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Prehistoric landscaping

As soon as we - Homo sapiens - emerged from them gloomy caves and started to live under the sun, we joined a selected group of animals that had had enough of constant adapting to the environment, and chose a different strategy: to change the environment in order to better suit their lifestyle. And thus we stumbled upon the ancient and sacred art of landscaping.

Termite mounds of Namibia. Those intrepid eusocial insects were probably the first landscapers on the planet. Courtesy of Wikimedia Commons user Olga Ernst.

When we started to become farmers - that crazy time of Neolithic Revolution, domesticating animals and plants, building huts and villages and irrigation canals and temples and fortresses - we changed the looks of the planet forever. And we are still changing it; our villages grew into towns and cities, small gardens and fields became vast agricultural estates, paths became roads and highways, powerlines cris-cross and mobile network towers dot the land.

But here and there, like a palimpsest of torn, crumbled, and forgotten pieces of primeval landscape, such as had been created by the first farmers, still remains - unchanged since before the dawn of History.

Kite aerial photo of a gently undulating meadow called 'V snožetih'.

Karstic hinterland of Slovenian Littoral has had a tumultous history. Mesolithic hunters and gatherers were the first to leave their traces here; there are a couple of Neolithic settlements, and later a vast network of Bronze and Iron age hillforts, villages and gravesites was created that persisted through the Roman conquests and even Slavic migrations up until the 8th century CE. Millennia of history - that can in places still be read.

One of such places is a meadow named 'V snožetih' north of the village Gorice pri Famljah near Divaca. It is an unassuming piece of land, a bit remote, used mainly for grazing and harvesting hay. Nothing much to be seen, even from the air:

Orthophoto shot of the area. Nothing really stands out, but ... Courtesy of ARSO, Slovenian Environment Agency.

However, a LIDAR scan of the meadow tells a different story - and speaks volumes:

LIDAR scan of the area. Walls and enclosures and cairns and mounds are revealed dramatically. Courtesy of ARSO.

What we see here is the first landscaping effort, started in the late Neolithic / Eneolithic and continuing into the Bronze and Iron Age.

This is a karst area, dry and rocky with just a thin cover of soil over eroded limestone. Farming is hard here; fields must literally be created by hand, clearing and removing rocks, stones and gravel.

From those stones and gravel dry walls were made, walls that enclosured the fields and separated one farm from another. Even paths were walled, so the animals couldn't roam too far. What remained was thrown onto cairns and mounds.

A thorough analysis of LIDAR scans by Dr. Dimitrij Mlekuž showed identified two intensive transformations in the landscape: the first one most likely took place in the Bronze Age, the second begun in the last millennium, shaping the medieval and modern landscape. There is almost no continuity between the two, with only a few barely visible marks and features testifying to the impact that prehistoric landscape had on the emergence of modern landscape.

Two cairns were excavated in late 1980s by Dr. Nada Osmuk - nothing much has been found, some pottery shards dating to the Bronze or Iron Age, and a Neolithic (or Eneolithic) ladle. The cairns were made of mostly stones and gravel, with an unusually large amount of soil present.

And so we went there with our kites and cameras - we wanted to check if anything else hides among and beneath those ancient structures ...

Kite aerial NDVI gradient map superimposed on an othophoto of the area. Some structures are clearly visible. 'V Snožetih' meadow lies below Vremscica mountain and northeastern Bora wind sweeps the landscape, creating tough kite flying conditions. In order to compute the NDVI, normalized difference vegetation index, one needs two photos; one infrared, and one visual (from which only the red channel is used).

Flying a vibrant dr.agon D90 BW mini delta kite with a double picavet rig attached was a bit crazy at times (not to mention forgetting to remove the lens cap on the first KAP session), and aligning the photos was a challenge. However, we did get something out of all this.

Orthophoto - LIDAR - NDVI gif of the area.

Subtle differences in soil conditions are responsible for different health of the grass and thus for differences in infrared reflectivity. Most of the structures are clearly visible; as the cairns contain an unusual amount of soil they have a positive signal. White areas on the NDVI are oversaturated; a bush or a tree grows there.

But not all cairns are created equal ...

'Round' cairns on the NDVI gradient map.

There are at least three types of elevated structures here. Round cairns or mounds, elongated cairns or barrows, and dry walls / dikes. And they clearly differ by the infrared reflectivity. Round cairns produce rather low signal - perhaps indicating lower amount of soil in their stones-and-gravel core.

'Elongated' cairns and enclosure walls / dikes have a stronger positive signal and stand out even more clearly.

Elongated cairns (and some shapeless cairns that are larger than most) have a much stronger signal than round ones. Again, a difference in their construction can be responsible for it - it is even possible that the two types of cairns aren't contemporary. Could it be that the ancients first built the elongated ones (that may have more soil in them), and the round cairns later when soil management in this unforgiving place was more important? Well, only a shovel can tell ...

But there is more ...

There are a couple of positive anomalies that are visible on NDVI but not on LIDAR.

What makes an archaeologist's (even an amateur one) heart skip a beat are anomalies. Two positive anomalies can be seen on the NDVI without corresponding features on LIDAR. What are they? Who knows!

And there is a negative anomaly in the centre of a triangle of three round cairns: