Climate change is causing the Arctic to warm faster than anywhere else on Earth. The Arctic is an important piece of the global carbon cycle, storing half of the Earth's soil carbon in perennially frozen permafrost. As temperatures rise, the balance of Arctic carbon stocks among the soil, vegetation, and atmosphere is changing in ways that are challenging to predict, which is complicated by wildfire regime shifts, water and nutrient availability, sea ice decline, etc., amplified by limited data. In this dissertation, I combined field observations, remote sensing datasets, laboratory elemental and isotopic analyses, and modeling to understand how vegetation changes are altering soil properties, permafrost thermal regimes, and emissions of biogenic volatile organic compounds (BVOCs) and carbonaceous aerosols in Alaska, USA. I focused on deciduous shrub expansion ("shrubification") in Arctic tundra—the most widely observed vegetation change in Northern Alaska—using observations from field sites with documented expansion, an approach distinct from theoretical or experimental approaches predominant in the literature. In Chapter 2, I documented increasing Alnus viridis (Chaix) DC. (alder) growth in alpine tundra using dendrochronology, remotely sensing, and allometry, finding reduced organic carbon and nitrogen stocks and organic layer thickness (OLT) linked to alder cover and biomass, which was possibly facilitated by wildfire. I found active layer thickness was the same under alder and adjacent graminoid tundra, suggesting instantaneous measurements may not capture long-term trends in ground thermal regimes. In Chapter 3, I examined alder cover and organic soil properties at one site (Sagwon Bluffs) in Arctic tundra on the North Slope of Alaska (NSA), USA, where locations with the highest shrub biomass (modeled using remote sensing products), dominated by alder, exhibited the fastest biomass accumulation rates. Alder presence was associated with a 25% reduction in OLT. Ground temperature modeling revealed this reduced OLT resulted in a warmer active layer, with decreased thermal offsets and freezing degree days. In Chapter 4, I characterized BVOC emissions and carbonaceous aerosols at two sites on the NSA, where surface carbonaceous aerosol studies were previously limited to the Arctic coast. Compared to other tall (>40 cm) deciduous shrub species (alder, Betula nana L. (birch)), Salix spp. (willow) had the highest total BVOC emission factor by at least 24 times, mostly comprised of isoprene. Ambient BVOC emissions did not vary by latitude nor landcover across the NSA, suggesting shrublands are not drivers of emissions. Carbonaceous aerosol concentrations, dominated by organic carbon, were twice as high inland as on the Arctic coast, and significantly elevated during wildfire smoke events. Isotopic source apportionment revealed that these aerosols were predominantly (86–100%) contemporary in origin from secondary organic aerosol formation and boreal forest fires—establishing baseline data for future radiative budget models. These results provide insight into how Arctic vegetation change influences soil properties, permafrost thermal regimes, and land-atmosphere interactions through complex feedbacks, with implications for regional carbon cycling and radiative forcing in the rapidly warming Arctic.