Yes these are the ones. I'm sorry to hear they can go uncollected. In our case they are always collected and often reused. It helps that the trees are being planted in the local area (the hills surrounding Stanford University) and the crews regularly check on them.

Is it possible to make them using other material?

What about wood?! My father had a 0°C to 100°C thermometer for the lab, and it has a wood tube to store it. It's probably more expensive than the plastic one, but it's 100% biodegradable.

These tubes are translucent to let light in and help the sapling grow. The saplings are only 20cm tall and takes them a couple of years to outgrow the tube. They will also have to last at least that long.

Also, probably wood would be chewed by animals, so one would need something that is both translucent and not edible/liked by deers, boars, etc.