AusBonsai

Hey ive had a look through the forum and seen using a toothbrush with some stuff works to get the moss off bark but i touched my bark this morning and the moss is keeping it so moist that it wants to fall off with the slightest touch.
i personally think it adds age to the tree but dont want it to ruin the bark or tree. Any ideas to remove this if its bad? More sun maybe ?

some of it looks like lichen, and maybe something called liverwort. no idea how to get rid of either of them, but the lichen should cause no damage as far as i know.

What you have on that tree is lichen. I'm told lichen is very sensitive to air pollution so , on the positive side, you must live somewhere with clean air. That also means that it is probably quite easy to get rid of it. Try diluted vinegar 50/50 vinegar and water. Spray it on to the trunk with a spray bottle and see what happens. A little bit running into the pot should not hurt because it will just be washed away when you water but I wouldn't flood the soil with the vinegar. Might take a couple of sprays to kill it off and then repeat whenever you notice it returning.
Iron sulphate is another thing that kills moss so would probably also deal with lichen. iron sulphate is a fertiliser so is also safe to use on the trees.

The bark on your elm does not really look like the corky variety to me. Should be much deeper cracks and far thicker bark by that stage but it might still be developing. It is normal for the bark of flaking bark varieties to peel off as the tree grows - seems like that's what is happening here.

Awesome thanks heaps for the info! Yeh its only a baby. Its just a real close up picture

Looks good i think. Makes it look older but each to their own

i say if its not hurting the tree dont get rid of it it makes it look awesome my opinion though

Yeh i like it! Ill be leaving it on.
Just didnt want it to be damaging. My mum and dad have 2 cherry trees in their yard in tassie with about 800mm to 1.2m diametres that have the same thing. Reminds me of an old tree

Mosses and Lichens are pioneer plants. It is their role to colonize bare rocks, logs, etc and start the process of breaking these inhospitable environments down into something where other plants can grow. They do this by secreting dilute acids that break down the surface they are growing on and by catching dust and soil that happens to blow/wash past. Takes many years to make much difference but those are the timescales that nature works at.

The point of this is that lichens do secrete substances that can slowly dissolve stuff like bark. The good news is that a living tree will produce bark much, much quicker than the lichen can dissolve it - Mum and Dad's cherry tree still has bark even after many years of lichen covered trunk, right

The Japanese bonsai growers hate anything growing on the trunks of their bonsai and will always get rid of any moss, etc. Hiro made the comment on his last visit that a tree with moss on the trunk reminded him of an old man that does not wash. He appeared less concerned about the health effects on the tree than the visual 'tidiness'
Up to you whether you keep it or not.

Thanks shibui interesting knowledge. And yes massive inch thick bark on mums trees. Yeh i like the 'natural' look of it. Im happy with my dirty old man