I bought a persimmon tree recently and planted it in my back yard, at the bottom of the tree on the trunk ,was a tube surrounding the trunk, when I removed that cardboard tube I noticed some X markings surrounding the trunk , does anyone know why somebody would do this? is there a reason why someone will cut the tree like that?

ps. all the persimmon trees had that

Is it a graft joint? I cannot tell from the photo if it goes all the way around.

maybe the person that sold it to you didnt like the the graft quality?
most nursery sold tree are bad grafts as i heard...
what can we retail buyers can do? nothing -its unfair . thats why i like figs-i bypass the middleman :)

Is it an Asian Persimmon?  If so most all of them are grafted on to native rootstocks.  My guess is that is the graft line and the X patterns were made by the material used to hold the graft together while it healed over.  Though I have never seen that before but it does seem logical.  

Yes that's a graft union. Sometimes it is marked with an orange marker, to know not to plant the graft union. Nothing to worry about.

Have had the exact same marking on my Asian persimmons.  It is just as said above...the graft union and tape sealant marks.  Nothing to worry about.  If you get any sprouts before this mark, prune them and seal with tape.  Regular elestrical tape will be fine or use teflon tape.  These will be the native root stock and should be removed.  It will take away from the growth of the tree and will not produce any viable fruit.

You can bury Persimmon grafts and it is the preferred method with commercial growers in California now. Research done in Florida found no negative effects from graft burial and they found no rooting above the graft when they did. If you get a Winter kill the regrowth will most likely be from above the graft and you will not have lost your investment.

definitely need to get some persimmon this winter. always miss the deadline for ordering one. then again, i keep noticing killing all the other trees other than figs. 

I tried grafting Asian varieties on American rootstock this spring but my inexperience showed. Out of thirty grafts only four Fuyu grafts took. I'll try again. Meanwhile I have plenty of rootstock! LOL

If you haven't eaten a non astringent Asian persimmon you need too. They are like a completely different fruit.

I tried grafting Izu, Fuyu, Hachiya, and Giombo this year (chip and whip). The success was not super but better for the chip. In terms of the variety success, this was approx it:

Fuyu
Giombo
Hachiya
.
Izu

I was grafting kaki to kaki. Izu was the hardest one, very weak somehow. The scions were from UCD, the rootstock was a grown up Hachiya tree. 
With persimmons, the timing is everything. It seems you need to wait for the leaves to break out first and then graft. I did 3-4 grafts of each.
I also tried rooting the cuttings like figs. No go. They leaf out without any roots and die ...

If you want to give it a try just don't do it in a heat wave--worth a shot. Also apparently persimmon is really good at not doing anything for a long time then taking off--so maybe you are ok? Just have to keep snubbing off any growth underneath that'll steal energy. Seems to do that very often. I wrapped up mine in aluminum foil at the graft union and couple inches above and below foil shiny side out to shield from sun/stabilize a temps a bit (i would def do that at this point of the season). Last tip I heard was to graft high on dominant branch or to cut back branches that are higher than the graft. I followed all this (and of course key waited for a couple inches of new growth in spring first)... and they all (knock on wood) so far seem to be doing OK...

The man that taught me said to wait too. Maybe I'll just try a couple if my graft wood in fridge is still good. Saijo and Matsumoto are the two I'm doing.