ObjectiveThis study aims to explore the effects of tending felling on forest ecological services, to provide advice for the establishment of forest ecological function evaluation system and for the management of mixed broadleaved-Korean pine forest in the future.

MethodTaking the mixed broadleaved-Korean pine forests of Forestry Experimental Administration in Jiaohe, Jilin Province, northeastern China as the research object,establishing four different harvesting intensity plots of 0 (control, CK), 15% (light treatment, LT), 35% (moderate treatment, MT) and 50% (high treatment, HT). Based on the evaluation factors and criteria of forest ecological function of the State Forestry Administration, eight factors, including forest volume stock, forest naturalness, forest community structure, tree species structure, average height of stand, total vegetation coverage, canopy closure and litter layer thickness, were selected as evaluation criteria of forest ecological function. The differences of ecological services of four plots before harvesting, after harvesting and four years later after restoration were compared.

ResultBefore harvesting, the forest ecological function index (FEFI) of each plot was 0.83. After harvesting, there were significant differences in the FEFI of the four forest plots with different cutting intensity: control (0.83) > light treatment (0.71) > moderate treatment (0.67) > high treatment (0.53). After four years’ restoration, the difference of FEFI between each plot decreased gradually. The ecological function of the light treatment plot returned to the origional state (FEFI = 0.83), the forest ecological function of the moderate and high treatment plots also restored in varying degrees, with the FEFI was 0.77 and 0.61, respectively. (2) The annual average growth rate of forest increased first and then decreased with the cutting intensity. (3) Harvesting promotes the growth of dominant species in mixed broadleaved Korean pine forest, but has insignificant effects on the growth of stand height.

ConclusionTending felling with light or moderate intensity can optimize the function of forest ecosystem, promote the growth of trees, improve the utilization of timber resources, and improve the ecological benefits of forests. High-intensity harvesting can seriously destroy the stability of forest ecosystem, affect the function of ecosystem, and make it unable to recover in a short time. Considering comprehensively, the cutting intensity at 15% is reasonable, and it is suggested that the cutting intensity should not exceed 25%.