scholarly journals Optimal Harvesting Decision Paths When Timber and Water Have an Economic Value in Uneven Forests

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 903
Author(s):  
Paola Ovando ◽  
Matthias Speich
Keyword(s):  
Economic Value ◽  
Yield Function ◽  
Swiss Alps ◽  
Water Yield ◽  
Optimal Harvesting ◽  
State Variables ◽  
Area Index ◽  
Economic Decision Making ◽  
Forest Landscape Model ◽  
Specific Species

We developed an uneven-aged forest economic decision-making framework that combines: (i) a size-structured matrix model, based on growth and mortality predictions of a dynamic process-based forest landscape model, (ii) an optimal control model that determines the dynamics of control and state variables, which in turn are defined by tree harvesting and forest stock, respectively, and (iii) a water yield function that depends on changes in the leaf area index (LAI), the latter being affected by forest management. This framework was used to simulate the effects of economic-driven harvesting decisions on water yields on a catchment of South-Western Swiss Alps when both timber and water benefits are considered. Water benefits are estimated as environmental prices considering current water demands for drinking, irrigation and hydropower production. We simulated optimal harvesting decisions given the initial forest structure at each 200 m × 200 m grid cells, a set of restrictions to harvesting, and specific species survival, recruitment and growth probabilities, all of which are affected by the stand’s LAI. We applied this model using different harvesting restriction levels over a period of 20 to 40-years, and accounting for single and joint timber and water benefits. The results suggested that at the environmental prices estimated at the catchment area, water benefits have a slight influence on harvesting decisions, but when water is accounted for, harvesting decisions would include more tree species and different diameter classes, which, in principle, is expected to favor more diverse forest structures.

Coupled Thermomechanical Modeling of Small Volume FCC Metals

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Danial Faghihi ◽  
George Z. Voyiadjis ◽  
Taehyo Park
Keyword(s):  
Small Volume ◽  
Bulk Material ◽  
Yield Function ◽  
Face Centered Cubic ◽  
State Variables ◽  
Transient Time ◽  
Cubic Model ◽  
Temperature Variable ◽  
Fast Transient ◽  
Face Centered

The mechanical and thermal behavior of small volume metallic compounds on the fast transient time are addressed in this work through developing a thermodynamically consistent nonlocal framework. In this regard, an enhanced gradient plasticity theory is coupled with the application of the micromorphic approach to the temperature variable. The yield function of the VA–FCC (Voyiadjis Abed Face Centered Cubic) model based on the concept of thermal activation energy and the dislocations interaction mechanisms including nonlinear hardening is taken into consideration in the derivation. The effect of the material microstructural interface between two materials is also incorporated in the formulation with both temperature and rate effects. In order to accurately address the strengthening and hardening mechanisms, the theory is developed based on the decomposition of the mechanical state variables into energetic and dissipative counterparts which provided the constitutive equations to have both energetic and dissipative gradient length scales for the bulk material and the interface. Moreover, the nonlocal evolution of temperature is addressed by incorporating the microstructural interaction effect in the fast transient process using two time scales in the microscopic heat equation.

Erratum for “Economics of a Water-Yield Function for Sugar Cane”

1969 ◽  
Vol 95 (4) ◽  
pp. 643-643
Author(s):  
Howard C. Hogg ◽  
Jack R. Davidson ◽  
Jen-hu Chang
Keyword(s):  
Sugar Cane ◽  
Yield Function ◽  
Water Yield

scholarly journals Assimilation of Wheat and Soil States into the APSIM-Wheat Crop Model: A Case Study

2021 ◽  
Vol 14 (1) ◽  
pp. 65
Author(s):  
Yuxi Zhang ◽  
Jeffrey P. Walker ◽  
Valentijn R. N. Pauwels ◽  
Yuval Sadeh
Keyword(s):  
Soil Moisture ◽  
Remotely Sensed ◽  
Crop Productivity ◽  
Open Loop ◽  
Wheat Crop ◽  
Spatial And Temporal Variability ◽  
Baseline Scenario ◽  
State Variables ◽  
Yield Estimation ◽  
Area Index

Optimised farm crop productivity requires careful management in response to the spatial and temporal variability of yield. Accordingly, combination of crop simulation models and remote sensing data provides a pathway for providing the spatially variable information needed on current crop status and the expected yield. An ensemble Kalman filter (EnKF) data assimilation framework was developed to assimilate plant and soil observations into a prediction model to improve crop development and yield forecasting. Specifically, this study explored the performance of assimilating state observations into the APSIM-Wheat model using a dataset collected during the 2018/19 wheat season at a farm near Cora Lynn in Victoria, Australia. The assimilated state variables include (1) ground-based measurements of Leaf Area Index (LAI), soil moisture throughout the profile, biomass, and soil nitrate-nitrogen; and (2) remotely sensed observations of LAI and surface soil moisture. In a baseline scenario, an unconstrained (open-loop) simulation greatly underestimated the wheat grain with a relative difference (RD) of −38.3%, while the assimilation constrained simulations using ground-based LAI, ground-based biomass, and remotely sensed LAI were all found to improve the RD, reducing it to −32.7%, −9.4%, and −7.6%, respectively. Further improvements in yield estimation were found when: (1) wheat states were assimilated in phenological stages 4 and 5 (end of juvenile to flowering), (2) plot-specific remotely sensed LAI was used instead of the field average, and (3) wheat phenology was constrained by ground observations. Even when using parameters that were not accurately calibrated or measured, the assimilation of LAI and biomass still provided improved yield estimation over that from an open-loop simulation.

scholarly journals Assessing the Impact of LAI Data Assimilation on Simulations of the Soil Water Balance and Maize Development Using MOHID-Land

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1367 ◽  
Author(s):  
Tiago Ramos ◽  
Lucian Simionesei ◽  
Ana Oliveira ◽  
Hanaa Darouich ◽  
Ramiro Neves
Keyword(s):  
Data Assimilation ◽  
Water Balance ◽  
Soil Water ◽  
Hydrological Modeling ◽  
Soil Water Balance ◽  
Landsat 8 ◽  
State Variables ◽  
Area Index ◽  
Final Model ◽  
The Impact

Hydrological modeling at the catchment scale requires the upscaling of many input parameters for better characterizing landscape heterogeneity, including soil, land use and climate variability. In this sense, remote sensing is often considered as a practical solution. This study aimed to access the impact of assimilation of leaf area index (LAI) data derived from Landsat 8 imagery on MOHID-Land’s simulations of the soil water balance and maize state variables (LAI, canopy height, aboveground dry biomass and yield). Data assimilation impacts on final model results were first assessed by comparing distinct modeling approaches to measured data. Then, the uncertainty related to assimilated LAI values was quantified on final model results using a Monte Carlo method. While LAI assimilation improved MOHID-Land’s estimates of the soil water balance and simulations of crop state variables during early stages, it was never sufficient to overcome the absence of a local calibrated crop dataset. Final model estimates further showed great uncertainty for LAI assimilated values during earlier crop stages, decreasing then with season reaching its end. Thus, while model simulations can be improved using LAI data assimilation, additional data sources should be considered for complementing crop parameterization.

scholarly journals The Land Variational Ensemble Data Assimilation Framework: LAVENDAR v1.0.0

2020 ◽  
Vol 13 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Ewan Pinnington ◽  
Tristan Quaife ◽  
Amos Lawless ◽  
Karina Williams ◽  
Tim Arkebauer ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Land Surface ◽  
Time Window ◽  
Real Data ◽  
Surface Model ◽  
State Variables ◽  
Maize Crop ◽  
Area Index ◽  
Ensemble Data Assimilation ◽  
Ensemble Data

Abstract. The Land Variational Ensemble Data Assimilation Framework (LAVENDAR) implements the method of four-dimensional ensemble variational (4D-En-Var) data assimilation (DA) for land surface models. Four-dimensional ensemble variational data assimilation negates the often costly calculation of a model adjoint required by traditional variational techniques (such as 4D-Var) for optimizing parameters or state variables over a time window of observations. In this paper we present the first application of LAVENDAR, implementing the framework with the Joint UK Land Environment Simulator (JULES) land surface model. We show that the system can recover seven parameters controlling crop behaviour in a set of twin experiments. We run the same experiments at the Mead continuous maize FLUXNET site in Nebraska, USA, to show the technique working with real data. We find that the system accurately captures observations of leaf area index, canopy height and gross primary productivity after assimilation and improves posterior estimates of the amount of harvestable material from the maize crop by 74 %. LAVENDAR requires no modification to the model that it is being used with and is hence able to keep up to date with model releases more easily than other DA methods.

Understanding the hydrologic impacts of wildfire management strategies using MIKE SHE

2021 ◽  
Author(s):  
Jake Kurzweil ◽  
Reza Abdi ◽  
Kerry Metlen ◽  
Terri Hogue
Keyword(s):  
Biological Diversity ◽  
Stand Density ◽  
Mitigation Strategies ◽  
Low Flow ◽  
Water Yield ◽  
Area Index ◽  
Mike She ◽  
Clear Cutting ◽  
Hydrologic Change ◽  
Fire Mitigation

<p>Proactive thinning and controlled burning are being utilized to mitigate the effects of severe wildfires across the globe. Hydrologic function of watersheds after wildfire and clear-cutting has been well documented, however the impacts of pre-fire mitigation strategies are less understood. The current study utilized two mixed precipitation watersheds, which supply drinking water for Ashland, Oregon, USA, to assess the effectiveness of restoration and fuel reduction strategies on hydrologic change. This Mediterranean dry mixed conifer-hardwood habitat is unique as it sits in the convergence point of several ecoregions, providing significant biological diversity for the region. Hydrologic response from prior mitigation strategies was evaluated using max monthly flow, mean annual 7-day low flow, runoff ratios, timing and total water yield. Results show an average decrease of 26% and 24% in total annual water yields in the West and East basins of the Ashland watershed, respectively. Analysis also showed that 66% (West) and 72% (East) of the changes in water yield were due to annual variations in precipitation, demonstrating that land cover changes were not the dominant driver of hydrologic change. Current work includes identifying the thresholds at which stand density reduction leads to an increase in annual surface water yield. The integrated surface and groundwater model, MIKE SHE, is developed and used to simulate a range of forest fire mitigation efforts based upon representative parameters in the model, including leaf area index. Findings will then be expanded to include stand density index for better interpretation of our findings to make recommendations for local and regional forest managers. Ultimately, results will help inform future implementation of forest restoration and climate adaptation at larger scales.</p>

scholarly journals Spatial conservation areas for water yield hydrological ecosystem services with their economic values effects under climate change: a case study of Teshio watershed located in northernmost of Japan

2019 ◽  
Vol 50 (6) ◽  
pp. 1679-1709 ◽  
Author(s):  
Min Fan ◽  
Daniel Ocloo Mawuko ◽  
Hideaki Shibata ◽  
Wei Ou
Keyword(s):  
Climate Change ◽  
Ecosystem Services ◽  
Water Resources ◽  
Climate Changes ◽  
Economic Value ◽  
Electricity Production ◽  
Water Yield ◽  
Conservation Areas ◽  
Economic Values ◽  
Hydro Power

Abstract Water resources prioritization conservation planners are increasingly becoming aware of the economic value of water supply ecosystem services (ESs) under climate changes. Here we assessed how the water yield ES framework is implemented in the current spatial prioritization conservation of the water resources under climate change across the Teshio River watershed. We applied the systematic conservation model to optimize the area for water resources which satisfied the protection targets with and without considering economic values of the water yield provision service. The model indicated that the areas of spatial optimal ES protection for water yield with considering economic values were totally different from those without considering economic values of water resources. The optimal priority conservation areas were concentrated in southwestern, southeastern, and some northern areas of this watershed. These places could guarantee water resources sustainability from both environmental protection and socio-economic development standpoints. Moreover, the spatial priority conservation areas for water yield with economic value from hydro-power electricity production were traded off against the areas for water yield with economic values from resident water-use and irrigation for rice. Therefore, the systematic conservation planning of water yield with economic values under climate changes may provide a useful argument to promote the conservation of water resources.

scholarly journals Characterizing drought in terms of changes in the precipitation–runoff relationship: a case study of the Loess Plateau, China

2018 ◽  
Vol 22 (3) ◽  
pp. 1749-1766 ◽  
Author(s):  
Yuan Zhang ◽  
Xiaoming Feng ◽  
Xiaofeng Wang ◽  
Bojie Fu
Keyword(s):  
Loess Plateau ◽  
Mean Annual Precipitation ◽  
Water Yield ◽  
Drought Severity ◽  
The Loess Plateau ◽  
Drought Duration ◽  
Continuous Precipitation ◽  
Area Index ◽  
Limited Region

Abstract. The frequency and intensity of drought are increasing dramatically with global warming. However, few studies have characterized drought in terms of its impacts on ecosystem services, the mechanisms through which ecosystems support life. As a result, little is known about the implications of increased drought for resource management. This case study characterizes drought by linking climate anomalies with changes in the precipitation–runoff relationship (PRR) on the Loess Plateau of China, a water-limited region where ongoing revegetation makes drought a major concern. We analyzed drought events with drought durations ≥ 5 years and mean annual precipitation anomaly (PA) values ≤ −5 % during drought periods. The results show that continuous precipitation shifts are able to change the water balance of watersheds in water-limited areas, and multi-year drought events cause the PRR to change with a significantly decreasing trend (p < 0.05) compared to other historical records. For the Loess Plateau as a whole, the average runoff ratio decreased from 10 to 6.8  % during 1991–1999. The joint probability and return period gradually increase with increasing of drought duration and severity. The ecosystem service of water yield is easily affected by drought events with durations equal to or greater than 6 years and drought severity values equal to or greater than 0.55 (precipitation ≤ 212 mm). At the same time, multi-year drought events also lead to significant changes in the leaf area index (LAI). Such studies are essential for ecosystem management in water-limited areas.

scholarly journals INITIAL DEVELOPMENT OF CORN SUBJECTED TO INCREASING NITROGEN DOSES

2021 ◽  
Vol 8 (1) ◽  
pp. e5226
Author(s):  
Dhiego César Oliveira Riva Neto ◽  
Leonardo Rodrigues Barros ◽  
Vinicius Silva Sousa ◽  
Eliana Paula Fernandes Brasil ◽  
Adriana Aparecida Ribon ◽  
...  
Keyword(s):  
Dry Matter ◽  
Economic Value ◽  
Fresh Matter ◽  
Agronomic Efficiency ◽  
Area Index ◽  
Initial Development ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Set Up ◽  
Almost All

Corn (Zea mays L.) is one of the most important cereals grown and consumed in the world not only for its economic value but also due to its importance in human and animal nutrition. This study aimed to assess the initial development of corn as a function of increasing nitrogen doses. The study was carried out in a greenhouse on the Sipal Farm, Confresa, MT, Brazil. The experiment was set up in a completely randomized design, consisting of five treatments (0, 100, 200, 300, and 400 mg N dm−3 soil), with four replications, conducted from April to June 2020. Four seeds of the hybrid K 9606 VIP 3 were sown per 8-L polyethylene pot. The plants were thinned at 7 days after emergence (DAE), leaving only one plant per pot. Morphological components were assessed. A significant effect was found for almost all the analyzed parameters, except for stem diameter and root dry matter. The maximum plant height, shoot fresh matter, leaf area index, shoot dry matter, root fresh matter, and root volume was obtained by applying the maximum agronomic efficiency doses of 248.83, 271.90, 336.91, 279.66, 403.92, and 272.90 mg N dm−3 soil, respectively. Nitrogen doses influenced the initial development of the corn crop.

Implicit Stress Integration and Consistent Tangent Matrix for Yoshida’s 6th Order Polynomial Yield Function Combined with Yoshida-Uemori Kinematic Hardening Rule

2015 ◽  
Vol 651-653 ◽  
pp. 558-563 ◽  
Author(s):  
Hiroshi Hamasaki ◽  
Fusahito Yoshida ◽  
Takeshi Uemori
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Equivalent Plastic Strain ◽  
Yield Function ◽  
Alloy Sheet ◽  
Integration Scheme ◽  
State Variables ◽  
Tangent Matrix ◽  
Fully Implicit ◽  
Stress Integration

This paper describes fully implicit stress integration scheme for Yoshida’s 6thorder yield function combined with Yoshida-Uemori kinematic hardening model and its consistent tangent matrix. Cutting plane method was employed for accurate integrations of stress and state variables appeared in Yoshida-Uemori model. In the present scheme, equivalent plastic strain, stress tensor and all the state variables are treated as independent variables in order to handle the 6th order yield function which is not the J2 yield function, and the equilibriums for each variables are solved for the stress integration. Subsequently, exact consistent tangent matrix which is necessary for implicit static finite element simulation was obtained. The proposed scheme was implemented into finite element code LS-DYNA and deep drawing process for aluminum alloy sheet was calculated. The earing appearance after drawing was compared with the experiment.

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