Effects of Forest Fragmentation on Carbon Sequestration and Respiration at Harvard Forest since 2016

Forest loss/fragmentation can have profound impacts on the terrestrial carbon (C) cycle by reducing forest uptake of carbon dioxide (CO2; the primary driver of anthropogenic climate change) through photosynthesis and C storage in forest biomass. Relative to intact rural forests, trees growing in forest fragments within developed landscapes typically experience conditions that can enhance growth such as warmer and longer growing seasons (i.e. urban heat island effect) and greater light and nutrient availability (e.g., nitrogen deposition) as well as conditions that can hinder growth such as increased exposure to damaging pollutants such as ozone and higher rates of disturbance. Our research quantifies the impact of fragmentation on C uptake and respiration near forest edges. In 2016 six 600‐m2 plots were installed along forest edges at the HF, measuring 20 m along the forest edge and extending 30 m into the forest perpendicular to the forest edge. Plot biomass was mapped and tree cores were taken in all trees >10cm diameter. The plots were installed at multiple edge aspects and adjacent land cover types (three meadows, two pastures, and one road). Within each plot, a pair of polyvinyl chloride soil respiration collars 20 cm in diameter × 7 cm tall and located 10 m apart was inserted approximately 2 cm into the soil at four distances from the edge (0, 10, 20, and 30m). Each plot had n = 8 collars for a total of n = 48 collars. Following installation, collars were left in the soil for at least 2 weeks to equilibrate. Air temperature, relative humidity, soil temperature, and soil moisture were logged along the center plot transect.