Vegetation successionnal dynamic greatly depends on plant-plant interferences during installation stage and saplings allocation trade-offs between growth and defence compounds. In Mediterranean region, Aleppo pine constitutes dense tree stands with low regeneration rate contrary to Quercus pubescens, a late successional species. Aleppo pine is known to produce secondary compounds may influence early recruitment. The purpose of this study is to compare the effects of direct competition, allelopathy and limiting resource (light and nutrient) on the competitiveness and the defence capacities of this two species. In a nursery experiment, we investigated changes in growth and the concentrations of foliar secondary metabolite compounds (soluble phenolics, and terpenoids) in response to the stresses: (i) competition (pine alone, oak alone, and pine with oak), (ii) allelopathy (with or without pinus leaf leachates), (iii) light (natural or shading conditions) and (iv) resource availability (low or high nutrient rates) in order to understand their interactions. Results show no effect of allelopathic compounds on oak growth which is limited by shading conditions, competition and low nutrient availability. As expected pine growth is also limited by competition and low resources availability. But for this last species, pinus leaf leachates strongly inhibit height growth, showing autotoxic effect during early development. Contrary to growth, phenolic compounds are only influenced by light availability. Higher irradiance strongly increases phenolics foliar concentrations in the two species. Competition, allelopathy and poor fertility don't influence defence compounds concentrations, light influences them in the same way than growth, so there are no trade-off to constraint growth and competitiveness. Moreover, this experiment highlights the importance of pine-oak interactions in regeneration stages. Hence, these phenomena (autotoxicity, and resources competition) could more affect pine growth and competitiveness, so indirectly facilitate Quercus pubescens regeneration in Aleppo pine forests and tree species alternation (pine  oak).