What is a Cornish Hedge

This is all a little advanced to where I am with this project but as you may have noticed my mind does race ahead of me at times. Anyway I do feel I need to plan ahead a little before I embark on any baseboard construction. I've been considering some of my planned scenic items and how they might affect the baseboards, thoughts have wandered to the lane at the right on the Tredethy Wharf layout.

Last time I was at Hellandbridge I remember the approach down Tredethy Road from Helland being a narrow Cornish lane. Each side of the lane being bordered by typical Cornish hedges and, in places, trees hanging over the road giving a secluded valley feel. But three questions come to mind;
What is a Cornish Hedge?
How is it constructed?
Are the lanes slightly below the surrounding landscape or are they just high hedges?
Hopefully know the answers to the above will help me model one.

While driving along these lanes I've never been that observant, I've probably just been concentrating on not hitting them while avoiding any oncoming traffic. A little research found a couple of interesting web sites that I hope will help me. Nothing will replace good photos (dear partner this is a gentle hint, can we get down there this year?) but these do give details on how the hedges are constructed.

Cornish Hedges Library

Practical Conservation Online

After looking at the above sites I think I can say that, in brief, a typical Cornish hedge is a hybrid between a stone wall and an earth bank. The hedge sides are typically built tapered with an inward curve from the base to half-way up. The top of the hedge is normally about half the width of the bottom. The base is created by placing large stone blocks into the earth and packing them in with sub-soil. The sides are then built using smaller rocks that interlock randomly. When the hedge reachs the required height, the random laying of stones turns into neat rows of square stones called "edgers". To finish, grass is sliced from the ground and stuck on top of the structure with sticks. The internal core of the hedge is earth.

There is a good cross sectional diagram of a Cornish hedge here.

What we see, as we travel along Cornwall's lanes, as a green hedge is the result of years of vegetation growing on/over the base structure.

Well you learn something everyday.........This is what I like about this hobby, it's not just about the railway with its track, locos and rolling stock, it gets you looking at and understanding your surroundings.........