I used a drop shadow of vertical 0, horizontal 5, opacity 75, blur 10.

Open a new transparent canvas 800 by 800 pixels and fill with white.

Make a new layer, select all, paste paper 3 into the selection, deselect, apply the mask and resize it 75%.

Paste element 23, duplicate, resize the bottom copy 80% then close it off for now (this will be the roots that show below the female).  Resize the top copy 55%, position and apply the shadow.

Paste element 8, resize 60%, position and apply the shadow.

Paste element 32, resize 40%, mirror and position.

Paste tagback, resize 25%, position on the right below the tree and apply the shadow.

Paste frame 3, resize 55%, select the interior with your magic wand and expand the selection by 10, paste paper 4 below the frame and resize it 30%, position in the frame, invert the selection and hit delete, deselect, apply the shadow to the frame, merge it down onto the paper and move into place.

Paste element 24 on the top, resize 55%, position and apply the shadow.

Paste element 9, resize 25%, mirror and position below element 24 on the right, duplicate, resize the copy 80% and move over to the left so the flowers show to the left of element 24, apply the shadow to each.

Paste element 10, resize 30%, mirror, position and apply the shadow.

Paste element 35 on the top, resize 15%, position and apply the shadow.

Paste element 4, resize 10%, position and apply the shadow.

Paste element 6, resize 10%, position and apply the shadow.

Paste element 29, resize 15%, position and apply the shadow.

Paste element 17, resize 20%, position and apply the shadow.

Paste element 27, resize 30% and mirror, position and apply the shadow.   When you have this element in position if you can see any of the mushroom from copy of element 9 erase it.

Paste element 5, resize 22%, position and apply the shadow.

Paste element 7, resize 30%, position and apply the shadow.

Open that copy of element 23 (the first tree) that you closed off, position so the roots show below the tube, erase all the large part of the tree leaving just the roots and apply the shadow.

Paste element 15, resize 30%, position below element 7 and apply the shadow.

Paste element 16, resize 30%, position and apply the shadow.

Paste element 18, resize 30%, mirror, position and apply the shadow.

Paste element 20, resize 10%, position and apply the shadow.

Paste element 3, resize 10%, position and apply the shadow.

Paste element 14, resize 30%, mirror, position and apply the shadow.

Paste element 12, resize 30%, mirror, position and apply the shadow.

Paste element 19, resize 25%, position and apply the shadow.

Paste element 21, resize 7%, position and apply the shadow.

Paste element 2 on the top, resize 10%, position and apply the shadow.

check your layers, add your copyright information and text. I duplicated my mask layer, brought the copy down so just a tiny bit showed at the bottom below the tree roots and erased the rest of it.  When you are done, export on a transparent background as a png.