That brown vertical streak visible in your second photo is very concerning. Is there any way you can get a closer image of that?

Are you having any other symptoms other than the trunk lesions? Any drop of leaves or fruit that is higher than normal? Any lesions on branches? Do you see any hard or soft gummy resin coming from anywhere on the tree?

The very small space where this tree is growing probably makes it hard to water it without getting the trunk damp. Does the trunk get wet regularly from spray?

yeah i can send more pictures.
in this tree we have very xylophagous beetles that they sear the wings and acarid ( phyllocoptruta olivora ).
but i see the wings that they are sear with out any symptom of xylophagous beetles.
i did not see any hard or soft gummy resin.

http://lh6.ggpht.com/_X1QmmvHvWqs/TIOvmw_HXzI/AAAAAAAAAPY/zuso_QXxmhI/s512/030920101294.jpg

please see this.

To me - and I stress that I might be wrong - that looks like a fungal infection. There is a type of fungus that causes what's called "dry root rot." There is no bleeding resin with dry rot. The bark peels and the wood under it is discolored and dark.

If it is - and I might be wrong! - but if it is, there is not a lot you can do. The tree itself has to fight off the infection. Sometimes the tree wins and sometimes it doesn't.

Keep the tree on the dry side, and ensure that the trunk does not get wet when you water it. Not even a tiny bit of water on the trunk.

If possible, you should dig some of the dirt out from around the base of the tree, going down at least a few inches. Keeping the wood dry helps the tree deal with the infection. However, you don't have much space there between the tree and your patio so I don't know how you'd do that.