Abstract. Carbon (C) and nitrogen (N) released from biomass burning have multiple effects on the Earth's biogeochemical cycle, climate change, and ecosystem. These effects depend on the relative abundances of C and N species emitted, which vary with fuel type and combustion conditions. This study systematically investigates the emission characteristics of biomass burning under different fuel moisture contents, through controlled burning experiments with biomass and soil samples collected from a typical alpine forest in North America. Fuel moisture in general lowers combustion efficiency, shortens flaming phase, and introduces prolonged smoldering before ignition. It increases emission factors of incompletely oxidized C and N species, such as carbon monoxide (CO) and ammonia (NH 3 ). Substantial particulate carbon and nitrogen (up to 4 times C in CO and 75% of N in NH 3 ) were also generated from high-moisture fuels, maily associated with the pre-flame smoldering. This smoldering process emits particles that are larger and contain lower elemental carbon fractions than soot agglomerates commonly observed in flaming smoke. Hydrogen (H)/C ratio and optical properties of particulate matter from the highmoisture fuels show their resemblance to plant cellulous and brown carbon, respectively. These findings have implications for modeling biomass burning emissions and impacts.

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Conventional soil solution lysimeters and snowmelt solution collectors suffer from a number of limitations when used to estimate yearly nutrient fluxes. This study describes an alternative technique to directly measure soil and snowmelt solution fluxes utilizing ion exchange resin-based collectors. Resin-lysimeters were constructed by enclosing a layer of resin between two layers of nutrient-free silica sand within a polyvinyl chloride tube. Nitrogen (N) and phosphorus (P) fluxes from resin based collectors were compared against buried resin bags, ceramic cup lysimeters, and traditional snowmelt solution collectors co-located in an eastern Sierra Nevada forest. Ammonium and P accumulation in resin lysimeters were one-to two orders of magnitude smaller than in buried resin bags placed in direct contact with the soil. Resin lysimeters and resin snowmelt collectors measured NH 4 -N and P 1261 fluxes that were three times greater than those estimated from ceramic cup lysimeters and solution snowmelt collectors. We hypothesize that this difference was due to spoilage of the solution sample in solution collectors between collections. Resin lysimeters are easy to construct, provide a direct measurement of nutrient fluxes, and are an alternative to solution snowmelt collectors and ceramic cup lysimeters, especially in areas where poor winter accessibility precludes constant maintenance.

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