In Tropical Forest Ecology, Egbert G. Leigh, Jr., one of the world's foremost tropical ecologists, introduces readers to the tropical forest and describes the intricate web of interdependence among the great diversity of tropical plants and animals. Focusing on the tropical forest of Barro Colorado Island, Panama, Leigh shows what Barro Colorado can tell us about other tropical forests--and what tropical forests can tell us about Barro Colorado. This book considers three essential questions for understanding the ecological organization of tropical forests. How do they stay green with their abundance of herbivores? Why do they have such a diversity of plants and animals? And what role does mutualism play in the ecology of tropical forests? Beautifully nwritten and abundantly illustrated, Tropical Forest Ecology will certainly appeal to a wide variety of scientists in the fields of evolution, tropical biology, botany, zoology, and natural history. n

Tropical Forest Ecology@@@Tropical Forest Ecology: A View from Barro Colorado Island

The spatial heterogeneity of element fluxes was quantified by meas- uring litterfall, throughfall and litter decomposition for 1 y in 30 randomly located sampling areas in a lowland dipterocarp rain forest. The idea tested was that turnover of elements is more variable than turnover of dry matter in a forest with extremely high tree species diversity. In spite of the low fertility of the soil (an ultisol), total litter production (leaves, trash, and wood <2 cm in diameter) was high (1105 g m -2 y -1 ) with inputs to the forest floor of carbon, nitrogen, phos- phorus, calcium, magnesium, potassium, manganese and iron of 550, 15.3, 0.47, 6.26, 2.49, 4.75, 0.95 and 0.14 g m -2 y -1 respectively. Throughfall was 81% of the annual rainfall and transferred 22.2, 1.37, 0.14, 1.07, 0.67, 0.39, 7.92, <0.06, and <0.06 g m -2 y -1 of organic carbon, nitrogen (all forms), phosphorus, sulphur, cal- cium, magnesium, potassium, manganese and iron, respectively. Average turnover rates of nutrients in litter were highest for potassium and decreased in the sequence calcium, magnesium, carbon, nitrogen and phosphorus. Concentrations of phosphorus, nitrogen and potassium in litterfall, litter mass and topsoil were closely correlated with each other. Concentrations of calcium and manganese were positively correlated with each other and with elevation. Variations in leaf chem- istry and total litterfall caused the spatial heterogeneity of element input to the forest floor to have a coefficient of variation of 30 - 70%, depending on the ele- ment. Due to the strong positive correlation between element fluxes and pools, the spatial variability of turnover rates (CV c. 20%) was lower than that of element input. Turnover rates for K varied by a factor of 4, and for Ca by a factor of 2.8 when the different sites were compared. The results strongly suggest that the most important factor determining spatial heterogeneity of organic matter and element dynamics on the forest floor is the site-specific amount of leaf fall, rather than spatially variable decomposition rates. 1 Corresponding author.

Spatial hetero-geneity of element and litter turnover in a Bornean rain forest.

Abstract Accurate modelling of the weather’s temporal and spatial impacts on building energy demand is critical to decarbonizing energy systems. Here we introduce a customizable model for hourly heating and cooling demand applicable globally at all spatial scales. We validate against demand from ~5,000 buildings and 43 regions across four continents. The model requires limited data inputs and shows better agreement with measured demand than existing models. We use it first to demonstrate that a 1 °C reduction in thermostat settings across all buildings could reduce Europe’s gas consumption by 240 TWh yr −1 , approximately one-sixth of historical imports from Russia. Second, we show that service demand for cooling is increasing by up to 5% per year in some regions due to climate change, and 5 billion people experience &gt;100 additional cooling degree days per year when compared with a generation ago. The model and underlying data are freely accessible to promote further research. 

A global model of hourly space heating and cooling demand at multiple spatial scales

Buildings consume 75% of U.S. electricity; therefore, improving the efficiency and flexibility of building operations could increase the reliability and resilience of the rapidly-changing electricity system. We estimate the technical potential near- and long-term impacts of best available building efficiency and flexibility measures on annual electricity use and hourly demand across the contiguous U.S. Co-deployment of building efficiency and flexibility avoids up to 742 TWh of annual electricity use and 181 GW of daily net peak load in 2030, rising to 800 TWh and 208 GW by 2050; at least 59 GW and 69 GW of the peak reductions are dispatchable. Implementing efficiency measures alongside flexibility measures reduces the potential for off-peak load increases, underscoring limitations on load shifting in efficient buildings. Overall, however, we find a substantial building-grid resource that could reduce future fossil-fired generation needs while also reducing dependence on energy storage with increasing variable renewable energy penetration.

/pdf/u-s-building-energy-efficiency-and-flexibility-as-an-3cenih0jv1.pdf

U.S. Building Energy Efficiency and Flexibility as an Electric Grid Resource

This paper introduces a methodology for building synthetic electric grid data sets that represent fictitious, yet realistic, combined transmission and distribution (T&D) systems. Such data sets have important applications, such as in the study of the wide-area interactions of distributed energy resources, in the validation of advanced control schemes, and in network resilience to severe events. The data sets created here are geographically located on an actual North American footprint, with the end-user load information estimated from land parcel data. The grid created to serve these fictional but realistic loads is built starting with low-voltage and medium-voltage distribution systems in full detail, connected to distribution and transmission substations. Bulk generation is added, and a high-voltage transmission grid is created. This paper explains the overall process and challenges addressed in making the combined case. An example test case, syn-austin-TDgrid-v03, is shown for a 307236-customer case located in central Texas, with 140 substations, 448 feeders, and electric line data at voltages ranging from 120 V to 230 kV. Such new combined test cases help to promote high quality in the research on large-scale systems, particularly since much actual power system data are subject to data confidentiality. The highly detailed, combined T&D data set can also facilitate the modeling and analysis of coupled infrastructures.

/pdf/building-highly-detailed-synthetic-electric-grid-data-sets-15spky30k1.pdf

Building Highly Detailed Synthetic Electric Grid Data Sets for Combined Transmission and Distribution Systems

The United States is embarking on an ambitious transition to a 100% clean energy economy by 2050, which will require improving the flexibility of electric grids. One way to achieve grid flexibility is to shed or shift demand to align with changing grid needs. To facilitate this, it is critical to understand how and when energy is used. High- quality end-use load profiles (EULPs) provide this information, and can help cities, states, and utilities understand the time-sensitive value of energy efficiency, demand response, and distributed energy resources. Publicly available EULPs have traditionally had limited application because of age and incomplete geographic representation (Frick, Eckman, and Goldman 2017; Frick 2019). To help fill this gap, the U.S. Department of Energy (DOE) funded a three-year project - End-Use Load Profiles for the U.S. Building Stock - that culminated in the release of a publicly available dataset1 of simulated EULPs representing residential and commercial buildings across the contiguous United States. The motivation for this work is further detailed in a November 2019 report: Market Needs, Use Cases, and Data Gaps (Mims Frick et al. 2019). This Methodology and Results report provides detailed descriptions of how the dataset was developed, intended for an audience of dataset and model users interested in the technical details. These details include descriptions of all of the model improvements made for calibration and the final comparisons to empirical data sources. A companion report, End-Use Load Profiles for the U.S. Building Stock: Applications and Opportunities, will be published subsequently and will describe example applications and considerations for using the dataset, intended for an audience of general dataset users. 

https://www.nrel.gov/docs/fy22osti/80889.pdf

End-Use Load Profiles for the U.S. Building Stock: Methodology and Results of Model Calibration, Validation, and Uncertainty Quantification

Fertilization experiments in tropical forests have shown that litterfall increases in response to the addition of one or more soil nutrients. However, the relationship between soil nutrient availability and litterfall is poorly defined along natural soil fertility gradients, especially in tropical montane forests. Here, we measured litterfall for two years in five lower montane 1-ha plots spanning a soil fertility and precipitation gradient in lower montane forest at Fortuna, Panama. Litterfall was also measured in a concurrent nitrogen fertilization experiment at one site. Repeated-measures ANOVA was used to test for site (or treatment), year, and season effects on vegetative, reproductive and total litterfall. We predicted that total litterfall, and the ratio of reproductive to leaf litterfall, would increase with nutrient availability along the fertility gradient, and in response to nitrogen addition. We found that total annual litterfall varied substantially among 1-ha plots (4.78 Mg/ha/yr to 7.96 Mg/ha/yr), and all but the most aseasonal plot showed significant seasonality in litterfall. However, litterfall accumulation did not track soil nutrient availability; instead forest growing on relatively infertile soil, but dominated by an ectomycorrhizal tree species, had the highest total litterfall accumulation. In the fertilization plots, significantly more total litter fell in nitrogen addition relative to control plots, but this increase in response to nitrogen (13%) was small compared to variation observed among 1-ha plots. These results suggest that while litterfall at Fortuna is nutrient-limited, compositional and functional turnover along the fertility gradient obscure any direct relationship between soil resource availability and canopy productivity.

Resumen

Se demostro con experimentos de fertilizacion en bosques tropicales incrementos en la caida de hojarasca asociados con la adicion de nutrientes; empero, se desconoce la relacion entre la disponibilidad de nutrientes del suelo con la produccion de hojarasca en gradientes naturales de fertilidad del suelo, especialmente en bosques montanos tropicales. Medimos la produccion de hojarasca durante dos anos en cinco parcelas (1-ha) en bosques montanos bajos, sobre gradientes de fertilidad y precipitacion y en un experimento paralelo de fertilizacion de nitrogeno en la Reserva Forestal Fortuna, Panama. Predijimos incrementos de hojarasca total y reproductiva con la disponibilidad de nutrientes en el gradiente de fertilidad del suelo y en respuesta a la adicion de nitrogeno (13%). Encontramos que la hojarasca total varia sustancialmente entre parcelas (4.78 Mg/ha/yr hasta 7.96 Mg/ha/yr) y que en todas las parcelas, excepto la menos estacional, hay estacionalidad significativa en la cantidad de hojarasca; pero, la acumulacion de hojarasca no coincide con la disponibilidad de nutrientes en el suelo, porque el bosque sobre suelo poco fertil con dominio de una especie ectomicorricica, presento mayor acumulacion de hojarasca. Las parcelas con fertilizacion tenian significativamente mas hojarasca que las control; pero, el incremento en hojarasca en respuesta a la adicion de nitrogeno fue menor respecto a la variacion entre parcelas. Los resultados sugieren que mientras la produccion de hojarasca en Fortuna es limitada por nutrientes, la variacion en la composicion de especies a traves de gradientes de fertilidad ocultan cualquier relacion directa entre la disponibilidad de nutrientes del suelo y la productividad del dosel.

Variation in Canopy Litterfall Along a Precipitation and Soil Fertility Gradient in a Panamanian Lower Montane Forest

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End-Use Load Profiles for the U.S. Building Stock: Methodology and Results of Model Calibration, Validation, and Uncertainty Quantification

Variation in Canopy Litterfall Along a Precipitation and Soil Fertility Gradient in a Panamanian Lower Montane Forest