Treesearch

A free-standing, lightweight, highly porous, and highly flexible cellulose nanofibril (CNF)–reduced graphene oxide (RGO)–molybdenum oxynitride (MoOxNy) aerogel film electrode was synthesized by freeze-drying a CNF/GO/MoO3 aqueous dispersion followed by subsequent in situ hydrazine reduction. Due to the partial reduction and nitrogen doping of the MoO3 nanobelts and the highly open and continuous porous structure, the free-standing CNF/RGO/MoOxNy aerogel film electrode delivered an outstanding specific capacitance of 680 F g
1 in an aqueous electrolyte and 518 F g
1 in an ionic liquid...

In New England (United States) climate change models forecast increasingly intense, frequent floods. Communities in this region are already experiencing these changes, along with the negative consequences associated with them, such as inundation, erosion, natural habitat destruction, and property damage. As it is in many places around the world, agriculture in New England is often in floodplains, which means that farmers are at greater risk due to where they farm. These farmers are already adapting to the increased risk of flooding; however, some of their actions may affect communities...

Se estudió la anatomía de porciones juveniles de tallos, en trece especies de Cactaceae que crecen en los estados Lara y Falcón, a fin de obtener información biológica que pueda contribuir a delimitarlas taxonómicamente. Las especies estudiadas fueron: Acanthocereus tetragonus, Cilindropuntia caribaea, Epiphyllum hookerii, Hylocereus lemairei, Melocactus curvispinus ssp. curvispinus, Opuntia caracasana, O. cf. bisetosa, Pilosocereus moritzianus, Praecereus euchlorus, Rhipsalis baccifera, Selenicereus inermis, Subpilosocereus russellianus y Stenocereus griseus. Se recolectaron trozos de...

Many municipalities are setting ambitious tree canopy cover goals to increase the extent of their urban forests. A historical perspective on urban forest development can help cities strategize how to establish and achieve appropriate tree cover targets. To understand how long-term urban forest change occurs, we examined the history of trees on an urban college campus: the University of Pennsylvania in Philadelphia, PA. Using a mixed methods approach, including qualitative assessments of archival records (1870–2017), complemented by quantitative analysis of tree cover from aerial imagery...

The complexity of processes and interactions that drive soil C dynamics necessitate the use of proxy variables to represent soil characteristics that cannot be directly measured (correlative proxies), or that aggregate information about multiple soil characteristics into one variable (integrative proxies). These proxies have proven useful for understanding the soil C cycle, which is highly variable in both space and time, and are now being used to make predictions of the fate and persistence of C under future climate scenarios. However, the C pools and processes that proxies represent must...

Organic carbon (OC) concentrations in subsurface sediments are typically 10 to 200 times lower than in surface soils, posing a distinct challenge for characterization. In this study, a range of chemical extractions were evaluated for extraction of natural organic matter (NOM) from two low-carbon (< 0.2%) alluvial sediments. The OC extraction efficiency followed the order pyrophosphate (PP) > NaOH > HCl, hydroxylamine hydrochloride > dithionite, water. A NOM extraction and purification scheme was developed using sequential extraction with water (MQ) and sodium pyrophosphate at pH 10 (PP),...

Urban trees experience site-induced stress and this leads to reduced growth and health. A site assessment tool would be useful for urban forest managers to better match species tolerances and site qualities, and to assess the efficacy of soil management actions. Toward this goal, a rapid urban site index (RUSI) model was created and tested for its ability to predict urban tree performance. The RUSI model is field-based assessment tool that scores 15 parameters in approximately five minutes. This research was conducted in eight cities throughout the Midwest and Northeast USA to test the...

Residential lands often represent the largest potential areas for expanding urban tree canopy cover (O'Neil-Dunne 2009; O'Neil-Dunne 2011; O'Neil-Dunne 2012). Thus, adding trees to private residential properties is critical to accomplishing urban greening goals, such as ambitious tree canopy cover targets. While municipal arborists and nonprofit urban forestry organizations have traditionally focused on tree planting in public lands along streets and in parks, some organizations are branching out to private residential properties to meet their greening objectives.

Northern wetland soils hold globally significant carbon (C) and mercury (Hg) stocks whose cycling feeds back to atmospheric pollution, climate change, and the trophic dynamics of adjacent aquatic ecosystems. At a more local level, patterns of variation in the hydrologic, physical and chemical properties of wetland soils inform the appreciation of these ecosystems in their own right; describing patterns of variation, their potential drivers and consequences is a key step towards placing wetland soils in the context of broader landscape-level processes, such as C and Hg export to aquatic...

Soil organic matter (SOM) plays a critical role in the global terrestrial carbon cycle, and a better understanding of soil processes involved in SOM stability is essential to determine how projected climate-driven changes in soil processes will influence carbon dynamics. We used 14C signature, analytical thermal analysis, and ultrahigh resolution mass spectrometry to determine the influence of deciduous and coniferous forest vegetation type and soil depth on the stability of soil C. The 14C mean residence time (MRT) of the illuvial B horizon soils averaged 1350 years for the deciduous...