Hello,
I have some conclusions:
1. The germination percentage was low due to old seeds (last season leftovers)
2. From the ones that germinated, a lot of them died after a couple of weeks. Their tap root was short and in poor health.
3. When I examined the roots of the surviving ones, I saw a very weak and short tap root with a few splittings at a higher area.
4. The overall health and vigour of the survival seedlings was poor.
It appears that this method did not work well on pines. nonetheless, i'll give it another shot next year with fresh seeds just to be sure it's not the seeds condition fault.