationDate":"2019-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43619444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.3959/1536-1098-75.2.160
N. Davi, P. Pringle, J. Lockwood, F. Fiondella, R. Oelkers
ABSTRACT Here we describe five publicly available online labs, geared to undergraduate students, which focus on foundational tree-ring research. Students are introduced to basic dendrochronological concepts and practices (Lab 1) while learning about research that has implications for human well-being. Students learn about the way scientists use tree-ring records to reconstruct drought in the Hudson Valley in New York (Lab 2), how tree-ring science began through its utility in putting exact calendar dates on ancestral pueblos (Lab 3), how tree-ring records can be used to put drought into a long-term context, reconstruct streamflow, and better manage water resources (Lab 4), and how tree rings have been used to reconstruct temperatures in the northern latitudes (Lab 5). These labs have the dual aim of guiding students to use many of the same tools as tree-ring scientists, while also giving them a sense of the nature-of-science and how scientists work. Throughout the labs, students are guided to explore virtual field sites, navigate public databanks, observe and measure tree-ring samples, and describe trends and extremes in paleoclimate records. Labs are designed for a 2 to 3-hour lab class and have been classroom-tested and assessed by faculty teams and students.
{"title":"DENDRO-EDUCATION REPORTTREE-RING EXPEDITIONS (TREX): ONLINE LABS THAT GUIDE UNDERGRADS TO THINK LIKE SCIENTISTS","authors":"N. Davi, P. Pringle, J. Lockwood, F. Fiondella, R. Oelkers","doi":"10.3959/1536-1098-75.2.160","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.160","url":null,"abstract":"ABSTRACT Here we describe five publicly available online labs, geared to undergraduate students, which focus on foundational tree-ring research. Students are introduced to basic dendrochronological concepts and practices (Lab 1) while learning about research that has implications for human well-being. Students learn about the way scientists use tree-ring records to reconstruct drought in the Hudson Valley in New York (Lab 2), how tree-ring science began through its utility in putting exact calendar dates on ancestral pueblos (Lab 3), how tree-ring records can be used to put drought into a long-term context, reconstruct streamflow, and better manage water resources (Lab 4), and how tree rings have been used to reconstruct temperatures in the northern latitudes (Lab 5). These labs have the dual aim of guiding students to use many of the same tools as tree-ring scientists, while also giving them a sense of the nature-of-science and how scientists work. Throughout the labs, students are guided to explore virtual field sites, navigate public databanks, observe and measure tree-ring samples, and describe trends and extremes in paleoclimate records. Labs are designed for a 2 to 3-hour lab class and have been classroom-tested and assessed by faculty teams and students.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"160 - 166"},"PeriodicalIF":1.6,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42912779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-25DOI: 10.3959/1536-1098-75.2.139
A. Fowler, G. Boswijk, A. Lorrey
ABSTRACT Expectations that a warming world will be associated with more hydro-climatological extremes has motivated research exploring if an associated signal is evident in paleoclimate archives. Tree-ring chronologies are central to this work because of their high temporal resolution, but they are also potentially compromised by variance artefacts associated with the evolving composition of the chronology and with data processing. Here we present two empirical methods to identify and quantify potential artefacts related specifically to temporally varying growth rate (local level, LL): LL-based partitioning analysis and LL-based chronology stripping. The two methods were developed and tested using a multi-site New Zealand kauri (Agathis australis) living-tree data set. Our results show that the methods are complementary in terms of artefact identification and quantification, and that they can provide useful insight into causal processes when used conjointly. Our results also indicate that data pre-processing to remove LL-related artefacts may be sub-optimal, that there may be an optimal standardization that minimizes bias, and that the evolving variance of kauri master chronologies over the last 500 years is not significantly affected by LL-related artefacts.
{"title":"IDENTIFYING AND QUANTIFYING TREE-RING CHRONOLOGY VARIANCE ARTEFACTS RELATED TO CO-OCCURRING CHANGES IN GROWTH RATE","authors":"A. Fowler, G. Boswijk, A. Lorrey","doi":"10.3959/1536-1098-75.2.139","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.139","url":null,"abstract":"ABSTRACT Expectations that a warming world will be associated with more hydro-climatological extremes has motivated research exploring if an associated signal is evident in paleoclimate archives. Tree-ring chronologies are central to this work because of their high temporal resolution, but they are also potentially compromised by variance artefacts associated with the evolving composition of the chronology and with data processing. Here we present two empirical methods to identify and quantify potential artefacts related specifically to temporally varying growth rate (local level, LL): LL-based partitioning analysis and LL-based chronology stripping. The two methods were developed and tested using a multi-site New Zealand kauri (Agathis australis) living-tree data set. Our results show that the methods are complementary in terms of artefact identification and quantification, and that they can provide useful insight into causal processes when used conjointly. Our results also indicate that data pre-processing to remove LL-related artefacts may be sub-optimal, that there may be an optimal standardization that minimizes bias, and that the evolving variance of kauri master chronologies over the last 500 years is not significantly affected by LL-related artefacts.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"139 - 151"},"PeriodicalIF":1.6,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48398361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-25DOI: 10.3959/1536-1098-75.2.127
M. Kilpatrick, James Roberts, F. Biondi
ABSTRACT Southwestern ponderosa pine forests have experienced reduced fire frequency since Euro-American settlement generally because of successful fire suppression policies. We report here on the fire history of a ponderosa pine stand located in the Sheep Range, which is part of the Desert National Wildlife Refuge, in the Mojave Desert. A total of 22 dominant, fire-scarred ponderosa pines were sampled by taking 29 partial cross-sections and 18 wood increment cores. Maximum age of ponderosa pines at the study area exceeded 800 years, and sampled trees were often older than 500 years, so that the site tree-ring chronology covered 522 years (1490–2011). Crossdating revealed both extreme sensitivity and highly synchronous patterns, with the expressed population signal (EPS) exceeding 0.9 in 30-year moving windows throughout the length of the chronology. Fire statistics were calculated for the 1565–2011 period, during which at least 10 of the crossdated trees had been scarred and were recording fire. During the recorder period, there were 16 fires that met the two-tree minimum threshold, yielding a mean fire interval (MFI) of 25 years, a median fire interval (MedFI) of 15 years, and a Weibull median probability interval (WMPI) of 18 years; the point mean fire interval (PMFI) was 69 years. The longest fire-free intervals since 1565 occurred in the past two centuries, with 70 years (1862–1931) followed by another 80 years (1933–2012). The stand-wide 1932 fire is the last event recorded by the sampled trees. Overall there was reduced fire frequency from the late 19th Century to present compared to the previous three centuries. Because there is no record of active fire management in the study area, this finding is consistent with similar results obtained in two remote mountains of the Great Basin Desert, and points to a need for greater spatial coverage in fire history information, even for species that have been actively studied in other environments.
{"title":"FIRE HISTORY OF AN OLD-GROWTH PONDEROSA PINE STAND IN THE SHEEP RANGE, DESERT NATIONAL WILDLIFE REFUGE, NEVADA, USA","authors":"M. Kilpatrick, James Roberts, F. Biondi","doi":"10.3959/1536-1098-75.2.127","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.127","url":null,"abstract":"ABSTRACT Southwestern ponderosa pine forests have experienced reduced fire frequency since Euro-American settlement generally because of successful fire suppression policies. We report here on the fire history of a ponderosa pine stand located in the Sheep Range, which is part of the Desert National Wildlife Refuge, in the Mojave Desert. A total of 22 dominant, fire-scarred ponderosa pines were sampled by taking 29 partial cross-sections and 18 wood increment cores. Maximum age of ponderosa pines at the study area exceeded 800 years, and sampled trees were often older than 500 years, so that the site tree-ring chronology covered 522 years (1490–2011). Crossdating revealed both extreme sensitivity and highly synchronous patterns, with the expressed population signal (EPS) exceeding 0.9 in 30-year moving windows throughout the length of the chronology. Fire statistics were calculated for the 1565–2011 period, during which at least 10 of the crossdated trees had been scarred and were recording fire. During the recorder period, there were 16 fires that met the two-tree minimum threshold, yielding a mean fire interval (MFI) of 25 years, a median fire interval (MedFI) of 15 years, and a Weibull median probability interval (WMPI) of 18 years; the point mean fire interval (PMFI) was 69 years. The longest fire-free intervals since 1565 occurred in the past two centuries, with 70 years (1862–1931) followed by another 80 years (1933–2012). The stand-wide 1932 fire is the last event recorded by the sampled trees. Overall there was reduced fire frequency from the late 19th Century to present compared to the previous three centuries. Because there is no record of active fire management in the study area, this finding is consistent with similar results obtained in two remote mountains of the Great Basin Desert, and points to a need for greater spatial coverage in fire history information, even for species that have been actively studied in other environments.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"127 - 138"},"PeriodicalIF":1.6,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43082594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-25DOI: 10.3959/1536-1098-75.2.73
S. Bhandari, N. P. Gaire, Santosh K. Shah, J. Speer, D. Bhuju, U. Thapa
ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation records across Nepal are too short to place the recent drought in a longer context to understand the full range of natural variability in the climate system. In the present study we have collected tree core samples of Tsuga dumosa from two sites, Chhetti and Ranghadi, in the Api Nampa Conservation Area of the western Nepal Himalayas to understand drought variation for the past three centuries. We have developed a 357-year (AD 1657–2013) tree-ring chronology. The tree growth-climate response analysis revealed a stronger positive correlation with spring (March-May) standardized precipitation evapotranspiration index (SPEI01) (r = 0.523, p < 0.01) than precipitation (r = 0.459, p < 0.01), self-calibrating Palmer drought severity index (scPDSI) (r = 0.250, p < 0.01), or temperature (r = -0.486, p < 0.01). Stronger positive correlation with SPEI01 indicates moisture availability is the limiting factor for the growth of this species on these sites. Based on this growth-climate response we reconstructed spring SPEI from AD 1707 to 2013 for the region. The reconstruction showed several dry and wet episodes indicating no persistent climate trend within the past three centuries. The current drought is one of the four most severe in our 307-year record.
尼泊尔西部在过去二十年中经历了严重的干旱，但整个尼泊尔的观测记录太短，无法将最近的干旱置于更长的背景下，以了解气候系统中自然变率的全部范围。在目前的研究中，我们从尼泊尔西部喜马拉雅山脉的Api Nampa保护区的Chhetti和Ranghadi两个地点收集了Tsuga dumosa的树芯样本，以了解过去三个世纪的干旱变化。我们开发了357年(公元1657-2013年)的树木年轮年表。树木生长-气候响应分析显示，春季(3 - 5月)标准化降水蒸散指数(SPEI01) (r = 0.523, p < 0.01)与降水(r = 0.459, p < 0.01)、自校准Palmer干旱严重指数(r = 0.250, p < 0.01)和温度(r = -0.486, p < 0.01)呈正相关。与SPEI01有较强的正相关，表明水分有效性是该树种生长的限制因子。基于这种生长-气候响应，我们重建了该地区公元1707年至2013年的春季SPEI。重建显示了几次干湿交替，表明在过去的三个世纪里没有持续的气候趋势。目前的干旱是我国307年历史上最严重的四次干旱之一。
{"title":"A 307-YEAR TREE-RING SPEI RECONSTRUCTION INDICATES MODERN DROUGHT IN WESTERN NEPAL HIMALAYAS","authors":"S. Bhandari, N. P. Gaire, Santosh K. Shah, J. Speer, D. Bhuju, U. Thapa","doi":"10.3959/1536-1098-75.2.73","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.73","url":null,"abstract":"ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation records across Nepal are too short to place the recent drought in a longer context to understand the full range of natural variability in the climate system. In the present study we have collected tree core samples of Tsuga dumosa from two sites, Chhetti and Ranghadi, in the Api Nampa Conservation Area of the western Nepal Himalayas to understand drought variation for the past three centuries. We have developed a 357-year (AD 1657–2013) tree-ring chronology. The tree growth-climate response analysis revealed a stronger positive correlation with spring (March-May) standardized precipitation evapotranspiration index (SPEI01) (r = 0.523, p < 0.01) than precipitation (r = 0.459, p < 0.01), self-calibrating Palmer drought severity index (scPDSI) (r = 0.250, p < 0.01), or temperature (r = -0.486, p < 0.01). Stronger positive correlation with SPEI01 indicates moisture availability is the limiting factor for the growth of this species on these sites. Based on this growth-climate response we reconstructed spring SPEI from AD 1707 to 2013 for the region. The reconstruction showed several dry and wet episodes indicating no persistent climate trend within the past three centuries. The current drought is one of the four most severe in our 307-year record.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"73 - 85"},"PeriodicalIF":1.6,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47025424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-05DOI: 10.3959/1536-1098-75.1.14
Justin R. Dee, M. Palmer
ABSTRACT Herb-chronology, the study of annual growth rings in the root to shoot transitional zone of perennial forbs, involves efforts mostly devoted to finding correlations between growth increment and annual climate. The potential of using growth rings as markers of plant growth response to more ecological phenomena such as periodic disturbance still remains mostly untapped. By monitoring the 2016 growth increment of 64 individuals of a common milkweed species (Asclepias viridis) from the US tallgrass prairie system we investigate plant response to factorial treatments of early season shoot removal and neighbor thinning. These treatments simulate bouts of herbivory, grazing, and dormant-season fire, each of which should have differential effects on plant growth. Neighbor thinning had the strongest effects of the study, moderately increasing ring widths. Conversely, ring widths were moderately decreased by shoot removal. Individual age had negative effects on ring width. These results are the first evidence of herbaceous annual ring sensitivity to sudden amelioration of resources as well as a significant loss of aboveground biomass. Herb-chronology could be useful in future studies monitoring the effects of disturbance on plant growth, increasing our understanding of these phenomena and their overall effect on grassland composition.
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Pub Date : 2019-03-05DOI: 10.3959/1536-1098-75.1.1
A. Vitas, M. Zunde
ABSTRACT Pinus sylvestris L. is the predominant tree species used for wooden constructions in the Baltic area. Accordingly, the timber of Pinus is the most important object for investigation and dating carried out by dendrochronologists of the Baltic countries. However, the dating of historical Pinus is often challenging when the outer sapwood rings are missing in the wood samples. In Pinus, sapwood rings increase in number as the tree ages, and therefore calculating the approximate number of missing outer rings from a set range, a technique used for oak, is not possible. In Norway, a simple method for estimating the number of sapwood rings has been developed for some native species of conifers. The aim of this small-scale study was to assess the validity and the practical suitability of the Norwegian method for estimating the number of missing sapwood rings of mostly historical Pinus wood samples obtained in the southeastern part of the Baltic region. Our findings indicate that this method is not acceptable for estimating the number of missing sapwood rings for individual trees, but suggest that it may be applicable when dating tree-ring chronologies for a minimum of 20 trees, containing individuals up to 200 years old.
{"title":"SAPWOOD RINGS ESTIMATION FOR PINUS SYLVESTRIS L. IN LITHUANIA AND LATVIA","authors":"A. Vitas, M. Zunde","doi":"10.3959/1536-1098-75.1.1","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.1","url":null,"abstract":"ABSTRACT Pinus sylvestris L. is the predominant tree species used for wooden constructions in the Baltic area. Accordingly, the timber of Pinus is the most important object for investigation and dating carried out by dendrochronologists of the Baltic countries. However, the dating of historical Pinus is often challenging when the outer sapwood rings are missing in the wood samples. In Pinus, sapwood rings increase in number as the tree ages, and therefore calculating the approximate number of missing outer rings from a set range, a technique used for oak, is not possible. In Norway, a simple method for estimating the number of sapwood rings has been developed for some native species of conifers. The aim of this small-scale study was to assess the validity and the practical suitability of the Norwegian method for estimating the number of missing sapwood rings of mostly historical Pinus wood samples obtained in the southeastern part of the Baltic region. Our findings indicate that this method is not acceptable for estimating the number of missing sapwood rings for individual trees, but suggest that it may be applicable when dating tree-ring chronologies for a minimum of 20 trees, containing individuals up to 200 years old.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"1 - 13"},"PeriodicalIF":1.6,"publicationDate":"2019-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45301069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-05DOI: 10.3959/1536-1098-75.1.67
Ryan Helcoski, A. Tepley, Jennifer C. Mcgarvey, E. Gonzalez-Akre, V. Meakem, Jonathan R. Thompson, K. Anderson‐Teixeira
ABSTRACT The collection of tree-ring data from living trees is widespread and highly valuable in ecological and dendro-climatological research, yet there is concern that coring injures trees, potentially contributing to mortality. Unlike resinous conifers that can quickly compartmentalize wounds, less decay-resistant angiosperms may face more pronounced risk of injury from coring. To test if coring increases mortality rates in temperate hardwood trees, we leverage a unique dataset tracking the mortality of cored and uncored hardwood trees representing 19 species from 10 genera in a 26-ha plot in Virginia, USA. We compare mortality rates between 935 cored trees and 8605 uncored trees for seven years following coring. Annual mortality rates did not differ between cored trees (1.71% yr–1; 95% CI 1.40 to 2.20) and uncored trees (1.85% yr–1; 95% CI 1.70 to 2.28) across the full dataset, nor were there differences by genus or size class. These results indicate that the risk of hardwood mortality caused by increment coring is probably lower than previously assumed. However, these results cannot rule out the possibility that coring elevates hardwood mortality in other climates or when trees face multiple additional stressors that were not influential over the course of our study.
活树年轮数据的收集在生态学和树木气候学研究中非常广泛和有价值，但人们担心取心会伤害树木，可能导致死亡。不像树脂针叶树，可以迅速分隔伤口，较不耐腐的被子植物可能面临更大的风险，从心脏受伤。为了测试取样是否会增加温带阔叶树的死亡率，我们利用了一个独特的数据集，跟踪了美国弗吉尼亚州26公顷地块中10属19种的取样和未取样阔叶树的死亡率。我们比较了935棵有芯树和8605棵没有芯树在取芯后7年内的死亡率。有芯树的年死亡率无显著差异(1.71% - 1;95% CI 1.40 - 2.20)和未覆盖树木(1.85%，年- 1;95% CI 1.70至2.28)，在整个数据集中也没有属或大小类的差异。这些结果表明，增量取心导致硬木死亡的风险可能比先前假设的要低。然而，这些结果不能排除在其他气候条件下，或者当树木面临多个额外的压力时，这些压力在我们的研究过程中没有影响时，取芯会提高硬木死亡率的可能性。
{"title":"NO SIGNIFICANT INCREASE IN TREE MORTALITY FOLLOWING CORING IN A TEMPERATE HARDWOOD FOREST","authors":"Ryan Helcoski, A. Tepley, Jennifer C. Mcgarvey, E. Gonzalez-Akre, V. Meakem, Jonathan R. Thompson, K. Anderson‐Teixeira","doi":"10.3959/1536-1098-75.1.67","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.67","url":null,"abstract":"ABSTRACT The collection of tree-ring data from living trees is widespread and highly valuable in ecological and dendro-climatological research, yet there is concern that coring injures trees, potentially contributing to mortality. Unlike resinous conifers that can quickly compartmentalize wounds, less decay-resistant angiosperms may face more pronounced risk of injury from coring. To test if coring increases mortality rates in temperate hardwood trees, we leverage a unique dataset tracking the mortality of cored and uncored hardwood trees representing 19 species from 10 genera in a 26-ha plot in Virginia, USA. We compare mortality rates between 935 cored trees and 8605 uncored trees for seven years following coring. Annual mortality rates did not differ between cored trees (1.71% yr–1; 95% CI 1.40 to 2.20) and uncored trees (1.85% yr–1; 95% CI 1.70 to 2.28) across the full dataset, nor were there differences by genus or size class. These results indicate that the risk of hardwood mortality caused by increment coring is probably lower than previously assumed. However, these results cannot rule out the possibility that coring elevates hardwood mortality in other climates or when trees face multiple additional stressors that were not influential over the course of our study.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"67 - 72"},"PeriodicalIF":1.6,"publicationDate":"2019-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48318771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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