I Making a scene, have already put a lot of work into it. Little town, with model T car's and misty mountains, using a lot of lamps. I wanted to add tree's to the scene and learned how to do them in cycles, but cycles is not working well in my scene. Is there a way I can create tree's without cycles or away I can link in the cycled tree's into scene and render it normally?
Perhaps you could add a tree image with a transparent backdrop. Then in the nodes remove the backdrop with a transparent node, and apply some different shaders such as specular and bump or normal maps to give the realism effect. This is what is used in most games as it uses minimalist faces which saves time in your final render, However they are used for distance scenes. This is the only other way of creating a tree that i can think of without creating a 3D tree, whether that be sculpted or generated with the Tree plugin. Hope this helps Mate.
This problem could be addressed using the multi-scene workflow.
You can make a linked copy of the current scene and choose cycles rendering for the new scene.
In the new scene, setup the renderlayer to render only the tree.
For the tree, use node based cycles materials.
You can then comp the images from generated from blender internal and cycles.