Monitoring urban and peri-urban green infrastructure as early detection of stress and environmental quality
- Project leaders
- Carlo Calfapietra, Mohamad Awad
- LIBANO - CNRS-L - National Council for Scientific Research of Lebanon
- CNR/CNRS-L biennio 2018-2019 2018-2019
- Earth system science and environmental technologies
- Thematic area
- Earth system science and environmental technologies
- Status of the project
The forests provide protection for the human beings and their environment. In particular, urban and peri-urban forest includes all trees and shrubs situated in the urban and peri-urban territory and are usually influenced by different stressors such as urban pollutants, biotic and abiotic stress, climate change factors.
It is important to understand what factors are affecting forest health and how these factors are related to the nature, and to the structure of the forest. In general, forest management and strategies can be adapted to maintain and improve forest health and to handle new and upcoming threats. For both, it is important to develop monitoring techniques, which provide information on the present state of forest health. Many factors must be considered in the monitoring process this include the size of the area and how many plots per specified area in the field monitoring process and in the remote sensing spatial and spectral resolution must be considered too. There must be pre-defined indicators which can be calculated to find out the current status of the forest. Some of these indicators are obtained using in-situ measurements such as forest soils, tree crown conditions, vegetation diversity and structure, and downed woody materials . In-situ forest status assessments are limited in area and time, however Remote Sensing (RS) techniques are regularly used for forest monitoring, cover large area, and less expensive
RS data are obtained from sensed reflected electromagnetic waves by sensors carried by satellites, aerial surveys or UAVs. Example of these indicators is Normalized Differences Vegetation Index (NDVI) and chlorophyll content estimated using vegetation indices.
Lebanon forest health is deteriorating especially the Stone pine "pinus pinea" species which is the largest forest cover in the country. According to a recent report by Mazloum  a disease that destroy trees branches, discolors their needles and slowly killing them, is spreading.
Moths, are among the main parasitic agents of this disease. The decline in numbers of their predator, namely the cuckoo bird, is allowing their population to increase and the pine trees to die .
Other kinds of insects namely "Bark beetles" are making the pine trees die, namely those in Park of Beirut "Horsh Beirut" the largest green area in greater Beirut. The pine beetle's ability to survive and thrive is highly sensitive to temperature and precipitation. Outbreaks have been correlated with slightly warmer winter temperatures, which allow more beetles to survive . In one study, biologists found that warmer temperatures allow the pine beetles to complete a full generation in just one year instead of two, allowing the population to grow faster .
Another problem for Stone pine near urban areas is 'acid rain'; a by-product of the air pollution from car exhausts and industrial processing.
It is important in remote sensing to monitor specific spectral responses that are caused by the differences in phenology and phylogenetics of forest species as well as by natural and anthropogenic effects. To correctly interpret these spectral response signals in terms of disturbance or stress, as well as to gain sufficient information for calibrating and validating airborne and space-borne RS data, extensive close-range RS measurements are required. This includes the use of spectroradiometer for detecting spectral signatures of the plant, SPAD meter for measuring chlorophyll content and laboratory analysis .
In addition, to the previous closed range RS devices, cheap price Unmanned Aerial Vehicle (UAV) within NIR camera can be used to monitor forests in close range.
The far range monitoring using RS can be achieved using available and free of charge satellite sensors such as Landsat (7 and 8), CHRIS-Proba and Sentinel-2 [9-11].
Areas of study
Green park of Beirut is considered as the only green Stone pine park available in the Lebanese capital. The health of this forest is deteriorating and it has been closed recently for the purpose of solving the problem before it gets worth.
The second area is selected within the province of "North Meten" specifically Stone pine forests near large cities such as Mansourieh, Beit Merry, Broumana...etc.
The last one is the Stone pine forests in the province of Jizzine and specifically near Jizzine city in the south of Lebanon where several anthropogenic factors plays important roles in the deterioration of these large Stone pine forests.
An additional study area in Italy will be the industrial city of Terni, located in central Italy. This site is one the most industrialized cities in Italy, characterized by high average levels of PM10 concentration in the air [12, 13] A steel factory is located in the eastern part of the city, occupying an area of approximately 158 ha.
Data and method
To achieve the objectives of this research, it is important to make available up to date data which can be collected in-situ, UAV or from satellites remote sensing. It is expected to collect data in-situ using the available spectroradiometer, Chlorophyll SPAD meter, and UAV in order to measure spectral signatures, chlorophyll content, and leaf area index. Although, the in-situ samples collection is a difficult process compared to other vegetation such as crop, but this can be overpassed using available elevator trucks or the UAV if available for taking photos or for taking NIR images. In addition, satellite images of CHRIS-Proba, Landsat 7, Landsat 8, and Sentinell-2 will be collected free of charge from different providers such as ESA Web site and USGS Web site [14, 15].
The pilot areas will be monitored periodically using the available listed data source. The data will be used to map different physiochemical variables of the forests such as NDVI, LAI, and Chlorophyll content. These parameters will be used to create models for periodical monitoring of the health status of the forests.
There are several objectives for implementing this research work and can be summarized as follow:
1- To study current impact of abiotic and biotic stress on urban and periurban Mediterranean forests.
2- To create models for detecting anomalies in Stone pine forests.
3- To suggest solutions for detected problems.
4- To support decision makers and forest managers to use geospatial technologies in the management and protection processes.
5- To monitor forests periodically through innovative techniques aimed at an early detection.
6- To increase the state profits in exploiting the forests economically and reduce expenses which result from maintaining the forests.
7- To introduce new technologies in forest management.
Last update: 27/11/2021