Background Pinus tabuliformis is widely distributed in eastern Liaoning province and is one of the main plantations in this area. This paper discusses the interference model of P. tabulaeformis plantation in Wandao Forest Farm of Fushun county, which provides certain quantitative basis for the study of plantation ecosystem in this area, and provides reference for the scientific and effective management and updating of plantation, and maximizes the ecological and economic benefits of plantation.

Methods Field survey was conducted in Wandao Forest Farm in June 2018. Three sample plots of 20 m×20 m were set up with P. tabuliformis plantation as the research object. By adopting the fixed sample plot survey method, the factors of the cardinal tree and its adjacent body in the sample plot were actually measured. In this study, an improved neighborhood interference model was adopted to calculate neighborhood interference index, and the relationship between interference index and DBH, tree height, habitat utilization ratio (crown width area) and height-to-diameter ratio was discussed.

Results 1) The interference index of adjacent body of P. tabuliformis in different P. tabuliformis sample plots was between 0.89 and 31.96, and the interference index decreased with the increase of DBH, tree height and habitat utilization ratio, and increased with the increase of height-to-diameter ratio. 2) Stand density also had some influence on interference index. The stand density of sample plot 1 was relatively large, thus the fluctuation range of interference index was larger, and the maximum interference index reached 31.96, the density of sample plot 2 and 3 was small, and the change of interference index was relatively stable. 3) Young trees in stands were disturbed by neighbors and were in an inferior position in the competition for resources and space, and the tall trees were in a dominant position with little interference. 4) The interference index varied with DBH, tree height, habitat utilization rate and height-diameter ratio within a certain range. When the interference index exceeded a certain range of a factor, it tended to be a certain fixed value. Interference index was significantly correlated with DBH, tree height and habitat utilization ratio (P < 0.01), but not significantly correlated with height-todiameter ratio (P>0.05).

Conclusions Through the above studies, it can be seen that the neighborhood interference model can accurately reflect the extent to which the cardinal tree is affected by neighborhood, it is a quantitative index describing the growth status and status of trees, which can be used to guide forest management activities and provide theoretical basis for rational management.