Are the old 2 by 4's stronger than the new?

3-Second Blueprint (English)

1. Modern plantation softwoods are harvested around 40 years at smaller diameters, yielding boards cut largely from fast-grown pith regions.
2. Trees grow rapidly during their first 20 years, forming wide annual rings rich in low-density juvenile wood rather than dense latewood.
3. Mechanical testing shows modern juvenile-wood 2x4s average 10% to 20% lower strength and stiffness than slow-grown old-growth timber.