Got 2k+ seeds, cold stratification?

[power270lb]

I know the ficus no but the maples, Chinese juniper, Chinese Elm and black pines do they need cold stratification?

 

[dbonsaiw]

Maples and Chinese Elms require cold stratification. I do not believe black pines do, but have little experience with pines.

 

[Shibui]

Stratification is generally recommended for black pine but I've germinated lots without cold treatment so I don't think it is necessary.
Maples germinate very well without any stratification provided the seed is fresh from last fall. After it has been dried and stored it enters deeper dormancy and will need treatment. Warm stratification for a few days followed by cold is generally recommended for seed of unknown age.
Chinese elm should germinate well without cold stratification but germination rates are variable anyway.
I have never grown Chinese juniper seed. They grow in high mountains so I think they would benefit from cold treatment. Online search shows a variety of different methods. All agree it's a long and tedious process, all agree on warm stratification and probably 6 moths or longer to germination. Some recommend hot water soak and others recommend 90 days cold.
Note that Chinese junipers are much easier and quicker to propagate as cuttings. You will also get the variety you know from cuttings. Growing from seed is a lottery, especially as Chinese juniper is a VERY variable species with types ranging from tall and open to the more desirable compact varieties we value for bonsai.