I'm assuming you are looking for TREE leaves. Where do you live? I'm supposing you live somewhere that is experiencing winter at this time, and therefore you can't find any leaves on deciduous trees? If you simply need living leaves and they don't need to belong to trees, you can get them from a local florist. If they have to be tree leaves, you might get them from a large conservatory, tho those are rare and far between. You don't mention what you intend to do with the leaves so it is hard to answer this question. But good luck!