Forestry activities, to some degree, affect the spatio-temporal pattern of regional forest as a carbon sink or source. With the aim to improve regional forest carbon sink and achieve to "Carbon Neutral" strategically, it is of great significance to clarify and quantify the impacts forestry activities on forest carbon sink or source on spatial level. Taking Nanping City, Fujian Province, a national ecological demonstration, as an example, this paper analyzed the spatial distribution of carbon sources and carbon sinks caused by land use changes and five forest activities, which are remaining forest as forest, afforestation, natural recovery, deforestation and forest degradation, based on the local forest resources planning survey data during 2013-2020 and the IPCC volume-biomass method. The results showed that the total forest carbon storage in Nanping City was 80.84Tg C and 89.87Tg C in 2013 and 2020, respectively, with a mean annual change of 1.29Tg C/a (or 4.73Tg CO₂/a). Forest stand characters such as the mean Diameter at Breast Height (DBH) and the growing stock per hectare are the most important factors that mainly affect forest carbon storage. Among other influencing factors, the forest biomass carbon density is higher in the dark red soil distribution area but lower in the paddy soil distribution area, and it is higher in the high altitude, medium-quality sites. For the five forestry activities, the forest remaining as forest, natural restoration and afforestation increased the forest biomass carbon stocks (BCS) by 0.34Tg C/a, 0.85Tg C/a and 1.05Tg C/a respectively, while deforestation and forest degradation decreased BCS by 0.75Tg C/a and 0.42Tg C/a, respectively, which led to a net increase of forest BCS by 1.09Tg C/a (or 3.98Tg CO₂/a) in Nanping during 2013-2020. Significantly lower than the net increase in forest carbon storage in 2013-2020. For those regions with intense land use changes, our method based on land use change or forest activities could more accurately estimate regional forest carbon sink and carbon source and their spatial pattern. Forest remaining forest only increased the forest biomass carbon density (BCD) by 0.22Mg C hm^-2 a^-1 in Nanping during 2013-2020, which was likely due to average forest growth rate decreasing caused by the increase in the area proportion of mature and over-mature forests. However, the BCD was increased by 4.00Mg C hm^-2 a^-1 and 4.10Mg C hm^-2 a^-1 for the new natural forests and plantations during 2013-2020. Optimizing forest age group structure to improve forest growth, reducing area of deforestation and forest degradation could be the optional measures to increase regional forest carbon sink and reduce carbon emission from forest.