The bunkers below represent two different Colt bunkers in various stages of grow-in. Not sure where these are, but they are in identical situations.
Let me state the obvious first:
It appears that the bunker cavity was cored out with the spoils being thrown up to shape the hummock. So the raising of the ground is directly proportionate to the culling of the ground. This is very key, I think, to how a bunker appears natural. For nature works the same way: nature builds with material that is close at hand. In the dunes, the sand on hummocks, generally comes from an adjoining cavity, with the top of the dunes hummock held together with native vegatation that grows in irregular clumps. In the dunes there is what we might call a direct proportionate balance between cut and fill at every feature.
Now the grassing is where this gets really interesting:
Theses hummocks appear to have been topdressed with a layer of sand and then planted with plugs of grass that were dug up from another source, possibly on-site, or possibly a nursery. In the top photo you can see that the plugs have been spaced every foot or so in a soil that appears to be sandy.
In the bottom photo we can see that the plugs have grown up and spread sideways. There was nothing especially inventive about this process, because it was basically happening in nature. People who lived along beaches might have even used this method to control the Sahara effect - this might been ancient common sense stuff?
I want to say that these were fescue plugs, but fescue generally does not grow sideways, to knit in like this, very quickly. My guess is it might take over two years for fescue plugs on 12-18 inch centers to come together with the kind of density that we see in the bottom photo.
Does anyone out there know for certain what species of grass might have been used for these plugs?
And also, do you think I am right in suggesting that the hummock was topdressed with a layer of sand before it was planted?
These may seem like simple observations and questions, but I think they are valuable to know.