im new here and have some concerns about my japanese mable.the tree was planted 20plus years ago.last three years in spring tree starts out looking awesome .then after leaves have turned green soon start dropping from tree .there is a green moss looking stuff on bark that are circular in shape.some of the leaves actually start turning brown like they do in the fall.have another japanese maple twenty feet from older one and it seems fine .not sure what is going on here but any suggestions would be great .thanks for reading this.
Can you get some photos? Moss or algae on the bark is harmless, but if there are problems with the leaves, there may be something else wrong with the tree.
Anything strange going on with your weather, or with other plants in the area? We've been having a disconcerting phenomenon here lately -- during one of the wettest summers on record -- of many plants turning brown and losing their leaves, as though they were drying up. It seems to affect everything from ferns and herbaceous plants to small trees (mature trees do not seem so strongly affected) and is causing some woodlands, especially, to take on a very sad appearance, when you'd expect them to be unusually lush and verdant.
here are some pics .like i said in spring and early summer tree looks great then slowly it starts looking bad .
The growths on the bark look like lichens, harmless to the tree and usually indicating good air quality. Has the level of the soil around the trunk been raised? It is hard to tell from the picture for sure, but if so that will be the cause of your problems.
I think you may have three potential issues. You need to peel back the weed barrier to expose the root flare. The mulch and rock also looks to be in the center of the tree and on the trunk. This may cause the base of the tree to rot.