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I recently got a bonsai tree for christmas- I have no idea about the nursery conditions etc because it was a gift.
I belive the tree is a chinese privet- it is my first ever tree
Arount the start of the tree trunk it looks as if it's decaying and it has white marks around it with orangeish crystals(?)
The leaves are turning a crinkled brown and falling off the tree. this has been happening for a couple weeks now but it is beginning to look a lot worse.
How should I help it?!
Many thanks in advance

Picture

I'm having trouble inserting the files so I'll put them on imgur
The photos are on

Difficult to tell from the pictures what the species is let alone the problem. It is in a very bad state possible from incorrect watering, and almost certainly lack of light. The fungus if there is any is the least of the problem with this plant, and without clear pictures not possible to say more.