Treesearch

Biodiversity change has elicited widespread concern over the consequences for functions and services provided by ecosystems1–3. Despite extensive evidence for a positive effect of biodiversity on ecosystem functioning within a single trophic level4,5, how this biodiversity effect varies with multi-trophic food web structure remains unresolved6 even though most ecosystems contain two to six trophic levels7. We investigate how food web complexity modulates biodiversity–ecosystem functioning relationships in nature by quantifying energy fluxes as proxies for two principal ecosystem functions8—...

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), native to Northeast Asia, is the most destructive invasive pest of ash (Fraxinus spp.) in North America. In this study, we exposed mature fourth-instar diapausing EAB larvae (J-shaped or J-larvae) to nine temperatures ranging from 1.7 to 23.9 °C for 90 days, and then evaluated their diapause termination by measuring both the probability and timing of post-chill development to adults under warm rearing conditions (27 ± 0.5 °C, 16:8 h L: D). We also determined the effect of chill temperature on the mortality...

Oak (Quercus) trees and forests have provided a myriad of utilitarian and ecosystem services for millennia. Oaks are considered a foundational species in many regions of the world but are increasingly threatened as global climate change and anthropogenic pressures alter disturbance regimes and successional dynamics. Gaps in critical knowledge for oak ecology and management are impeding sustainability and restoration at small and large scales. This special issue was borne from attendees who attended a recent symposium, the International Oak Symposium that was held in Knoxville, Tennessee...

American elm ( Ulmus americana L.), an important floodplain tree species in the Eastern U.S., continues to suffer widespread mortality from the non‐native pathogen Ophiostoma novo‐ulmi . Reliable and efficient methods for screening potted American elms for resistance to the pathogen are lacking, hindering efforts to restore the species. The objective of this study was to compare various screening methods for efficacy in separating known‐resistant from known‐susceptible American elm genotypes. Over the course of three experiments, we evaluated symptom development in potted American elms...

The frequency and severity of natural disturbances and forest harvests are changing in many temperate and boreal forests worldwide, at a time when regional surveys suggest deficiencies in tree regeneration. This combination suggests the utility of assessing how regeneration existing prior to disturbance (i.e. advance regeneration) translates to forest recovery following recent disturbances.We used repeated plot measurements from nationwide forest inventory data to link advance seedling regeneration to post‐disturbance seedling abundance and sapling recruitment across forests of the...

Tree regeneration is vital to shaping characteristics of future forests, including vulnerability to climate change; resilience to pests, pathogens and disturbance; and departure from historical species composition. We used data from nationwide forest inventory plots to investigate trends in sapling abundance and recruitment as well as tree density for common tree species from 2003 to 2023 across forests of the northeastern United States . Tree seedling composition was then examined using (1) predicted sapling recruitment based on seedling abundance and (2) abundance of small‐sized seedlings...

The Urban National Landowner Survey (UNLS) is part of the U.S. Department of Agriculture (USDA), Forest Service, Forest Inventory and Analysis (FIA) program and has the mission of providing information about the ownership, objectives, management, and future plans of people who own trees in urban areas. This report summarizes data collected from private, residential landowners in Houston, TX, from 2019 (n = 209). While normally collected over 5 years, implementation was intensified in Houston to complete data collection in 1 year. Private, residential landowners in Houston believe that...

Data collected from over 200 plots in Milwaukee, Wisconsin from 2015 through 2021 reveal that the city has an estimated 3.7 million live trees at least 1.0 inch in diameter across all ownerships. The most common tree species by number are common buckthorn, boxelder, and green ash, while those at least 5.0 inches in diameter are led by green ash, boxelder, and Norway maple. The largest number of trees (31.4 percent; 1.1 million trees) are found on forest land. Trees on public lands total 2.1 million and account for over 57 percent of all live trees. Trees at least 15.0 inches in diameter...

Domestic selection creates the assemblages of organisms found in human-dominated environments, and urban forestry is a useful illustration of this process in action. In this study, we aim to understand how the process of domestic selection influences the nursery supply chain of trees to Baltimore, Maryland, USA. We interviewed actors in the supply chain to ask how they make decisions about which trees to grow, sell, select, and plant. We find tension between prioritizing diversity (at the species or genetic level) and other factors such as planting site conditions, esthetics, availability,...

The U.S. Department of Agriculture (USDA), Forest Service, Forest Inventory and Analysis (FIA) program provides this resource update yearly as an overview of forest resources in Maryland. These estimates are derived from field data collected across a systematic network of fixed-radius forest monitoring plots located on both public and private land. New updates are provided annually as a subset of plots within the State are remeasured. Each year, field crews visit and measure a subset of all FIA plots across the entire State (the size of the subset varies by State and year). Combining all...