Introducing trees to agricultural lands increases greenhouse gas emission during spring thaw in Canadian agroforestry systems

Abstract The role of agroforestry systems in mitigating greenhouse gas (GHG) emission from agricultural soils during spring thaw (early April to mid-May) has been poorly studied. Soil CO 2 , CH 4 and N 2 O fluxes were measured from treed areas and adjacent herblands (areas without trees) during spring thaw in 2014 and 2015 at 36 agroforestry sites (12 hedgerow, 12 shelterbelt and 12 silvopasture) in central Alberta, Canada. Fluxes of those GHGs varied with agroforestry systems and land-cover types. We found greater CO 2 emission ( P 4 uptake ( P 2 O emission ( P 2 emissions ( P 4 uptake ( P 2 O emissions ( P P P 2 -eq m −2  day −1 ), the GWP of these land uses during spring thaw was small ( 2 -eq m −2  day −1 ). Although GHG emissions during spring thaw were small compared to those in the growing season, they should not be ignored.