Can a tree shaped like a Y be used as a lechi for a tzuras hapesach. The string passes over the trunk between the two arms. The trunk is vertical and smooth.
Thank youi for your question.
When the string passes over the trunk between the two branches, if the braches are higher than the string it is controversial.
If however the string is above the branches, but on top of the actual trunk, itis kosher. However when making such a eruv one has to be careful that the wind or something else not move the string from being above the trunk the whole Shabbos.
See O:CH 362-11. Also see Mishna Berura 364-64 who brings Pri Megadim who says that it isn’t kosher, on the other hand in Shar Hatzion 364-52 he brings Mekor Chaim who permits it. Additionally Chazon Ish O:CH 75-9 permits it.