scholarly journals Review on the Use of Remote Sensing for Urban Forest Monitoring

2016 ◽  
Vol 42 (6) ◽  
Author(s):  
Razieh Shojanoori ◽  
Helmi Shafri
Keyword(s):  
Remote Sensing ◽  
Urban Areas ◽  
Urban Forest ◽  
Urban Forests ◽  
Potential Method ◽  
Forest Monitoring ◽  
Species Discrimination ◽  
Imaging Method ◽  
Object Based ◽  
Crown Delineation

Urban forests are vital in urban areas because they clean the air, absorb water, and protect the environment from intense heat. Destruction of the urban forest by increased urbanization is a considerable threat to the ecosystem. Hence, urban planners must obtain and manage information about urban forests, but the complexity of urban areas has made these tasks difficult. With developments in remote-sensing technologies, the monitoring and detection of urban forests can be achieved without performing any field measurements. In this study, different remote-sensing imageries and various methods are evaluated to obtain urban forest information. This review demonstrates that very high resolution (VHR) satellite imagery, such as from WorldView-2, is the most efficient data that can be used to obtain urban forest information. The use of the combination of LiDAR data with VHR imagery increases the accuracy of information, particularly about tree crown delineation. Traditional pixel-based classification methods are not effectively applicable to obtain urban tree information because of significant spectral variability in urban areas. An object-based classification technique, which uses spatial, textural, and color information, can be a potential method to detect urban forest and tree species discrimination. The new VHR imaging method, which uses the object-based technique, is recommended to overcome limitations of collecting urban forest information.

scholarly journals Intelligent Mapping of Urban Forests from High-Resolution Remotely Sensed Imagery Using Object-Based U-Net-DenseNet-Coupled Network

2020 ◽  
Vol 12 (23) ◽  
pp. 3928 ◽  
Author(s):  
Shaobai He ◽  
Huaqiang Du ◽  
Guomo Zhou ◽  
Xuejian Li ◽  
Fangjie Mao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Urban Forest ◽  
Urban Forests ◽  
Urban Land ◽  
Urban Land Use ◽  
Classification Error ◽  
Object Based ◽  
Land Use Types ◽  
Multiresolution Segmentation

The application of deep learning techniques, especially deep convolutional neural networks (DCNNs), in the intelligent mapping of very high spatial resolution (VHSR) remote sensing images has drawn much attention in the remote sensing community. However, the fragmented distribution of urban land use types and the complex structure of urban forests bring about a variety of challenges for urban land use mapping and the extraction of urban forests. Based on the DCNN algorithm, this study proposes a novel object-based U-net-DenseNet-coupled network (OUDN) method to realize urban land use mapping and the accurate extraction of urban forests. The proposed OUDN has three parts: the first part involves the coupling of the improved U-net and DenseNet architectures; then, the network is trained according to the labeled data sets, and the land use information in the study area is classified; the final part fuses the object boundary information obtained by object-based multiresolution segmentation into the classification layer, and a voting method is applied to optimize the classification results. The results show that (1) the classification results of the OUDN algorithm are better than those of U-net and DenseNet, and the average classification accuracy is 92.9%, an increase in approximately 3%; (2) for the U-net-DenseNet-coupled network (UDN) and OUDN, the urban forest extraction accuracies are higher than those of U-net and DenseNet, and the OUDN effectively alleviates the classification error caused by the fragmentation of urban distribution by combining object-based multiresolution segmentation features, making the overall accuracy (OA) of urban land use classification and the extraction accuracy of urban forests superior to those of the UDN algorithm; (3) based on the Spe-Texture (the spectral features combined with the texture features), the OA of the OUDN in the extraction of urban land use categories can reach 93.8%, thereby the algorithm achieved the accurate discrimination of different land use types, especially urban forests (99.7%). Therefore, this study provides a reference for feature setting for the mapping of urban land use information from VHSR imagery.

scholarly journals An Effect of Urban Forest on Urban Thermal Environment in Seoul, South Korea, Based on Landsat Imagery Analysis

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 630
Author(s):  
Peter Sang-Hoon Lee ◽  
Jincheol Park
Keyword(s):  
South Korea ◽  
Vegetation Cover ◽  
Land Surface ◽  
Urban Areas ◽  
Vegetation Index ◽  
Urban Forest ◽  
Thermal Environment ◽  
Urban Forests ◽  
Cooling Effect ◽  
Surrounding Areas

The urban heat island effect has posed negative impacts on urban areas with increased cooling energy demand followed by an altered thermal environment. While unusually high temperature in urban areas has been often attributed to complex urban settings, the function of urban forests has been considered as an effective heat mitigation strategy. To investigate the cooling effect of urban forests and their influence range, this study examined the spatiotemporal changes in land surface temperature (LST) of urban forests and surrounding areas by using Landsat imageries. LST, the size of the urban forest, its vegetation cover, and Normalized Difference Vegetation Index (NDVI) were investigated for 34 urban forests and their surrounding areas at a series of buffer areas in Seoul, South Korea. The mean LST of urban forests was lower than that of the overall city, and the threshold distance from urban forests for cooling effect was estimated to be roughly up to 300 m. The group of large-sized urban forests showed significantly lower mean LST than that of small-sized urban forests. The group of urban forests with higher NDVI showed lower mean LST than that of urban forests with lower mean NDVI in a consistent manner. A negative linear relationship was found between the LST and size of urban forest (r = −0.36 to −0.58), size of vegetation cover (r = −0.39 to −0.61), and NDVI (r = −0.42 to −0.93). Temporal changes in NDVI were examined separately on a specific site, Seoul Forest, that has experienced urban forest dynamics. LST of the site decreased as NDVI improved by a land-use change from a barren racetrack to a city park. It was considered that NDVI could be a reliable factor for estimating the cooling effect of urban forest compared to the size of the urban forest and/or vegetation cover.

scholarly journals Potensi Biomassa Dan Karbon Tersimpan Tegakan di Ruang Terbuka Hijau Kota Polewali, Sulawesi Barat

2020 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Daud Irundu ◽  
Mir A Beddu ◽  
Najmawati Najmawati
Keyword(s):  
Global Warming ◽  
Urban Areas ◽  
Green Space ◽  
Urban Forest ◽  
Urban Forests ◽  
Tree Height ◽  
Strong Relationship ◽  
Coefficient Of Determination ◽  
Relationship Of ◽  
The Relationship

Global warming is one of the major environmental issues of this century. Carbon dioxide (CO2) emissions are the main cause of global warming. Green open space (RTH) such as urban parks, urban forests and green lines play an important role in mitigating global warming and climate change in urban areas because it is able to reduce CO2 from the atmosphere. This study aims to determine the potential of biomass and carbon stored in the Green Open Green Space of Polewali, West Sulawesi. Data collection for stored biomass and carbon is carried out at three green space locations including; Urban forest and city park and green lane each made three plots measuring 20 m x 20 m, and three plots on the Green Line measuring 1200 m. Retrieval of data by measuring tree height and diameter, analysis to obtain the dry volume, biomass and carbon stored for each tree species contained in the Polewali green space. Biomass is obtained by the formula M = BJ x Vk x BEF, the stored carbon value is obtained from the product of biomass by 0.47. The magnitude of the relationship of volume with biomass and carbon uses a regression equation (Ŷ=a+bX). The results show there are types of Glodokan (Polyalthia longifolia), Johar (Senna siamea), Mahogany (Swetenia sp) and Trambesi (Samanea saman) which are spread in the Polewali open green space. Trambesi is a type that has dominant biomass and stored carbon of 381.95 (tons / ha) and 179.52 (ton/ha). Green lane is the type of green space that has the most stored carbon and is currently 440.94 (ton/ha) and 207.24 (ton/ha). The overall green space biomass is 571.83 (ton/ha) and stored carbon is 268.76 (ton/ha) found in urban forests, urban gardens and green belt. The relationship of volume with biomass and stored carbon shows a very strong relationship with the coefficient of determination (R2) of 0.96.  

scholarly journals Traces of urban forest in temperature and CO<sub>2</sub> signals in monsoon East Asia

2021 ◽  
Author(s):  
Keunmin Lee ◽  
Je-Woo Hong ◽  
Jeongwon Kim ◽  
Jinkyu Hong
Keyword(s):  
Co2 Emissions ◽  
Urban Areas ◽  
Urban Forest ◽  
Urban Forests ◽  
Forest Canopies ◽  
Area Index ◽  
Drought Period ◽  
Vegetation Activity ◽  
Urban Heat ◽  
The Impact

Abstract. Cities represent a key space for our sustainable trajectory in a changing environment, and our society is steadily embracing urban green space for its role in mitigating heatwaves and anthropogenic CO2 emissions. This study reports two-year surface fluxes of energy and CO2 measured via the eddy covariance method in an artificially constructed urban forest to examine the impact of urban forests on air temperature and net CO2 exchange. The urban forest site shows typical seasonal patterns of forest canopies with the seasonal march of the East Asian summer monsoon. Our analysis indicates that the urban forest reduces both the warming trend and urban heat island intensity compared to the adjacent high-rise urban areas and that photosynthetic carbon uptake is large despite relatively small tree density and leaf area index. During the significant drought period in the second year, gross primary production and evapotranspiration decreased, but their reduction was not as significant as those in natural forest canopies. We speculate that forest management practices, such as artificial irrigation and fertilization, enhance vegetation activity. We also stipulate that ecosystem respiration in urban forests is more pronounced than typical natural forests in a similar climate zone. This can be attributed to the substantial amount of soil organic carbon available due to intensive historical soil use and soil transplantation during forest construction, as well as relatively warmer temperatures in urban heat domes. Our observational study also indicates the need for caution in soil management for less CO2 emissions in urban areas.

scholarly journals Assessing the relative importance of human and spatial pressures on non-native plant establishment in urban forests using citizen science

NeoBiota ◽  
2021 ◽  
Vol 65 ◽  
pp. 1-21
Author(s):  
Katherine Duchesneau ◽  
Lisa Derickx ◽  
Pedro M. Antunes
Keyword(s):  
Species Richness ◽  
Rural Areas ◽  
Urban Areas ◽  
Native Species ◽  
Urban Forest ◽  
Urban Forests ◽  
Native Plant ◽  
Plant Introductions ◽  
Native Species Richness ◽  
Urban Activities

Since 2007, more people in the world live in urban than in rural areas. The development of urban areas has encroached into natural forest ecosystems, consequently increasing the ecological importance of parks and fragmented forest remnants. However, a major concern is that urban activities have rendered urban forests susceptible to non-native species incursions, making them central entry sites where non-native plant species can establish and spread. We have little understanding of what urban factors contribute to this process. Here we use data collected by citizen scientists to determine the differential impacts of spatial and urban factors on non-native plant introductions in urban forests. Using a model city, we mapped 18 urban forests within city limits, and identified all the native and non-native plants present at those sites. We then determined the relative contribution of spatial and socioeconomic variables on the richness and composition of native and non-native plant communities. We found that socioeconomic factors rather than spatial factors (e.g., urban forest area) were important modulators of overall or non-native species richness. Non-native species richness in urban forest fragments was primarily affected by residential layout, recent construction events, and nearby roads. This demonstrates that the proliferation of non-native species is inherent to urban activities and we propose that future studies replicate our approach in different cities to broaden our understanding of the spatial and social factors that modulate invasive species movement starting in urban areas.

scholarly journals Remote Sensing in Urban Forestry: Recent Applications and Future Directions

2019 ◽  
Vol 11 (10) ◽  
pp. 1144 ◽  
Author(s):  
Xun Li ◽  
Wendy Y. Chen ◽  
Giovanni Sanesi ◽  
Raffaele Lafortezza
Keyword(s):  
Remote Sensing ◽  
Data Processing ◽  
Urban Forest ◽  
Scale Effects ◽  
Urban Forestry ◽  
Urban Forests ◽  
Accurate Information ◽  
Multi Scale ◽  
Sensing Applications ◽  
Multi Temporal

Increasing recognition of the importance of urban forest ecosystem services calls for the sustainable management of urban forests, which requires timely and accurate information on the status, trends and interactions between socioeconomic and ecological processes pertaining to urban forests. In this regard, remote sensing, especially with its recent advances in sensors and data processing methods, has emerged as a premier and useful observational and analytical tool. This study summarises recent remote sensing applications in urban forestry from the perspective of three distinctive themes: multi-source, multi-temporal and multi-scale inputs. It reviews how different sources of remotely sensed data offer a fast, replicable and scalable way to quantify urban forest dynamics at varying spatiotemporal scales on a case-by-case basis. Combined optical imagery and LiDAR data results as the most promising among multi-source inputs; in addition, future efforts should focus on enhancing data processing efficiency. For long-term multi-temporal inputs, in the event satellite imagery is the only available data source, future work should improve haze-/cloud-removal techniques for enhancing image quality. Current attention given to multi-scale inputs remains limited; hence, future studies should be more aware of scale effects and cautiously draw conclusions.

scholarly journals Strong variations in urban allergenicity riskscapes due to poor knowledge of tree pollen allergenic potential

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rita Sousa-Silva ◽  
Audrey Smargiassi ◽  
Daniel Kneeshaw ◽  
Jérôme Dupras ◽  
Kate Zinszer ◽  
...  
Keyword(s):  
New York ◽  
Urban Areas ◽  
Urban Forest ◽  
Pollen Allergy ◽  
Urban Forests ◽  
Urban Environments ◽  
Tree Pollen ◽  
Allergenic Potential ◽  
Common Tree ◽  
Pollen Allergenicity

AbstractExposure to allergenic tree pollen is an increasing environmental health issue in urban areas. However, reliable, well-documented, peer-reviewed data on the allergenicity of pollen from common tree species in urban environments are lacking. Using the concept of ‘riskscape’, we present and discuss evidence on how different tree pollen allergenicity datasets shape the risk for pollen-allergy sufferers in five cities with different urban forests and population densities: Barcelona, Montreal, New York City, Paris, and Vancouver. We also evaluate how tree diversity can modify the allergenic risk of urban forests. We show that estimates of pollen exposure risk range from 1 to 74% for trees considered to be highly allergenic in the same city. This variation results from differences in the pollen allergenicity datasets, which become more pronounced when a city’s canopy is dominated by only a few species and genera. In an increasingly urbanized world, diverse urban forests offer a potentially safer strategy aimed at diluting sources of allergenic pollen until better allergenicity data is developed. Our findings highlight an urgent need for a science-based approach to guide public health and urban forest planning.

scholarly journals Breeding density of the Tawny Owl Strix aluco in urban forests of Ljubljana City (Central Slovenia)

Acrocephalus ◽  
2017 ◽  
Vol 38 (172-173) ◽  
pp. 31-35
Author(s):  
Tjaša Pršin ◽  
Darja Kušar ◽  
Tanja Obermajer ◽  
Al Vrezec
Keyword(s):  
Urban Areas ◽  
Urban Forest ◽  
Urban Forests ◽  
Forest Patches ◽  
Tawny Owl ◽  
Point Count ◽  
Strix Aluco ◽  
Nature Park ◽  
Territory Density ◽  
Point Count Method

SummaryResults of the survey carried out in the territories of Tawny Owl Strix aluco in Ljubljana urban forests (Tivoli, Rožnik and Šišenski hrib Nature Park and Golovec Hill) were compared with the species territory density in non-urban forest of Mt. Krim. Surveys were performed with the point count method using playback in the springs of 2002 and 2016. The density established at Golovec Hill was 9.3 territories / 10 km2, while in Tivoli, Rožnik and Šišenski hrib Nature Park it reached 10.4 territories / 10 km2, which was higher than at Mt. Krim (4.1-5.8 territories / 10 km2), although densities between sites were not statistically different. Based on our surveys, the estimated population size of the urban Tawny Owl in Ljubljana would consist of 57 to 65 pairs. Our results suggest that the Tawny Owl can adapt well to the living conditions in the city urban forests and indicate the importance of the forest patches in urban areas.

scholarly journals PEMENUHAN LUASAN HUTAN KOTA SEBAGAI PENCEGAH MASALAH LINGKUNGAN DI SURABAYA

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Martika Dini Syaputri ◽  
Nany Suryawati
Keyword(s):  
Urban Areas ◽  
Local Governments ◽  
Open Space ◽  
Central Government ◽  
Urban Forest ◽  
Urban Forests ◽  
Community Needs ◽  
Management And Development ◽  
The Government ◽  
The City

AbstractEnvironmental problems in urban areas are a problem that never stops. That every community needs a healthy life, but this seems difficult to become a reality for urban communities because the population continues to increase every year so that land conversion occurs which results in increased air and water pollution. Therefore, the central government hopes that each region or region can provide RTH 30% of the city area. The purpose of this study is to analyze the enforcement of the City Forest Regulations in Surabaya and to find out the efforts of local governments in fulfilling urban forest land in urban areas. This study uses a normative juridical method. As part of RTH, the development of urban forests in Surabaya is very much needed by the community, therefore cooperation between the government and the community is needed in the management and development of urban forests. Fulfillment of urban forest areas in Surabaya can be done by maximizing the form of urban forest that has been regulated based on the City Forest Regulation, either in the form of channels, groups or scattered.Keywords: city forest; green open space; urbanAbstrakMasalah lingkungan hidup diwilayah perkotaan merupakan masalah yang tak kunjung berakhir. Bahwa setiap masyarakat membutuhkan hidup sehat, namun hal tersebut seolah sulit menjadi kenyataan bagi masyarakat perkotaan yang disebabkan karena jumlah penduduk yang tiap tahun meningkat sehingga terjadi pengalihfungsian lahan yang berakibat pada semakin meningkatnya pencemaran udara maupun pencemaran air. Oleh karena itu, pemerintah pusat mengharapkan bagi setiap wilayah atau daerah menyediakan RTH 30% dari luasan kota. Tujuan dilakukannya penelitian ini adalah untuk menganalisa pemberlakuan Perda Hutan Kota di Surabaya serta mengetahui upaya pemerintah daerah dalam memenuhi lahan hutan kota pada wilayah perkotaan. Penelitian ini menggunakan metode yuridis normatif. Sebagai bagian dari RTH, pengembangan hutan kota di Surabaya sangat dibutuhkan oleh masyarakat oleh karenanya diperlukan kerjasama antara pemerintah dengan masyarakat dalam pengelolaan dan pengembangan hutan kota. Pemenuhan luasan hutan kota di Surabaya dapat dilakukan dengan mamaksimalkan bentuk dari hutan kota yang telah diatur berdasarkan pada Perda Hutan Kota, yakni dapat dengan bentuk jelaur, mengelompok maupun menyebar.

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