I have this Tropical Tree Seed Manual in real book form, just found it in free e-form. This is a good resource for anyone interested in tree seed, seed biology, collection, storage, viability, dormancy, germination, etc. Click on the following link to access PDF chapters: RNGR -Tropical Tree Seed Manual.
The RNGR (reforestation, nurseries, & genetic resources) website seems like a good resource in general. The website mission is as follows: “This web site was developed by the technical specialists of the Reforestation, Nurseries and Genetic Resources (RNGR) program whose mission is to supply people who grow forest and conservation seedlings with the very latest technical information, and to provide links to other organizations and individuals with similar interests. As you browse through the following sections, we hope that you learn more about the art and science of raising forest and conservation plants. Note that many of the listed publications and services are free and that you can order complimentary copies by sending us your mailing address.”