I quite often fly to a friend with a grass strip - 2850ft long at 5600'. I've take off out of there at MAUW on a cool morning and although the take off run took some time, I didn't encounter any problems. I would not try it at higher temps though. I fly an F though and I use 1 and a half pumps which returns about 12 deg of flaps for take off.
There used to be trees on the one threshold, but they didn't really pose any problem or prompt any change in final approach or over the fence speed for landings. On take offs, however, most pilots would rather choose a slight tailwind take off than going towards the trees.
There are two C models resident at that airfield and they operate in and out of there like normal. The grass is well maintained, but I've landed on quite a few other grass strips and have never had problems with grass interfering with the gear doors.
I checked the elevation of the airfields in your post above. At those, your C model will be in the air with lots of runway to spare and should be way up in the air by the time you reach the trees.