Temporal controls on crown nonstructural carbohydrates in southwestern US tree species

2020 ◽  
Author(s):  
Drew M P Peltier ◽  
Jessica Guo ◽  
Phiyen Nguyen ◽  
Michael Bangs ◽  
Linnea Gear ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Populus Tremuloides ◽  
Tree Species ◽  
Supply And Demand ◽  
Soluble Sugars ◽  
Ring Width ◽  
Moisture Stress ◽  
Strong Interactions ◽  
Nonstructural Carbohydrates

Abstract In trees, large uncertainties remain in how nonstructural carbohydrates (NSCs) respond to variation in water availability in natural, intact ecosystems. Variation in NSC pools reflects temporal fluctuations in supply and demand, as well as physiological coordination across tree organs in ways that differ across species and NSC fractions (e.g., soluble sugars vs starch). Using landscape-scale crown (leaves and twigs) NSC concentration measurements in three foundation tree species (Populus tremuloides, Pinus edulis, Juniperus osteosperma), we evaluated in situ, seasonal variation in NSC responses to moisture stress on three timescales: short-term (via predawn water potential), seasonal (via leaf δ13C) and annual (via current year’s ring width index). Crown NSC responses to moisture stress appeared to depend on hydraulic strategy, where J. osteosperma appears to regulate osmotic potentials (via higher sugar concentrations), P. edulis NSC responses suggest respiratory depletion and P. tremuloides responses were consistent with direct sink limitations. We also show that overly simplistic models can mask seasonal and tissue variation in NSC responses, as well as strong interactions among moisture stress at different timescales. In general, our results suggest large seasonal variation in crown NSC concentrations reflecting the multiple cofunctions of NSCs in plant tissues, including storage, growth and osmotic regulation of hydraulically vulnerable leaves. We emphasize that crown NSC pool size cannot be viewed as a simple physiological metric of stress; in situ NSC dynamics are complex, varying temporally, across species, among NSC fractions and among tissue types.

How anatomical and morphological characteristics affect the flexural properties of two angiosperm species at the sapling stage

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5843-5858
Author(s):  
Seray Özden Keleş
Keyword(s):  
Tree Species ◽  
Ring Width ◽  
Morphological Characteristics ◽  
Deciduous Tree ◽  
Flexural Properties ◽  
Functional Stability ◽  
Growth Stability ◽  
Fagus Orientalis Lipsky ◽  
Angiosperm Species ◽  
Common Oak

The sapling stage is an important phase due to maintaining plant growth, stability, and survival over the life cycle of trees. However, there are limited investigations in the literature related to both growth and stability of different tree species. This study thus investigated how different tree species at the sapling stage showed different anatomical, morphological, and flexural traits despite being of similar age and growing under the same environmental conditions. The variation of sapling properties was determined in two deciduous tree species: common oak (Quercus robur L.) and Oriental beech (Fagus orientalis Lipsky). The results of anatomical and morphological measurements showed that the highest average values of ray length, ray width, pith radius, pith%, bark%, and node numbers were obtained in oak saplings, whereas average ring width, number of rays, and wood% were found to be higher in beech saplings. Oak also exhibited better functional stability in its saplings. The flexural properties were almost 60% greater in oak stems than beech stems. The variations in flexural properties were explained by the morphological and anatomical traits since stability was positively correlated with pith radius, pith%, and bark% and negatively correlated with the number of rays and wood%.

scholarly journals Contrasting Signals of the Westerly Index and North Atlantic Oscillation over the Drought Sensitivity of Tree-Ring Chronologies from the Mediterranean Basin

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 644 ◽  
Author(s):  
Pablo Casas-Gómez ◽  
Raúl Sánchez-Salguero ◽  
Pedro Ribera ◽  
Juan C. Linares
Keyword(s):  
North Atlantic Oscillation ◽  
Tree Ring ◽  
North Atlantic ◽  
Tree Species ◽  
Ring Width ◽  
Pinus Nigra ◽  
Western Mediterranean ◽  
Drought Severity ◽  
Drought Sensitivity ◽  
Westerly Index

Extreme drought events are becoming increasingly frequent and extended, particularly in Mediterranean drought-prone regions. In this sense, atmospheric oscillations patterns, such as those represented by the North Atlantic Oscillation (NAO) index and the Westerly Index (WI) have been widely proven as reliable proxies of drought trends. Here, we used the Standardized Precipitation–Evapotranspiration Index (SPEI), as a reliable indicator of drought, to investigate the drought sensitivity of tree-ring width data (TRW) from several long-lived tree species (Abies borisii-regis, Abies cilicica, Abies pinsapo, Cedrus atlantica, Cedrus libanii, Pinus nigra, Pinus heldreichii). NAO and WI relations with TRW were also investigated in order to identify potential non-stationary responses among those drought proxies. Our temporal and spatial analyses support contrasting Mediterranean dipole patterns regarding the drought sensitivity of tree growth for each tree species. The spatial assessment of NAO and WI relationships regarding SPEI and TRW showed on average stronger correlations westward with non-stationary correlations between annual WI index and TRW in all species. The results indicate that the drought variability and the inferred drought-sensitive trees species (e.g., C. atlantica) are related to the NAO and the WI, showing that TRW is a feasible proxy to long-term reconstructions of Westerly Index (WI) variability in the Western Mediterranean region. Spatial variability of drought severity suggests a complex association between NAO and WI, likely modulated by an east–west Mediterranean climate dipole.

scholarly journals Improved understanding of drought controls on seasonal variation in Mediterranean forest canopy CO<sub>2</sub> and water fluxes through combined in situ measurements and ecosystem modelling

2009 ◽  
Vol 6 (8) ◽  
pp. 1423-1444 ◽  
Author(s):  
T. Keenan ◽  
R. García ◽  
A. D. Friend ◽  
S. Zaehle ◽  
C. Gracia ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Canopy ◽  
Moisture Stress ◽  
Mediterranean Ecosystems ◽  
Forest Growth ◽  
Water Fluxes ◽  
Soil Moisture Stress ◽  
Dynamic Global Vegetation Model ◽  
Forest Growth Model

Abstract. Water stress is a defining characteristic of Mediterranean ecosystems, and is likely to become more severe in the coming decades. Simulation models are key tools for making predictions, but our current understanding of how soil moisture controls ecosystem functioning is not sufficient to adequately constrain parameterisations. Canopy-scale flux data from four forest ecosystems with Mediterranean-type climates were used in order to analyse the physiological controls on carbon and water flues through the year. Significant non-stomatal limitations on photosynthesis were detected, along with lesser changes in the conductance-assimilation relationship. New model parameterisations were derived and implemented in two contrasting modelling approaches. The effectiveness of two models, one a dynamic global vegetation model ("ORCHIDEE"), and the other a forest growth model particularly developed for Mediterranean simulations ("GOTILWA+"), was assessed and modelled canopy responses to seasonal changes in soil moisture were analysed in comparison with in situ flux measurements. In contrast to commonly held assumptions, we find that changing the ratio of conductance to assimilation under natural, seasonally-developing, soil moisture stress is not sufficient to reproduce forest canopy CO2 and water fluxes. However, accurate predictions of both CO2 and water fluxes under all soil moisture levels encountered in the field are obtained if photosynthetic capacity is assumed to vary with soil moisture. This new parameterisation has important consequences for simulated responses of carbon and water fluxes to seasonal soil moisture stress, and should greatly improve our ability to anticipate future impacts of climate changes on the functioning of ecosystems in Mediterranean-type climates.

scholarly journals Zuwachs und Klimasensitivität von Baumarten im Ökogramm der kollinen und submontanen Stufe

2015 ◽  
Vol 166 (6) ◽  
pp. 380-388 ◽  
Author(s):  
Pascale Weber ◽  
Caroline Heiri ◽  
Mathieu Lévesque ◽  
Tanja Sanders ◽  
Volodymyr Trotsiuk ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Properties ◽  
Climate Sensitivity ◽  
Tree Species ◽  
Ring Width ◽  
Basal Area ◽  
Growth Potential ◽  
Basal Area Increment ◽  
Tree Ring Data ◽  
Mean Sensitivity

Growth potential and climate sensitivity of tree species in the ecogram for the colline and submontane zone In forestry practice a large amount of empirical knowledge exists about the productivity of individual tree species in relation to site properties. However, so far, only few scientific studies have investigated the influence of soil properties on the growth potential of various tree species along gradients of soil water as well as nutrient availability. Thus, there is a research gap to estimate the productivity and climate sensitivity of tree species under climate change, especially regarding productive sites and forest ad-mixtures in the lower elevations. Using what we call a «growth ecogram», we demonstrate species- and site-specific patterns of mean annual basal area increment and mean sensitivity of ring width (strength of year-to-year variation) for Fagus sylvatica, Quercus spp., Fraxinus excelsior, Picea abies, Abies alba and Pinus sylvestris, based on tree-ring data from 508 (co-)dominant trees on 27 locations. For beech, annual basal area increment ( average 1957–2006) was significantly correlated with tree height of the dominant sampling trees and proved itself as a possible alternative for assessing site quality. The fact that dominant trees of the different tree species showed partly similar growth potential within the same ecotype indicates comparable growth limitation by site conditions. Mean sensitivity of ring width – a measure of climate sensitivity – had decreased for oak and ash, while it had increased in pine. Beech showed diverging reactions with increasing sensitivity at productive sites (as measured by the C:N ratio of the topsoil), suggesting an increasing limitation by climate at these sites. Hence, we derive an important role of soil properties in the response of forests to climate change at lower elevations, which should be taken into account when estimating future forest productivity.

scholarly journals Characteristics of Diurnal Rainfall over Peatland Area of South Sumatra, Indonesia

2020 ◽  
Vol 5 (4) ◽  
pp. 136
Author(s):  
Puad Maulana Mandailing ◽  
Wijaya Mardiansyah ◽  
Muhammad Irfan ◽  
Arsali Arsali ◽  
Iskhaq Iskandar
Keyword(s):  
Seasonal Variation ◽  
Early Morning ◽  
Temporal Variations ◽  
In Situ Observation ◽  
Peak Time ◽  
The South ◽  
Night Time ◽  
Late Night ◽  
Diurnal Rainfall

The peak time of rainfall occurrence over an area has certain characteristics in which the difference in time and intensity of rainfall varies depending on its location and distance from the sea. This variation can be determined based on the phase and amplitude obtained using harmonic analysis. In this study, combined data from in-situ observation, satellite remote sensing and reanalysis were used to analyze spatial and temporal variations of peak rainfall events over peatland area of the South Sumatra Province. The results show that most of the South Sumatra Province has a diurnal peak of rainfall during afternoon ranging from 16.00 to 19.00 Western Indonesian Time. In addition, the results also indicate that the analysis on the in situ data revealed seasonal variation both in amplitude and time of maximum diurnal rainfall, while the reanalysis data only indicated a weak seasonal variation on the amplitude of the diurnal rainfall. Furthermore, spatial analysis shows that the time of maximum diurnal rainfall has spatial variation. Over the ocean, the time of maximum diurnal rainfall occurs during night time/early morning. Over the lowland or coastal area, the time of maximum diurnal rainfall occurs during afternoon, while over the high altitude (mountain) it occurs during late night.

In situ ruminal degradation and effective degradation of foliage from six tree species during dry and rainy seasons in Veracruz, Mexico

2018 ◽  
Vol 93 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Lidia Ascencio-Rojas ◽  
Braulio Valles-de la Mora ◽  
Epigmenio Castillo-Gallegos ◽  
Muhammad Ibrahim
Keyword(s):  
Tree Species ◽  
Ruminal Degradation ◽  
Dry And Rainy Seasons

Population Assessment of An Endemic Tree, Croton Scabiosus Bedd. (Euphorbiaceae)

2017 ◽  
Vol 24 (4) ◽  
pp. 209-216
Author(s):  
S. Salamma ◽  
A. Narayanaswamy ◽  
M. Naik ◽  
D. Veeranjaneyulu ◽  
M.V. Babu ◽  
...  
Keyword(s):  
Tree Species ◽  
Random Sampling ◽  
Andhra Pradesh ◽  
Ex Situ Conservation ◽  
Adult Population ◽  
Ex Situ ◽  
Eastern Ghats ◽  
Population Assessment ◽  
Conservation Measures

The population of Croton scabiosus, an endemic tree species of southern Eastern Ghats of Andhra Pradesh, India was assessed through random sampling in 15 localities spread over 8 locations. In sampled 37.5 h area, a total of 8737 mature individuals of Croton scabiosus was recorded. Of the 8 locations, Sanipaya sub population was found stable and considered elite owing to the maximum number of mature individuals, girth and height. In spite of good adult population, low number of seedlings and saplings of the species across the native terrain indicates its poor germination and recruitment warranting both in situ and ex situ conservation measures.

scholarly journals Root Traits Determine Variation in Nonstructural Carbohydrates (NSCs) under Different Drought Intensities and Soil Substrates in Three Temperate Tree Species

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 415 ◽  
Author(s):  
Li Ji ◽  
Khan Attaullah ◽  
Jun Wang ◽  
Dapao Yu ◽  
Yuchun Yang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Environmental Conditions ◽  
Tree Species ◽  
Soluble Sugar ◽  
Specific Root Length ◽  
Root Traits ◽  
Root Tip ◽  
Root Surface Area ◽  
Nonstructural Carbohydrates ◽  
Soil Substrates

Nonstructural carbohydrates (NSCs) are a key factor in the physiological regulation of plants and can reflect buffering capacity of plants under diverse environmental conditions. The effects of diverse environmental conditions on plant NSCs and tissue or organ scales have been thoroughly studied, but their effects on fine root (root diameter < 2 mm) NSC concentrations are still not completely understood. Our aims were to explore the synergistic fluctuations in root traits and NSC concentrations under diverse environmental conditions. This study was conducted on two-year-old temperate seedling tree species (Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., and Phellodendron amurense Rupr.) with different drought intensities and soil substrates. The specific root length (SRL) and specific root surface area (SRA) were significantly affected by drought intensities and soil substrates, while the root tissue density (RTD) and average diameter (AD) were not significantly affected by water intensities and soil substrates in all three species. The root C, N, and P concentration did not change according to drought stress but were significantly affected by the soil substrates in all three species. Similarly, the soluble sugar (SS) and starch (ST) concentrations were significantly affected by both the drought stress and the soil substrates in all three species. The AD explained 6.8% of the total variations in soluble sugar, while the SRL explains 32.1% of the total variation in starch. The root tip C, N, and P concentrations were not significantly correlated with NSCs under different treatments. The total variations in root tip morphology, chemistry, and NSC concentrations are greater among species than compared to different drought intensities and soil substrates. However, the root NSC concentrations were closely related to root morphological traits (SRL and AD) rather than chemical traits. On the basis of different soil resources, the species with thinner diameters have higher SS concentrations, while those of a thicker diameter have higher ST concentrations.

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