For tumas ohel, the only material from trees that accepts such tumah is flax. This is bc it is the only material from trees that we find is called אהל. We find flax called ohel from the mishkan where it was used as one of the 3 coverings for the mishkan.

Wood beams are not subject to tumas ohel even though the קרשים in the mishkan were world, bc the pasuk language is make kerashim for the mishkan, implying the kerashim was not the mishkan/ohel itself.

Hides and goat hairs are subject to tumas ohel, as they were used for the ohel of the mishkan.

R elazar wonders about non kosher hides being subject to tumas ohel bc the תחש that Moshe used for the mishkan covering may have been non kosher. It comes out a dispute in the Gemara if the תחש was kosher or not.

In regard to laws of tzaras and sheretz, where hides can become tamei, even non kosher hides can become tamei.

Tefillin parchment must be from Kosher animal. The Tefillin boxes as well. And even the straps. And the sinews that sew the boxes.

The תחש was used only once in history for the mishkan. It had one horn and we are not sure if it was domestic or wild animal.

A wick made of a garment folded up but not yet singed, R Eliezer says it is still susceptible to Tumah. He holds folding it does not nullify the status of בגד. R akiva says once it is folded it loses its status of בגד.

On Yom tov, there’s a dispute between r Yehuda and r Shimon if one can light with broken keilim (broken on Yom tov.) this is a muktzeh question.

When one lights Shabbos candles, they should light most of the wick protruding from the oil. (Not just the top)

Accordingly, if a folded up garment was exactly 3x3 fingers wide, like r Eliezer that it is still a garment, it can’t be used for Shabbos candles on erev shabbat that is also Yom tov, bc as soon as a tiny amount is lit it will lose its status of a בגד and it’s forbidden to light the broken pieces of keilim on Yom tov.