A Life Cycle Analyses (LCA) assessment was evaluated comparing three harvesting systems on intensively managed Pinus radiata (radiata pine) plantations growing in the Biobío Region, Chile. Evaluated systems considered semi-mechanized, mechanized, and tower logging in steep slope forest operations. Our LCA study focused on CO2 emissions from six harvesting activities: felling, logging, processing, sorting, loading, and transportation, all under the ISO 14040 and ISO 14044 standards. The average and maximum monthly production scenarios were the highest for the semi-mechanized system with 24 and 25.2 kg CO2e m-3, followed by the tower logging with 23.2 and 24.5 kg CO2 e m-3 and, lastly, the mechanized system with 11 and 12.1 kg CO2e m-3. Similar to other studies, harvesting phases that contributed the most were logging, loading and transport. Concerning LCA stages, forest equipment operation generated the highest CO2 level across the three harvesting systems where fuel consumption was the activity that contributed with 76% of CO2e for the mechanized system, and 50% in the case of the tower logging and semi-mechanized systems. The mechanized system had the highest fuel use efficiency and the lowest CO2e emissions.