How to convert 400,000 particles to single mesh?

Technical Support Basics & Interface
1

Hello,
Is there any way possible to convert 400,000 particles to a single mesh object. These particles are single planes so there’s only 800,000 triangles.
The situation, imagine leaves on a tree.

I know about converting particles to real object(duplicates) but Blender cannot handle 4000 objects let alone 400,000.

Is there someway to bypass make Duplicates Real +merging, and instead go immediately from particles into a single mesh?

Thanks,