Could be part of prepping wood to integrate into an enclosure for a reptile or similar. You have to be really particular about contamination and moisture so I could see using a low heat to dry it out as part of prep

Seems like a stoner attempt at homemade potpourri.

Is your friend by any chance a beefaloo?

Just kind of spit-balling, but I imagine it dries them out really quickly, and as a bonus gets hot enough to probably kill off most bugs, spores, etc. that may be in/on them

Someone mentioned potpourri, I don't really know anything about how that's normally made, I don't think of these sticks and gumballs as being particularly aromatic, and even if they were the higher heat of an air fryer might cook off some of those aromatic compounds, if that's the plan maybe the idea is to infuse them with essential oils or spices or something after they're dried, but again not really my area of expertise.

It's probably not much of a fire hazard, depending on what temperature they're running it at, where the heating element is, and exactly what kind of stuff is in there. There's a lot of variables, but in general wood needs to get up to at least about 450°F/232°C, and often a good bit higher to spontaneously catch fire, and I'd imagine the gumballs are similar. Most air fryers I've seen max out at around 400-450, so unless you have one that is working at the higher temperatures and they're cranking it on max for a long time, probably not too much to worry about.

Like I said, a lot of variables there, might be something worth worrying about if there's maybe something like maybe pitch pine in the mix that has a lot of oils and resins and such that might have a lower ignition temp. Maybe there's some danger of the wood getting charred and smoking a bit but not outright catching fire or smouldering.

Wild guess at the motivation, they want to dry out the wood and kill off any pests to use it for some kind of art project. Seems like overkill to make fire starters or dry out kindling to me.

This is at best nonsense and at worst a fire hazard.

I guess treating twigs and such this way makes it better to use as kindling for starting fires. Dry wood/kindling is much easier to light

Fuck Reddit and Fuck Spez.

Have you considered asking your room mate?

Does "gumball" have a meaning I'm not familiar with? These don't look like bubble gum with a brightly coloured candy shell...

Is that what those spikey tree seeds are called? Gumballs? I was wondering this the other day (all the trees in my apartment complex drop them and the wind the last few days has made the floor a minefield of the little fuckers).