@Nation Wide Lines posted:Sounds like you are describing something similar to these
These trees came to me with an American Flyer set c. 1925 and I can verify they came with the set through an advertisement in a Butler Brother's catalog from 1925.
The trees are comprised of what I believe is natural sponge. I know American Flyer cataloged trees and shrubs in their 1922-1924 catalogs.
NWL
Those are really neat looking and are probably very close or spot on to some of the smaller trees Lionel used . Certainly they are from the correct era. I'm sure they are also difficult to find.
Since I posted I found an old thread where Ron Morris offered some of the examples from his collection. He shows the No. 505 Oak Tree as one of the "Sisal twine" style trees commonly seen on the Scenic Plots with the exception that these have a stand alone base rather than the roots being glued directly to the platform. While it deviates from what is shown in the catalog illustration I have to defer to Ron's expertise as he devoted many years to collecting and studying Lionel's Pre-War scenic offerings.
Lionel No.505 Oak Tree (photo Ron Morris)
He also showed some interesting looking Pre-war trees made of wire ...presumably of German origin :
Another thread pointed to a German Company called Erzgebirge as a manufacturer of Pre War trees with wooden trunks.
Thanks for the input, the search continues...