Learning from nature: evaluating site-based conservation approaches to mitigating climatic risks to earthen heritage sites in north west China (Spotlight on SEAHA)

Next up in our Spotllight on SEAHA series is a guest post from Jenny Richards, presenting her research into the conservation of sites made from one of the oldest known materials: earth. 

Earth is one of the oldest and most universal construction materials. It has been used by humans since Neolithic times to build structures such as homes, temples and even entire cities.

As built earthen sites are found on every continent, they provide us with the opportunity to improve our understanding of past cultures across the world and learn how traditional buildings were used; the sites are also accessible for many people to visit and enjoy.

However, earthen structures are susceptible to damage by climatic and other natural processes such as earthquakes. Despite this vulnerability, the conservation of earthen sites has lagged behind other building materials, partly because earth has been viewed as a primitive building material. This has meant that many conservation methods have either i) been ineffective, ii) only worked for a few years, or iii) in extreme cases, have sped up the rate of degradation.

My research is aiming to use heritage science to improve the long-term conservation of earthen heritage by understanding how climatic and environmental processes interact with earthen sites. In my research, I will also investigate the potential of using natural, site-scale conservation methods such as planting a windbreak downwind of the site to reduce the impact of the climate on the earthen site.

The ancient city of Souyang located on the Silk Road, China. Each of the outer city walls are about 500 m in length. Source: Dunhuang Academy
My research is based at the ancient city of Souyang, located on the Silk Road in north west China. Souyang is one of the most intact cities from the Han, Sui and Tang Dynasties and is an exceptional example of a frontier defence city. However, its walls are degrading and future climatic changes are expected to increase rates of degradation.

Examples of deterioration seen at Souyang, caused by a) cracking, b) vegetation growth, and c) wind. Source: Dunhuang Academy
I am undertaking my research in collaboration with the Dunhuang Academy. This has meant that I have been able to utilise the extensive climate and vegetation data they have already collected. I will also be undertaking my own fieldwork at the site to investigate the relationship between microclimatic conditions and the extent to which the walls are degraded.

In addition to fieldwork at Souyang, I am using a computer model to understand how earthen heritage is affected by climatic processes and vegetation patterns. The computer model allows me to model complex interacting processes, use different initial conditions to understand how different climatic scenarios would affect the earthen site, and model the long-term impact of potential conservation strategies.

The Dunhuang Academy will be able to implement any findings at Souyang to improve its conservation strategy. The model will hopefully be able to be applied to other earthen heritage sites.

Find out more
Read more at: http://www.seaha-cdt.ac.uk/people/meet-our-students/
Follow updates on Twitter: @jcjrichards18

The 3rd International Conference on Science and Engineering in Arts, Heritage and Archaeology (SEAHA) will take place on 19-20 June 2017 at the University of Brighton. Click here to view the programme of themed sessions and flash presentations, and here to register.

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