Effect of climate change, drought, and insects on oak-pine forests in the Ozark highlands

2020 ◽  
Author(s):  
◽  
Shengwu Duan
Keyword(s):  
Climate Change ◽  
Forest Growth ◽  
Pine Forests ◽  
Spatial And Temporal Variation ◽  
Oak Forests ◽  
Drought Effect ◽  
Ozark Highlands ◽  
Disturbance Regimes ◽  
Warming Climate ◽  
The Impact

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI--COLUMBIA AT REQUEST OF AUTHOR.] Oak-dominated forests in the Ozarks Highlands of Arkansas and Missouri have been suffering severe oak decline and this became a chronic problem since the late 1970s. Such decline became increasingly severe as numerous dense oak forests in this region approaching physiological maturity. Repeated droughts and insect outbreaks in the Ozarks Highlands from 1998 to 2015 accelerate the decline process and resulted in increased mortality of the oaks, particularly those in red oak group. Given these concerns, the overall objective of this dissertation was to conduct a regional scale assessment to evaluate and predict the impact of drought and insects on the oak forests under changing climate. This dissertation contained three main objectives: 1) to evaluate the drought effect on forest growth phenology and productivity by using spatially-explicit drought indices and land surface phenology techniques to capture oak, pine and mixed oak-pine forests' responses to repeated droughts; 2) to develop a climate sensitive biotic disturbance agent (BDA) module in forest landscape modeling framework to quantify the relative importance in determining the insect disturbance regimes under the warming climate; and 3) to predict the effects of insect disturbance, climate change and their interactions on forest composition under alternative climate and insect disturbance scenarios. The dissertation provided a methodology to disassemble the spatial and temporal variation of drought conditions in the Ozark Highlands and provided new insights into improving drought resistance and recovery capacity of forests with different species under climate change. The results from this dissertation also helped to understand the importance of vegetation feedback in predicting inset disturbance regimes under a warming climate as they may mediate or even reverse the expectation of increased insect disturbance in this region. In addition, the projections of how tree species will response to insect disturbance will benefit decision making in silvicultural prescriptions and longterm management plans in the Ozark Highlands.

scholarly journals HETEROFOR 1.0: a spatially explicit model for exploring the response of structurally complex forests to uncertain future conditions. II. Phenology and water cycle

2019 ◽  
Author(s):  
Louis de Wergifosse ◽  
Frédéric André ◽  
Nicolas Beudez ◽  
François de Coligny ◽  
Hugues Goosse ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Tree Growth ◽  
Leaf Development ◽  
Forest Growth ◽  
Spatially Explicit ◽  
Model Assessment ◽  
Pearson's R ◽  
The Impact ◽  
Pearson’S R

Abstract. Climate change affects forest growth in numerous and sometimes opposite ways and the resulting trend is often difficult to predict for a given site. Integrating and structuring the knowledge gained from the monitoring and experimental studies into process-based models is an interesting approach to predict the response of forest ecosystems to climate change. While the first generation of such models operates at stand level, we need now individual-based and spatially-explicit approaches in order to account for structurally complex stands whose importance is increasingly recognized in the changing environment context. Among the climate-sensitive drivers of forest growth, phenology and water availability are often cited as crucial elements. They influence, for example, the length of the vegetation period during which photosynthesis takes place and the stomata opening, which determines the photosynthesis rate. In this paper, we describe the phenology and water balance modules integrated in the tree growth model HETEROFOR and evaluate them on six Belgian sites. More precisely, we assess the ability of the model to reproduce key phenological processes (budburst, leaf development, yellowing and fall) as well as water fluxes. Three variants are used to predict budburst (Uniforc, Unichill and Sequential), which differ regarding the inclusion of chilling and/or forcing periods and the calculation of the coldness or heat accumulation. Among the three, the Sequential approach is the least biased (overestimation of 2.46 days) while Uniforc (chilling not considered) best accounts for the interannual variability (Pearson’s R = 0.68). For the leaf development, yellowing and fall, predictions and observation are in accordance. Regarding the water balance module, the predicted throughfall is also in close agreement with the measurements (Pearson’s R = 0.856, bias = −1.3 %) and the soil water dynamics across the year is well-reproduced for all the study sites (Pearson’s R comprised between 0.893 and 0.950, and bias between −1.81 and −9.33 %). The positive results from the model assessment will allow us to use it reliably in projection studies to evaluate the impact of climate change on tree growth and test how diverse forestry practices can adapt forests to these changes.

Eco-efficient flight trajectories – Using a Lagrangian approach in EMAC to investigate contrail formation in the mid latitudes 

2021 ◽  
Author(s):  
Patrick Peter ◽  
Sigrun Matthes ◽  
Christine Frömming ◽  
Volker Grewe
Keyword(s):  
Climate Change ◽  
Life Cycle ◽  
Co2 Emissions ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Spatial And Temporal Variation ◽  
Climate Effects ◽  
Aircraft Trajectories ◽  
The Impact

<p>Air transport has for a long time been linked to environmental issues like pollution, noise and climate change. While CO2 emissions are the main focus in public discussions, non-CO2 emissions of aviation may have a similar impact on the climate as aviation's carbon dioxide, e.g. contrail cirrus, nitrogen oxides or aviation induced cloudiness. While the effects of CO2 on climate are independent of location and situation during release, non-CO2 effects such as contrail formation vary depending on meteorological background. Previous studies investigated the influence of different weather situations on aviation’s climate change contribution, identifying climate sensitive regions and generating data products which enable air traffic management (ATM) to plan for climate optimized trajectories.</p> <p>The research presented here focuses on the further development of methods to determine the sensitivity of the atmosphere to aviation emissions with respect to climate effects in order to determine climate optimized aircraft trajectories. While previous studies focused on characterizing the North Atlantic Flight Corridor region, this study aims to extend the geographic scope by performing Lagrangian simulations in a global climate model EMAC for the northern hemispheric extratropical regions and tropical latitudes. This study addresses how realistically the physical conditions and processes for contrail formation and life cycle are represented in the upper troposphere and lower stratosphere by comparing them to airborne observations (HALO measurement campaign, CARIBIC/IAGOS scheduled flight measurements), examining key variables such as temperature or humidity. Direct comparison of model data with observations using clusters of data provides insight into the extent to which systematic biases exist that are relevant to the climate effects of contrails. We perform this comparison for different vertical resolutions to assess which vertical resolution in the EMAC model is well suited for studying contrail formation. Together with this model evaluation using aircraft measurements, the overall concept for studying the life cycle of contrails in the modular global climate model EMAC is introduced. Hereby, the concept for the development of a MET service that can be provided to ATM to evaluate contrail formation and its impact on the climate along planned aircraft trajectories is presented.</p> <p>Within the ClimOP collaborative project, we can investigate which physical processes determine the effects of contrails on climate and study their spatial and temporal variation. In addition, these climate change functions enable case studies that assess the impact of contrails on climate along trajectories and use alternative trajectories that avoid these regions of the atmosphere that have the potential to form contrails with a large radiative effect.</p> <p>This study is part of the ClimOP project and has received funding from European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement N° 875503 (ClimOP) and from the SESAR Joint Undertaking under grant agreements No 699395 (FlyATM4E). </p>

Flash drought as a new normal in a warming climate

2021 ◽  
Author(s):  
Xing Yuan ◽  
Yumiao Wang ◽  
Miao Zhang
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Anthropogenic Activities ◽  
Coupled Model ◽  
Late Summer ◽  
Rapid Onset ◽  
New Normal ◽  
Climate Anomalies ◽  
Warming Climate ◽  
The Impact

<p>Conventional droughts are creeping climate anomalies that take months or years to fully develop, causing devastating impact silently. In contrast, flash droughts have been considered as a type of drought with more rapid onset, develop and terminate at a shorter time scale. There has been a hot debate on the definition of flash drought, and whether it is necessary to investigate the impact of flash drought given the duration is usually shorter than conventional drought. We clarify that flash drought is not a monster, while it has complete onset and recovery processes as conventional drought. Flash drought expands the conventional drought from seasonal-to-decadal scales to sub-seasonal scale, where synoptic land-atmospheric coupling might become critical for its onset. Focusing on a once-in-a-century flash drought in late summer of 2019, we analyze the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) climate model data and show that climate change caused by anthropogenic activities (e.g., emissions of greenhouse gases and aerosols, land use change, etc) has increased the likelihood of such drought onset speed by 42±19%. A further analysis based on CMIP6 multi-model ensemble simulations over the global land areas shows that there was no significant trend in frequency during 1850-1970, but flash drought became more frequency in the recent 40 years. All these results suggest that climate change accelerates the drought development speed, and flash drought might become as a new normal in a warming climate. The eco-hydrological impact of this “new normal” will also be discussed by investigating FLUXNET in-situ observations and MODIS satellite retrievals.</p>

scholarly journals Modeling the hydrological response to climate change in a glacierized high mountain region, northwest China

2015 ◽  
Vol 61 (225) ◽  
pp. 127-136 ◽  
Author(s):  
Meiping Sun ◽  
Zhongqin Li ◽  
Xiaojun Yao ◽  
Mingjun Zhang ◽  
Shuang Jin
Keyword(s):  
Climate Change ◽  
Source Area ◽  
Northwest China ◽  
Change Scenario ◽  
High Mountain ◽  
Complete Disappearance ◽  
Glacier Area ◽  
Warming Climate ◽  
Mountain Catchment ◽  
The Impact

AbstractThe impact of climate change on the variability of local discharge was investigated in a glacierized high mountain catchment located in the source area of the Ürümqi river, northwest China. We used past climate records to drive a hydrological model to simulate the discharge from 2000 to 2008. The model was then used to project future discharge variations for the period 2041–60, based on a regionally downscaled climate-change scenario combined with three stages of glacier coverage (i.e. compared to the glacier coverage in 2008): unchanged glacier size (100% glacierized), recession of half the glacier area (50% glacierized) and complete disappearance of glaciers (0% glacierized). In each scenario, snowmelt will begin half a month earlier and the discharge will increase in May. For the 100% glacierized scenario, the discharge will increase by 66 ± 35% in a smaller (3.34 km2) and more glaciated (50%) catchment and 33 ± 20% in a larger (28.90 km2) and proportionally less glaciated (18%) catchment. If the glacier area reduces by half, the discharge will decrease by 8 ± 5% and 9 ± 6%, respectively. Once the glacier disappears, the discharge will decrease by 58 ± 20% and 40 ± 13%, respectively. Together, the results indicate that a warming climate and the resulting glacier shrinkage will cause significant changes in the volume and timing of runoff.

scholarly journals Using 3PG to assess climate change impacts on management plan optimization of Eucalyptus plantations. A case study in Southern Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
João HN Palma ◽  
Rodrigo Hakamada ◽  
Gabriela Gonçalves Moreira ◽  
Silvana Nobre ◽  
Luiz Carlos Estraviz Rodriguez
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Management Plan ◽  
Empirical Models ◽  
Forest Growth ◽  
Future Climate ◽  
Empirical Equations ◽  
Complete Replacement ◽  
Physiological Models ◽  
The Impact

AbstractEucalyptus plantations around the world have been largely used by the paper industry. Optimizing the management of resources is a common practice in this highly competitive industry and new forest growth models may help to understand the impact of climate change on the decisions of the optimization processes. Current optimized management plans use empirical equations to predict future forest stands growth, and it is currently impractical to replace these empirical equations with physiological models due to data input requirements. In this paper, we present a different approach, by first carrying out a preliminary assessment with the process-based physiological model 3PG to evaluate the growth of Eucalyptus stands under climate change predictions. The information supplied by 3PG was then injected as a modifier in the projected yield that feeds the management plan optimizer allowing the interpretation of climate change impacts on the management plan. Modelling results show that although a general increase of rain with climate change is predicted, the distribution throughout the year will not favor the tree growth. On the contrary, rain will increase when it is less needed (summer) and decrease when it is most needed (winter), decreasing forest stand productivity between 3 and 5%, depending on the region and soil. Evaluation of the current optimized plan that kept constant the relation between wood price/cellulose ton shows a variation in different strategic management options and an overall increase of costs in owned areas between 2 and 4%, and a decrease of cumulated net present value, initially at 15% with later stabilization at 6–8%. This is a basic comparison to observe climate change effects; nevertheless, it provides insights into how the entire decision-making process may change due to a reduction in biomass production under future climate scenarios. This work demonstrates the use of physiological models to extract information that could be merged with existing and already implemented empirical models. The methodology may also be considered a preliminary alternative to the complete replacement of empirical models by physiological models. Our approach allows some insight into forest responses to different future climate conditions, something which empirical models are not designed for.

scholarly journals Variation in Water Supply Leads to Different Responses of Tree Growth to Warming

2021 ◽  
Author(s):  
Pengfei Zheng ◽  
Dandan Wang ◽  
Xinxiao Yu ◽  
Guodong Jia ◽  
Ziqiang Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Supply ◽  
Climate Warming ◽  
Tree Growth ◽  
Structural Equation Models ◽  
Growing Season ◽  
Forest Growth ◽  
Arid Ecosystems ◽  
Carbon Sinks ◽  
The Impact

Abstract Background: Global climate change, which includes changes in precipitation, prolonged growing seasons, and drought stress caused by overall climate warming, is putting increased pressure on forest ecosystems globally. Understanding the impact of climate change on drought-prone forests is a key objective in assessing forest responses to climate change.Results: In this study, we assessed tree growth trends and changes in physiological activity under climate change based on patterns in tree rings and stable isotopes. Additionally, structural equation models were used to analyze the climate drivers influencing tree growth, with several key results. (1) The climate in the study area showed a trend of warming and drying, with the growth of tree section areas decreasing first and then increasing, while the water use efficiency showed a steady increase. (2) The effects of climate warming on tree growth in the study area have transitioned from negative to positive. The gradual advance of the growing season and the supply of snowmelt water in the early critical period of the growing season are the key factors underlying the reversal of the sensitivity of trees to climate. (3) Variation in water supply has led to different responses of tree growth to warming, and the growth response of Pinus tabuliformis to temperature rise was closely related to increased water availability.Conclusions: Our study indicates that warming is not the cause of forest decline, and instead, drought caused by warming is the main factor causing this change. If adequate water is available during critical periods of the growing season, boreal forests may be better able to withstand rising temperatures and even exhibit increased growth during periods of rising temperatures, forming stronger carbon sinks. However, in semi-arid regions, where water supply is limited, continued warming could lead to reduced forest growth and even death, which would dramatically reduce carbon sinks in arid ecosystems.

Quantifying forest growth and uncertainty across Brazil under potential future climates: combing models and Earth Observation

2020 ◽  
Author(s):  
Thomas Smallman ◽  
David Milodowski ◽  
Mathew Williams
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Carbon Cycling ◽  
Earth Observation ◽  
Forest Growth ◽  
Forest Carbon ◽  
Carbon Accumulation ◽  
Terrestrial Ecosystem Model ◽  
New Forest ◽  
The Impact

<p>Forest play a major role in the global carbon cycle storing large amounts of carbon in both living and dead organic matter. Forests can be either a sink or source of carbon depending on the net of far larger fluxes of carbon into (photosynthesis) and out of (mortality, decomposition and disturbance) forest ecosystems. Due to the potential for substantial accumulation of carbon in forests, has led to nationally determined commitments (NDCs) by Governments across the world to protect existing and plant large areas of new forest. However, significant uncertainty remains in our understanding of current forest carbon cycling, especially mortality and decomposition processes, and how carbon cycling will change under climate change. These uncertainties present two connected challenges to effective forest protection and new planting; (i) which existing forests are under the greatest risk to climate change and (ii) where are the most climate safe locations for new forest planting to maximise carbon accumulation.</p><p>Here we combine a terrestrial ecosystem model of intermediate complexity (DALEC) with Earth observation (e.g. leaf area, biomass, disturbance) and databased information (soil texture and carbon stocks) within a Bayesian model-data fusion framework (CARDAMOM) to retrieve location specific carbon cycle analyse (i.e. parameter retrievals) across Brazil at 0.5 x 0.5 degree spatial resolution between 2001 and 2015. CARDAMOM allows us to retrieve, independently for each location analysed, an ensemble of parameters for DALEC which are consistent with the location specific observational constraints and their uncertainties. These ensembles give us multiple potential, but observation consistent, realisations of forest carbon cycling and ecosystem traits. We directly quantify our uncertainty in forest carbon cycling and ecosystem traits from these ensembles. The DALEC parameterisations are then simulated into the future under a range of climate scenarios from the CMIP6 model dataset. From these simulations we will, with defined uncertainty, quantify the impact on forest carbon accumulation of existing forest and the potential accumulation of new planting. This information can feed into national planning identifying locations which have the greatest confidence of being a net sink of carbon under climate change highlighting forest areas which are most important to protect and suitable for new planting.</p>

The role of alpha and beta diversity in buffering the effects of intensifying natural disturbance regimes

2020 ◽  
Author(s):  
Julius Sebald ◽  
Timothy Thrippleton ◽  
Werner Rammer ◽  
Harald Bugmann ◽  
Rupert Seidl
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Species Diversity ◽  
Tree Species ◽  
Beta Diversity ◽  
Alpha Diversity ◽  
Tree Species Diversity ◽  
Alpha And Beta Diversity ◽  
Disturbance Regimes ◽  
The Impact

<div> <div> <div> <p>Forests are strongly affected by climatic changes, but impacts vary between tree species and prevailing site conditions. A number of studies suggest that increasing tree species diversity is a potent management strategy to decrease climate change impacts in general, and increase the resilience of forest ecosystems to changing disturbance regimes. However, most studies to date have focused on stand-level diversity in tree species (alpha diversity), which is often difficult to implement in operational forest management. Inter-species competition requires frequent management interventions to maintain species mixture and complicates the production of high-quality stemwood. An alternative option to increasing alpha diversity is to increase tree species diversity between forest stands (beta diversity). Here we quantify the effects of alpha and beta diversity on the impact of forest disturbances under climate change. We conducted a simulation experiment applying two forest landscape models (i.e. iLand and LandClim) in two landscapes with strongly contrasting environmental conditions in Central Europe. Simulations investigate different levels of tree species diversity (no diversity, low diversity and high diversity) in different spatial arrangements (alpha diversity, beta diversity). Subsequently a standard forest management regime and a series of prescribed disturbances are applied over 200 years. By analyzing biomass values relative to a no-disturbance run, variation in biomass over time and the number of trees > 30 cm dbh per hectare, we isolate the effect of tree species diversity on the resistance of forests to disturbances.</p> </div> </div> </div>

Climatic and economic drivers of the Bering Sea walleye pollock (Theragra chalcogramma) fishery: implications for the future

2013 ◽  
Vol 70 (6) ◽  
pp. 841-853 ◽  
Author(s):  
Alan C. Haynie ◽  
Lisa Pfeiffer
Keyword(s):  
Climate Change ◽  
Bering Sea ◽  
Climate Models ◽  
Walleye Pollock ◽  
Spatial And Temporal Variation ◽  
Theragra Chalcogramma ◽  
Climate Change Scenarios ◽  
Walleye Pollock Theragra Chalcogramma ◽  
The Impact ◽  
The Bering Sea

This paper illustrates how climate, management, and economic drivers of a fishery interact to affect fishing. Retrospective data from the Bering Sea walleye pollock (Theragra chalcogramma) catcher–processer fishery were used to model the impact of climate on spatial and temporal variation in catch and fishing locations and make inferences about harvester behavior in a warmer climate. Models based on Intergovernmental Panel on Climate Change scenarios predict a 40% decrease in sea ice by 2050, resulting in warmer Bering Sea temperatures. We find that differences in the value of catch result in disparate behavior between winter and summer seasons. In winter, warm temperatures and high abundances drive intensive effort early in the season to harvest earlier-maturing roe. In summer, warmer ocean temperatures were associated with lower catch rates and approximately 4% less fishing in the northern fishing grounds, contrary to expectations derived from climate-envelope-type models that suggest fisheries will follow fish poleward. Production-related spatial price differences affected the effort distribution by a similar magnitude. However, warm, low-abundance years have not been historically observed, increasing uncertainty about future fishing conditions. Overall, annual variation in ocean temperatures and economic factors has thus far been more significant than long-term climate change-related shifts in the fishery's distribution of effort.

scholarly journals Increased Drought Sensitivity Results in a Declining Tree Growth of Pinus latteri in Northeastern Thailand

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 361
Author(s):  
Sakkarin Rakthai ◽  
Pei-Li Fu ◽  
Ze-Xin Fan ◽  
Narayan Prasad Gaire ◽  
Nathsuda Pumijumnong ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Ring Width ◽  
Forest Growth ◽  
Pine Forests ◽  
Future Climate Change ◽  
Transition Season ◽  
Moisture Availability ◽  
Lowland Area ◽  
Northeastern Thailand

Climate change may lead to alterations in tree growth and carbon cycling. Interpreting the response of forest growth to climate change requires an understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of tree species. However, the effects of climate change on pine forest dynamics in tropical region of Thailand remain poorly understood. This study develops three new tree ring-width chronologies of Pinus latteri (Tenasserim pine) in northern and northeastern Thailand and analyzes their climate-growth relationships and temporal stability. Ring-width chronologies of P. latteri at three sites showed significantly positive correlations with precipitation, relative humidity and self-calibrated Palmer Drought Severity Index (scPDSI) during the dry season (previous November to current April) and early rainy season (May–June). Conversely, significantly negative correlations were found between ring-width site chronologies and air temperatures (mean, maximum and minimum) from April to August. Therefore, our results revealed that radial growth of Tenasserim pines from northern and northeastern Thailand was mainly limited by moisture availability during the dry-to-wet transition season from April to June. Moving correlations revealed that Tenasserim pines in the lowland area of northeastern Thailand became more sensitive to moisture availability in recent 30 years (1985–2017) as compared with early period (1951–1984). Accompanying the shifted growth sensitivity to climate change, growth synchrony among trees was increasing and tree growth rates of Tenasserim pines have been declining during recent decades at two more moisture-limited sites in northeastern Thailand. Recent rapid warming and increasing drought during the transition season (April–June) together intensify climatic constrains on tree growth of Tenasserim pines in the lowland area of northeastern Thailand. Considering continued regional climate change, pine forests in tropical lowland areas may encounter intensified drought stresses, and thus, become more vulnerable to future climate change. Our results serve as an early indicator of potential effects of climate change on tropical pine species and raise concerns about sustainable managements of pine forests under a changing climate.

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