Treesearch

The atmospheric boundary layer mediates the exchange of energy, matter, and momentum between the land surface and the free troposphere, integrating a range of physical, chemical, and biological processes and is defined as the lowest layer of the atmosphere (ranging from a few meters to 3 km). In this review, we investigate how continuous, automated observations of the atmospheric boundary layer can enhance the scientific value of co-located eddy covariance measurements of land-atmosphere fluxes of carbon, water, and energy, as are being made at FLUXNET sites worldwide. We highlight four...

Evergreen conifer forests are the most prevalent land cover type in North America. Seasonal changes in the color of evergreen forest canopies have been documented with near-surface remote sensing, but the physiological mechanisms underlying these changes, and the implications for photosynthetic uptake, have not been fully elucidated. Here, we integrate on-the-ground phenological observations, leaf-level physiological measurements, near surface hyperspectral remote sensing and digital camera imagery, towerbased CO2 flux measurements, and a predictive model to simulate seasonal canopy color...

Disturbances, both natural and anthropogenic, affect the configuration, composition, and function of forested ecosystems. Complex system behaviors emerge from the interactions between disturbance regimes, the vegetation response to those disturbances, and their interplay with multiple drivers (climate, topography, land use, etc.) across spatial and temporal scales. Here, we summarize conceptual advances and empirical approaches to disturbance interaction investigation, and used those insights to evaluate and categorize 146 landscape modeling studies emerging from a systematic review of the...

As part of national biosecurity programs, cargo imports, passenger baggage, and international mail are inspected at ports of entry to verify compliance with phytosanitary regulations and to intercept potentially damaging nonnative species to prevent their introduction. Detection of organisms during inspections may also provide crucial information about the species composition and relative arrival rates in invasion pathways that can inform the implementation of other biosecurity practices such as quarantines and surveillance. In most regions, insects are the main taxonomic group encountered...

Background. Natural outdoor environments including green spaces play an important role in preserving population health and wellbeing in cities, but the number of deaths that could be prevented by increasing green space in European cities is not known. We aimed to estimate the number of natural-cause deaths among adult residents that could be prevented in cities in 31 European countries, if the WHO recommendation for universal access to green space was achieved. Methods.In this health impact assessment study we focused on adult residents (aged ≥20 years; n=169 134 322) in 978 cities and 49...

Mixed-species forests are, or were, a common feature of most forested regions around the globe (Bauhus et al. 2017b). The ecology and silviculture of these systems has been a consistent area of study given the potential benefits of mixed-species forests in relation to minimizing forest health and climate change impacts (Bauhus et al. 2017a) and the occasional higher levels of productivity observed for species mixtures relative to single-species stands (Lu et al. 2016). Nevertheless, the restoration and maintenance of mixed-species forests remains a significant challenge given the complexiti...

In 1993 the apple buprestid, Agrilus mali Matsumura (Coleoptera: Buprestidae) native to northeast Asia, invaded the Yili River valley, Xinjiang Uyghur Autonomous Region, China. It is now widespread across 95% of wild apple forests (Malus sieversii (Ledeb.) Roem) in the region. This invasive species poses a major threat to wild apple populations serving as the key germplasm refuge for the ancestor of domestic apples across 6 countries in Central Eurasia. We first described the symptoms and damage caused by A. mali to wild apple trees, and then assessed abundance of A. mali and tree damage...

Sirex noctilio is a Eurasian species in the woodwasp (Siricidae) insect family, a small and poorly understood group of insects. Several siricid species have invaded various world regions due to their frequent presence in wood moving in international trade. Like most other woodwasps, feeding by S. noctilio occurs in weakened or dying pines in its native range, and populations exist there at relatively low levels. But in non-native regions of the Southern Hemisphere, S. noctilio populations have thrived, colonizing hosts in plantations of non-native pines planted at high densities. Under...

The effects of forest management on native fauna are of key interest to managers and conservationists. Individual studies have expanded our knowledge of management impacts, but meta-analyses of multiple studies are needed to summarize and integrate findings into a more generalizable form. Most meta-analyses on the effects of tree harvesting have focused on mature forest taxa because of concerns for these species; however, early-successional specialists, such as shrubland birds in the eastern United States, are also of key conservation concern. Using data from 34 studies that examined the...

Resilience can seem like a buzzword in natural resource management, but it is also a concept with deep roots in ecological and sustainability science. In the context of urban forests, resilience has many meanings, including ecological, social, and institutional components, which are often intertwined. Broadly speaking, resilience refers to the capacity of systems to absorb stresses and changes, and recover from disturbances.