Using sticks from outside in jarrarium?

Hey everybody, i’ve had a gallon jar going for a few months now using some mud and water i gathered from an outside marsh. I added some plants and it’s been going well. It’s mostly filled with copepods and a snail that seemed to just spawn in one day.

I’m trying to simulate a natural ecosystem and I know that in the wild small pools get some nutrients from leaves and sticks that fall into the water. I’m thinking of gathering a stick from outside to place in the jar to make it look nice and add some extra environment.

My question is: is this safe for the creatures in the jar? i know that in aquariums people often have to boil or prepare the sticks beforehand to prevent tannins or sap from leeching in out and harming the fish. But in the wild, doesn’t this happen all the time? I’m worried that since the creatures are so small, even the tiniest bit of something would harm them. Is there a certain type of tree i tree i should be looking for? Any help is greatly appreciated.

Thanks 🙂