Color/Clarity problem..I think

A friend of mine asked me to do a print for him. 60" by 40". The original file size was just over 5mb and it came as a jpeg 60x40 -72dpi with those measurements already. I saved it as a pdf with cmyk checked. I put into flexi12 and printed at 1440x1440. When my buddy saw it he was disappointed that the trees in the bottom left hand corner are not really that clear as well as the trees in between the buildings..at least not as clear as his picture. Did I do something wrong, or is there a way I can do it better?

I know that I have a streak as well in the bottom left hand corner and I have no clue why it does this now and again. I am going to print it again, due to that but if I could get the trees a bit more clear...I will try that as well.

Thanks for any help/suggestions you could provide. My printer is the mutoh 1624. I ran it 1440x1440 vacuum middle 31/33 an 50 as heat settings. If that matters for this. the first picture is the original and the next 2 are the actual print.

 

Sorry it was sent as a jpg an when I open in photoshop an see if images right size etc. when i go to save it as a pdf is when i check the cmyk box, so i should just leave as it originally came?