Nutrient limitation of forest growth has been difficult to predict, and in temperate forests, long‐term tests of single‐nutrient versus multiple‐element limitation are few. Nutrient co‐limitation is the expected outcome of the ability of plants to adjust allocation to minimize limitation by any single resource. Nutrient limitation of productivity in northern hardwood forests was predicted by the Multiple Element Limitation (ME...

Soil respiration (Rsoil) is the second largest terrestrial carbon (C) flux, and therefore, it is imperative to understand and quantify its responses to global environmental change. Rsoil consists of two component CO 2 fluxes: autotrophic respiration from the metabolic activity of roots (Ra ‐root ) and heterotrophic respiration (Rh) derived from the metabolic activity of mycorrhizal fungi and microbial decomposition of detritus...

Summary Soil microbial community composition routinely correlates with pH, reflecting both direct pH effects on microbial physiology and long‐term biogeochemical feedbacks. We used two watershed‐scale liming experiments to identify short‐ (2 years) and long‐term (25 years) changes in the structure and function of bacterial and fungal communities in organic horizons (O e and O a ) of acid forest soils. Liming increased soil pH,...

Microbial community structure and function regularly covary with soil pH, yet effects of these interactions on soil carbon are rarely tested experimentally within natural ecosystems. We investigated the enduring (25 year) impacts of liming on microbial community structure and decomposition at an acidic northern hardwood forest, where experimental liming increased pH one unit and surprisingly doubled the organic carbon stocks o...

Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250‐fold increase in seed abundance from cold‐dry to warm‐wet climates, driven primarily by a 100‐fold increase in seed production for a given tree size. The modest (three...

Forest productivity on glacially derived soils with weatherable phosphorus (P) is expected to be limited by nitrogen (N), according to theories of long‐term ecosystem development. However, recent studies and model simulations based on resource optimization theory indicate that productivity can be co‐limited by N and P. We conducted a full factorial N × P fertilization experiment in 13 northern hardwood forest stands of three a...

Globally, biological invasions can have strong impacts on biodiversity as well as ecosystem functioning. While less conspicuous than introduced aboveground organisms, introduced belowground organisms may have similarly strong effects. Here, we synthesize for the first time the impacts of introduced earthworms on plant diversity and community composition in North American forests. We conducted a meta‐analysis using a total of 6...

Snow cover is projected to decline during the next century in many ecosystems that currently experience a seasonal snowpack. Because snow insulates soils from frigid winter air temperatures, soils are expected to become colder and experience more winter soil freeze‐thaw cycles as snow cover continues to decline. Tree roots are adversely affected by snowpack reduction, but whether loss of snow will affect root‐microbe interacti...

Previous studies have attempted to link foliar resorption of nitrogen and phosphorus to their respective availabilities in soil, with mixed results. Based on resource optimization theory, we hypothesized that the foliar resorption of one element could be driven by the availability of another element. We tested various measures of soil N and P as predictors of N and P resorption in six tree species in 18 plots across six stands...

Ecological research is increasingly concentrated at particular locations or sites. This trend reflects a variety of advantages of intensive, site‐based research, but also raises important questions about the nature of such spatially delimited research: how well does site based research represent broader areas, and does it constrain scientific discovery? We provide an overview of these issues with a particular focus on one prom...

Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots...