Non-urban Forests Research Articles

Can behaviour and physiology mitigate effects of warming on ectotherms? A test in urban ants.

Global climate change is expected to have pervasive effects on the diversity and distribution of species, particularly ectotherms whose body temperatures depend on environmental temperatures. However, these impacts remain difficult to predict, in part because ectotherms may adapt or acclimate to novel conditions or may use behavioural thermoregulation to reduce their exposure to stressful microclimates. Here we examine the potential for physiological and behavioural changes to mitigate effects of environmental warming on five species of ants in a temperate forest habitat subject to urban warming. We worked in eight urban and eight non-urban forest sites in North Carolina, USA; sites experienced a 1.1°C range of mean summer air temperatures. At each site, we documented species-specific microclimates (ant operative temperatures, Te ) and ant activity on a transect of 14 bait stations at three times of day. In the laboratory, we measured upper thermal tolerance (CTmax ) and thermal preference (Tpref ) for each focal species. We then asked whether thermal traits shifted at hotter sites, and whether ants avoided non-preferred microclimates in the field. CTmax and Tpref did not increase at warmer sites, indicating that these populations did not adapt or acclimate to urban warming. Consistent with behavioural thermoregulation, four of the five species were less likely to occupy baits where Te departed from Tpref . Apparent thermoregulation resulted from fixed diel activity patterns that helped ants avoid the most inappropriate temperatures but did not compensate for daily or spatial temperature variation: Hotter sites had hotter ants. This study uses a novel approach to detect behavioural thermoregulation and sublethal warming in foraging insects. The results suggest that adaptation and behaviour may not protect common temperate forest ants from a warming climate, and highlight the need to evaluate effects of chronic, sublethal warming on small ectotherms.

Comparison of vascular plants in herb layers of ecotones in urban and non-urban forests in Brzesko city (Polish Carpathian foreland)

Abstract Nowadays, human influence is more noticeable in urban and non-urban ecosystems, which, in turn, leads to the transformation of valuable natural resources. This article presents a study on the diversity of species composition of the vascular herb layer species of ecotones in selected urban forests of the city of Brzesko and in forests outside the city. All forests represented the association of oak–hornbeam plant. The results showed that there are inconsistent and consistent vascular plant species with the Tilio-Carpinetum habitat in urban and non-urban forests. Plant species were significantly (c2 test, p < 0.05) found more frequently in the herb layer of non-urban forests than in urban forests. This proves, among other things, that the influence of anthropogenic activity is more on these objects than in forests outside the city.

Frequent infection of urban grass snakes (Natrix natrix) oral cavity with Leptophallus nigrovenosus trematode.

Land disturbances caused by urban development modify and create novel habitats with novel ecological pressures, which in turn may negatively affect remaining wildlife populations, e.g. by altering interspecific interactions. However, it is not clear whether these modified interactions, e.g. parasitism, affect urban wildlife negatively. This is especially true for reptiles, as even parasitism under natural conditions is understudied in this group. We have observed that up to 35% of grass snakes (Natrix natrix) are infected with the trematode Leptophallus nigrovenosus in urban areas of Kraków, while none of snakes sampled in nearby suburban and non-urban forests exhibited this infection. As this trematode typically inhabits the intestine, we suggest that its occurrence in the oral cavity may be a sign of very high infection rates. However, we did not detect any negative effects of observed infection on body size, mass and body condition of affected individuals. On the other hand, competition with other parasite species in suburban and non-urban habitats may be responsible for not detecting L. nigrovenosus in grass snakes from these sites. Nevertheless, interpretation of our findings is difficult, as knowledge on L. nigrovenosus biology is very limited. Our study underlines the necessity to fill the research gap in reptile parasitology.

Climate Adaptive Silviculture for the City: Practitioners and Researchers Co-create a Framework for Studying Urban Oak-Dominated Mixed Hardwood Forests

Urban forested natural areas are an important component of the forest and tree canopy in northeastern United States urban areas. Although similar to native forests in surrounding regions in structure, composition, and function, these natural areas are threatened by multiple, co-occurring biological and climate stressors that are exacerbated by the urban environment. Furthermore, forests in cities often lack application of formal silvicultural approaches reliant upon evidence-based applied ecological sciences. These include both urban- and climate-adapted silvicultural techniques to increase the resilience and sustainability of native forests in cities. With this in mind, we convened a group of urban forest practitioners and researchers from along a latitudinal gradient in the northeastern United States to participate in a workshop focused on co-developing long-term, replicated ecological studies that will underlie the basis for potential silvicultural applications to urban forests. In this article we review the process and outcomes of the workshop, including an assessment of forest vulnerability, and adaptive capacity across the region, as well as shared management goals and objectives. We discuss the social and ecological challenges of managing urban oak-dominated mixed hardwood forests relative to non-urban forests and identify potential examples of urban- and climate-adapted silviculture strategies created by practitioners and researchers. In doing so, we highlight the challenges and need for basic and long-term applied ecological research relevant to silvicultural applications in cities.

Vegetation type and age matter: How to optimize the provision of ecosystem services in urban parks

As cities grow, urban greenspace assumes a more central role in the provision of ecosystem services (ESS). Many ecosystem services depend on the interactions of soil-plant systems, with the quantity and quality of services affected by plant type and age. The question, however, remains whether urban greenspace can be included in the same ecological framework as non-urban greenspace. Our previous studies have contributed towards filling this knowledge gap by investigating the effects of plant functional type (evergreen trees, deciduous trees and lawn) and plant age on soil characteristics and functionality in urban greenspace, offering also a comparison with non-urban greenspace. A total of 41 urban parks and five non-urban forest sites within and adjacent to the cities of Helsinki and Lahti (Finland) were included in this project. Path analyses presented in this contribution, combined with a synthesis of previous findings, offer strong evidence that urban greenspace functions similarly to non-urban greenspace. In particular, plant functional types lead to soil environmental modifications similar to those in non-urban ecosystems. Therefore, vegetation choice upon park construction/implementation can improve the quality and quantity of ESS provided by urban greenspace. However, although vegetation modifies urban greenspace soils with time in a fashion similar to non-urban greenspace, the vegetation type effect is greater in non-urban greenspaces. To conclude, our synthesis of previous studies provides science-based guidance for urban planners who aim to optimize ESS in urban greenspaces.

Seasonality and social factors, but not noise pollution, influence the song characteristics of two leaf warbler species.

Changes in the acoustic signalling of animals occupying urban ecosystems is often associated with the masking effects of noise pollution, but the way in which they respond to noise pollution is not straightforward. An increasing number of studies indicate that responses can be case specific, and some species have been found to respond differently to high levels of natural versus anthropogenic noise, as well as different levels of the latter. While the perception of noise between species may vary with its source, amplitude and temporal features, some species may possess broader environmental tolerance to noise pollution, as they use higher frequency vocalizations that are less masked by low-frequency urban noise. In this study, we explored the song variation of two closely related leaf warblers, the Common Chiffchaff Phylloscopus collybita and the Willow Warbler Phylloscopus trochilus, inhabiting urban green spaces and nonurban forests. The main goal of our study was to evaluate the impact of moderate levels of noise pollution on the songs of species which use higher frequency vocalizations and large frequency bandwidth. Previous studies found that the Common Chiffchaff modified their song in response to intense noise pollution, while no such data is available for the Willow Warbler. However, the majority of urban green spaces, which serve as wildlife hot spots in urban environments are usually polluted with moderate noise levels, which may not mask the acoustic signals of species that communicate with higher frequency. We analysed the spectral and temporal song parameters of both warblers and described the ambient noise present in males’ territories. Additionally, we looked at the social and seasonal aspects of bird song, since there is more than just noise in urban ecosystems which may affect acoustic communication. We found no evidence for noise-related bird song divergence in either species, however, we showed that social factors, time of day and season influence certain Common Chiffchaff and Willow Warbler song characteristics. Lack of noise-related bird song divergence may be due to the relatively low variation in its amplitude or other noise features present within the song frequency range of the studied species. Similar results have previously been shown for a few songbird species inhabiting urban ecosystems. Although in many cases such results remain in the shadow of the positive ones, they all contribute to a better understanding of animal communication in urban ecosystems.

The interaction of land-use history and tree species diversity in driving variation in the aboveground biomass of urban versus non-urban tropical forests

Understanding the drivers of aboveground biomass (AGB) variation in present-day tropical forests can contribute to management strategies that help mitigate against CO2-driven climate change and provide other services related to high AGB. Higher tree diversity can lead to higher woody productivity and carbon storage, but how diversity interacts with land-use history is less certain. We assessed variation in AGB across forests with different land-use histories and surrounding landscapes in southeastern Brazil and how AGB relates to tree diversity per se, while controlling for important factors such as mean functional trait values, stem density and soil fertility. Our findings indicate that aboveground biomass of forests is dependent on land-use history and the landscape matrix in which they occur (urban or non-urban). We found that tree diversity, measured as the average evolutionary divergence among close relatives, shows a strong positive relationship to AGB, but only in old-growth, non-urban forests. This suggests that higher niche complementarity leads to higher AGB in certain ecological contexts. Forests in an urban matrix, and those that regenerated from cropland (in an urban or non-urban matrix), showed weak or insignificant relationships between AGB and diversity, and forests that regenerated from completely denuded landscapes, including soil removal, actually showed a negative relationship between diversity and AGB. Meanwhile, across all forest classes, the abundance-weighted mean wood density of tree species present showed a consistent positive correlation with AGB, indicating the ubiquity of mass-ratio effects on AGB. Overall, our study suggests that strategies for conservation and restoration should account for past land-use and the matrix where forests are inserted, as the distribution of carbon stocks and biodiversity may need to be considered separately.

Genetic structure of urban and non-urban populations differs between two common parid species

Landscape conversions induced by human activities can affect dispersal patterns of various bird species and, as a result, affect genetic structure of their populations. Genetic differentiation of bird populations may be enhanced by habitat variation, especially in urban-non-urban systems. The majority of population genetic studies focus on single species, which inflicts limitations for direct comparisons of genetic responses of avian populations to urbanization. Here, we used a set of microsatellite markers to examine genetic diversity, gene flow and population structure in two common parid species, great tits Parus major and blue tits Cyanistes caeruleus occupying three sites in habitats with contrasting urbanization level in central Poland. We found low but significant divergence of urban park population with both suburban and non-urban forest great tit populations, while no differentiation was found between suburban forest and non-urban forest populations. In contrast, no evidence for genetic differentiation was found between blue tit populations from the urban park, suburban forest and non-urban forest sites. We conclude that great tits and blue tits respond to urbanization-related changes in a different way, which may be a result of different rates of migration and/or dispersal, likely higher in blue tits. Some impact may be also induced by interspecific competition. We suggest that changing the focus of urban genetic research from single to multiple species may provide novel insights into how natural populations respond to the processes of urbanization.

The evolutionary diversity of urban forests depends on their land-use history

Urbanization leads to strong modifications of landscape structure and ecosystem functioning, and urban areas are spreading rapidly. The aim of this study was to investigate how phylogenetic diversity and composition of tree species are affected by urbanization itself and land-use history. We found that species richness, rarefied species richness and phylogenetic diversity are all affected by the land-use history of urban forests. Indeed, forests that regenerated from cropland, and particularly those regenerated from denuded landscapes, showed strong phylogenetic clustering, which was also related to their high perimeter-area ratio. Our analyses of phylogenetic composition show that urban forests without land-use history are compositionally indistinguishable from mature, non-urban forests. These two forest types house a diversity of evolutionary lineages and no specific lineage is a strong indicator of these forest types. In contrast, the two urban forest types with anthropogenic land-use history have a few, distinct lineages that are strongly associated with each of them, respectively. Overall, our results suggest that urban forests without previous land-use can house substantial amounts of angiosperm evolutionary diversity, which highlights the importance of preserving natural forest fragments as cities expand. This study highlights the substantial value of tropical urban forests and the importance of considering information on land-use history, even when studying urban environments.

Land use history drives differences in functional composition and losses in functional diversity and stability of Neotropical urban forests

With urbanisation rapidly transforming our world, a better understanding of how urban ecosystems can contribute to biodiversity conservation is urgently needed. Here, we investigated the functional composition and diversity of plant assemblages in different types of urban forests with the intent to predict the stability of the functions provided by these forests through the functional redundancy and response diversity of species. For this, we used data from non-urban mature forests, remnant urban forests, urban forests regenerated from croplands and urban forests regenerated from soil denudation, all located in the Brazilian Atlantic Forest. Our results showed that species functional composition shifted among urban and non-urban forests. However, functional diversity was lost only in urban forests with some previous use, indicating that the natural regeneration of urban forests after previous land use results in functionally poor forests. Urban forests regenerated from soil denudation (more intense disturbance) had a lower functional diversity. Conversely, urban forests regenerated from cropland (less intense disturbance) showed only a reduction in the number of functions provided. Our analysis also revealed the reduced functional redundancy and response diversity of urban forests with previous land use, which may indicate a greater vulnerability of the functions provided by these forests. Thus, we emphasise in this study the importance of land use history for decision making in urban forest conservation policies and highlight the crucial role of natural remnant urban forests as reservoirs of functional diversity and stability in highly degraded and fragmented landscapes.

Carabidae assemblages in pine forests with different recreation regimes within and outside a megalopolis

The expansion of cities highlights the need for studies of the biodiversity on urban territories and factors affecting the structure and functioning of communities. In 2010–2011, we compared the abundance and diversity of carabid beetles in pine forests of natural origin within the Russian megalopolis Yekaterinburg and outside. To estimate the effects of recreation (R+: trampling, soil compaction, eutrophication) and other urbanization factors (U+: pollution, habitat fragmentation, adventive species), we selected 12 urban and non-urban forest sites with contrasting recreation regimes (U + R+, U + R−, U − R+, U − R−; three sites in each combination). We hypothesized that both urbanization and recreation decrease the abundance and diversity of carabids; the combination of two factors enhances negative effects. The total activity density of carabids and the abundances of all ecological groups increased in urban forests compared to non-urban ones. In urban forests, the Simpson dominance decreased, while Shannon diversity, total species richness, and mean number of species per site increased. The most abundant species in all forests were Pterostichus oblongopunctatus, P. mannerheimii, and P. magus, while Carabus nemoralis was abundant in urban forests only. Proportion (by the number of individuals) of forest species was lower and that of generalists and large-sized species higher in urban forests. High recreation load resulted in lower total abundance and diversity of ground beetles. Negative effect of recreation load on carabids leveled positive effect of urbanization: both abundance and diversity of ground beetles were lower at urban sites with intense recreational use compared to forest sites closed for townspeople.

Comparing climate-growth responses of urban and non-urban forests using L. tulipifera tree-rings in southern Indiana, USA

Urban forests have many positive effects on human health and recreation. However, urban areas can create stressful environments for native trees, leading to increased mortality and an altered ecosystem. Here, we compare growth variability and the climate response from old (>200 years) L. tulipifera growing in an urban forest in Bloomington, IN to surrounding non-urban sites in southern Indiana using dendrochronological techniques. We found that L. tulipifera growing in the urban forest responded similarly with small differences to climate compared to the non-urban sites. Radial growth from urban L. tulipifera had statistically similar correlation values with temperature, soil moisture, and precipitation compared to the trees in non-urban forests. Growth variability between the urban and non-urban L. tulipifera trees showed good agreement through time with the exception of the 20th century, where the urban forest experienced a stand-wide release from competition. Our results indicate that some urban forests may function similarly to non-urban forests from an ecological perspective. These findings suggest management practices from non-urban old-growth forest could be useful for management of rare urban old-growth forests.

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

Summary Results 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.

Carbon Storage and Sequestration of Urban Street Trees in Beijing, China

Anthropogenic carbon dioxide (CO2) emissions from cities have significantly increased over the past several decades along with rapid urbanization. To what extent anthropogenic CO2 emissions generated from cities can be offset through conserving or increasing carbon (C) stored within urban areas themselves is a significant scientific question. The role of urban street trees in offsetting anthropogenic CO2 emissions still remains uncertain. Here, using data from field surveys, tree growth measurements and governmental statistical yearbooks, we estimated the C storage and C sequestration capacity of street trees in Beijing. Results showed that the C density and C sequestration rate in Beijing’s urban street trees were about 1/3 ~1/2 of the corresponding magnitudes of non-urban forests in China. However, the total C sequestration of street trees in Beijing’s urban districts was 3.1±1.8 Gg C yr-1 (1 Gg = 109 g) in 2014, equivalent to only about 0.2% of its annual CO2-equivalent emissions from total energy consumption, indicating a rather limited role in offsetting overall anthropogenic CO2 emissions.

Variability of soil organic carbon stocks and soil CO2 efflux across urban land use and soil cover types

Urban soils are an important soil organic carbon (SOC) store, but soils are also a natural source of carbon dioxide (CO2) due to soil CO2 efflux derived from decomposition and root related respiration. Little is known about the temporal and spatial variability of SOC stocks and soil CO2 efflux in urban areas, in particular in the southern hemisphere. The objectives of our study were to quantify SOC stocks and soil CO2 efflux in tree (urban forests) and grass dominated (parklands) urban ecosystems and to investigate the underlying processes which determine urban SOC stocks and soil CO2 efflux. Soil organic C stocks were quantified to 30cm depth and soil CO2 efflux was determined using a closed chamber technique at 16 sites across Auckland, New Zealand. Vegetation and soil characteristics were measured to 30cm depth at each study plot. In addition, the diurnal and seasonal variability in soil CO2 efflux was assessed at six sites. Median soil organic C stocks (0–10cm) were significantly higher in parkland soils (4.8kgm−2, IQR: 0.9) compared to urban forest soils (2.7kgm−2, IQR: 0.1), which was largely due to higher bulk densities in parkland soils. In contrast, median soil CO2 efflux was not significantly different between parklands (5.2μmolm−2s−1, IQR: 0.8) and urban forests (4.5μmolm−2s−1, IQR: 1.9) sites. This suggests that increasing soil bulk densities without restricting root growth may enhance SOC stocks without increasing soil CO2 efflux. Soil temperature and soil water content explained 54% (urban parkland) and 71% (urban forests) of the temporal variation in soil CO2 efflux. Urban SOC stocks and soil CO2 efflux were similar to non-urban forests and grasslands in New Zealand, highlighting the importance of considering urban soils when assessing SOC stocks and soil CO2 efflux.

Plasma Metabolites and Mass Changes of Migratory Landbirds Indicate Adequate Stopover Refueling in a Heavily Urbanized Landscape

Abstract. Large concentrations of migrating landbirds in cities have been well documented, but the refueling conditions urban stopover sites provide are almost entirely unknown. We compared plasma triglyceride (indicator of mass gain) and B-OH-butyrate (indicator of mass loss) concentrations in landbirds in three New York City forests to those of conspecifics in two less disturbed, non-urban forests outside the city to evaluate the quality of urban stopover habitats. We quantified diurnal mass gains with regressions of body mass and capture time and measured arthropod biomass in leaf litter to assess food abundance for ground-foraging insectivores. Metabolite concentrations in Ovenbirds (Seiurus aurocapilla) at urban and non-urban sites did not differ during spring or autumn. In autumn, triglyceride levels of Swainson's Thrushes (Catharus ustulatus) indicated significantly higher refueling rates at the urban sites. In the Yellow-rumped Warbler (Dendroica coronata), butyrate was lowest out-side the city, s...

The abundance of hollow-bearing trees in urban dry sclerophyll forest and the effect of wind on hollow development

Anthropogenic change, particularly in urban landscapes, has resulted in the fragmentation of indigenous vegetation into often small isolated ‘remnants’. The persistence of arboreal fauna in small urban remnants in part depends on the distribution and abundance of habitat resources within the remnant. We surveyed 44 small (<2.5 ha) eucalypt remnants located within the south-eastern suburbs of metropolitan Melbourne to ascertain the abundance of hollow-bearing trees, an important ecological resource. The probability of a live or dead tree containing a hollow was investigated in relation to site variables that influenced exposure to wind, a factor thought to increase the propensity of hollow formation in eucalypt trees. A total of 2678 live and 224 dead eucalypt trees were surveyed, of which 350 live (12%) and 70 dead (31%) trees were hollow-bearing. The probability of a tree being hollow-bearing was strongly positively associated with the diameter of the tree, however, past management practices have lead to a paucity of large (>80 cm DBH) trees in small urban remnants. We found that variables that measured exposure to wind were correlated with the chance that a live tree will be hollow-bearing while reducing the chance that a dead tree will be hollow-bearing. Although highly variable, the number of hollow-bearing trees contained within small urban remnants (mean of 5.8 ha −1) fell well below that contained in areas of un-logged non-urban forest. Our results indicated that large numbers of hollow-bearing tree are unlikely to be recruited into urban remnants for a significant time-span and as such there is an increased importance placed on maintaining the current inventory of hollow-bearing trees for the maintenance of biodiversity in urban areas.

The soil seed bank and its relationship to the aboveground vegetation in deciduous forests in New York City

The soil seed bank was studied in two deciduous forests in Bronx (New York City), NY. The purpose of this study was to determine how the biotic andabiotic differences between urban and rural forests arereflected in urban forest seed banks. Soil samples werecollected in two consecutive years and monitored for emergencein the greenhouse over two years. In 1993, the mean number ofemergents ranged from 4636 to 5373 m-2 (excluding ferns), or from 6972 to 9651 m-2 (including ferns). In 1994, the mean number of emergents ranged from 1656 to 2013 m-2 (excluding ferns), or from 5019 to 5992 m-2 (including ferns). Graminoids and fernscombined accounted for approximately 70% of all emergents eachyear. Three taxa, Rubus spp., Betula lenta, and Liriodendron tulipifera, comprised 60–80% of the woody emergents and were theonly woody taxa to exhibit delayed germination. A substantialnumber of forbs, graminoids and ferns (15–50%) exhibiteddelayed germination. The nonnative woody species Ailanthusaltissima, Morus alba, and Celastrus orbiculatus were absentfrom the aboveground vegetation of some forest plots yet werepresent at low densities in the seed bank. A greater meandensity of emergents and the presence of nonnative species arethe main differences between the seed banks of these urbanforests and those reported for similar nonurban forests in thisregion.

Comparative anałysis of dominant species in springtail communities (Hexapoda: Collembola) of urban greens in Moscow and Warsaw

Authors compared collembolan communities dwelling urboecosystems of Eastern and Central Europe using urban greens of Moscow and Warsaw as an example. Two types of urban biotopes (parks and street lawns) were analysed in comparison to non-urban forests and meadows. The regional peculiarities of springtail communities in the same type of urboecosystems were investigated. It was revealed that communities of soil-dwelling Collembola in parks of different cities are more similar than those of street lawns.

Monitoring urban forest canopy cover using satellite imagery

The urban forest is being recognized for not only aesthetic benefits but for carbon storage, air filtration, noise reduction and wildlife habitat. This acknowledgment has resulted in actions supporting the urban forest ranging from federal funding of state urban forestry programs to grassroot urban tree planting/advocacy groups. As with any forestry related project, there is an interest to know how much, and where the vegetation exists. Landsat satellite imagery (Thematic Mapper) has been proved effective for mapping the density (crown closure) of non-urban forests. This project uses this same imagery to map the density of the urban forest within the City of Portland, Oregon. In a second phase, this map along with other mapped information will form a model of the city for the purpose of locating areas that could sustain more vegetation. (This work is currently in progress and to date has produced a preliminary map of urban forest density using the imagery.) Computer image processing of the satellite imagery provides the basis for a city-wide map of urban forest density. Color infrared aerial photos supplies the initial ground truth for vegetation density and to also distinguish among trees, shrubs and grass. Particular emphasis is put on residential lands containing yard and street trees as mapping of urban natural areas (patches of remaining forest and meadows) has already been accomplished by other mapping projects. The final map of vegetation density will be a digital map ready for use within a geographic information sysem (GIS). This will start the second phase of the project where a more representative model of the urban environment will be constructed by joining the vegetation map with other GIS maps of population streets, tax parcels and zoning. The forest density map by itself will certainly show areas that are below average density. However, by making spatial correlations between the forest density map and population density, street density, tax parcel density and zoning, it is hoped to improve the accuracy in showing areas that could support more vegetation.