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

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.

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Radial Growth Decline of White Spruce (Picea glauca) During Hot Summers without Drought: Preliminary Results from a Study Site South of a Boreal Forest Border

Canadian Journal of Forest Research ◽

10.1139/cjfr-2021-0268 ◽

2022 ◽

Author(s):

Andrei Lapenis ◽

George Robinson ◽

Gregory B. Lawrence

Keyword(s):

New York ◽

Boreal Forest ◽

Picea Glauca ◽

Radial Growth ◽

Summer Precipitation ◽

White Spruce ◽

Southern Limit ◽

Central New York ◽

Growth Decline ◽

Hot Days

Here we investigate the possible<sup></sup> future response of white spruce (Picea glauca) to a warmer climate by studying trees planted 90 years ago near the southern limit of their climate tolerance in central New York, 300 km south of the boreal forest where this species is prevalent. We employed high-frequency recording dendrometers to determine radial growth phenology of six mature white spruce trees during 2013-2017. Results demonstrate significant reductions in the length of radial growth periods inversely proportional to the number of hot days with air temperature exceeding 30 oC. During years with very hot summers, the start of radial growth began about 3 days earlier than the 2013-2017 average. However, in those same years the end of radial growth was also about 17 days earlier resulting in a shorter (70 versus 100 day), radial growth season. Abundant (350-500 mm) summer precipitation, which resulted in soil moisture values of 20-30% allowed us to dismiss drought as a factor. Instead, a likely cause of reduced radial growth was mean temperature that exceeded daily average of 30<sup> o</sup>C that lead to photoinhibition.

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Influences of climate on the radial growth of lodgepole pine in Alberta

Botany ◽

10.1139/b07-120 ◽

2008 ◽

Vol 86 (2) ◽

pp. 167-178 ◽

Cited By ~ 17

Author(s):

Sophan Chhin ◽

E.H. (Ted) Hogg ◽

Victor J. Lieffers ◽

Shongming Huang

Keyword(s):

Radial Growth ◽

Climatic Factors ◽

Lodgepole Pine ◽

Regional Growth ◽

Regional Scale ◽

Summer Precipitation ◽

Late Summer ◽

Moisture Stress ◽

Late Winter ◽

Spring Precipitation

We examined a network of 17 lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) sites in Alberta in the cordilleran forests along the eastern slopes of the Rocky Mountains and in western Cypress Hills, using a dendrochronological approach to identify the principal climatic factors that have influenced the historical, regional-scale pattern of radial growth of lodgepole pine. Correlation and regression analysis of the regional growth–climate relationships showed that radial growth was negatively associated with late-summer temperatures, and positively related to the late-summer precipitation totals from the previous growth season. Radial growth also responded positively to winter and spring temperatures, and was negatively related to late winter–early spring precipitation. The results suggested that the lag in response to heat and moisture stress, cold and snowy winters, and the length of the current growing season are important determinants of the radial growth of lodgepole pine in Alberta.

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Effects of climate on radial growth of subalpine conifers in the North Cascade Mountains

Canadian Journal of Forest Research ◽

10.1139/x94-247 ◽

1994 ◽

Vol 24 (9) ◽

pp. 1921-1932 ◽

Cited By ~ 74

Author(s):

David W. Peterson ◽

David L. Peterson

Keyword(s):

Radial Growth ◽

Growth Response ◽

Growth Patterns ◽

Future Climate Change ◽

Summer Drought ◽

Cascade Mountains ◽

Subalpine Fir ◽

Species Response ◽

Engelmann Spruce ◽

The North

Dendroecological techniques were used to study the influence of climate on the growth of subalpine fir (Abieslasiocarpa (Hook.) Nutt.), Engelmann spruce (Piceaengelmannii Parry), and subalpine larch (Larixlyallii Parl.) in the North Cascade Mountains of Washington state. Study sites were selected on different topographic features at three points along an elevation gradient (ridgetop, valley slope, and valley floor) to characterize site influences on growth response to climate. Mixed species stands were sampled to identify possible differences in species response to climate on a common site. Species differences account for most of the variability in radial growth patterns and response to climate. The greatest differences are between subalpine fir and subalpine larch, while the greatest similarities are between subalpine fir and Engelmann spruce. After species, aspect is the most significant factor affecting growth response to climate. Spring snowpack and summer temperature are the primary climatic factors influencing growth. Spring snowpack is negatively correlated with growth for all three species, but the relationship is strongest for subalpine fir and weakest for subalpine larch. Subalpine larch growth is positively correlated with June temperature. Subalpine fir growth is positively correlated with July–August temperature. Engelmann spruce growth is positively correlated with June–August temperature, but unusually warm July–August temperatures are associated with reduced growth the following year. The response of subalpine forests in the North Cascades to future climate change will depend on winter snowpack accumulations and spring snowmelt rates. Earlier meltouts and warmer summers would benefit growth on north aspect sites, but could also increase the frequency and severity of summer drought conditions on ridges and south-aspect sites, where summer soil moisture may already be limiting.

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Radial growth patterns and the effects of climate on second-growth Douglas-fir (Pseudotsugamenziesii) in the Siskiyou Mountains, Oregon

Canadian Journal of Forest Research ◽

10.1139/x95-080 ◽

1995 ◽

Vol 25 (5) ◽

pp. 724-735 ◽

Cited By ~ 20

Author(s):

Ronda L. Little ◽

David L. Peterson ◽

David G. Silsbee ◽

Lauri J. Shainsky ◽

Larry F. Bednar

Keyword(s):

Soil Moisture ◽

Radial Growth ◽

Moisture Stress ◽

Climatic Conditions ◽

Douglas Fir ◽

Growth Patterns ◽

Carbon Gain ◽

Drought Severity ◽

Soil Moisture Stress ◽

Second Growth

Three sites with fire-generated second-growth (70–100 years old) Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in southwestern Oregon were examined using dendroecological techniques to determine (1) temporal patterns of radial growth and (2) the effects of variation in climate on growth. Long-term patterns of radial growth vary among sites, but similar interannual variation in radial growth indicates a common response to regional climate. Growth is positively correlated with the Palmer Drought Severity Index and precipitation during summer. Furthermore, growth is positively correlated with precipitation during autumn prior to the growth year, which suggests the benefits of soil moisture recharge for subsequent stemwood production. Annual precipitation is strongly seasonal, and soil moisture stress in summer is apparently severe enough to be the dominant climatic influence on radial growth. Positive correlations of growth with most monthly temperatures reflect the benefit of warm temperatures on photosynthesis and radial growth during periods of adequate soil moisture. Although coastal Oregon is generally considered to be a high precipitation environment, conditions are clearly dry enough during summer to limit carbon gain in second-growth Douglas-fir. If future climatic conditions result in increased soil moisture stress during summer, productivity of such second-growth stands may decrease below current levels.

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The impacts of climatic factors on radial growth patterns at different stem heights in Schrenk spruce (Picea schrenkiana)

Trees ◽

10.1007/s00468-019-01908-4 ◽

2019 ◽

Vol 34 (1) ◽

pp. 163-175 ◽

Cited By ~ 1

Author(s):

Tongwen Zhang ◽

Liping Huang ◽

Ruibo Zhang ◽

Yaqi Gao ◽

Dongyu Hu ◽

...

Keyword(s):

Radial Growth ◽

Climatic Factors ◽

Growth Patterns ◽

Picea Schrenkiana

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

Forests ◽

10.3390/f11121339 ◽

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.

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Assessment of the Reactions of Algal Communities to Influence of Climatic Factors in the North-Western Black Sea Ecosystem

International Journal on Algae ◽

10.1615/interjalgae.v20.i2.20 ◽

2018 ◽

Vol 20 (2) ◽

pp. 121-134 ◽

Cited By ~ 1

Author(s):

G. G. Minicheva ◽

V. N. Bolshakov ◽

E. S. Kalashnik ◽

A. B. Zotov ◽

A. V. Marinets

Keyword(s):

Black Sea ◽

Climatic Factors ◽

Algal Communities ◽

The North ◽

North Western

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Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽

10.3390/f12081015 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1015

Author(s):

Xuan Wu ◽

Liang Jiao ◽

Dashi Du ◽

Changliang Qi ◽

Ruhong Xue

Keyword(s):

Climate Change ◽

Tree Growth ◽

Central Region ◽

Radial Growth ◽

Growing Season ◽

Qilian Mountains ◽

Growth Patterns ◽

Total Precipitation ◽

Picea Crassifolia ◽

The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

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Radial Growth Response of European Larch Provenances to Interannual Climate Variation in Poland

Forests ◽

10.3390/f12030334 ◽

2021 ◽

Vol 12 (3) ◽

pp. 334

Author(s):

Norbert Szymański ◽

Sławomir Wilczyński

Keyword(s):

Radial Growth ◽

Climatic Factors ◽

Principal Component ◽

Climatic Conditions ◽

Growth Responses ◽

European Larch ◽

Temperature And Precipitation ◽

Provenance Trials ◽

High Precipitation ◽

Climatic Elements

The present study identified the similarities and differences in the radial growth responses of 20 provenances of 51-year-old European larch (Larix decidua Mill.) trees from Poland to the climatic conditions at three provenance trials situated in the Polish lowlands (Siemianice), uplands (Bliżyn) and mountains (Krynica). A chronology of radial growth indices was developed for each of 60 European larch populations, which highlighted the interannual variations in the climate-mediated radial growth of their trees. With the aid of principal component, correlation and multiple regression analysis, supra-regional climatic elements were identified to which all the larch provenances reacted similarly at all three provenance trials. They increased the radial growth in years with a short, warm and precipitation-rich winter; a cool and humid summer and when high precipitation in late autumn of the previous year was noted. Moreover, other climatic elements were identified to which two groups of the larch provenances reacted differently at each provenance trial. In the lowland climate, the provenances reacted differently to temperature in November to December of the previous year and July and to precipitation in September. In the upland climate, the provenances differed in growth sensitivity to precipitation in October of the previous year and June–September. In the mountain climate, the provenances responded differently to temperature and precipitation in September of the previous year and to precipitation in February, June and September of the year of tree ring formation. The results imply that both climatic factors and origin (genotype), i.e., the genetic factor, mediate the climate–growth relationships of larch provenances.

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Assessing the Sensitivity of Main Crop Yields to Climate Change Impacts in China

Atmosphere ◽

10.3390/atmos12020172 ◽

2021 ◽

Vol 12 (2) ◽

pp. 172

Author(s):

Yuan Xu ◽

Jieming Chou ◽

Fan Yang ◽

Mingyang Sun ◽

Weixing Zhao ◽

...

Keyword(s):

Climate Change ◽

Crop Yield ◽

Food Production ◽

Crop Yields ◽

Climatic Factors ◽

Climatic Data ◽

The South ◽

The North ◽

Output Elasticity ◽

The Impact

Quantitatively assessing the spatial divergence of the sensitivity of crop yield to climate change is of great significance for reducing the climate change risk to food production. We use socio-economic and climatic data from 1981 to 2015 to examine how climate variability led to variation in yield, as simulated by an economy–climate model (C-D-C). The sensitivity of crop yield to the impact of climate change refers to the change in yield caused by changing climatic factors under the condition of constant non-climatic factors. An ‘output elasticity of comprehensive climate factor (CCF)’ approach determines the sensitivity, using the yields per hectare for grain, rice, wheat and maize in China’s main grain-producing areas as a case study. The results show that the CCF has a negative trend at a rate of −0.84/(10a) in the North region, while a positive trend of 0.79/(10a) is observed for the South region. Climate change promotes the ensemble increase in yields, and the contribution of agricultural labor force and total mechanical power to yields are greater, indicating that the yield in major grain-producing areas mainly depends on labor resources and the level of mechanization. However, the sensitivities to climate change of different crop yields to climate change present obvious regional differences: the sensitivity to climate change of the yield per hectare for maize in the North region was stronger than that in the South region. Therefore, the increase in the yield per hectare for maize in the North region due to the positive impacts of climate change was greater than that in the South region. In contrast, the sensitivity to climate change of the yield per hectare for rice in the South region was stronger than that in the North region. Furthermore, the sensitivity to climate change of maize per hectare yield was stronger than that of rice and wheat in the North region, and that of rice was the highest of the three crop yields in the South region. Finally, the economy–climate sensitivity zones of different crops were determined by the output elasticity of the CCF to help adapt to climate change and prevent food production risks.

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