Aims Evaluation of the interaction intensity between Masson pine (Pinus massoniana) and broadleaved trees will facilitate selecting tree combinations suitable for reforestation in abandoned sites in subtropical areas.
Methods Pinus massoniana and seven broadleaved trees species were grown either in monoculture or in two-species mixture. Biomass of tree species was measured and inter-specific interactions were estimated using log response ratio. Test of homogeneity of variances was performed to compare the stability of biomass in the monoculture of the broadleaved trees with that in the mixture.
Important findings Our results showed that the direction and intensity of interactions between P. massoniana and the broadleaved trees varied from year to year and the identity of the broadleaved species. Facilitative interactions were found between Camellia oleifera, Rhus chinensis and P. massoniana. Pinus massoniana had competitive effects on Lithocarpus glaber, Cyclobalanopsis glauca and Elaeocarpus japonicus. Significantly negative relations were found between biomass of P. massoniana and the broadleaved trees in the third year of the experiment, and the compensatory effects between P. massoniana and the broadleaved trees may be involved in stability maintenance in the multi-species forests in the subtropical area. The results of homogeneity test of variances also showed that the biomass per pot in the mixture had significantly lower variances than that in the monoculture, suggesting that total biomass is more stable in the mixture than the monoculture.