Construction cost (CC) of leaves was studied in 73 boreal plant species differing in ecological strategy. CC is the energy cost, expressed as glucose weight, of the plant weight unit formation. The perennial species that exhibited the stress-tolerant (S) type of strategy had the highest, whereas the annual plants of the ruderal type (R) of strategy had the lowest CC values, and the individual plant species from these two groups significantly differed in their CC indices. Plant species of diverse strategies were regularly distributed in the Grime's triangle, according to their CC values. The analysis of leaf chemical components has shown that high CC values in plants of the S-group correlated with a higher content of energy-expensive organic compounds, pigments, lignin, waxes, phenolics, etc. In contrast, in the plants that exhibited the r-strategy, the majority of photosynthetically assimilated carbon was utilized in the synthesis of functional substances, namely, proteins and carbohydrates. Our data showed the differential organization of plant metabolism in the plants exhibiting different types of ecological strategies. The CC values of leaf, together with other known characteristics, can be used for the identification of the types of ecological strategies and the assessment of the resistance of plant species and varieties to environmental stress.