Abstract
Lorestan bridges have been of particular importance in different eras due to being located on ancient roads. Bridges built for various purposes, including political, religious and economic, have acted as valley bridges in addition to linking different areas through crossing ravaged rivers of Lorestan at the time such as Kashkan and establishing road safety. Lack of awareness by the local people, the country and the international community of the value of these properties, the destruction of their properties and their associated environments by indigenous peoples and domestic tourists, the lack of a comprehensive and integrated conservation program and the lack of proper budget allocation for their restoration, Their natural context for conservation and restoration has all made these valuable and indigenous properties in the process of destruction. Accordingly, the purpose of the research is to identify the cultural landscape of historical bridges attributed to the Sassanid period of the Kashkan River and to establish a structuralist framework through the analysis of national and international laws, charters, conventions, and treaties to conserve their cultural landscape. In this research, library and field data were collected and four bridges: Kashan, Kelahor-e-Mamulan, pol-e-dokhtar, and Gavmishan were selected as study samples due to historical and architectural values. In the following, recommendations for the conservation of selected bridges’ cultural landscapes were categorized into two categories, generic and specific to the selected bridges themselves using qualitative research method, data analysis, and coding operations at three levels to reach the final results of the research. 
Keywords: Conservation of Cultural Landscape, Historic Bridges, Sassanid Period, Lorestan, Kashkan River.

Introduction
Lorestan province, with its rich and important rivers such as Seymareh, Kashkan and Cesar, has one of the richest flowing water networks. In addition to communicating with the two capitals (Susa-Ekbatan), this province has always established the connection between the old Babylon, then Ctesiphon, and then Baghdad, to Isfahan, through Khorramabad. (Siroux, 1978: 32-33). From other roads, separated from Lorestan, we can refer to Susa to Bisotun and Susa to Masbazan road (Minorsky, 1937). The need for quick and easy access and constant communication between these areas, despite the rich rivers and deep valleys, has led to the construction of huge bridges that makes a man wonder7 (UNESCO, 2016). These bridges have been built to connect large civilizations and some extent of the realization of human rights, religious, ethnic, economic and cultural ties, as well as development, prosperity, security and comfort in difficult mountainous regions (UNESCO, 2016). The undiscovered identity and value of these works for the indigenous people of Lorestan and at higher levels, the country and the international community, the destruction of the works themselves and the natural environment, associated with, by indigenous people (intentionally interfering with the cultural landscape of the bridges), lack of comprehensive conservation and restoration plans and lack of necessary credit allocations from organizations, entrusted with these works, the non-formal and mere physical restoration of some properties, regardless of the context in which, they are formed, have all made these valuable properties of art and cultural landscape associated with, to increasing degradation. In Lorestan cultural domain, these properties have been constructed with the highest quality of locating and building, and study of these works and conservation challenges of their cultural landscapes, can certainly Conserve bridges, with addition follows:
• To illuminate and conserve various historical layers of the region;
• To preserve the natural environment (including river, valley, etc.) where the bridges are located;
• For legibility and conservation of the region’s indigenous culture and
• To achieve construction technologies of bridges, for future conservation and restoration of these properties.
This research seeks to identify the Cultural landscape of Historic Bridges on the River Kashkan and its conservation challenges, in order to provide a basis for helping, define a systematic model to conserve its cultural landscape. In this regard, the following question is defined as:
• What is the definition of the cultural landscape of historic Bridges on the River Kashkan?
• How can a systematic, structuralist model be achieved to conserve the cultural landscape of historic bridges over the Kashkan River?

Discussion
According to the epigraph left by the bridge, Badr-ibn-Hasanwayeh has introduced himself as a constructor to this bridges. The cultural landscape of these Bridges is an integrated collection, interacting with humans over time in the geographical domain of middle Zagros. Despite the vagueness of the “cultural landscape” meanings, today this word has become one of the most controversial words in the World Heritage Convention. Challenges are coming into place when modern science cannot face the challenges of different levels and disciplines (Zibalkalam, 2018). Conservation is also no exception to this and has undergone various changes over time to respond to problems, encountered in conservation. The analysis of this research is carried out through “codifying” at three levels: first cycle codifying, second cycle (middle) codifying, and third or final cycle codifying (post-coding). The codes were reviewed and stored to verify the qualitative data, in order to identify conservation principles of the cultural landscape of these Bridge (the core of the research), at the final stage (Afshar, 2014). In the following, by integrating, the results of code analysis are compatible with the dispersive components of the image (Giviyan, 2016). In the following, recommendations for the conservation of selected bridges’ cultural landscapes were categorized into two categories, generic and specific to the selected bridges themselves using qualitative research method, data analysis, and coding operations at three levels to reach the final results of the research.

Conclusion
This research, in the form of fundamental-applied research, was able to identify the conservation of the cultural landscapes of the studied historical bridges and make them applicable to other similar historical bridges in Lorestan. This study was able to introduce recommendations in two general categories Generic and specific to the bridges themselves. In response to the first part of the research question, the concepts and constituent elements of the cultural landscape of historical bridges were identified through the library, field studies, and analysis of various concepts in the subject literature and in accordance with the native conditions of the cultural landscape under study. In answer to the second part of the research question, it can be said that by analyzing the collected literature and taking a look at field studies, by examining and analyzing the challenges of conserving cultural landscapes and the meanings and concepts of conservation in national charters, conventions and treaties, and International; Investigating and analyzing the meanings and concepts of cultural landscapes in national and international charters, conventions and treaties. These recommendations, since taken from the very context of the aforementioned research and context, have been categorized into a specific framework and have created a systematic model for the conservation of the cultural landscapes of the historical bridges studied. 

Abstract
Lorestan province has established the connection between the capitals and important cities of Iran during different eras. The need for quick and easy access and permanent communication between these areas has led to the construction of huge bridges despite the rivers full of water and deep valleys. Because these bridges are a natural interwoven complex and have interactions with humans, bridges over time in the geographical area of Middle Zagros of Lorestan connect with great civilizations and in a way realize human rights and religious, ethnic, and economic relations. and cultural as well as the development of welfare, security and comfort are used in difficult mountainous areas, they can well represent the concepts of the cultural landscape. Studying these properties and their cultural landscape can help to identify the components of cultural landscapes and their conservation in addition to conserving the bridges themselves. On the other hand, the first and most important step is to identify the challenges that have not been identified and classified so far. Based on this, the research aims to identify the challenges of conserving the cultural landscapes of Lorestan’s historical bridges through the review and analysis of documents related to this issue. In this research, library and field information was collected on the valuable historical bridges of the Kashkan River, and then the concepts of challenges and their subsets through analysis using the qualitative research method. Data analysis was done through coding operations at 3 levels and finally, the challenges and sub-challenges related to it were categorized into 6 general categories according to the characteristics and indicators of the study samples.
Keywords: Conservation Challenges, Historical Bridges of Lorestan, Cultural landscape, Kashkan River, Coding.

Introduction
Bridges have existed in the mountainous land of Iran as buildings with Iranian architecture since prehistoric times. These properties made the distances shorter and faster because they made it possible to pass easily and safely through the natural complications of rivers and valleys. The need for quick and easy access and permanent communication between these areas has led to the construction of huge bridges (Minorsky, 1937). So far, a significant number of bridges have been reported in the mountainous land of Zagros, which surrounds Khuzestan (Siroux, 1949). Most of these bridges are located in Lorestan. Lorestan is located between the two ancient capitals of Susa and Hamedan. Therefore, the existence of roads, highways and bridges has been necessary as a means of communication. The traces of 100 historical bridges have been observed in more than 25 ancient sites on the map of Lorestan, some of which were built in the Sassanid period in parallel with the expansion of cities and have made great progress in terms of engineering methods and understanding of hydrodynamics it has been observed. Lack of awareness and knowledge of the high value of these properties and related elements (cultural landscape) have caused them to be exposed to much damage. On the other hand, the custodians of conservation have never been able to achieve the necessary successes in the field of conservation of Lorestan historical bridges due to a lack of knowledge of the challenges of conserving these properties and the context in which they are located and the one-dimensional view of conservation on this issue.
The challenges faced in conserving cultural landscapes show the inefficiency of the current system of conserving cultural landscapes, which, if not identified and categorized and solutions are not considered, can lead to the following crises at different times:
• The emergence of a one-dimensional perspective (mere physical protection) and one-dimensional approaches such as a product-oriented approach to the issue of cultural conservation of historical bridges of Lorestan;
• Ignoring the important and key issues in planning the cultural landscape of Lorestan historical bridges;
• Inability to educate and attract the participation of the public to preserve these valuable properties;
• Failure to provide appropriate solutions and not identify internal and external threats in the field of policy and legislation to conserve the aforementioned properties;
• Making the problem of increasing the level of expertise of experts concerning the mentioned cultural landscapes.
Therefore, this research has tried to introduce and categorize the challenges as far as possible to understand. Considering the qualitative and objective of the research, to achieve the research objectives, the following questions are raised:
• What are the challenges of cultural conservation of Lorestan historical bridges? 
• How can we achieve a classified, classified structure of the challenges of conserving cultural landscapes of Lorestan historical bridges?

Identified Traces 
Since each qualitative research is unique and inimitable, the analytical approach used in this research is also unique, but as mentioned, coding was done in 3 Stages through searching in documents, and related charters and used in the form of first-round, second-round (middle) and third round (post-coding). The term “cultural landscape” itself has been a double essence in its nature since the early years of its creation in the field of scientific societies. The challenges posed in conserving cultural landscapes themselves demonstrate the inefficiency of the current system of cultural landscape conservation. Eventually, 137 codes to 68 codes and finally 18 common codes in the field of cultural landscape conservation challenges were achieved. This research has been conducted by continuing to analyze and adapt the common outcomes with the study samples, reaching 10 common categories and 6 main concepts that form the main framework and conclusion framework of the research.
“These concepts are the beginning of writing theories, reading the challenges of conserving the cultural landscape of Lorestan historical bridges, and the last stage of the journey from reality to abstraction.”
Therefore, as mentioned, the challenges that have been achieved from the researcher’s study in the literature of the research subject to conserve cultural landscapes have been used and adapted with the field studies of the researcher to achieve the challenges of cultural landscape conservation of historical bridges, were finally categorized into the following 6 categories:  
• Policy making and legislation;
• Conservation approaches;
• The level of expertise of cultural landscape experts in the areas of identification, evaluation, monitoring and management of cultural landscapes;
• Educating the community to conserve cultural landscapes
• Threats arising from internal and external factors of cultural landscapes; and
• The paradigm shift of Conserving Cultural Landscapes.

Conclusion
This research tried to identify the meanings and concepts of challenge, as qualitative and applied research, and to classify the challenges of cultural conservation of historical bridges of Kashkan River in Lorestan by analyzing the literature and theoretical foundations. Finally, these challenges were divided into 6 groups through coding in three stages and the path from reality to abstraction, with related sub-challenges of each category. The number of codes and percentage of each of the challenges were presented in the relevant tables to be able to familiarize readers with them, study the most important of these challenges and their impact on the studied properties in different dimensions if needed and be aware of them. 
In response to the first question of the research, all the challenges of conserving the cultural landscapes of the mentioned historical bridges were obtained through library and field studies and then by analyzing the literature and theoretical foundations of the subject in 6 general categories along with the sub-challenges. Challenges that each one needs to understand, plan and use different experts to meet them at different time intervals.
In response to the second question, the research attempted to achieve a structured, classified, and categorized framework by collecting, and analyzing the literature and theoretical foundations of the research, exploring the concepts and challenges of conserving cultural landscapes through the process of conservation in charters, conventions and treaties related to the subject, and localizing the mentioned challenges to be adaptable and using them as a conservation factor.
These achievements are certainly not complete and only part of the researcher’s achievements in this field are due to interest and dependence on valuable and unrepeatable properties of the historical bridges of Lorestan. properties that have embraced the identity and cultural values of a people from a long time ago and require the participation of all people, especially local communities whose main beneficiaries. In all stages from identifying challenges to conserving cultural landscapes of Lorestan historical bridges, the unmatched role of indigenous people and local communities should be considered the most important factor in conserving historical bridges, because they are the main owners of these monuments and the most important unclaimed conservationists.