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Cities measure the structure and function of their urban forest resource to optimize forest management and the provision of ecosystem services. Measurements made using plot sampling methods yield useful results including citywide or land-use level estimates of species counts, leaf area, biomass, and air pollution reduction. However, these quantities are statistical estimates made over large areas and thus are not spatially explicit. Maps of forest structure and function at the individual tree crown scale can enhance management decision-making and improve understanding of the spatial distribution of ecosystem services relative to humans and infrastructure. In this research we used hyperspectral imagery and waveform lidar data to directly map urban forest species, leaf area index (LAI), and carbon storage in downtown Santa Barbara, California. We compared these results to estimates produced using field-plot sampling and the i-Tree Eco model. Remote sensing methods generally reduced uncertainty in species-level canopy cover estimates compared to field-plot methods. This was due to high classification accuracy for species with large canopies (e.g., Platanus racemosa with ∼90% average accuracy, Pinus pinea at ∼93%, Quercus agrifolia at ∼83%) and high standard error of the plot-based estimates due to the uneven distribution of canopy throughout the city. Average LAI in canopy, based on lidar measurements was 4.47 while field measurements and allometry resulted in an LAI of 5.57. Citywide carbon storage, based on lidar measurements and allometry was estimated at 50,991 metric tons (t) and 55,900 t from plot-sampling. As others have noted, carbon density varied substantially by development intensity based largely on differences in fractional cover but less so when only evaluating canopy biomass. Using separate biomass equations for each leaf type (broadleaf, needleleaf, palm) resulted in a more accurate carbon map but a less accurate citywide estimate. [ABSTRACT FROM AUTHOR]

Vegetation in urban areas can provide many ecosystem services, such as cooler temperatures. In water-limited climates, maintaining benefits from vegetation during droughts requires significant water inputs and can be challenging due to the uneven effects of drought on vegetation. Here, we tracked changes in vegetation cover in Los Angeles, California using airborne hyperspectral imagery acquired annually from 2013 to 2018 and coinciding with the exceptional 2012–2016 California drought. Subpixel fractions for trees, turfgrass, non-photosynthetic vegetation (NPV; e.g., senesced plant material), and non-vegetated urban surfaces were mapped at 18 m spatial resolution using Multiple Endmember Spectral Mixture Analysis. We quantified cover changes through time, comparing how different physiographic regions of the city experienced vegetation change and assessing changes based on income and outdoor water use. From 2013 to 2018, overall turfgrass cover decreased (−17%) and NPV cover increased (+22%). Tree cover was more stable but decreased in 2018 (−6%). The inland valleys consistently lost more turfgrass than coastal areas. Higher income and water use areas had larger absolute changes in vegetation cover, likely due to their higher baseline of vegetation cover. • Drought-driven changes in vegetation cover in Los Angeles were mapped over 6 years. • Turfgrass losses occurred more rapidly and widely compared to tree cover losses. • Inland valleys had greater turfgrass losses than the Los Angeles Basin. • Absolute vegetation cover losses were larger in areas of higher income and water use. • Low income areas had proportionally similar vegetation changes as high income areas. [ABSTRACT FROM AUTHOR]

• Fatty acids in the blood reflect dietary intake modified by individual metabolism. • Plasma fatty acids were measured during a 12-week DASH-based diet with lean beef (3 or 6 oz/d). • Sustained or homeostatic changes of individual fatty acids were observed. • Plasma linoleic acid decreased in a sustained manner, possibly affecting fatty acid metabolism. • Plasma docosahexaenoic and arachidonic acids increased initially but returned to baseline. Plasma fatty acid (FA) levels are used as biomarkers of health outcomes and nutritional intake. This was an exploratory analysis of the plasma FA profile from a parallel-designed, controlled-feeding study in older, obese adults (females, n = 17; males, n = 11) consuming a DASH-based diet with two levels of lean beef (3oz and 6oz per day). Plasma FA levels (as percent composition) were measured by gas chromatography from five timepoints over the 12-week intervention. The primary plasma FA change patterns modeled were sustained (initial change to 'new normal') or homeostatic (initial change, then return toward original baseline). The study diet was low in fat (< 60 g/d), especially polyunsaturated FAs (PUFAs; < 5 g/d), compared to the average American diet of obese individuals as described by a nationally representative sample. Participants lost ∼6% of body mass and lowered plasma fasting triglyceride levels by ∼9% over the course of the study. With strong to very strong strength of evidence, the individual FAs displaying a sustained response were C16:1n7t, C18:1n9, C20:1n9, and C18:2n6, and homeostatic response, C18:0, 24:0, C24:1n9, C18:3n6, C20:4n6, and C22:6n3 (Ps < 0.0021, Bonferroni-adjusted). The data suggested that systematic changes in both the PUFA and de novo lipogenesis pathways occurred. Diet can affect plasma FA changes both due to nutritional composition and by affecting metabolic processes. [ABSTRACT FROM AUTHOR]

Urban vegetation mitigates elevated temperatures in cities. Drought presents an important challenge to urban heat mitigation as prolonged dry periods cause reduced evapotranspiration and losses of green vegetation cover. To measure drought impacts on the urban environment and climate, we used visible short-wave infrared satellite imagery acquired throughout the 2012–16 drought in California to quantify effects on fractional vegetation cover in the Los Angeles urbanized region. We then used satellite thermal imagery with repeat high-resolution airborne thermal imagery to measure how drought-induced reductions of green vegetation cover affected urban land surface temperature (LST) and the cooling effect of urban vegetation. Green vegetation cover declined from 29.3% in 2011 to 24.6% in 2016 in urban Los Angeles County. Over the drought, the annual mean daytime LST increased from 34.4 °C in 2010 to 37.1 °C in 2014. Despite the large-scale homogenization of LST, tree- and grass-dominated areas differed in how they were affected by the drought, with larger losses of vegetation fractional cover and stronger reductions in cooling effect for grass compared to tree-covered areas due to different plant physiological responses and irrigation changes. Results suggest that drought presents a challenge to urban resiliency, as vegetation is often a main component of heat mitigation plans. • Satellite and airborne time series of VSWIR and LST imagery measured drought impacts. • Green vegetation cover declined from 29.3% in 2011 to 24.6% in 2016. • Annual mean daytime LST increased from 34.4 °C to a maximum value of 37.1 °C. • Cooling per unit vegetation cover declined by 15.3% for trees and 25.0% for grass. • Results suggest tradeoffs between heat mitigation and water conservation measures. [ABSTRACT FROM AUTHOR]

Local and regional urban surface heterogeneity produces diverse urban climates, significantly impacting water use, energy consumption, and human health. This study examines urban energy flux variability across landcover and climate gradients for 2123 km2 of urbanized Los Angeles County, USA, by using high resolution remote sensing combined with spatially distributed simulations with an urban energy balance model, covering the complete diurnal cycle of the remote sensing flights. Localized parameters, including landcover, plant type, albedo, building and tree height, and irrigation, were derived from hyperspectral and LiDAR imagery, and GIS. Modeled latent heat fluxes (LE) were linearly correlated with measured land surface temperature at the neighborhood scale (R2 = 0.51), and modeled Bowen ratio values closely agreed with previous values derived from eddy covariance observations. LE across the region displayed spatial and temporal responses to irrigation and regional climate. Peak LE occurred 3 h before solar noon, driven by early morning irrigation characteristic of the region. This suggests that schedule-based water conservation policies could reduce the cooling capacity of urban vegetation in late afternoon. Additionally, a negative effect of distance from the coast on LE was observed to strengthen through the day, reducing LE in interior areas relative to coastal areas. • Spatially-explicit energy fluxes were modeled for 2123 km2 of urbanized Los Angeles • Surface parameters were derived from hyperspectral, thermal, and LiDAR remote sensing • Drought irrigation schedules shifted peak latent heat fluxes to 3 h before solar noon • Midday to afternoon interior latent heat flux was lower than coastal latent heat flux • Vegetation fraction had larger effect on latent heat flux than distance to the coast [ABSTRACT FROM AUTHOR]