scholarly journals Disentangling Mechanisms of Drought-Induced Dieback in Pinus nigra Arn. from Growth and Wood Isotope Patterns

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1339
Author(s):  
Ester González de Andrés ◽  
Jesús Julio Camarero
Keyword(s):  
Water Use ◽  
Radial Growth ◽  
Tree Mortality ◽  
Pinus Nigra ◽  
Growth Patterns ◽  
Natural Forests ◽  
Northern Spain ◽  
Hydraulic Failure ◽  
Intrinsic Water Use Efficiency ◽  
Growth Decline

The increased frequency and intensity of warming-induced droughts have triggered dieback episodes affecting many forest types and tree species worldwide. Tree plantations are not exempt as they can be more vulnerable to drought than natural forests because of their lower structural and genetic diversity. Therefore, disentangling the physiological mechanisms leading to growth decline and tree mortality can provide tools to adapt forest management to climate change. In this study, we investigated a Pinus nigra Arn. plantation situated in northern Spain, in which some trees showed canopy dieback and radial-growth decline. We analyzed how radial growth and its responses to drought events differed between non-declining (ND) and declining (D) trees showing low and high canopy defoliation, respectively, in combination with carbon (δ13C) and oxygen (δ18O) isotope ratios in tree rings. The radial growth of P. nigra was constrained by water availability during the growing season and the previous autumn. The radial growth of D trees showed higher sensitivity to drought than ND trees. This fact is in accordance with the lower drought resilience and negative growth trends observed in D trees. Both tree classes differed in their growth from 2012 onwards, with D trees showing a reduced growth compared to ND trees. The positive δ13C-δ18O relationship together with the uncoupling between growth and intrinsic water-use efficiency suggest that D trees have less tight stomatal regulation than ND trees, which could involve a high risk of xylem embolism in the former class. Our results suggest that different water use strategies between coexisting ND and D trees were behind the differences in growth patterns and point to hydraulic failure as a possible mechanism triggering dieback and growth decline.

scholarly journals A synthesis of radial growth patterns preceding tree mortality

2016 ◽  
Vol 23 (4) ◽  
pp. 1675-1690 ◽  
Author(s):  
Maxime Cailleret ◽  
Steven Jansen ◽  
Elisabeth M. R. Robert ◽  
Lucía Desoto ◽  
Tuomas Aakala ◽  
...  
Keyword(s):  
Radial Growth ◽  
Tree Mortality ◽  
Growth Patterns

scholarly journals Radial Growth Patterns Associated with Tree Mortality in Nothofagus pumilio Forest

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 489 ◽  
Author(s):  
Milagros Rodríguez-Catón ◽  
Ricardo Villalba ◽  
Ana Srur ◽  
A. Park Williams
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Forest Dynamics ◽  
Radial Growth ◽  
Tree Mortality ◽  
Growth Patterns ◽  
Severe Drought ◽  
Nothofagus Pumilio ◽  
Total Size ◽  
Growth Trends

Tree mortality is a key process in forest dynamics. Despite decades of effort to understand this process, many uncertainties remain. South American broadleaf species are particularly under-represented in global studies on mortality and forest dynamics. We sampled monospecific broadleaf Nothofagus pumilio forests in northern Patagonia to predict tree mortality based on stem growth. Live or dead conditions in N. pumilio trees can be predicted with high accuracy using growth rate as an explanatory variable in logistic models. In Paso Córdova (CO), Argentina, where the models were calibrated, the probability of death was a strong negative function of radial growth, particularly during the six years prior to death. In addition, negative growth trends during 30 to 45 years prior to death increased the accuracy of the models. The CO site was affected by an extreme drought during the summer 1978–1979, triggering negative trends in radial growth of many trees. Individuals showing below-average and persistent negative trends in radial growth are more likely to die than those showing high growth rates and positive growth trends in recent decades, indicating the key role of droughts in inducing mortality. The models calibrated at the CO site showed high verification skill by accurately predicting tree mortality at two independent sites 76 and 141 km away. Models based on relative growth rates showed the highest and most balanced accuracy for both live and dead individuals. Thus, the death of individuals across different N. pumilio sites was largely determined by the growth rate relative to the total size of the individuals. Our findings highlight episodic severe drought as a triggering mechanism for growth decline and eventual death for N. pumilio, similar to results found previously for several other species around the globe. In the coming decades, many forests globally will be exposed to more frequent and/or severe episodes of reduced warm-season soil moisture. Tree-ring studies such as this one can aid prediction of future changes in forest productivity, mortality, and composition.

scholarly journals Drought Enhances the Role of Competition in Mediating the Relationship between Tree Growth and Climate in Semi-Arid Areas of Northwest China

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 804 ◽  
Author(s):  
Kanglong Lu ◽  
Ning Chen ◽  
Cankun Zhang ◽  
Xiaoxue Dong ◽  
Changming Zhao
Keyword(s):  
Climate Variability ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tree Growth ◽  
Radial Growth ◽  
Intrinsic Water Use Efficiency ◽  
Adverse Weather ◽  
Significant Difference ◽  
Use Efficiency ◽  
The Relationship

Climate variability can exert a powerful impact on biotic competition, but past studies have focused largely on short-lived species, with a lack of attention to long-lived species such as trees. Therefore, there is a need to evaluate how competition regulates the climate-growth relationship in mature trees. We sampled the dominant tree species, Picea wilsonii Mast., on Xinglong Mountain, China, and studied the above issues by analyzing the relationship between tree radial growth, precipitation, and competition. In relatively wet years (precipitation > average), there was no significant difference in climate sensitivity between different competition classes. However, trees suffering from highly competitive stress were more sensitive to climate variability in all years, and particularly in the subset of years that was relatively drought (precipitation < average). These results suggest that competition enhances its ability to regulate tree growth response to climate variability in adverse weather conditions. Competition for resources between trees was asymmetrical, and an increase in height could give trees a disproportionate benefit. Thus, at trunk-level, both basal area incremental growth and intrinsic water-use efficiency of trees subjected to low competitive stress were significantly higher than trees that are subjected to highly competitive stress. Although the intrinsic water-use efficiency of trees under highly competitive stress increased more rapidly as the drought level increases, this did not change the fact that the radial growth of them declined more. Our research is valuable for the development of individual-tree growth models and advances our understanding for forest management under global climate change.

scholarly journals Dwarf Mistletoe and Drought Contribute to Growth Decline, Dieback and Mortality of Junipers

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1199
Author(s):  
Elisa Tamudo ◽  
J. Julio Camarero ◽  
Gabriel Sangüesa-Barreda ◽  
José Daniel Anadón
Keyword(s):  
Radial Growth ◽  
Elevated Temperatures ◽  
Negative Impact ◽  
Climatic Factors ◽  
Summer Precipitation ◽  
Growth Patterns ◽  
Drought Severity ◽  
Dwarf Mistletoe ◽  
The North ◽  
Growth Decline

Rising temperatures and aridification, combined with the stressing effect of some hemiparasitic plants such as mistletoes, may contribute to reduce vigour and growth of trees and shrubs leading to dieback and increasing mortality. This has been rarely explored in pioneer shrubs such as junipers, which are assumed to be more drought tolerant than coexisting trees. To test these ideas, we reconstructed radial growth patterns of common junipers (Juniperus communis L.) with different crown cover and infestation degree by dwarf mistletoe (Arceuthobium oxycedri (DC.) M. Bieb.) in two sites with contrasting aspect and water availability located in north-eastern Spain. We used dendrochronology to study the response of junipers’ radial growth to climatic factors (temperature, precipitation, and soil moisture), an index of drought severity, and mistletoe infestation. Juniper growth was constrained by elevated temperatures and low precipitation leading to drought during the growing season. Infestation by dwarf mistletoe contributed to a short-term growth decline in junipers. The interaction between low summer precipitation and high dwarf mistletoe infestation constrained juniper growth, particularly in the north-oriented wetter site, where hosts presented higher growth rates during wet periods. The negative impact of low summer precipitation on juniper growth overrides the effects due to dwarf mistletoe infestation. Aridification and mistletoe infestation could trigger dieback and mortality of shrubs slowing down successional dynamics and delaying shrub encroachment into former croplands and grasslands.

scholarly journals Oak Competition Dominates Interspecific Interactions in Growth and Water-Use Efficiency in a Mixed Pine–Oak Mediterranean Forest

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1093
Author(s):  
Juan Pedro Ferrio ◽  
Tatiana A. Shestakova ◽  
Jorge del Castillo ◽  
Jordi Voltas
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Interspecific Interactions ◽  
Growth Patterns ◽  
Climate Response ◽  
Niche Segregation ◽  
Mixed Stands ◽  
Positive Effects ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

In the Mediterranean, mixed forests of Aleppo pine and holm oak are widespread. Generally considered a transition stage in the succession towards climax oak communities, niche segregation may also contribute to the prevalence of these communities. So far, there is increasing evidence of hydrological niche segregation, with the two species showing complementary water use and seasonal growth patterns. However, it remains unknown whether interspecific interactions affect the response to climate and the mid-term (decadal) growth and water-use efficiency of pines and oaks in mixed stands. Here, we combined tree-ring chronologies, built on different competition classes within a mixed stand, with a spatially explicit assessment of individual growth and wood carbon isotope discrimination (∆13C), as a proxy of intrinsic water-use efficiency, and compared these results with previously reported water uptake patterns. We found that competition with pines modulated the climate response of oaks, whereas pine climate response was insensitive to competition. On the other hand, pine density affected only pine growth, whereas oak competition affected both species. We conclude that the presence of pines had negligible or even positive effects on the oaks, but competition with neighbor oaks limited their ability to recover after drought. Conversely, pines experienced greater drought stress under competition, with both oaks and pines.

scholarly journals Drought-induced mortality selectively affects Scots pine trees that show limited intrinsic water-use efficiency responsiveness to raising atmospheric CO2

2014 ◽  
Vol 41 (3) ◽  
pp. 244 ◽  
Author(s):  
Ana-Maria Hereş ◽  
Jordi Voltas ◽  
Bernat Claramunt López ◽  
Jordi Martínez-Vilalta
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Mortality ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Growth Enhancement ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
The Impact

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.

An invasive urban forest pest invades natural environments — Asian longhorned beetle in northeastern US hardwood forests

2011 ◽  
Vol 41 (9) ◽  
pp. 1729-1742 ◽  
Author(s):  
Kevin J. Dodds ◽  
David A. Orwig
Keyword(s):  
Acer Saccharum ◽  
Radial Growth ◽  
Urban Forest ◽  
Ring Width ◽  
Acer Rubrum ◽  
Growth Patterns ◽  
Natural Environments ◽  
Longhorned Beetle ◽  
Natural Forests ◽  
Asian Longhorned Beetle

An infestation of Asian longhorned beetle (ALB) ( Anoplophora glabripennis (Motschulsky)) was detected in Worcester, Massachusetts, in 2008. The discovery of this pest, previously only seen in urban environments of North America, led to the unprecedented establishment of a 243 km2quarantine zone that included urban parks, neighborhoods, and natural forests. Because ALB behavior in forested stands is virtually unknown, two closed-canopied forested stands (Bovenzi and Delaval) infested with ALB within this zone were sampled during 2008–2010 to document stand conditions, assess ALB host selection, and determine ALB impact on tree growth. Thirty-two percent of the Acer sampled in Bovenzi were infested with ALB compared with 63% in Delaval. In Delaval where three maple host species were available, ALB was found more often in Acer rubrum L. than in Acer saccharum Marsh. or Acer platanoides L. Radial growth patterns did not differ between ALB-infested and uninfested Acer trees in Bovenzi. In contrast, ALB-infested trees in Delaval were significantly older and larger than uninfested trees and exhibited slower radial growth and ring width index patterns compared with uninfested trees. Results suggest that if left uncontrolled, ALB can readily disperse into natural forest landscapes and alter the makeup of North America’s hardwood forest region.

Sign in / Sign up

Export Citation Format

Share Document