I have spent many hours looking into "how to look after carvings" and have found that there are so many theory's that i am not going to get too specific!
One of the main problems with carvings is splitting.
Unfortunately, wood is wood and will most probably split at some point in its life time.
There are some things you can do to reduce the chances of this happening.
Here are a few (of many) things that can help.
Also, have a look online and you may find other methods that you may want to try.
I must be clear though that splitting/checking etc is not under my control, i am happy to help/suggest/advise.
Extreme changes in heat will make the wood expand and contract in turn causing splits, so keeping your carving out of an area that is in shade then in direct sunlight will reduce chances of splitting.
When your carving gets wet, the wood will expand and if it dries to fast splits may occur.
If you bring your carving indoors please remember there is not really a breeze and its generally warmer so the carving is far more likely to split (you will also most likely to hear it splitting!)
A suggestion would be to let the carving very slowly (over a few weeks) "warm up"
Obviously when water freezes it expands so if your carving is wet and then we have a freezing winter then this also will cause splitting.
Another trick that can help to keep your carving healthy is to stand it on some small stones, this will stop the wood soaking up liquid from the ground and also let air circulate underneath it helping to reduce rotting.
All this said
I have quite a few carvings in and outside of my home and in general i dont have any problems with splitting ( i may just be lucky), any that do split actually look a little more rustic and i feel it gives them more character (in my opinion)
Obviously i cannot say that your carving will split or not but if you have any problems then please contact me and i will do my best to advise you on what to do.