scholarly journals Evaluation of Forest Edge Structure and Stability in Peri-Urban Forests

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 338
Author(s):  
David Hladnik ◽  
Andrej Kobler ◽  
Janez Pirnat
Keyword(s):  
Urban Forest ◽  
Residential Buildings ◽  
Canopy Structure ◽  
Urban Forests ◽  
Forest Edge ◽  
Canopy Height ◽  
Forest Edges ◽  
Forest Patches ◽  
Forest Patch ◽  
Edge Structure

In the presented research, we studied the forest edge structure of urban and peri-urban forests on the outskirts of Ljubljana (Slovenia) consisting of a number of patches covering the collective surface of 1884 ha. They differ from each other according to the degree of fragmentation and by the share of the interior forest area. On the basis of LiDAR data, we conducted an analysis of the edges of the persistent forest patches and estimated them with regard to the land use they bordered on. The horizontal estimation of forest edges and the changes of forest edges, in the last decades, were estimated using digital orthophoto images of cyclic aerial surveys of Slovenia, from 1975 to 2018. The data, provided by LiDAR, were used to obtain an accurate estimate of forest edges and the metrics of their vertical canopy structure. On the basis of the canopy height model (CHM), we determined the height classes, the heights of the tallest trees, and indices of canopy height diversity (CHD) as variables subjected to a k-means cluster analysis. To determine the forest edge and trees stability, their heights and diameters at breast height (DBH) were measured and their canopy length and h/d (height/diameter) dimension ratios were estimated. In the study area of the Golovec forest patch, more than half of the forest edge segments (56%) border on residential buildings. After the construction of buildings, 54% of the newly formed forest edges developed a high and steep structure. Unfavorable h/d dimension ratio was estimated for 16% of trees, more among the coniferous than among the deciduous trees. Similar characteristics of newly formed forest edges bordering on built-up areas were determined in other sub-urban forest patches, despite the smaller share of such forest edges (19% and 10%, respectively). Tools and methods presented in the research enable the implementation of concrete silvicultural practices in a realistic time period and extend to ensure that adequate forestry measures are taken to minimize possible disturbances.

scholarly journals The Spatial Response of Male Hooded Warblers to Edges in Isolated Fragments

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 595-600 ◽  
Author(s):  
D. Ryan Norris ◽  
Bridget J. M. Stutchbury ◽  
Trevor E. Pitcher
Keyword(s):  
Space Use ◽  
Forest Edge ◽  
Time Of Day ◽  
Forest Edges ◽  
Forest Patches ◽  
Wilsonia Citrina ◽  
Use Patterns ◽  
Continuous Forest ◽  
Hooded Warblers ◽  
Occupancy Rates

Abstract We tested whether Hooded Warblers (Wilsonia citrina) avoided abrupt forest edges by radiotracking males breeding in small, isolated forest patches (0.5–2.0 ha) in northwest Pennsylvania. Because territory edges were synonymous with abrupt forest edges in all cases, we compared space use patterns with males radiotracked in a nearby continuous forest (150 ha), where we defined edge from territorial boundaries. Based on the proportion of edge to core area, males in both habitats avoided the area within 20 m of the edge, implying that males responded to the presence of territory edge rather than forest edge. Surprisingly, however, males in isolated fragments used the edge area significantly more than males in continuous forest, even when measured against the relative amount of edge area within each territory. Elevated levels of edge use were not related to distance of nests to edges, nest stage, or time of day. We conclude that the presence of physical edges is not the sole determinant of territorial space use in this species and there are likely additional social factors influencing occupancy rates in small, isolated woodlots. Therefore, definitions of forest-interior species based on edge use need to be reconsidered.

scholarly journals Adaptive Framework for the Delineation of Homogeneous Forest Areas Based on LiDAR Points

2019 ◽  
Vol 11 (2) ◽  
pp. 189 ◽  
Author(s):  
Moritz Bruggisser ◽  
Markus Hollaus ◽  
Di Wang ◽  
Norbert Pfeifer
Keyword(s):  
Laser Scanning ◽  
Water Cycle ◽  
Canopy Structure ◽  
Point Clouds ◽  
Forest Patches ◽  
Forest Patch ◽  
Flexible Framework ◽  
Foliage Density ◽  
The One ◽  
Forest Conditions

We propose a flexible framework for automated forest patch delineations that exploits a set of canopy structure features computed from airborne laser scanning (ALS) point clouds. The approach is based on an iterative subdivision of the point cloud using k-means clustering followed by an iterative merging step to tackle oversegmentation. The framework can be adapted for different applications by selecting relevant input features that best measure the intended homogeneity. In our study, the performance of the segmentation framework was tested for the delineation of forest patches with a homogeneous canopy height structure on the one hand and with similar water cycle conditions on the other. For the latter delineation, canopy components that impact interception and evapotranspiration were used, and the delineation was mainly driven by leaf area, tree functional type, and foliage density. The framework was further tested on two scenes covering a variety of forest conditions and topographies. We demonstrate that the delineated patches capture well the spatial distributions of relevant canopy features that are used for defining the homogeneity. The consistencies range from R 2 = 0 . 84 to R 2 = 0 . 86 and from R 2 = 0 . 80 to R 2 = 0 . 91 for the most relevant features in the delineation of patches with similar height structure and water cycle conditions, respectively.

scholarly journals Study of the Spatiotemporal Variation Characteristics of Forest Landscape Patterns in Shanghai from 2004 to 2014 Based on Multisource Remote Sensing Data

2018 ◽  
Vol 10 (12) ◽  
pp. 4397 ◽  
Author(s):  
Yang Li ◽  
Chunyan Xue ◽  
Hua Shao ◽  
Ge Shi ◽  
Nan Jiang
Keyword(s):  
Spatial Distribution ◽  
Landscape Pattern ◽  
Urban Forest ◽  
Urban Forests ◽  
Urban Ecosystem ◽  
Landscape Patterns ◽  
Forest Landscape ◽  
Forest Patches ◽  
Forest Coverage ◽  
High Degree

The landscape patterns of urban forests not only reflect the influence of urbanization on urban forests, but also determines its function in urban ecosystem services. In the case of mastering the overall forest landscape pattern of a city, a study of the structure of urban forest landscapes at different scales and in urbanized regions is beneficial to a comprehensive understanding of the forest characteristics of a city. In the present study, an attempt was made to map and monitor the spatio-temporal dynamics of an urban forest in Shanghai from 2004 to 2014 using remote sensing techniques. Methods of landscape ecology analysis are followed to quantify the spatiotemporal patterns of an urban forest landscape by urban and rural gradient regionalization. The results show that the spatial structure of an urban forest landscape is essentially consistent with an urban landscape pattern. Due to strong interference from human activities, the ecological quality of forest landscapes is low. At the landscape level, the urban forest coverage rate increased from 11.43% in 2004 to 16.02% in 2014, however, the number of large patches decreased, there was a high degree of urban forest landscape fragmentation, landscape connectivity was poor, landscape patch boundaries were uniform, and weak links were present between ecological processes. Different urban and rural gradient division methods exhibit obvious gradient characteristics along the urban–rural gradient in Shanghai. The regional differences in the urban forest landscape ecological characteristics have further increased as a result of urban planning and zoning. The total amount of urban forest is located closer to the urban center, which has the smallest total amount of forest; however, in terms of urban forest coverage, the suburbs have more coverage than do the outer suburbs and the central urban areas. The urban forest landscape’s spatial distribution area is evidently different. Urbanization affects the areas closest to urban residential areas, which are markedly disturbed by humans, and the urban forest landscape has a high degree of fragmentation. The forest patches have become divided and unconnected, and the degree of natural connectivity has gradually decreased over the past 10 years. At the landscape class level, broadleaf forests are dominant in Shanghai, and their area exhibits an increasing trend; shrublands and needleleaf forests, however, show a decreasing trend. Compared with other forest types, the spatial distribution of broadleaf forest is concentrated in the suburbs, and the aggregation effect is relatively apparent. From the perspective of urban forest landscape pattern aggregation characteristics in Shanghai, the spatial distribution of urban forest landscape point patterns in the study area exhibit extremely uneven characteristics. The point density of urban forest patches larger than 1 ha in Shanghai increased from 2004 to 2014. However, the total number of patches with areas larger than 5 ha decreased, and this decrease plays an important role in the ecological environment. In the past 10 years, the concentration characteristics of urban forests with large patches has gradually decreased. In 2014, the urban forest landscapes decreased by 5 km compared to the intensity of aggregates in 2004, which also indicates that urban forests in Shanghai tend to be fragmented. The results of this study can be useful to help improve urban residents’ living environments and the sustainable development of the urban ecosystem, and they will also be vital to future management.

Distribution of arthropods in relation to forest patch size, edge, and stand characteristics

1998 ◽  
Vol 28 (7) ◽  
pp. 1068-1072 ◽  
Author(s):  
Jukka Jokimäki ◽  
Esa Huhta ◽  
Juhani Itämies ◽  
Pekka Rahko
Keyword(s):  
Patch Size ◽  
Forest Edge ◽  
Total Abundance ◽  
Forest Patches ◽  
Forest Patch ◽  
Edge Orientation ◽  
Open Land ◽  
Net Method ◽  
Deciduous Shrubs ◽  
Stand Characteristics

We studied the abundance of arthropods in relation to forest patch size, edge orientation, distance from the forest - open-land edge, and stand characteristics in pine-dominated forests in northern Finland. Arthropod samples were collected using the sweep-net method. The total catch of arthropods, catches from the field layer and deciduous shrubs, the numbers of flying arthropods, small (<1 mm) arthropods, and the numbers of seven different arthropod taxa (viz. Linyphiidae (Arachnida), Cicadellidae (Homoptera), Diptera, Brachycera (Diptera), Nematocera (Diptera), and Hymenoptera and Ichneumonidae (Hymenoptera)) were lower in large forest patches (>5 ha) than in small patches (5 ha). The edge orientation and the type of adjacent open area (clearcut area or treeless mire) had no impact on the abundance of arthopods in the patches. The distance from the forest edge affected the total abundance of arthropods, small arthropods, flying arthropods, and Coleoptera (especially Cantharidae) in that all decreased in number from the forest edge to the interior of the forest stand. The abundance of many arthropod taxa correlated positively with the numbers of saplings, deciduous shrubs, and spruces. It was clear that the existence of these vegetation characteristics mainly explained the observed differences in the abundance of arthropods between forest patches of different sizes and also between forest edges and stand interiors.

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 Measuring Multi-Scale Urban Forest Carbon Flux Dynamics Using an Integrated Eddy Covariance Technique

2019 ◽  
Vol 11 (16) ◽  
pp. 4335 ◽  
Author(s):  
Kaidi Zhang ◽  
Yuan Gong ◽  
Francisco J. Escobedo ◽  
Rosvel Bracho ◽  
Xinzhong Zhang ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Green Infrastructure ◽  
Urban Forest ◽  
Scale Effects ◽  
Atmospheric Stability ◽  
Urban Forests ◽  
Co2 Flux ◽  
Forest Patches ◽  
Multi Scale ◽  
Co2 Dynamics

The multi-scale carbon-carbon dioxide (C-CO2) dynamics of subtropical urban forests and other green and grey infrastructure types were explored in an urbanized campus near Shanghai, China. We integrated eddy covariance (EC) C-CO2 flux measurements and the Agroscope Reckenholz-Tänikon footprint tool to analyze C-CO2 dynamics at the landscape-scale as well as in local-scale urban forest patches during one year. The approach measured the C-CO2 flux from different contributing areas depending on wind directions and atmospheric stability. Although the study landscape was a net carbon source (2.98 Mg C ha−1 yr−1), we found the mean CO2 flux in urban forest patches was −1.32 μmol m−2s−1, indicating that these patches function as a carbon sink with an annual carbon balance of −5.00 Mg C ha−1. These results indicate that urban forest patches and vegetation (i.e., green infrastructure) composition can be designed to maximize the sequestration of CO2. This novel integrated modeling approach can be used to facilitate the study of the multi-scale effects of urban forests and green infrastructure on CO2 and to establish low-carbon emitting planning and planting designs in the subtropics.

Forest edge structure as a shaping factor of understorey vegetation in urban forests in Finland

2009 ◽  
Vol 257 (2) ◽  
pp. 712-722 ◽  
Author(s):  
Leena Hamberg ◽  
Susanna Lehvävirta ◽  
D. Johan Kotze
Keyword(s):  
Urban Forests ◽  
Forest Edge ◽  
Understorey Vegetation ◽  
Edge Structure

scholarly journals Forest Structure and Anthropogenic Disturbances Regulate Plant Invasion in Urban Forests

2021 ◽  
Author(s):  
Prakash Chandra Aryal ◽  
Chandramani Aryal ◽  
Kiran Bhusal ◽  
Devendra Chapagain ◽  
Man Kumar Dhamala ◽  
...  
Keyword(s):  
Invasive Species ◽  
Forest Structure ◽  
Urban Forest ◽  
Urban Forests ◽  
Principal Component ◽  
Anthropogenic Disturbances ◽  
Invasion Success ◽  
Anthropogenic Factors ◽  
Forest Patches ◽  
Factors Affecting

Abstract Urban forest ecosystems, the structure and functions therein, are subjected to anthropogenic disturbances. Native and sensitive species from those forests might be lost due to such disturbances. At the same time, supplemented anthropogenic resources might create opportunities for exotic and invasive species. Although, invasive species are considered as one of the major threats to the urban biodiversity and ecosystems, the researches on invasion dynamics in the Himalayas have mostly focused on the impacts of invasion on forest structure and productivity. This study aims to understand the influence of forest structure and anthropogenic factors in invasion success that are poorly covered in the existing literature. We selected 11 urban forest patches for the study considering the presence-absence of selected invasive species and structural attributes. We used Principal Component Analysis (PCA) to reduce co-linearity in the covariates and generalized linear mixed effects model (GLMM) to identify the factors affecting the invasion success. We found that the structural attributes of the forests and anthropogenic disturbances regulated invasion success in urban forests. This implies that maintaining urban forest structural attributes, especially maintaining the stands with large-sized trees, are essential to regulate and control invasion in the context of urbanization.

Island biogeography theory and the urban landscape: stopover site selection by the silver-haired bat (Lasionycteris noctivagans)

2022 ◽  
Author(s):  
Hannah Adams ◽  
Liam McGuire
Keyword(s):  
Island Biogeography ◽  
Urban Forest ◽  
Natural Habitat ◽  
Negative Relationship ◽  
Urban Forests ◽  
Forest Patches ◽  
Stopover Site ◽  
Island Biogeography Theory ◽  
The Impact ◽  
Lasionycteris Noctivagans

Many migratory bats require forested sites for roosting and foraging along their migration path, but increased urbanization and intensive agricultural practices may reduce the availability of stopover sites. Urban forests may provide important stopover habitat, maintaining landscape connectivity in regions where the majority of natural habitat has been cleared for development. Island biogeography theory can be applied to urbanized temperate forest biomes where small urban forests represent islands separated from the larger “mainland” forest. We used acoustic monitoring during the fall migration period to investigate the use of urban forest habitat by the migratory species Lasionycteris noctivagans Le Conte, 1831. We predicted that recorded activity would have a positive relationship with forest patch area and shape and a negative relationship with isolation from other forest patches, as suggested by island biogeography theory. We observed greater activity at larger forest patches, and although relationships for shape and isolation were not statistically supported the observed patterns were consistent with predictions. Our results demonstrate the need for more in-depth research on the habitat requirements for both migratory and resident bat species and the impact that ongoing urbanization has on local bat populations.

scholarly journals Influence of Scale Effect of Canopy Projection on Understory Microclimate in Three Subtropical Urban Broad-Leaved Forests

2021 ◽  
Vol 13 (18) ◽  
pp. 3786
Author(s):  
Xueyan Gao ◽  
Chong Li ◽  
Yue Cai ◽  
Lei Ye ◽  
Longdong Xiao ◽  
...  
Keyword(s):  
Scale Effect ◽  
Laser Scanning ◽  
Urban Forest ◽  
Canopy Structure ◽  
Urban Forests ◽  
Small Scale ◽  
Strong Negative Correlation ◽  
Vegetation Growth ◽  
Broad Leaved Forest ◽  
Leaved Forest

The canopy is the direct receiver and receptor of external environmental variations, and affects the microclimate and energy exchange between the understory and external environment. After autumn leaf fall, the canopy structure of different forests shows remarkable variation, causes changes in the microclimate and is essential for understory vegetation growth. Moreover, the microclimate is influenced by the scale effect of the canopy. However, the difference in influence between different forests remains unclear on a small scale. In this study, we aimed to analyze the influence of the scale effect of canopy projection on understory microclimate in three subtropical broad-leaved forests. Three urban forests: evergreen broad-leaved forest (EBF), deciduous broad-leaved forest (DBF), and mixed evergreen and deciduous broad-leaved forest (MBF) were selected for this study. Sensors for environmental monitoring were used to capture the microclimate data (temperature (T), relative humidity (RH), and light intensity (LI)) for each forest. Terrestrial laser scanning was employed to obtain the canopy projection intensity (CPI) at each sensor location. The results indicate that the influence range of canopy projection on the microclimate was different from stand to stand (5.5, 5, and 3 m). Moreover, there was a strong negative correlation between T and RH, and the time for T and LI to reach a significant correlation in different urban forests was different, as well as the time for RH and LI during the day. Finally, the correlation between CPI and the microclimate showed that canopy projection had the greatest effect on T and RH in MBF, followed by DBF and EBF. In conclusion, our findings confirm that canopy projection can significantly affect understory microclimate. This study provides a reference for the conservation of environmentally sensitive organisms for urban forest management.

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