Adam Berland | Ball State University (original) (raw)

Papers by Adam Berland

BioScience, 2016

This article brings together the concepts of shrinking cities-the hundreds of cities worldwide ex... more This article brings together the concepts of shrinking cities-the hundreds of cities worldwide experiencing long-term population loss-and ecology for the city. Ecology for the city is the application of a social-ecological understanding to shaping urban form and function along sustainable trajectories. Ecology for the shrinking city therefore acknowledges that urban transformations to sustainable trajectories may be quite different in shrinking cities as compared with growing cities. Shrinking cities are well poised for transformations, because shrinking is perceived as a crisis and can mobilize the social capacity to change. Ecology is particularly well suited to contribute solutions because of the extent of vacant land in shrinking cities that can be leveraged for ecosystem-services provisioning. A crucial role of an ecology for the shrinking city is identifying innovative pathways that create locally desired amenities that provide ecosystem services and contribute to urban sustainability at multiple scales.

Cities and the Environment, 2015

Understanding the spatial distribution of environmental amenities requires consideration of socia... more Understanding the spatial distribution of environmental amenities requires consideration of social and biogeophysical factors, and how they interact to produce patterns of environmental justice or injustice. In this study, we explicitly account for terrain, a key local environmental factor, while assessing whether tree canopy is distributed equally in Cincinnati, Ohio, USA. We conducted separate analyses for all land and for residential land only. For all land, terrain alone accounted for 59% of the variation in tree canopy cover. In our spatial autoregressive model, socioeconomic variables describing race, wealth, and education did not explain significant variation in canopy cover. In other words, terrain is the primary factor related to tree canopy in Cincinnati. In our analysis of residential land only, terrain was again the dominant predictor of tree canopy cover, and percent black population and median home value were also positive, significant explanatory variables. Tree canopy was abundant in two hilly areas with dissimilar socioeconomic characteristics, with proportionally larger black populations in the western hills and higher home values in the eastern hills. In summary, the overwhelming importance of terrain may obscure subtler patterns between tree canopy and socioeconomic variables. Although general social processes may drive environmental injustice across disparate cities, our study highlights the need to account for local biogeophysical context.

Urban forestry professionals can use online tools to learn a lot about a site before a field visi... more Urban forestry professionals can use online tools to learn a lot about a site before a field visit. For example, Google Street ViewTM (GSV) provides street-level panoramic photographs that can be used to preview a street tree that is slated for maintenance or removal so that an arborist can anticipate what equipment will be needed in the field. Using street-level imagery, a person may be able to record the tree's street address, identify its species, estimate its size, note overhead wire conflicts, and so on. If this is possible for one tree, could we reliably use online resources like GSV to conduct an inventory of street trees across an entire city?

These digital resources can be used to facilitate virtual street tree surveys. Four files are inc... more These digital resources can be used to facilitate virtual street tree surveys. Four files are included: (1) GSV_overview_document – a user manual describing the data collection process using Google Street View to inventory trees; (2) DBH_reference_guide – reference material for visually estimating tree diameter at breast height (DBH); (3) Tree_ID_guide – identification guide for the most common street trees in the Midwest U.S.; and (4) Tree_Data_Collection_Form – a spreadsheet for recording street tree data.

Urban trees provide an abundance of benefits to city residents. Information about the geographic ... more Urban trees provide an abundance of benefits to city residents. Information about the geographic distribution of urban trees is critical to ensure equitable access to these benefits. Street trees are unique among urban trees because they are often managed by municipalities as a public resource, but they are challenging to manage in part because they are spatially dispersed across a city in close proximity to private property. While street tree inventory data sets are costly to generate, they provide important information to understand the spatial distribution of trees in the city and to plan for ongoing street tree management. Here, we utilize two street inventories collected at a 13-year interval to assess patterns and changes in municipal street tree distributions in Center Township, Indianapolis, IN. In the township as a whole, tree density, basal area, and taxonomic diversity increased markedly over time. Spatial autoregressive models were constructed to examine the relationship between socioeconomic characteristics and street tree population dynamics. Concurrent, legacy, and change models revealed significant associations between socioeconomic factors and street tree distributions. Specifically, tree density and taxonomic diversity were positively associated with educational attainment, and increases in tree density over time were negatively associated with the percent of the population that identifies as black or African American. Results suggest that despite overall increases in street trees, persistent inequalities in street tree access should be addressed in central Indianapolis neighborhoods.

Frontiers in Ecology and Evolution

Nature Ecology & Evolution

Nature Ecology & Evolution

Ecosystems, 2011

Dynamic relationships among climate, disturbance, and vegetation affect the spatial configuration... more Dynamic relationships among climate, disturbance, and vegetation affect the spatial configuration and composition of ecological communities. Paleoecological records indicate the importance of such relationships in Minnesota's Big Woods (BW) region, where isolated hardwood forest populations expanded to regional dominance after AD 1250. We used LANDIS-II to model the BW forest expansion, and conducted simulation experiments that isolated the important ecological factors in this regional change. In our simulations, BW forest expanded at approximately 15 m per year to achieve regional dominance within 600 years, which is comparable to empirical records. The distribution of the BW depended on the locations of scattered pre-existing tree populations that were sheltered from previous severe fire regimes by firebreaks. During the simulated spread of the tree populations, however, the presence or absence of firebreaks did not further influence vegetation pattern. When we assumed a fire rotation of 10-13 years in grasslands/woodlands and more than 400 years in BW, the feedback between fireresistant BW fuels and fire severity caused fire severity to decline in a time frame consistent with sedimentary data. In our simulations, seed dispersal from core initial populations caused forest expansion, changed fuel loads, and thus reduced fire severity-not the other way around as has been commonly proposed. Forest expansion was slowed by fire, but species' life history attributes, namely seed dispersal distances and maturity ages, asynchronous successional dynamics across many stands, and landscape history were at least as important in the temporal and spatial patterns of the regional response to climate change.

BioScience, 2016

This paper brings together the concepts of shrinking cities – the hundreds of cities worldwide ex... more This paper brings together the concepts of shrinking cities – the hundreds of cities worldwide experiencing long-term population loss – and ecology for the city. Ecology for the city is the application of social-ecological understanding to shaping urban form and function along sustainable trajectories. Ecology for the shrinking city thus acknowledges that urban transformations to sustainable trajectories may be quite different in shrinking cities as compared to growing cities. Shrinking cities are well poised for transformations because shrinking is perceived as a crisis and can mobilize the social capacity to change. Ecology is particularly well-suited to contribute solutions due to the extent of vacant land in shrinking cities that can be leveraged for ecosystem services provisioning. A critical role of an ecology for the shrinking city is identifying innovative pathways that create locally desired amenities that provide ecosystem services and contribute to urban sustainability at multiple scales.

Arboriculture & Urban Forestry, 2016

Tree City USA is a national program that recognizes municipal commitment to community forestry. I... more Tree City USA is a national program that recognizes municipal commitment to community forestry. In return for meeting program requirements, Tree City USA participants expect social, economic, and/or environmental benefits. Understanding the geographic distribution and socioeconomic characteristics of Tree City USA communities at the national scale can offer insights into the motivations or barriers to program participation, and provide context for community forestry research at finer scales. In this study, we assessed patterns in Tree City USA participation for all US communities with more than 2,500 people according to geography, community population size, and socioeconomic characteristics such as income, education, and race. Nationally, 23.5% of communities studied were Tree City USA participants, and this accounted for 53.9% of the total population in these communities. Tree City USA participation rates varied substantially by US region, but in each region participation rates were higher in larger communities, and long-term participants tended to be larger communities than more recent enrollees. In logistic regression models, owner occupancy rates were significant negative predictors of Tree City USA participation, education and percent white population were positive predictors in many US regions, and inconsistent patterns were observed for income and population age. Our findings indicate that communities with smaller populations, lower education levels, and higher minority populations are underserved regionally by Tree City USA, and future efforts should identify and overcome barriers to participation in these types of communities.

Landscape and Urban Planning, 2017

Urban impervious surfaces convert precipitation to stormwater runoff, which causes water quality ... more Urban impervious surfaces convert precipitation to stormwater runoff, which causes water quality and quantity problems. While traditional stormwater management has relied on gray infrastructure such as piped conveyances to collect and convey stormwater to wastewater treatment facilities or into surface waters, cities are exploring green infrastructure to manage stormwater at its source. Decentralized green infrastructure leverages the capabilities of soil and vegetation to infiltrate, redistribute, and otherwise store stormwater volume, with the potential to realize ancillary environmental, social, and economic benefits. To date, green infrastructure science and practice have largely focused on infiltration-based technologies that include rain gardens, bioswales, and permeable pavements. However, a narrow focus on infiltration overlooks other losses from the hydrologic cycle, and we propose that arboriculture – the cultivation of trees and other woody plants – deserves additional consideration as a stormwater control measure. Trees interact with the urban hydrologic cycle by intercepting incoming precipitation, removing water from the soil via transpiration, enhancing infiltration, and bolstering the performance of other green infrastructure technologies. However, many of these interactions are inadequately understood, particularly at spatial and temporal scales relevant to stormwater management. As such, the reliable use of trees for stormwater control depends on improved understanding of how and to what extent trees interact with stormwater, and the context-specific consideration of optimal arboricultural practices and institutional frameworks to maximize the stormwater benefits trees can provide.

Urban foresters routinely emphasize the importance of taxonomic diversity to reduce the vulnerabi... more Urban foresters routinely emphasize the importance of taxonomic diversity to reduce the vulnerability of tree assemblages to invasive pests, but it is unclear to what extent diversity reduces vulnerability to polyphagous (i.e., generalist) pests. Drawing on field data from seven communities in metropolitan Cincinnati, Ohio, USA, we tested the hypothesis that communities with higher diversity would exhibit lower vulnerability to the polyphagous Asian longhorned beetle, which currently threatens the region. Based on street tree compositions and the beetle's host preferences, Asian longhorned beetle threatened up to 35.6% of individual street trees and 47.5% of the total basal area across the study area, but we did not see clear connections between taxonomic diversity and beetle vulnerability among study communities. For example, the city of Fairfield was among the least diverse communities but had the lowest proportion of trees vulnerable to Asian longhorned beetle, whereas the city of Wyoming exhibited high diversity and high vulnerability. On the other hand, Forest Park aligned with our original hypothesis, as it was characterized by low diversity and high vulnerability. Our results demonstrate that relatively high taxonomic diversity in street tree assemblages does not necessarily lead to reduced vulnerability to a polyphagous pest. Considering the threats posed by polyphagous pests, selecting a set of relatively pest resistant trees known to perform well in urban areas may promote long-term stability better than following simple heuristics for maximizing taxonomic diversity, but further study is warranted.

Sustainability, 2015

Ecological Footprint Analysis (EFA) is appealing as a metric of sustainability because it is stra... more Ecological Footprint Analysis (EFA) is appealing as a metric of sustainability because it is straightforward in theory and easy to conceptualize. However, EFA is difficult to implement because it requires extensive data. A simplified approach to EFA that requires fewer data can serve as a perfunctory analysis allowing researchers to examine a system with relatively little cost and effort. We examined whether a simplified approach using freely available data could be applied to Puerto Rico, a densely populated island with limited land resources. Forty-one years of data were assembled to compute the ecological footprint from 1970 to 2010. According to EFA, individuals in Puerto Rico were moving toward sustainability over time, as the per capita ecological footprint decreased from 3.69 ha per capita (ha/ca) in 1970 to 3.

Urban Ecosystems, 2015

ABSTRACT Managing urban green space as part of an ongoing social-ecological transformation poses ... more ABSTRACT Managing urban green space as part of an ongoing social-ecological transformation poses novel governance issues, particularly in post-industrial settings. Urban green spaces operate as small-scale nodes in larger networks of ecological reserves that provide and maintain key ecosystem services such as pollination, water retention and infiltration, and sustainable food production. In an urban mosaic, a myriad of social and ecological components factor into aggregating and managing land to maintain or increase the flow of ecosystem services associated with green spaces. Vacant lots (a form of urban green space) are being repurposed for multiple functions, such as habitat for biodiversity, including arthropods that provide pollination services to other green areas; to capture urban runoff that eases the burden on ageing wastewater systems and other civic infrastructure; and to reduce urban heat island effects. Because of the uncertainty and complexities of managing for ecosystem services in urban settings, we advocate for a governance approach that is adaptive and iterative in nature—adaptive governance—to address the ever changing social order underlying postindustrial cities and offer the rise of land banks as an example of governance innovation.

Urban Forestry & Urban Greening, 2014

Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Mu... more Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Municipal street trees are crucial components of urban green infrastructure because they provide stormwater interception benefits and other ecosystem services. Thus, it is important to understand the patterns and drivers of structural heterogeneity in urban street tree assemblages. In this study, we compared the forest structure of street trees across nine communities along both geographic and demographic gradients in metropolitan Cincinnati, Ohio, USA. Specifically, we used a two-part statistical model to compare both the proportion of sampled street segments containing zero trees, and basal area magnitude for street segments with trees. We made community-scale comparisons based on street tree management, socioeconomics, and geographic setting. Then, using modeled stormwater interception estimates from i-Tree Streets, we investigated the implications of heterogeneity in street tree assemblages for stormwater interception benefits. The forest structure of street trees varied across communities in relation to management practices, namely participation in the Tree City USA program. As a consequence of this structural difference, we observed a stark discrepancy in estimated stormwater interception between Tree City USA participants (128.7 m 3 /km street length) and non-participants (59.2 m 3 /km street length). While street tree assemblages did not vary by community poverty status, we did find differences according to community racial composition. In contrast to previous research, basal area was greater in predominantly black (i.e., African American) and racially mixed communities than in predominantly white communities. We did not observe structural differences across geographic strata. This research underscores the importance of proactive management practices for increasing the forest structure of street trees. Our findings regarding socioeconomics and geographic setting contrast previous studies, suggesting the need for continued research into the drivers of structural heterogeneity in street tree assemblages.

Urban Ecosystems, 2012

Urban forestry can benefit from improved knowledge of urbanization's effects on tree canopy cover... more Urban forestry can benefit from improved knowledge of urbanization's effects on tree canopy cover (TCC), a prominent urban forest indicator. This study examined changes in TCC over a long time frame, with respect to land cover (LC) changes, and across municipal boundaries. Specifically, I used air photos at 14 dates from 1937-2009 to develop an exceptionally long record of TCC change in Minnesota's Twin Cities Metropolitan Area. During the study period overall TCC nearly doubled from 17% to 33% while the proportion urban land cover rose by 47%, highlighting the opportunity for substantial TCC gains following urbanization in previously agricultural landscapes, even in regions that were forested prior to European settlement. Results demonstrate that more intensely developed sites generally had lower TCC, and older urban sites had higher TCC. Modern TCC was not adequately characterized by linear distance along the urban-rural gradient, but instead peaked near the center of the gradient where mature residential neighborhoods are prevalent. Compared to other land cover changes, urbanization events caused the highest rate of immediate TCC loss (9.6% of events), yet urban areas had the second highest TCC (>35%) in 2009, indicating that urban land gained TCC relatively efficiently following development. The results of this study provide new historical context for urban forest management across an urban-rural gradient, and emphasize the need to consider ecological legacies and temporal lags following land cover changes when considering TCC goals in urban settings.

BioScience, 2016

This article brings together the concepts of shrinking cities-the hundreds of cities worldwide ex... more This article brings together the concepts of shrinking cities-the hundreds of cities worldwide experiencing long-term population loss-and ecology for the city. Ecology for the city is the application of a social-ecological understanding to shaping urban form and function along sustainable trajectories. Ecology for the shrinking city therefore acknowledges that urban transformations to sustainable trajectories may be quite different in shrinking cities as compared with growing cities. Shrinking cities are well poised for transformations, because shrinking is perceived as a crisis and can mobilize the social capacity to change. Ecology is particularly well suited to contribute solutions because of the extent of vacant land in shrinking cities that can be leveraged for ecosystem-services provisioning. A crucial role of an ecology for the shrinking city is identifying innovative pathways that create locally desired amenities that provide ecosystem services and contribute to urban sustainability at multiple scales.

Cities and the Environment, 2015

Understanding the spatial distribution of environmental amenities requires consideration of socia... more Understanding the spatial distribution of environmental amenities requires consideration of social and biogeophysical factors, and how they interact to produce patterns of environmental justice or injustice. In this study, we explicitly account for terrain, a key local environmental factor, while assessing whether tree canopy is distributed equally in Cincinnati, Ohio, USA. We conducted separate analyses for all land and for residential land only. For all land, terrain alone accounted for 59% of the variation in tree canopy cover. In our spatial autoregressive model, socioeconomic variables describing race, wealth, and education did not explain significant variation in canopy cover. In other words, terrain is the primary factor related to tree canopy in Cincinnati. In our analysis of residential land only, terrain was again the dominant predictor of tree canopy cover, and percent black population and median home value were also positive, significant explanatory variables. Tree canopy was abundant in two hilly areas with dissimilar socioeconomic characteristics, with proportionally larger black populations in the western hills and higher home values in the eastern hills. In summary, the overwhelming importance of terrain may obscure subtler patterns between tree canopy and socioeconomic variables. Although general social processes may drive environmental injustice across disparate cities, our study highlights the need to account for local biogeophysical context.

Urban forestry professionals can use online tools to learn a lot about a site before a field visi... more Urban forestry professionals can use online tools to learn a lot about a site before a field visit. For example, Google Street ViewTM (GSV) provides street-level panoramic photographs that can be used to preview a street tree that is slated for maintenance or removal so that an arborist can anticipate what equipment will be needed in the field. Using street-level imagery, a person may be able to record the tree's street address, identify its species, estimate its size, note overhead wire conflicts, and so on. If this is possible for one tree, could we reliably use online resources like GSV to conduct an inventory of street trees across an entire city?

These digital resources can be used to facilitate virtual street tree surveys. Four files are inc... more These digital resources can be used to facilitate virtual street tree surveys. Four files are included: (1) GSV_overview_document – a user manual describing the data collection process using Google Street View to inventory trees; (2) DBH_reference_guide – reference material for visually estimating tree diameter at breast height (DBH); (3) Tree_ID_guide – identification guide for the most common street trees in the Midwest U.S.; and (4) Tree_Data_Collection_Form – a spreadsheet for recording street tree data.

Urban trees provide an abundance of benefits to city residents. Information about the geographic ... more Urban trees provide an abundance of benefits to city residents. Information about the geographic distribution of urban trees is critical to ensure equitable access to these benefits. Street trees are unique among urban trees because they are often managed by municipalities as a public resource, but they are challenging to manage in part because they are spatially dispersed across a city in close proximity to private property. While street tree inventory data sets are costly to generate, they provide important information to understand the spatial distribution of trees in the city and to plan for ongoing street tree management. Here, we utilize two street inventories collected at a 13-year interval to assess patterns and changes in municipal street tree distributions in Center Township, Indianapolis, IN. In the township as a whole, tree density, basal area, and taxonomic diversity increased markedly over time. Spatial autoregressive models were constructed to examine the relationship between socioeconomic characteristics and street tree population dynamics. Concurrent, legacy, and change models revealed significant associations between socioeconomic factors and street tree distributions. Specifically, tree density and taxonomic diversity were positively associated with educational attainment, and increases in tree density over time were negatively associated with the percent of the population that identifies as black or African American. Results suggest that despite overall increases in street trees, persistent inequalities in street tree access should be addressed in central Indianapolis neighborhoods.

Frontiers in Ecology and Evolution

Nature Ecology & Evolution

Nature Ecology & Evolution

Ecosystems, 2011

Dynamic relationships among climate, disturbance, and vegetation affect the spatial configuration... more Dynamic relationships among climate, disturbance, and vegetation affect the spatial configuration and composition of ecological communities. Paleoecological records indicate the importance of such relationships in Minnesota's Big Woods (BW) region, where isolated hardwood forest populations expanded to regional dominance after AD 1250. We used LANDIS-II to model the BW forest expansion, and conducted simulation experiments that isolated the important ecological factors in this regional change. In our simulations, BW forest expanded at approximately 15 m per year to achieve regional dominance within 600 years, which is comparable to empirical records. The distribution of the BW depended on the locations of scattered pre-existing tree populations that were sheltered from previous severe fire regimes by firebreaks. During the simulated spread of the tree populations, however, the presence or absence of firebreaks did not further influence vegetation pattern. When we assumed a fire rotation of 10-13 years in grasslands/woodlands and more than 400 years in BW, the feedback between fireresistant BW fuels and fire severity caused fire severity to decline in a time frame consistent with sedimentary data. In our simulations, seed dispersal from core initial populations caused forest expansion, changed fuel loads, and thus reduced fire severity-not the other way around as has been commonly proposed. Forest expansion was slowed by fire, but species' life history attributes, namely seed dispersal distances and maturity ages, asynchronous successional dynamics across many stands, and landscape history were at least as important in the temporal and spatial patterns of the regional response to climate change.

BioScience, 2016

This paper brings together the concepts of shrinking cities – the hundreds of cities worldwide ex... more This paper brings together the concepts of shrinking cities – the hundreds of cities worldwide experiencing long-term population loss – and ecology for the city. Ecology for the city is the application of social-ecological understanding to shaping urban form and function along sustainable trajectories. Ecology for the shrinking city thus acknowledges that urban transformations to sustainable trajectories may be quite different in shrinking cities as compared to growing cities. Shrinking cities are well poised for transformations because shrinking is perceived as a crisis and can mobilize the social capacity to change. Ecology is particularly well-suited to contribute solutions due to the extent of vacant land in shrinking cities that can be leveraged for ecosystem services provisioning. A critical role of an ecology for the shrinking city is identifying innovative pathways that create locally desired amenities that provide ecosystem services and contribute to urban sustainability at multiple scales.

Arboriculture & Urban Forestry, 2016

Tree City USA is a national program that recognizes municipal commitment to community forestry. I... more Tree City USA is a national program that recognizes municipal commitment to community forestry. In return for meeting program requirements, Tree City USA participants expect social, economic, and/or environmental benefits. Understanding the geographic distribution and socioeconomic characteristics of Tree City USA communities at the national scale can offer insights into the motivations or barriers to program participation, and provide context for community forestry research at finer scales. In this study, we assessed patterns in Tree City USA participation for all US communities with more than 2,500 people according to geography, community population size, and socioeconomic characteristics such as income, education, and race. Nationally, 23.5% of communities studied were Tree City USA participants, and this accounted for 53.9% of the total population in these communities. Tree City USA participation rates varied substantially by US region, but in each region participation rates were higher in larger communities, and long-term participants tended to be larger communities than more recent enrollees. In logistic regression models, owner occupancy rates were significant negative predictors of Tree City USA participation, education and percent white population were positive predictors in many US regions, and inconsistent patterns were observed for income and population age. Our findings indicate that communities with smaller populations, lower education levels, and higher minority populations are underserved regionally by Tree City USA, and future efforts should identify and overcome barriers to participation in these types of communities.

Landscape and Urban Planning, 2017

Urban impervious surfaces convert precipitation to stormwater runoff, which causes water quality ... more Urban impervious surfaces convert precipitation to stormwater runoff, which causes water quality and quantity problems. While traditional stormwater management has relied on gray infrastructure such as piped conveyances to collect and convey stormwater to wastewater treatment facilities or into surface waters, cities are exploring green infrastructure to manage stormwater at its source. Decentralized green infrastructure leverages the capabilities of soil and vegetation to infiltrate, redistribute, and otherwise store stormwater volume, with the potential to realize ancillary environmental, social, and economic benefits. To date, green infrastructure science and practice have largely focused on infiltration-based technologies that include rain gardens, bioswales, and permeable pavements. However, a narrow focus on infiltration overlooks other losses from the hydrologic cycle, and we propose that arboriculture – the cultivation of trees and other woody plants – deserves additional consideration as a stormwater control measure. Trees interact with the urban hydrologic cycle by intercepting incoming precipitation, removing water from the soil via transpiration, enhancing infiltration, and bolstering the performance of other green infrastructure technologies. However, many of these interactions are inadequately understood, particularly at spatial and temporal scales relevant to stormwater management. As such, the reliable use of trees for stormwater control depends on improved understanding of how and to what extent trees interact with stormwater, and the context-specific consideration of optimal arboricultural practices and institutional frameworks to maximize the stormwater benefits trees can provide.

Urban foresters routinely emphasize the importance of taxonomic diversity to reduce the vulnerabi... more Urban foresters routinely emphasize the importance of taxonomic diversity to reduce the vulnerability of tree assemblages to invasive pests, but it is unclear to what extent diversity reduces vulnerability to polyphagous (i.e., generalist) pests. Drawing on field data from seven communities in metropolitan Cincinnati, Ohio, USA, we tested the hypothesis that communities with higher diversity would exhibit lower vulnerability to the polyphagous Asian longhorned beetle, which currently threatens the region. Based on street tree compositions and the beetle's host preferences, Asian longhorned beetle threatened up to 35.6% of individual street trees and 47.5% of the total basal area across the study area, but we did not see clear connections between taxonomic diversity and beetle vulnerability among study communities. For example, the city of Fairfield was among the least diverse communities but had the lowest proportion of trees vulnerable to Asian longhorned beetle, whereas the city of Wyoming exhibited high diversity and high vulnerability. On the other hand, Forest Park aligned with our original hypothesis, as it was characterized by low diversity and high vulnerability. Our results demonstrate that relatively high taxonomic diversity in street tree assemblages does not necessarily lead to reduced vulnerability to a polyphagous pest. Considering the threats posed by polyphagous pests, selecting a set of relatively pest resistant trees known to perform well in urban areas may promote long-term stability better than following simple heuristics for maximizing taxonomic diversity, but further study is warranted.

Sustainability, 2015

Ecological Footprint Analysis (EFA) is appealing as a metric of sustainability because it is stra... more Ecological Footprint Analysis (EFA) is appealing as a metric of sustainability because it is straightforward in theory and easy to conceptualize. However, EFA is difficult to implement because it requires extensive data. A simplified approach to EFA that requires fewer data can serve as a perfunctory analysis allowing researchers to examine a system with relatively little cost and effort. We examined whether a simplified approach using freely available data could be applied to Puerto Rico, a densely populated island with limited land resources. Forty-one years of data were assembled to compute the ecological footprint from 1970 to 2010. According to EFA, individuals in Puerto Rico were moving toward sustainability over time, as the per capita ecological footprint decreased from 3.69 ha per capita (ha/ca) in 1970 to 3.

Urban Ecosystems, 2015

ABSTRACT Managing urban green space as part of an ongoing social-ecological transformation poses ... more ABSTRACT Managing urban green space as part of an ongoing social-ecological transformation poses novel governance issues, particularly in post-industrial settings. Urban green spaces operate as small-scale nodes in larger networks of ecological reserves that provide and maintain key ecosystem services such as pollination, water retention and infiltration, and sustainable food production. In an urban mosaic, a myriad of social and ecological components factor into aggregating and managing land to maintain or increase the flow of ecosystem services associated with green spaces. Vacant lots (a form of urban green space) are being repurposed for multiple functions, such as habitat for biodiversity, including arthropods that provide pollination services to other green areas; to capture urban runoff that eases the burden on ageing wastewater systems and other civic infrastructure; and to reduce urban heat island effects. Because of the uncertainty and complexities of managing for ecosystem services in urban settings, we advocate for a governance approach that is adaptive and iterative in nature—adaptive governance—to address the ever changing social order underlying postindustrial cities and offer the rise of land banks as an example of governance innovation.

Urban Forestry & Urban Greening, 2014

Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Mu... more Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Municipal street trees are crucial components of urban green infrastructure because they provide stormwater interception benefits and other ecosystem services. Thus, it is important to understand the patterns and drivers of structural heterogeneity in urban street tree assemblages. In this study, we compared the forest structure of street trees across nine communities along both geographic and demographic gradients in metropolitan Cincinnati, Ohio, USA. Specifically, we used a two-part statistical model to compare both the proportion of sampled street segments containing zero trees, and basal area magnitude for street segments with trees. We made community-scale comparisons based on street tree management, socioeconomics, and geographic setting. Then, using modeled stormwater interception estimates from i-Tree Streets, we investigated the implications of heterogeneity in street tree assemblages for stormwater interception benefits. The forest structure of street trees varied across communities in relation to management practices, namely participation in the Tree City USA program. As a consequence of this structural difference, we observed a stark discrepancy in estimated stormwater interception between Tree City USA participants (128.7 m 3 /km street length) and non-participants (59.2 m 3 /km street length). While street tree assemblages did not vary by community poverty status, we did find differences according to community racial composition. In contrast to previous research, basal area was greater in predominantly black (i.e., African American) and racially mixed communities than in predominantly white communities. We did not observe structural differences across geographic strata. This research underscores the importance of proactive management practices for increasing the forest structure of street trees. Our findings regarding socioeconomics and geographic setting contrast previous studies, suggesting the need for continued research into the drivers of structural heterogeneity in street tree assemblages.

Urban Ecosystems, 2012

Urban forestry can benefit from improved knowledge of urbanization's effects on tree canopy cover... more Urban forestry can benefit from improved knowledge of urbanization's effects on tree canopy cover (TCC), a prominent urban forest indicator. This study examined changes in TCC over a long time frame, with respect to land cover (LC) changes, and across municipal boundaries. Specifically, I used air photos at 14 dates from 1937-2009 to develop an exceptionally long record of TCC change in Minnesota's Twin Cities Metropolitan Area. During the study period overall TCC nearly doubled from 17% to 33% while the proportion urban land cover rose by 47%, highlighting the opportunity for substantial TCC gains following urbanization in previously agricultural landscapes, even in regions that were forested prior to European settlement. Results demonstrate that more intensely developed sites generally had lower TCC, and older urban sites had higher TCC. Modern TCC was not adequately characterized by linear distance along the urban-rural gradient, but instead peaked near the center of the gradient where mature residential neighborhoods are prevalent. Compared to other land cover changes, urbanization events caused the highest rate of immediate TCC loss (9.6% of events), yet urban areas had the second highest TCC (>35%) in 2009, indicating that urban land gained TCC relatively efficiently following development. The results of this study provide new historical context for urban forest management across an urban-rural gradient, and emphasize the need to consider ecological legacies and temporal lags following land cover changes when considering TCC goals in urban settings.