HOA forcing me to remove trees in my "parkway area" (curb strip)

[Kevin Turano]

Hello,  I'm in Texas, my HOA sent me certified letter that I would be fined if I did not remove 6 trees that are within my "parkway area" (aka parking strip or road verge).  What is the best way to fight this?  
Note: 
-The trees have been there for over 10 years
-The trees are Crepe Myrtles (native to Texas)
- They are well maintained
- About 10 years ago they sent me a letter and when i pushed back they said they would be ok as long as i did not plant more and i maintained them (i can't find the ppwk)
- There are other Crepe myrtles in the HOA park way areas less then 200 feet from my house

Any advise is appreciated