Rosecroft Avenue: On Hampstead Heath: The West Heath, Pt. 1

We have so far discussed Golders Hill Park and the Hampstead Heath Extension, both of which were relatively late additions to the Heath, added in 1898 and 1907, respectively. In contrast, the West Heath has been a part of the Heath for all of recorded history.

Prelude: What is a ‘Heath,’ Anyway?

“Heath” is one of those peculiarly English words (like “moor” and “dale”) that most Americans have heard but never use. I always assumed that “heath” was a posh synonym for “park.” It is not, of course; indeed, the Heath was called such for centuries before it was a public open space.

Rather, a “heath” is a type of terrain: specifically, “a large open area, usually with sandy soil and scrubby vegetation, esp heather.“[1] This is precisely what the Heath was, and why it persisted as open land when all of the surrounding land was used for agriculture. The reason for this is geological. The top layer of soil on the Heath is a type of sand called Bagshot, deposited by a river flowing from the west of England approximately 40 million years ago. This sandy topsoil is acidic and infertile, and therefore unsuitable for agriculture. For this reason the Heath was not farmed, but instead was used as the village “common” of the Manor of Hampstead where, under English manorial tradition, the commoners had the right to graze animals on the scrubby flora, to cut turf for fuel and building materials, and to dig sand.

Bog, West Heath

Beneath the sand is a transitional layer called the Claygate Beds, which in turn covers a deeper layer of stiff, bluish London clay. In the lower portions of the Heath, where less sand was deposited and more has eroded away, these deeper layers have been exposed, and trees and grasses more typical of the region have sprung up.

This geology also accounts for another dominant feature of the Heath: its perpetual damp. Rainwater—of which the Heath receives copious amounts—drains easily down through the sandy layers. When the water hits the denser layers below, it moves horizontally, eventually seeping out of the ground, creating boggy conditions or collecting into streams. The Heath is thus the source of five rivers that empty into the Thames, although all are now channeled underground: the Fleet, the Holborn, the Tyburn, the Kilburn (Westbourne), and the Brent.

West Heath

The West Heath: Back to Nature

I’ve just told you that the West Heath is part of the original Heath, and that heathland is characterized by low scrubby vegetation such as heather. Why, then, do all of our photos of the West Heath look like they were taken in woodland? The answer lies in prehistory.

As explained by Wolton & McDowall,[2] heathland is rarely naturally occurring. Rather, it typically occurs when areas of well-draining, acidic sandy soil—such as that on the Heath—are cleared of trees and shrubbery and used to graze livestock. Over time, the grazing alters the flora into the scrubby heather and gorse typical of heathland. The remains of a Mesolithic-period encampment on the West Heath, near Leg o’ Mutton Pond, suggest that the West Heath was cleared of its original vegetation as early as 7,000 years ago, and the land probably was used for grazing thereafter until well into the Nineteenth Century. Indeed, John Constable’s 1821-1822 painting of the West Heath, West End Fields, Hampstead, noon, depicts a flock of sheep grazing on typically open heathland.

The grazing of livestock on the West Heath stopped, of course, when the Heath (then comprised of 220 acres of the West Heath, the Sandy Heath, and the East Heath) passed into the public trust in January 1872. In the ensuing 140 years, the West Heath has been recolonized by trees and shrubbery; birch trees, in particular, are known to thrive on open, acidic ground, and many large, mature birch trees now thrive in the West Heath.[3]

In Part 2, we look at the landmarks of the West Heath.