Let it dry out between waterings, as overwatering is a frequent killer. Compost such as cocunut fiber is best as it can dry out easily and does not retain moisture too much like everyday compost. Try repotting it with dry compost and make sure the roots aren't rotten, then carry on with a reduced watering regime if you feel this is the problem.
Tree sap?
could be lots of things. can you be more specific? where are the spots, how big, what time of year, wet or dry? can you see any bugs on the tree? ect...
salt spray carried over by air from the ocean can be fixed with spraying the crown of the tree once a week.
I even saw a female Merlin with buff and brown spots perched in a tree.
woodland tree frogs brown with a black pach around there eyes and some times black spots and lines. by Tyson
There is no way to get rid of the brown spots that appear on leaves of a persimmon tree. This is a symptom of leaf blight disease, and there is a way to prevent it from spreading, if you remove the infected plant matter immediately, but fungicide treatments are not usually warranted to control leaf spot or leaf blight.
Answer to all of the above questions - can be found in Wikipedia - see related link !
Brown tree snake was created in 1802.
It is possible this is Powdery Mildew. If required the treatment is to spray with Bordeaux mixture. This is an unsightly disease but not normally serious.
Red spots on the leaves of a eucalyptus tree could be caused by a fungus called Phytophthora. This fungus usually spreads to other parts of the tree and is not usually treatable.
Once a Christmas tree has turned brown, it will not regain it's natural green color. Brown needles on a pine tree indicate dead areas of the tree.
If by money tree you mean a tree the produces money, there isn't one sorry