The variation in functional traits of branches and leaves, along with their correlations, plays a crucial role in shaping plant resource allocation and carbon investment strategies. Understanding these trait dynamics is essential for elucidating species-specific ecological adaptations, particularly in evergreen conifers. This study investigated the branch and leaf functional traits of two dominant plantation species, Pinus thunbergia and Pinus densiflora, in the Laoshan District of Qingdao, located in the eastern Shandong Peninsula. We measured key morphological and physiological traits, including leaf mass density (LMD), leaf dry matter content (LDMC), total leaf area (TLA), branch wood density (BWD), branch dry matter content (BDMC), leaf intensity volume (LIV), and specific branch length (SBL), in both current-year and perennial-year branches and leaves. Differences in these traits across age classes and between species were assessed using one-way analysis of variance (One-way ANOVA), while trait correlations were examined using standardized major axis estimation (SMA). Principal component analysis (PCA) was further employed to explore the multidimensional coordination among traits and identify potential trade-offs. The results demonstrated that LMD, LDMC, and BWD significantly increased with branch and leaf age in both species, indicating a shift toward greater structural investment and resource conservation in older tissues. In contrast, SBL and LIV exhibited a negative correlation with age, suggesting a decline in resource acquisition efficiency over time. Notably, the strength and direction of trait correlations varied significantly between species and age classes, highlighting divergent ecological strategies. At the species level, Pinus thunbergia exhibited a ‘slow investment-return’ strategy (conservative strategy), characterized by higher LMD and BDMC but lower SBL and LIV, which enhances stress tolerance and long-term resource retention. Conversely, Pinus densiflora displayed a ‘fast investment-return’ strategy (acquisitive strategy), with opposite trait patterns favoring rapid growth and resource acquisition. Furthermore, age-dependent shifts in strategy were observed: both species tended toward an acquisitive strategy in current-year branches and leaves but transitioned to a conservative strategy in perennial tissues, reflecting adaptive adjustments to ontogenetic and environmental constraints. These findings underscore the importance of age- and species-specific trait variations in mediating ecological strategies. The divergent resource allocation patterns between P. thunbergia and P. densiflora provide insights into their niche differentiation and competitive coexistence in plantation ecosystems. Moreover, the observed trade-offs between acquisitive and conservative traits highlight the dynamic balance between growth and persistence in evergreen conifers. This study contributes to a deeper understanding of plant functional ecology and offers a theoretical basis for forest management and species selection in afforestation projects under changing environmental conditions.