There are some "cracks" and there are some "seams" where the boards were splined together.... as I see it.
The cracks are a natural phenomenon, just like the seams, which are man made and both are a result of the wood expanding.
Water must be kept out of the cracks, especially if in freezing conditions which will open them further.
It is a great looking gate! The cap strip on the top edge sets it off nicely and keeps the water out of the ends.
A Cathedral Arch which you don't often see on a gate.
There have been the following recommendations:
Do Nothing.
Sand it only.
Sand it, stain it and caulk the cracks and seams. (my advice)
Keep epoxy coating it until it will absorb no more.
There are so many opinions, it may be confusing to the OP.
Protect and color your deck, porch, siding and trim. With exterior stain colors, you can lengthen wood's life and beautify its natural appearance.
www.sherwin-williams.com
To follow up on my advice, use Woodscapes, a water based solid color stain like I posted by Sherman Williams because any residual water in the cracks will work with the stain and dry out eventually, and not be captured under an oil film surface. Most caulks are water based these days, I use a DAP product just today in a great shade of dark brown.
They also list Transparent colors if you want the grain to show, but I have no first hand experience with those.
