Pub Date : 2019-03-05DOI: 10.3959/1536-1098-75.1.61
M. Salzer, C. Pearson, C. Baisan
ABSTRACT Two floating, ring-width chronologies predate the long bristlecone pine (Pinus longaeva) absolutely-dated, ring-width chronology from the Methuselah Walk (MWK) site in the White Mountains of California. The two non-overlapping floating chronologies were derived from samples that crossdate internally but are temporally unconnected to each other and to the nearly 9000-year, ring-width sequence that is crossdated to the calendar year. We used radiocarbon wiggle-matching and crossdating to place the two floating sequences more accurately in time and to better understand the temporal relationships between the three time series. The trees from the oldest floating sequence were alive near the beginning of the Pleistocene/Holocene boundary and they do not overlap with the other chronologies because of a gap of two-to-three centuries between the two floating series. However, the trees from the younger floating sequence likely do overlap with the long, calendar-dated MWK chronology. We find a possible 57-year overlap that connects these two. If confirmed with additional work, the resulting tree-ring dated annual record from this single location will span 10,359 years, a unique accomplishment in dendrochronology.
{"title":"DATING THE METHUSELAH WALK BRISTLECONE PINE FLOATING CHRONOLOGIES","authors":"M. Salzer, C. Pearson, C. Baisan","doi":"10.3959/1536-1098-75.1.61","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.61","url":null,"abstract":"ABSTRACT Two floating, ring-width chronologies predate the long bristlecone pine (Pinus longaeva) absolutely-dated, ring-width chronology from the Methuselah Walk (MWK) site in the White Mountains of California. The two non-overlapping floating chronologies were derived from samples that crossdate internally but are temporally unconnected to each other and to the nearly 9000-year, ring-width sequence that is crossdated to the calendar year. We used radiocarbon wiggle-matching and crossdating to place the two floating sequences more accurately in time and to better understand the temporal relationships between the three time series. The trees from the oldest floating sequence were alive near the beginning of the Pleistocene/Holocene boundary and they do not overlap with the other chronologies because of a gap of two-to-three centuries between the two floating series. However, the trees from the younger floating sequence likely do overlap with the long, calendar-dated MWK chronology. We find a possible 57-year overlap that connects these two. If confirmed with additional work, the resulting tree-ring dated annual record from this single location will span 10,359 years, a unique accomplishment in dendrochronology.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"61 - 66"},"PeriodicalIF":1.6,"publicationDate":"2019-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43763366","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: 10.3959/1536-1098-75.1.25
P. T. Soulé, Justin T. Maxwell, P. Knapp
ABSTRACT When using old-growth trees from semiarid, open-canopy environments, basal area increment (BAI), an absolute measure of radial growth, is sometimes used instead of the more commonly used ‘conservative techniques’ (negative exponential or linear regression with a negative slope; NegX) because narrow rings have been shown to potentially bias results. In this study we explore the relationship between radial growth of ponderosa pine from four study sites in Montana and climate (temperature, precipitation, drought severity) using unstandardized raw ring width and BAI values, and standardized values generated via Friedman Super Smoother and NegX. All sites are minimally disturbed, and our selection criteria are limited to older (interior dates pre-A.D. 1850 at breast height) trees growing in open-canopy environments free of visible disturbance such as lightning strikes. We found the strongest relationships (r > 0.60) for radial growth with July and prior-year October Palmer Drought Severity Index values. Our results show that radial growth-climate responses generally fall within a narrow range regardless of the representation of annual growth (e.g. for July temperature r-values are largely –0.3 to – 0.4) and that site conditions determine which radial-growth values (i.e. unstandardized or standardized) optimize climate-growth responses.
摘要：当使用来自半干旱、开放树冠环境的老树时，有时会使用基底面积增量（BAI），一种径向生长的绝对测量方法，而不是更常用的“保守技术”（负指数或负斜率线性回归；NegX），因为窄环已被证明可能会对结果产生偏差。在本研究中，我们使用未标准化的原始环宽和BAI值，以及通过Friedman Super Smoother和NegX生成的标准化值，探讨了蒙大拿州四个研究地点黄松的径向生长与气候（温度、降水、干旱严重程度）之间的关系。所有地点都受到了最小的干扰，我们的选择标准仅限于生长在没有可见干扰（如雷击）的开放式树冠环境中的较老（内部日期在公元1850年之前，齐胸高）树木。我们发现径向生长与7月和前一年10月的Palmer干旱严重性指数值之间的关系最强（r>0.60）。我们的研究结果表明，无论年增长的代表性如何，径向增长气候响应通常都在一个狭窄的范围内（例如，7月份的温度r值主要为-0.3至-0.4），而场地条件决定了哪些径向增长值（即非标准化或标准化）优化了气候增长响应。
{"title":"CLIMATE-GROWTH RESPONSES FROM PINUS PONDEROSA TREES USING MULTIPLE MEASURES OF ANNUAL RADIAL GROWTH","authors":"P. T. Soulé, Justin T. Maxwell, P. Knapp","doi":"10.3959/1536-1098-75.1.25","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.25","url":null,"abstract":"ABSTRACT When using old-growth trees from semiarid, open-canopy environments, basal area increment (BAI), an absolute measure of radial growth, is sometimes used instead of the more commonly used ‘conservative techniques’ (negative exponential or linear regression with a negative slope; NegX) because narrow rings have been shown to potentially bias results. In this study we explore the relationship between radial growth of ponderosa pine from four study sites in Montana and climate (temperature, precipitation, drought severity) using unstandardized raw ring width and BAI values, and standardized values generated via Friedman Super Smoother and NegX. All sites are minimally disturbed, and our selection criteria are limited to older (interior dates pre-A.D. 1850 at breast height) trees growing in open-canopy environments free of visible disturbance such as lightning strikes. We found the strongest relationships (r > 0.60) for radial growth with July and prior-year October Palmer Drought Severity Index values. Our results show that radial growth-climate responses generally fall within a narrow range regardless of the representation of annual growth (e.g. for July temperature r-values are largely –0.3 to – 0.4) and that site conditions determine which radial-growth values (i.e. unstandardized or standardized) optimize climate-growth responses.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"38 9-10","pages":"25 - 33"},"PeriodicalIF":1.6,"publicationDate":"2019-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41288562","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 : 2019-03-01DOI: 10.3959/1536-1098-75.1.34
P. Brown, Benjamin M. Gannon, M. Battaglia, P. Fornwalt, L. Huckaby, A. Cheng, L. Baggett
ABSTRACT Old trees (defined here as ≥150 years old) can be rare in many forests because of past timber harvest, uncharacteristically severe wildfires, and – increasingly – climate change. Old trees provide unique structural, ecological, scientific, and aesthetic values missing in forests containing only younger trees. Here we compile crossdated ages from over 10,000 living and dead trees sampled in montane forests of the central Rocky Mountains in Colorado and southern Wyoming, USA, to examine changes in age structure of the oldest trees since Euro-American settlement and to provide guidelines to aid in identification of old trees for retention during ecological restoration treatments. Eroded stumps (containing only heartwood) were found in over 93% of 179 randomly sampled plots. Number of stumps found in each plot was proportional to reconstructed historical (1860 C.E.) stand basal area. The regional median date of maximum plot tree recruitment was over 150 years older when including stumps versus only living trees, suggesting that if all those harvested trees had survived to the present, the ages of oldest trees would be substantially greater than it is today. However, the regional median age of oldest trees in 1860 before harvesting was not different from the median age of oldest living trees in the current forest (246 vs. 248 years), which alternatively suggests that the regional population of oldest trees has recovered to near historical levels in the time since early Euro-American harvests. Each living tree at the time of sampling was assigned to one of three potential age classes based on a subjective assessment of tree morphology: old (likely ≥150 years old), young (likely <150 years old), or transitional (containing a mixture of young and old tree characteristics). Trees assigned to the old and young morphology categories were classified correctly 88% to 96% of the time depending on species as confirmed by their crossdated ages. Regression tree analysis revealed that tree diameter at breast height was not as reliable a predictor of tree age as were morphological characteristics. A measure of site productivity was a significant variable to use to separate transitional morphology trees into old and young age classes, but classification accuracy was not high because of large variability in ages of these trees. Our results suggest that residual live old trees in the current forest, although perhaps not rare compared to historical age distributions, should be retained during restoration treatments, and that using simple morphological and environmental criteria to identify old trees is more reliable than tree size alone.
{"title":"IDENTIFYING OLD TREES TO INFORM ECOLOGICAL RESTORATION IN MONTANE FORESTS OF THE CENTRAL ROCKY MOUNTAINS, USA","authors":"P. Brown, Benjamin M. Gannon, M. Battaglia, P. Fornwalt, L. Huckaby, A. Cheng, L. Baggett","doi":"10.3959/1536-1098-75.1.34","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.34","url":null,"abstract":"ABSTRACT Old trees (defined here as ≥150 years old) can be rare in many forests because of past timber harvest, uncharacteristically severe wildfires, and – increasingly – climate change. Old trees provide unique structural, ecological, scientific, and aesthetic values missing in forests containing only younger trees. Here we compile crossdated ages from over 10,000 living and dead trees sampled in montane forests of the central Rocky Mountains in Colorado and southern Wyoming, USA, to examine changes in age structure of the oldest trees since Euro-American settlement and to provide guidelines to aid in identification of old trees for retention during ecological restoration treatments. Eroded stumps (containing only heartwood) were found in over 93% of 179 randomly sampled plots. Number of stumps found in each plot was proportional to reconstructed historical (1860 C.E.) stand basal area. The regional median date of maximum plot tree recruitment was over 150 years older when including stumps versus only living trees, suggesting that if all those harvested trees had survived to the present, the ages of oldest trees would be substantially greater than it is today. However, the regional median age of oldest trees in 1860 before harvesting was not different from the median age of oldest living trees in the current forest (246 vs. 248 years), which alternatively suggests that the regional population of oldest trees has recovered to near historical levels in the time since early Euro-American harvests. Each living tree at the time of sampling was assigned to one of three potential age classes based on a subjective assessment of tree morphology: old (likely ≥150 years old), young (likely <150 years old), or transitional (containing a mixture of young and old tree characteristics). Trees assigned to the old and young morphology categories were classified correctly 88% to 96% of the time depending on species as confirmed by their crossdated ages. Regression tree analysis revealed that tree diameter at breast height was not as reliable a predictor of tree age as were morphological characteristics. A measure of site productivity was a significant variable to use to separate transitional morphology trees into old and young age classes, but classification accuracy was not high because of large variability in ages of these trees. Our results suggest that residual live old trees in the current forest, although perhaps not rare compared to historical age distributions, should be retained during restoration treatments, and that using simple morphological and environmental criteria to identify old trees is more reliable than tree size alone.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"34 - 48"},"PeriodicalIF":1.6,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43773873","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 : 2019-01-23DOI: 10.3959/1536-1098-75.2.116
T. Fletcher, R. Touchan, K. Lepley, N. Rouini, Robert R. Bloye, Thomas S. Tremarelli, Kelly Peña, D. Meko
ABSTRACT 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 growth year. The chronologies account for 50% of the variance of observed annual precipitation in the regional model and 59%, 60%, and 47% and 35% in the nested models. The two reconstructions are highly correlated (Pearson's correlation r > 0.97, p < 0.001) demonstrating that the reconstructions are highly similar over the period common to both reconstructions, with the nested-models’ advantage of extending the range of the reconstruction. The precipitation reconstructions are significantly correlated (r = 0.66, p < 0.001) with the North American Drought Atlas (NADA).
摘要:本研究报道了美国亚利桑那州中北部4个地点的黄松和毛竹的2个多世纪区域年降水量重建。它比较了标准的区域和时间嵌套方法，分别生成1581-2016年和1529-2016年的重建。环总宽度与生长期结束于7月的12个月总降水量呈显著正相关。在区域模式中，年表对年降水观测方差的贡献率为50%，在嵌套模式中为59%、60%、47%和35%。这两个重建是高度相关的(Pearson’s correlation r > 0.97, p < 0.001)，这表明重建在两个重建共同的时期内是高度相似的，嵌套模型的优势是扩展了重建的范围。降水重建结果与北美干旱图谱(NADA)呈显著相关(r = 0.66, p < 0.001)。
{"title":"TWO RECONSTRUCTIONS OF AUGUST–JULY PRECIPITATION FOR CENTRAL NORTHERN ARIZONA FROM TREE RINGS","authors":"T. Fletcher, R. Touchan, K. Lepley, N. Rouini, Robert R. Bloye, Thomas S. Tremarelli, Kelly Peña, D. Meko","doi":"10.3959/1536-1098-75.2.116","DOIUrl":"https://doi.org/10.3959/1536-1098-75.2.116","url":null,"abstract":"ABSTRACT 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 growth year. The chronologies account for 50% of the variance of observed annual precipitation in the regional model and 59%, 60%, and 47% and 35% in the nested models. The two reconstructions are highly correlated (Pearson's correlation r > 0.97, p < 0.001) demonstrating that the reconstructions are highly similar over the period common to both reconstructions, with the nested-models’ advantage of extending the range of the reconstruction. The precipitation reconstructions are significantly correlated (r = 0.66, p < 0.001) with the North American Drought Atlas (NADA).","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"116 - 126"},"PeriodicalIF":1.6,"publicationDate":"2019-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44815511","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 : 2019-01-01DOI: 10.3959/1536-1098-75.1.49
L. Marshall, D. Falk, N. McDowell
ABSTRACT Extreme stand density increases have occurred in ponderosa pine forests throughout the western U.S. since the early 20th Century, with adverse implications for growth, physiological functioning, and mortality risk. Identifying primary stressors on large, old overstory trees in dense forests can inform management decisions to promote resilience and survival. We tested the impact of stand density increase on overstory tree-ring growth, and the relative influence of water and nitrogen, in an old-growth ponderosa pine forest in northern New Mexico subject to variable density increase. We measured annual tree-ring growth and carbon discrimination in trees before stand density increased, in a climatically-similar period post-density increase, and in recent transition to drought. We expected density-driven water stress to drive reduced tree-ring growth in overstory trees in dense stands. We found reduced growth and higher mortality in dense stands, but nitrogen rather than water constrained growth, as determined by carbon isotope discrimination in tree rings, leaf nitrogen concentration, and soil nitrogen supply. In dense stands, less available nitrogen limited photosynthetic rate, leading to reduced assimilation of intracellular 13 C and higher discrimination with low tree-ring growth and a reduced relationship with climate. This unexpected result illustrates that a variety of limiting factors can influence forest dynamics, as density-driven nitrogen limitation interacts with water stress to influence tree growth and physiological functioning.
{"title":"NITROGEN CAN LIMIT OVERSTORY TREE GROWTH FOLLOWING EXTREME STAND DENSITY INCREASE IN A PONDEROSA PINE FOREST","authors":"L. Marshall, D. Falk, N. McDowell","doi":"10.3959/1536-1098-75.1.49","DOIUrl":"https://doi.org/10.3959/1536-1098-75.1.49","url":null,"abstract":"ABSTRACT Extreme stand density increases have occurred in ponderosa pine forests throughout the western U.S. since the early 20th Century, with adverse implications for growth, physiological functioning, and mortality risk. Identifying primary stressors on large, old overstory trees in dense forests can inform management decisions to promote resilience and survival. We tested the impact of stand density increase on overstory tree-ring growth, and the relative influence of water and nitrogen, in an old-growth ponderosa pine forest in northern New Mexico subject to variable density increase. We measured annual tree-ring growth and carbon discrimination in trees before stand density increased, in a climatically-similar period post-density increase, and in recent transition to drought. We expected density-driven water stress to drive reduced tree-ring growth in overstory trees in dense stands. We found reduced growth and higher mortality in dense stands, but nitrogen rather than water constrained growth, as determined by carbon isotope discrimination in tree rings, leaf nitrogen concentration, and soil nitrogen supply. In dense stands, less available nitrogen limited photosynthetic rate, leading to reduced assimilation of intracellular 13 C and higher discrimination with low tree-ring growth and a reduced relationship with climate. This unexpected result illustrates that a variety of limiting factors can influence forest dynamics, as density-driven nitrogen limitation interacts with water stress to influence tree growth and physiological functioning.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"75 1","pages":"49 - 60"},"PeriodicalIF":1.6,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70036562","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}
ABSTRACT When using old-growth trees from semiarid, open-canopy environments, basal area increment (BAI), an absolute measure of radial growth, is sometimes used instead of the more commonly used ‘conservative techniques’ (negative exponential or linear regression with a negative slope; NegX) because narrow rings have been shown to potentially bias results. In this study we explore the relationship between radial growth of ponderosa pine from four study sites in Montana and climate (temperature, precipitation, drought severity) using unstandardized raw ring width and BAI values, and standardized values generated via Friedman Super Smoother and NegX. All sites are minimally disturbed, and our selection criteria is limited to older (interior dates pre-A.D. 1850 at breast height) trees growing in open-canopy environments free of visible disturbance such as lightning strikes. We found the strongest relationships (r > 0.60) with radial growth with July and prior-year October Palmer Drought Severity Index value...
当使用来自半干旱、开放冠层环境的古树时，有时使用基面积增量(BAI)作为径向生长的绝对度量，而不是更常用的“保守技术”(负斜率的负指数或线性回归;NegX)，因为窄环已被证明可能会对结果产生偏差。在这项研究中，我们利用未标准化的原始环宽度和BAI值，以及通过Friedman Super smooth和NegX生成的标准化值，探索蒙大拿州四个研究地点黄松径向生长与气候(温度、降水、干旱严重程度)之间的关系。所有的地点都是最小的干扰，我们的选择标准仅限于更古老的(公元前的内部日期)。(1850年(胸围高度)生长在开阔树冠环境中的树木，没有可见的干扰，如雷击。我们发现径向增长与7月和前一年10月Palmer干旱严重指数值的关系最强(r > 0.60)。
{"title":"Pinus ponderosa climate/growth responses: Climate-growth responses from Pinus ponderosa trees using multiple measures of annual radial growth","authors":"P. T. Soulé, Justin T. Maxwell, P. Knapp","doi":"10.3959/TRR2017-18","DOIUrl":"https://doi.org/10.3959/TRR2017-18","url":null,"abstract":"ABSTRACT When using old-growth trees from semiarid, open-canopy environments, basal area increment (BAI), an absolute measure of radial growth, is sometimes used instead of the more commonly used ‘conservative techniques’ (negative exponential or linear regression with a negative slope; NegX) because narrow rings have been shown to potentially bias results. In this study we explore the relationship between radial growth of ponderosa pine from four study sites in Montana and climate (temperature, precipitation, drought severity) using unstandardized raw ring width and BAI values, and standardized values generated via Friedman Super Smoother and NegX. All sites are minimally disturbed, and our selection criteria is limited to older (interior dates pre-A.D. 1850 at breast height) trees growing in open-canopy environments free of visible disturbance such as lightning strikes. We found the strongest relationships (r > 0.60) with radial growth with July and prior-year October Palmer Drought Severity Index value...","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43059054","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 : 2018-08-03DOI: 10.3959/1536-1098-74.2.185
Christopher J. Ratcliff, S. Voelker, A. Nolin
Abstract Here we examine climatic influences on inter-annual variation in latewood tree growth (i.e. ring-width indices, RWILW) and stable-carbon isotope discrimination (Δ13CLW) from 1950 to 2013 at two SNOTEL snowpack monitoring sites in the Oregon Cascade Mountains. Douglas-fir and mountain hemlock trees were sampled at the lower and upper elevation sites where annual peak snow water equivalent (SWE) averaged 467 and 1128 mm, respectively. RWILW chronologies were poorly correlated among sites/species (r = 0.23, P = 0.063) and neither exhibited strong correlations with monthly or seasonal climate variables. By contrast, Δ13CLW chronologies were significantly correlated (r = 0.69, P < 0.001) and exhibited stronger climate responses. Multiple regression analyses identified summertime maximum temperature (Tmax) and/or vapor pressure deficit (VPD) as the primary drivers of Δ13CLW. Secondary influences included summertime precipitation, specific humidity, cloud cover, and SWE from the previous fall and winter. Overall, our findings suggest that Cascade mixed conifer forests will become increasingly drought stressed as rising temperatures cause progressively diminished snowpacks. Moreover, our Δ13CLW records also provide a proof of concept showing strong potential to expand summertime Tmax reconstructions to other snowy, montane locations.
{"title":"Tree-Ring Carbon Isotope Records from the Western Oregon Cascade Mountains Primarily Record Summer Maximum Temperatures","authors":"Christopher J. Ratcliff, S. Voelker, A. Nolin","doi":"10.3959/1536-1098-74.2.185","DOIUrl":"https://doi.org/10.3959/1536-1098-74.2.185","url":null,"abstract":"Abstract Here we examine climatic influences on inter-annual variation in latewood tree growth (i.e. ring-width indices, RWILW) and stable-carbon isotope discrimination (Δ13CLW) from 1950 to 2013 at two SNOTEL snowpack monitoring sites in the Oregon Cascade Mountains. Douglas-fir and mountain hemlock trees were sampled at the lower and upper elevation sites where annual peak snow water equivalent (SWE) averaged 467 and 1128 mm, respectively. RWILW chronologies were poorly correlated among sites/species (r = 0.23, P = 0.063) and neither exhibited strong correlations with monthly or seasonal climate variables. By contrast, Δ13CLW chronologies were significantly correlated (r = 0.69, P < 0.001) and exhibited stronger climate responses. Multiple regression analyses identified summertime maximum temperature (Tmax) and/or vapor pressure deficit (VPD) as the primary drivers of Δ13CLW. Secondary influences included summertime precipitation, specific humidity, cloud cover, and SWE from the previous fall and winter. Overall, our findings suggest that Cascade mixed conifer forests will become increasingly drought stressed as rising temperatures cause progressively diminished snowpacks. Moreover, our Δ13CLW records also provide a proof of concept showing strong potential to expand summertime Tmax reconstructions to other snowy, montane locations.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"74 1","pages":"185 - 195"},"PeriodicalIF":1.6,"publicationDate":"2018-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3959/1536-1098-74.2.185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48086311","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 : 2018-07-01DOI: 10.3959/1536-1098-74.2.162
G. Pereira, A. Barbosa, M. Torbenson, D. Stahle, D. Granato-Souza, R. M. Santos, J. P. D. Barbosa
Abstract The São Francisco River basin is one of the most drought-prone regions of Brazil. Seasonally dry tropical forests (SDTF) are widely distributed in the basin and we developed a short chronology of Cedrela fissilis annual ring widths from SDTF fragments based on 89 cores from 44 trees dating from 1961 to 2015. The average correlation among all radii (RBAR) is 0.52. The tree-ring chronology is correlated with wet season precipitation totals, must strongly and consistently near the beginning of the wet season. The spatial pattern of correlation covers most of the southern portion of the Brazilian Drought Polygon and the sub-basins of the two largest tributaries of the São Francisco River, in some areas exceeding r = 0.60. The chronology is also correlated with total annual discharge of the Rio São Francisco River measured at Barra (r = 0.489; 1961–2015), which is very promising in a country that generates two thirds of its electricity from hydroelectric power plants, particularly if this short chronology can be extended with trees exceeding 150-years old known to still exist in the region.
摘要旧金山河流域是巴西最易发生干旱的地区之一。季节性干旱热带森林（SDTF）广泛分布在盆地中，我们根据1961年至2015年44棵树的89个岩芯，从SDTF碎片中开发了一个裂缝雪松年环宽度的短年表。所有半径之间的平均相关性（RBAR）为0.52。树木年轮年表与雨季降水总量相关，必须在雨季开始时强烈且一致。相关性的空间模式涵盖了巴西干旱多边形南部的大部分地区和São Francisco河两条最大支流的子流域，在某些地区超过r=0.60。该年表还与巴拉河测得的Rio São Francisco河年总流量相关（r=0.489；1961–2015），在一个三分之二的电力来自水力发电厂的国家，这是非常有希望的，特别是如果这个短年表可以用该地区已知仍存在的树龄超过150年的树木来延长的话。
{"title":"The Climate Response of Cedrela Fissilis Annual Ring Width in the Rio São Francisco Basin, Brazil","authors":"G. Pereira, A. Barbosa, M. Torbenson, D. Stahle, D. Granato-Souza, R. M. Santos, J. P. D. Barbosa","doi":"10.3959/1536-1098-74.2.162","DOIUrl":"https://doi.org/10.3959/1536-1098-74.2.162","url":null,"abstract":"Abstract The São Francisco River basin is one of the most drought-prone regions of Brazil. Seasonally dry tropical forests (SDTF) are widely distributed in the basin and we developed a short chronology of Cedrela fissilis annual ring widths from SDTF fragments based on 89 cores from 44 trees dating from 1961 to 2015. The average correlation among all radii (RBAR) is 0.52. The tree-ring chronology is correlated with wet season precipitation totals, must strongly and consistently near the beginning of the wet season. The spatial pattern of correlation covers most of the southern portion of the Brazilian Drought Polygon and the sub-basins of the two largest tributaries of the São Francisco River, in some areas exceeding r = 0.60. The chronology is also correlated with total annual discharge of the Rio São Francisco River measured at Barra (r = 0.489; 1961–2015), which is very promising in a country that generates two thirds of its electricity from hydroelectric power plants, particularly if this short chronology can be extended with trees exceeding 150-years old known to still exist in the region.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"74 1","pages":"162 - 171"},"PeriodicalIF":1.6,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3959/1536-1098-74.2.162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42339154","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 : 2018-07-01DOI: 10.3959/1536-1098-74.2.172
J. Pettit, R. DeRose, J. Long
Abstract Despite the widespread use of ponderosa pine as an important hydroclimate proxy, we actually understand very little about its climate response in the Northern Rockies. Here, we analyze two new ponderosa pine chronologies to investigate how climate influences annual growth. Despite differences in precipitation amount and timing and large elevation differences (1820 m versus 1060 m), ring width at both sites was strongly driven by water availability. The mid-elevation, water-limited site responded well to previous fall precipitation whereas the wetter, high-elevation site responded to growing season precipitation and temperature. When precipitation and temperature were simultaneously accounted for using the standardized precipitation evapotranspiration index, ring-width response between sites converged and appeared nearly identical. Water stress drove the timing of ponderosa pine growth by a combination of factors such as strong water dependence, and determinate growth physiology, as indicated by lag-1 autocorrelation. When analyzing response to single-month climate variables, precipitation from growing-season months dominates. When we examined seasonal variables, climate from the previous year became more important. Temporal fidelity of the climatic response at both sites maintained significance across the historical record, although the relationship weakened at the low-elevation site. The collection of new tree-ring data sets such as these for central Idaho improves our understanding of ponderosa pine growth response to climate.
{"title":"Climatic Drivers of Ponderosa Pine Growth in Central Idaho","authors":"J. Pettit, R. DeRose, J. Long","doi":"10.3959/1536-1098-74.2.172","DOIUrl":"https://doi.org/10.3959/1536-1098-74.2.172","url":null,"abstract":"Abstract Despite the widespread use of ponderosa pine as an important hydroclimate proxy, we actually understand very little about its climate response in the Northern Rockies. Here, we analyze two new ponderosa pine chronologies to investigate how climate influences annual growth. Despite differences in precipitation amount and timing and large elevation differences (1820 m versus 1060 m), ring width at both sites was strongly driven by water availability. The mid-elevation, water-limited site responded well to previous fall precipitation whereas the wetter, high-elevation site responded to growing season precipitation and temperature. When precipitation and temperature were simultaneously accounted for using the standardized precipitation evapotranspiration index, ring-width response between sites converged and appeared nearly identical. Water stress drove the timing of ponderosa pine growth by a combination of factors such as strong water dependence, and determinate growth physiology, as indicated by lag-1 autocorrelation. When analyzing response to single-month climate variables, precipitation from growing-season months dominates. When we examined seasonal variables, climate from the previous year became more important. Temporal fidelity of the climatic response at both sites maintained significance across the historical record, although the relationship weakened at the low-elevation site. The collection of new tree-ring data sets such as these for central Idaho improves our understanding of ponderosa pine growth response to climate.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"74 1","pages":"172 - 184"},"PeriodicalIF":1.6,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3959/1536-1098-74.2.172","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45952741","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 : 2018-07-01DOI: 10.3959/1536-1098-74.2.196
M. Pompa-García, A. Venegas‐González, A. A. Júnior, J. A. Sigala-Rodríguez
Abstract Global climate change will alter forests by shifting species ranges, which has implications for their ecological functions. Annual tree-ring widths and wood density are useful proxies for carbon cycle studies across a range of species. Here, using a dendroecological approach we sought to understand the carbon accumulation rates of two representative pine species growing on contrasting wet (P. arizonica) and dry (P. cembroides) sites and reveal how such species cope with climate variability. Although the rate of carbon gain was not significantly different across sites, we found that variations in carbon accumulation responded differently to specific hydroclimate drivers, site conditions, or to functional features of each species, which are still to be explored. Overall, annual carbon accumulation (C) was less sensitive to climate variability than ring width and wood density. Annual C was more sensitive to rainfall in the cold season (P. arizonica) and to the start of spring (both species). Our species-specific approach provided a suitable basis for modeling projections in the long-term carbon balance in these forests. Using species-specific tree-ring data has the potential to yield better estimations given that tree rings reflect fine spatial and temporal resolution, thereby reducing the uncertainty in forest carbon budgets.
{"title":"Dendroecological Approach to Assessing Carbon Accumulation Dynamics in Two Pinus Species from Northern Mexico","authors":"M. Pompa-García, A. Venegas‐González, A. A. Júnior, J. A. Sigala-Rodríguez","doi":"10.3959/1536-1098-74.2.196","DOIUrl":"https://doi.org/10.3959/1536-1098-74.2.196","url":null,"abstract":"Abstract Global climate change will alter forests by shifting species ranges, which has implications for their ecological functions. Annual tree-ring widths and wood density are useful proxies for carbon cycle studies across a range of species. Here, using a dendroecological approach we sought to understand the carbon accumulation rates of two representative pine species growing on contrasting wet (P. arizonica) and dry (P. cembroides) sites and reveal how such species cope with climate variability. Although the rate of carbon gain was not significantly different across sites, we found that variations in carbon accumulation responded differently to specific hydroclimate drivers, site conditions, or to functional features of each species, which are still to be explored. Overall, annual carbon accumulation (C) was less sensitive to climate variability than ring width and wood density. Annual C was more sensitive to rainfall in the cold season (P. arizonica) and to the start of spring (both species). Our species-specific approach provided a suitable basis for modeling projections in the long-term carbon balance in these forests. Using species-specific tree-ring data has the potential to yield better estimations given that tree rings reflect fine spatial and temporal resolution, thereby reducing the uncertainty in forest carbon budgets.","PeriodicalId":54416,"journal":{"name":"Tree-Ring Research","volume":"74 1","pages":"196 - 209"},"PeriodicalIF":1.6,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3959/1536-1098-74.2.196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44897620","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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