3-4 decades to maturity, before you can harvest seeds, and it looks like you need male and female plants to cause seeding - I wonder if that can be gamed by grafting from mature trees, or artificial hormone sprays?

3-5 cm pine nuts sound awesome, though. 50m tall trees with giant cones and tasty nuts that can live a thousand years - a grove of these on a farm seems like a cool legacy investment, with little chance of becoming invasive or problematic.