Ectomycorrhizal (EM) fungi are a prominent and ubiquitous feature of forest soils, forming symbioses with most tree species, yet little is known about the magnitude of their impact on forest carbon cycles. A subset of EM fungi form dense, perennial aggregations of hyphae, which have elevated respiration rates compared with neighboring non-mat soils. These mats are a foci of EM activity and thereby a natural laboratory for examining how EM fungi impact forest soils.

Soil microbes are key drivers of ecosystem processes, yet their role in regulating landscape-scale vegetation change is not known. Comprehensive studies of treeline position have noted that ectomycorrhizal fungi may be an important factor delineating the boundary between forest and tundra. Yet, these critical plant-fungal symbioses are sensitive to wildfires. Fire is the primary landscape-scale disturbance in the boreal forest and increasingly important in tundra.

Large forest dynamics plots across the LTER and NEON network.

Jill Thompson, David Foster, David Orwig, Stuart Davis and Jerry Franklin

The Detritus Inputs and Removal Treatments (DIRT) were established at the H.J. Andrews Experimental Forest to examine the effects of organic matter manipulations on soil organic matter (SOM) chemistry and nutrient cycling. In 2007, after ten years of manipulations, isotope dilution methods were used to estimate gross N mineralization and nitrification rates among the six treatments that control the rate and quality of SOM inputs (control, double wood, double litter, no roots, no litter, and no inputs).

LiDAR (Light Detection and Ranging) has become an important tool for investigating the structure of the earth's surface and vegetation. It permits high vertical and special resolution characterization of ground and vegetation surface heights and structure across large areas. LiDAR has been used to characterize vegetation cover, biomass, leaf area, and basal area for live and dead vegetation. Software is now readily available for 3-D visualization of canopy surfaces.

Oaks are a dominant component of many North American forests, yet in many areas oak seedling production is declining. Oaks are generally thought to be highly dispersal limited, which could hamper reaching scarce recruitment sites and limit oaks’ ability to respond to climate change via migration or local adaptation. In this study, we apply a Bayesian parentage model developed for monoecious plants to two populations of red oak (Q. rubra) in North Carolina: in the Piedmont (12 ha) and the Coweeta LTER in the southern Appalachians (7.5 ha).