I am so googly-eyed from looking at hundreds of photos trying to figure out what trees these are and I still haven't found an exact match. Although difficult to see, the leaves appear to be alternate. With the third photo, I'm not real sure what's what; it looks like there are vines growing up through the tree.

Growing in zone 10a - Sebastian, Fl
Photos taken April 1, 2015

I think this is likely Ailanthus altissima commonly called Tree of Heaven. Everything looks right and those look to be vines growing up the trunk, but the trunk still looks right to me. Those that grow on my place even have those whitish blotches.

Donald, that was my very first thought but this tree has alternate leaves, doesn't Ailanthus altissima have opposite leaves?

@needrain Donald, Thank you so much for confirming that this is the Tree of Heaven. I had a few saplings sprout up in our yard a number of years ago and I sure thought it reminded me of those. I thought Ailanthus had opposite leaves but upon looking more closely at photos of stems and leaves of Ailanthus altissima, the leaves are indeed alternate.

I will have to tell my sister and brother in law about their invasiveness as there is a huge stand of really tall trees growing on the property line between their house and their next door neighbors. They are on the neighbors property but my sister and brother in law need to be aware of their invasiveness.

Thanks again!
Lin

Those things love property lines aka fence rows!

Can we revisit this one, because the leaflets don't appear to have lobes at their basis so I'm thinking it is not Ailanthus.

@sooby, I've submitted proposals to have my images deleted from the Ailanthus altissima database entry. The plants are growing in between my sisters and her neighbors property. Next time I'm down there I will get some better images and start a new thread for suggestions. I came across photos a couple of days ago when googling that looked identical to the plants in question but got sidetracked and now for the life of me I can't remember the name! I will try again for a correct ID once I get closer and better photos.

I'm wondering if the plants in question might be Shining Sumac (Rhus copallina) which are fairly common here in Florida. We have a small one growing at the corner of our property and I'm going to try to get a better look at it and then a closer look at those growing along the property line between my sister and her neighbor.

It doesn't look like there are wings on your mystery plant, Lin, and the leaves look narrower on the sumac. If you can get a close-up of a leaflet so we can see the teeth, if any, note whether the leaves are opposite or alternate, and if there are any leaf scars get a close-up of those it should help. Also a picture of the back of a leaf could be useful.

Will do, thanks so much @sooby!