guava?

Carrotwood (Cupaniopsis anacardioides). HTH Chris

I am not surprised about the citrus being all rootstock. It wad indicative to what i had seen in various photos while researching. Now, i was reading up on rootstock, and came across some info on grafting. With it being all rootstock, would grafting be a possibility i can consider with that one, if i cut most of it down and got some budded branches from a different, healthy tree? As far as getting thr owners get new trees, i cant even get them to let me just remove them,, so anything i do at this point is out of my pocket, so I'm trying to be economical. If grafting is possible, i would like to at least try before replacibg it entirely. As for the other tree, the other day, i noticed these green fruits growing in little bunches of 3 up near tge top that lpok like apples, maybe?? So could they be apples? And if it's growing fruit, then is the tree ok?

Thanks you guys! I have an Owari Satsuma but the fruit shaped differently than this. This one is round but is kinda flattened on both the ends. The skin is really smooth. I went out and dug around the bottom of the trunks. They were buried under a bunch of leaves and stuff, and I did find a place that was cut or broke off like maybe someone originally cut a tree down. So if these are suckers, the original tree must not have been grafted or it would be a sour orange right? and these are definitely not sour at all. I took some pics of the tree before it got dark tonight. The trees around it have lost their leaves for the winter so it shows up now. It is tall and skinny about 10ft. It was trying to reach for light most of the year, I guess. Normally, the citrus blends in and was hidden in the 'thicket' of green lol. Since the fruit is so good, I plan to cut these other 2 trees down (on the left and right of the green leafed area) that are shading the citrus out. I need help figuring out what to do with the "trunks"..just leave them or thin it to one or two? The whole citrus tree (the green part) you can't see the trnks from here. The bottom where I uncovered the leaves and soil. Side of the bottom..all those trunks come from the base...I think.. Close up of the leaves