This dataset contains in situ CO2 efflux, root production and fungal hyphae production from plots distributed across a subarctic landscape in Northern Sweden. Six paired plots were established in mountain birch forest and five paired plots were established in tall shrub tundra where one of each pair was 'girdled' and one acted as a non girdled 'control'. Efflux measurements were made during six sampling campaigns over 2017 and 2018 at an approximate frequency of once per week during each campaign, constituting a time series of measurements. Production measurements integrated root or hyphae production over the whole growing season (June-September) and therefore there is one datapoint per plot per year.