The overall long-term goal of harvesting is to modify the existing, aspen-dominated forest of the management area into a matrix of conditions better positioned to maintain their ecological functions as climate continues to change. The more immediate goal of harvesting is to provide locations and funds for studying forest management impacts on carbon forms, turnover, and mobility in soils and groundwater. Treatments will produce immediate changes in forest composition, structure, hydrology, and biogeochemistry that then play out over longer time frames, as the units undergo succession. In 2019, the treatments removed standing biomass (mostly aspen) in order to either: 1) regenerate young, homogenous-structure aspen/birch cover types (resistance); 2) regenerate aspen-dominated cover, but with greater structural and compositional diversity (resilience); 3) encourage succession to more structurally and compositionally diverse cover types (transition). Specific treatments varied according to the cover types, soils, and hydrology present on the units. These treatments integrate with ongoing and create new opportunities for research projects. The project team will continue publishing papers on soil and ecosystem hydrology and biogeochemistry. Management treatments will address objectives of the original McIntire-Stennis grant (Drevnick, Kerkez, Nave) that funded the initiation of the HCW study, pertaining to the effects of harvesting on the hydrologic movement of C and Hg. Key projects completed or ongoing are: 1. Forest inventory: The 2018 AAME team (Olivia Brinks, John Den Uyl, Elizabeth Feliciano, Edie Juno, Katy Hofmeister, Luke Nave, and Adam Schubel) marked and GPS’d 53 permanent plots (10 m radius each) distributed across the management units (blue points in Fig. 2). Data recorded includes: 1) for every standing tree >8 cm dbh: species, dbh, status (live or dead), azimuth from plot center, approximate distance, whether marked for retention during harvest, and if beech, the density of scale infestation [3 categories]; 2) for every tree <8 cm dbh but reaching dbh, the species and size class (0-2, 2-4, 4-6, or 6-8 cm dbh). These data were the basis for Elizabeth Feliciano’s Frontiers project at UMBS, and provide a complete forest inventory baseline before management treatments occurred. Data are available upon request by any researcher. 2. Soil sampling for post-hoc experiment: The 2018 AAME team sampled 25 soil profiles (to E’Bt horizon or 2 m depth, whichever is shallower) from Units 2, 3, 4, 15, and 16. This sample set is being used to test for impacts of past harvesting on the storage and stability of C in multiple soil C pools. Laboratory processing has been completed and extractions and analyses are in progress. Analyses for this study are expected to run into 2020; most will be performed in the UMBS Analytical Lab, and some will occur through NIACS’ Carbon, Water, and Soils Lab. This will eventually yield a novel paper on multiple mechanisms of soil C stabilization in Spodosols and accompanying analysis of management effects on soil C stability. 3. Groundwater, porewater, and soil sampling for real-time experiment: Den Uyl, Hofmeister, and Nave augmented existing monitoring locations in Units 12 (1980s harvest), 13 (2019 harvest), and 14 (reference) for a study of the real-time effects of management on water table dynamics, soil C stability and transport in pore- and groundwater. In these units, 13 water table wells are installed to the restrictive layer (till) or to 2m (whichever is shallower); 12 possess water level loggers. Soils have been collected, processed and archived for all of these locations. Tension lysimeters were deployed to the B1 horizon (~30 cm) at 12 of the locations in fall 2018 by Den Uyl. In 2019, Technician Brooke Propson, Adam Schubel, and Nave deployed 3 new wells on private property ~1km south of Honeysuckle Creek. This property, owned by Lynn Lord (summer resident of W. Burt Lake Rd.) and overseen by UMBS friend /year-round resident Rick Johnson, was logged in 2018. Soils were sampled while installing these wells, which are paired with the three along Honeysuckle Creek by elevation and landscape ecosystem type. 4. Groundwater and porewater sampling: Biweekly to monthly collections of groundwater and porewater (from wells and lysimeters) are planned to begin with spring melt 2020. These water samples, along with the soils from the water sampling locations, will be analyzed for C forms and fluxes for a paper documenting the real-time changes in C hydrobiogeochemistry following harvest. As of this writing, 6 collections have been made (2x in May 2019, 1x each in October and November 2019, February and March 2020). 5. Microclimate sampling: Brooke Propson, John Den Uyl, and Nave collected soil moisture (May 2019) and soil moisture, temperature, air temperature, humidity, and sunlight data (July 2019) across 53 permanent plots. Data are planned to be collected at more regular intervals in 2020 beginning with snowmelt. This plot-based distributed data collection is to augment, and capture spatial variability in meteorological parameters being recorded at half-hourly intervals by weather / soil stations in Units 12, 13, 14, which were installed in Autumn 2019. The stations are deployed at similar elevation, slope and aspect, allowing for comparison of real-time weather variables in the Resistance cut, ~35 year old, and reference aspen areas.