scholarly journals Climate Differently Impacts the Growth of Coexisting Trees and Shrubs under Semi-Arid Mediterranean Conditions

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero
Keyword(s):  
Soil Moisture ◽  
Radial Growth ◽  
Pinus Halepensis ◽  
Growth Dynamics ◽  
Early Summer ◽  
Growth Responses ◽  
Shrub Species ◽  
High Soil Moisture ◽  
Semi Arid ◽  
Mediterranean Conditions

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.

scholarly journals Relating Climate, Drought and Radial Growth in Broadleaf Mediterranean Tree and Shrub Species: A New Approach to Quantify Climate-Growth Relationships

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1250
Author(s):  
J. Julio Camarero ◽  
Álvaro Rubio-Cuadrado
Keyword(s):  
Radial Growth ◽  
Explanatory Power ◽  
Ring Width ◽  
Early Summer ◽  
Theoretic Approach ◽  
Growth Responses ◽  
Functional Responses ◽  
Shrub Species ◽  
Information Theoretic ◽  
Correlation Analyses

The quantification of climate–growth relationships is a fundamental step in tree-ring sciences. This allows the assessment of functional responses to climate warming, particularly in biodiversity and climate-change hotspots including the Mediterranean Basin. In this region, broadleaf tree and shrub species of pre-Mediterranean, subtropical origin, have to withstand increased aridification trends. However, they have not been widely studied to assess their long-term growth responses to climate and drought. Since these species evolved under less seasonal and wetter conditions than strictly Mediterranean species, we hypothesized that their growth would mainly respond to higher precipitation and water availability from spring to early summer. Here, we quantified climate–growth relationships in five of these broadleaf species showing different leaf phenology and wood type (Pistacia terebinthus L., Pistacia lentiscus L., Arbutus unedo L., Celtis australis L., and Laurus nobilis L.) by using dendrochronology. We calculated Pearson correlations between crossdated, indexed, mean ring width series of each species (chronologies) and monthly climate variables (mean temperature, total precipitation). We also calculated correlations between the species’ chronologies and a drought index on 7-day scales. Lastly, we compared the correlation analyses with “climwin” analyses based on an information-theoretic approach and subjected to cross-validation and randomization tests. As expected, the growth of all species was enhanced in response to wet and cool conditions during spring and early summer. In some species (P. lentiscus, A. unedo, C. australis,) high prior-winter precipitation also enhanced growth. Growth of most species strongly responded to 9-month droughts and the correlations peaked from May to July, except in L. nobilis which showed moderate responses. The “climwin” analyses refined the correlation analyses by (i) showing the higher explanatory power of precipitation (30%) vs. temperature (7%) models, (ii) selecting the most influential climate windows with June as the median month, and (iii) providing significant support to the precipitation model in the case of P. terebinthus confirming that the radial growth of this species is a robust proxy of hydroclimate variability. We argue that “climwin” and similar frameworks based on information-theoretic approaches should be applied by dendroecologists to critically assess and quantify climate–growth relationships in woody plants with dendrochronological potential.

Radial growth responses of post oak (Quercus stellata) to climate variability and management in southeastern Oklahoma, USA

2021 ◽  
Author(s):  
Arjun Adhikari ◽  
Ronald E. Masters ◽  
Henry D. Adams ◽  
Rodney E. Will
Keyword(s):  
Climate Variability ◽  
Prescribed Fire ◽  
Radial Growth ◽  
Early Summer ◽  
Late Spring ◽  
Daily Temperature ◽  
Daily Minimum Temperature ◽  
Growth Responses ◽  
Post Oak ◽  
Quercus Stellata

We investigated radial growth of post oak (Quercus stellata) growing in a range of stand structures (forest to savanna) created in 1984 by different harvesting and thinning treatments followed by different prescribed fire intervals. We related ring width index (RWI) to monthly and seasonal climate variables and time since fire to assess impacts of climate variability and interactions with management on radial growth. RWI of all treatments was positively correlated to minimum daily temperature the previous September and precipitation late spring/early summer the current-year, and negatively correlated to maximum daily temperatures and drought index late spring/early summer. June weather was most strongly correlated in four of five treatments. While stand structure affected absolute diameter growth, RWI of savanna and forest stands responded similarly to climate variability, and low intensity prescribed fire did not influence RWI. On average, 100 mm reduction in June precipitation decreased RWI by 8%, 1oC increase in previous-year September daily minimum temperature increased RWI by 3.5%, and 1oC increase in June maximum daily temperature decreased RWI by 3.7%. Therefore, negative effects of drought and warmer spring/summer temperatures may be reduced by longer growing seasons under warmer climate scenarios. However, management did not appear to influence RWI.

Radial growth responses of Pinus halepensis Mill. and Pinus pinea L. forests to climate variability in Western Albania

2015 ◽  
Vol 42 (1) ◽  
Author(s):  
Elvin Toromani ◽  
Edmond Pasho ◽  
Arben Q. Alla ◽  
Vasillaq Mine ◽  
Nehat Çollaku
Keyword(s):  
Tree Ring ◽  
Radial Growth ◽  
Pinus Halepensis ◽  
Potential Evapotranspiration ◽  
Late Summer ◽  
Pinus Pinea ◽  
Growth Responses ◽  
Climate Conditions ◽  
Early Autumn ◽  
Mediterranean Countries

Abstract In this study are presented chronologies of earlywood (EW), latewood (LW) and tree-ring widths (RW) of a Pinus halepensis (P. halepensis) and Pinus pinea (P. pinea) natural forest stand growing in western Albania. Bootstrapped correlations and pointer year analysis were combined in a dendroclimatological study to evaluate climate-growth relationships in both pine species as well as to assess the spatial outreach of our chronologies evaluating them with those of the same species from other Mediterranean countries. We found that both species responded positively to precipitation and Indexed Percentage Average Precipitation (%AvP) in late summer-early autumn, particularly the LW, whereas summer temperatures constrained the growth of P. halepensis tree-ring features. Current January temperature and Potential Evapotranspiration (PET) showed positive relationship with P. pinea LW and RW. The same association was observed when considering PET in spring and P. halepensis LW and RW. Pointer year analysis showed that inhibitory climatic drivers of radial growth for both species were low precipitation from previous winter and current summer, associated with low temperatures during autumn. Our P. halepensis chronology showed a wider spatial outreach than that of P. pinea when compared to those from other Mediterranean countries. We conclude that current January temperatures and September precipitation are very important for P. pinea growth influencing both EW and LW growth whereas P. halepensis is mostly affected by the summer-early autumn climate conditions.

scholarly journals Examining the relationship between intermediate scale soil moisture and terrestrial evaporation within a semi-arid grassland

2016 ◽  
Author(s):  
Raghavendra B. Jana ◽  
Ali Ershadi ◽  
Matthew F. McCabe
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Root Zone ◽  
Water Cycle ◽  
Cosmic Ray ◽  
Moisture Distribution ◽  
Observation Data ◽  
Cold Temperatures ◽  
High Soil Moisture ◽  
Semi Arid

Abstract. Interactions between soil moisture and terrestrial evaporation affect water cycle behaviour and responses between the land surface and the atmosphere across scales. With strong heterogeneities at the land surface, the inherent spatial variability in soil moisture makes its representation via point-scale measurements challenging, resulting in scale-mismatch when compared to coarser-resolution satellite-based soil moisture or evaporation estimates. The Cosmic Ray Soil Moisture Observing System (COSMOS) was developed to address such issues in the measurement and representation of soil moisture at intermediate scales. Here we present an examination of the links observed between COSMOS soil moisture retrievals and evaporation estimates over a pasture in the semi-arid central-west region of New South Wales, Australia. The COSMOS soil moisture product was compared to evaporation derived from three distinct approaches, including the Priestley-Taylor (PT-JPL), Penman-Monteith (PM-Mu) and Surface Energy Balance System (SEBS) models, driven by forcing data from local meteorological station data and remote sensing retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Pearson’s Correlations, Quantile-Quantile (Q-Q) plots, and Analysis of Variance (ANOVA) were used to qualitatively and quantitatively evaluate the temporal distributions of soil moisture and evaporation over the study site. The relationships were examined against nearly two years of observation data, as well as for different seasons and for defined periods of analysis. Results highlight that while direct correlations of raw data were not particularly instructive, the Q-Q plots and ANOVA illustrate that the root-zone soil moisture represented by the COSMOS measurements and the modelled evaporation estimates reflect similar distributions under most meteorological conditions. The PT-JPL and PM-Mu model estimates performed contrary to expectation when high soil moisture and cold temperatures were present, while SEBS model estimates displayed a disconnect from the soil moisture distribution in summers with long dry spells. Importantly, no single evaporation model matched the statistical distribution of the measured soil moisture for the entire period, highlighting the challenges in effectively capturing evaporative flux response within changing landscapes.

Influence of Fire and Edaphic Factors on Germination of the Arid Zone Shrubs Acacia aneura, Cassia nemophila and Dodonaea Viscosa

1990 ◽  
Vol 38 (3) ◽  
pp. 269 ◽  
Author(s):  
KC Hodgkinson ◽  
RE Oxley
Keyword(s):  
Soil Moisture ◽  
Arid Zone ◽  
Moisture Level ◽  
Fuel Load ◽  
Dodonaea Viscosa ◽  
Shrub Species ◽  
Soil Moisture Level ◽  
Germination Response ◽  
Acacia Aneura ◽  
Semi Arid

The germination of some shrub species may be enhanced following fire in shrublands and woodlands. This paper reports the germination response of Acacia aneura, Cassia nemophila and Dodonaea viscosa - common shrub species in semi-arid and arid woodlands - to laboratory fires over a range of intensities and durations. Seeds were subjected to fires of different intensities in the controlled environment of a glasshouse. Depth of seed placement in the soil, soil moisture level and amount and type of fuel influenced the percentage of seeds that germinated. Amounts of shredded paper fuel, equivalent to typical grass fuel levels in semi-arid woodlands did not enhance the germinability of seeds of any of the species, except for A. aneura on a moist or wet soil surface. A high, dense fuel load (simulating slow burning, low- intensity litter fires) either increased or decreased the germinability of surface and buried seeds of all species, depending upon soil moisture level and depth of seeds. The germination response to the heat of fires differed significantly between species: A . Aneura germination increased substantially at low levels of peak temperature up to 60°C whereas germination of C. nemophila increased to a lesser extent and D. viscosa was not affected at all over this low temperature range. Seeds of all species were killed by slow burning litter fires when the temperature exceeded 80°C. These results confirm the view that fire- promoted germination does not result from the burning of fine fuels per se but occurs only where there is litter buildup and when the soil temperature does not exceed the lethal threshold of 70-80°C.

Evaluation of Presswheels and Seed Coverers for Direct Seeding of Brassica

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Visual Observation ◽  
Mustard Seed ◽  
High Soil Moisture ◽  
Loam Soil ◽  
Direct Seeded ◽  
Plant Emergence ◽  
Moisture Conditions ◽  
Determine Effect

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

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

Forests ◽  
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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