Very interesting question @ Elaheh Daghighi. In Asia perspective I would say Prosopis Juliflora and Leucaena leucocephala are some effective tree species that can be suitable for soil health improvement. Also you can go for Azadirachta indica that tree sp. has good insecticidal properties, air purification properties and also improves soil health.

Thank you @Debabratha Nath for your valuable and precise answer to my question. We are looking forward to hearing more commets from you in the case of agroforestry.

Dear Colleague

You asked a very interesting question. Although it is not possible to introduce a specific tree for a continent, the following article can help you (especially the supplementary):

Thank you @Mohammad Kheiri for your participation in answering my question and sharing the link of a valuable publication.