Populus euphratica, commonly known as the Russian poplar, is generally harder than pine wood. This conclusion is based on the Janka hardness test, which measures the resistance of wood to indentation. Populus euphratica typically has a Janka hardness of around 680 lbf (pounds-force), while pine wood, which includes various species, generally has a Janka hardness ranging from 380 to 500 lbf. The higher the Janka hardness, the harder the wood is considered to be.

The difference in hardness can be attributed to several factors. First, Populus euphratica is a deciduous tree that grows in cold climates, which often results in denser wood with a higher wood density. This density contributes to the wood's hardness. In contrast, pine trees are conifers that grow in a variety of climates, and their wood is generally softer and less dense. The softer nature of pine wood is due to its lower wood density and the presence of more resinous material, which can make it more susceptible to decay and less durable.

According to the American Hardwood Export Council, Populus euphratica is often used in construction, furniture, and veneer due to its strength and workability. Its hardness makes it suitable for applications where durability and resistance to wear are important. Pine wood, on the other hand, is more commonly used for construction, furniture, and paper products due to its lower cost and ease of processing.

In summary, Populus euphratica is harder than pine wood, primarily due to its higher wood density and growth conditions. This difference in hardness affects the wood's suitability for various applications and its overall durability.