Remotely Sensed Tree Characterization in Urban Areas: A Review

Urban trees and forests provide multiple ecosystem services (ES), including temperature regulation, carbon sequestration, and biodiversity. Interest in ES has increased amongst policymakers, scientists, and citizens given the extent and growth of urbanized areas globally. However, the methods and techniques used to properly assess biodiversity and ES provided by vegetation in urban environments, at large scales, are insufficient. Individual tree identification and characterization are some of the most critical issues used to evaluate urban biodiversity and ES, given the complex spatial distribution of vegetation in urban areas and the scarcity or complete lack of systematized urban tree inventories at large scales, e.g., at the regional or national levels. This often limits our knowledge on their contributions toward shaping biodiversity and ES in urban areas worldwide. This paper provides an analysis of the state-of-the-art studies and was carried out based on a systematic review of 48 scientific papers published during the last five years (2016–2020), related to urban tree and greenery characterization, remote sensing techniques for tree identification, processing methods, and data analysis to classify and segment trees. In particular, we focused on urban tree and forest characterization using remotely sensed data and identified frontiers in scientific knowledge that may be expanded with new developments in the near future. We found advantages and limitations associated with both data sources and processing methods, from which we drew recommendations for further development of tree inventory and characterization in urban forestry science. Finally, a critical discussion on the current state of the methods, as well as on the challenges and directions for future research, is presented.

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Urban Tree Growth & Longevity: Introduction

Arboriculture & Urban Forestry ◽

10.48044/jauf.2012.025 ◽

2012 ◽

Vol 38 (5) ◽

pp. 171

Author(s):

E. Gregory McPherson ◽

Bryant Scharenbroch

Keyword(s):

Tree Growth ◽

Special Section ◽

Urban Forestry ◽

Urban Trees ◽

Future Research ◽

Urban Tree ◽

Course Of Action ◽

New Information ◽

Site Design ◽

Research And Education

This special issue of Arboriculture & Urban Forestry contains a series of papers related to urban tree growth and longevity. Research and new information on urban tree growth and longevity is important for improved management of our urban trees and forests, as well as assessing their function and value. The papers in this issue were presented at the Urban Tree Growth & Longevity Conference held on September 12–13, 2011 at The Morton Arboretum (Lisle, Illinois, U.S.). This international conference brought together researchers and practitioners to discuss the current state of knowledge concerning urban tree growth and longevity. The conference covered four topic areas: 1) Descriptive studies of tree growth, longevity, and mortality, 2) Roles of tree production and sales on tree growth and longevity, 3) Roles of site design and tree selection on tree growth and longevity, and 4) Roles of tree and site management on tree growth and longevity. The objectives of the conference and these papers are to: develop collaboration among professionals and researchers to help identify important gaps in our knowledge, foster discussions about promising new methodologies, prioritize research and education needs, and outline a course of action for future research and outreach on urban tree growth and longevity. A few additional papers from the conference will be published in a special section of a future issue of this journal.

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The Cost of Not Maintaining Trees: Findings and Recommendations from an International Symposium and Summit

Arboriculture & Urban Forestry ◽

10.48044/jauf.2016.032 ◽

2016 ◽

Vol 42 (6) ◽

Author(s):

Andrew Koeser ◽

Jess Vogt ◽

Richard Hauer ◽

Robert Northrop ◽

Ward Peterson

Keyword(s):

Urban Areas ◽

Structural Integrity ◽

Urban Forestry ◽

Past Research ◽

Urban Trees ◽

Environmental Benefits ◽

Future Research ◽

The Social ◽

The Cost ◽

Care Costs

Urban trees are both an asset and a cost to municipalities. Past research has focused largely on the asset—quantifying and valuing the social, economic, and environmental benefits provided by trees in urban areas. Relatively fewer studies have focused on defining the appropriate level of tree care (costs or inputs) for efficiently maintaining tree health and structural integrity, and potential resulting liabilities. On 18–20 March 2015, the International Society of Arboriculture assembled a panel of research and industry experts for a research symposium and summit titled, The Costs of Not Maintaining Trees. In the weeks leading up to the summit, the Delphi technique was initiated to help build consensus on key research questions related to the economics of trees and their care. After three iterations of questions and discussion, the panel identified 14 research topics that were deemed “very important” or “important” by at least 12 of the 14 expert panelists (80% being a commonly used threshold for consensus). Results of this work are intended to help focus future research and funding efforts in arboriculture and urban forestry.

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Combining remotely sensed data using aggregation algorithms

Hydrology and Earth System Sciences ◽

10.5194/hess-2-149-1998 ◽

1998 ◽

Vol 2 (2/3) ◽

pp. 149-158 ◽

Cited By ~ 16

Author(s):

W. J. Shuttleworth

Keyword(s):

Surface Energy ◽

Land Surface ◽

Remotely Sensed ◽

Surface Radiation ◽

Control Surface ◽

Future Research ◽

Practical Implementation ◽

Remotely Sensed Data ◽

Theoretical Concepts ◽

Average Value

Abstract. This paper describes a strategic approach for providing documentation of the surface energy exchange for heterogeneous land surfaces via the simultaneous, four-dimensional assimilation of several streams of remotely sensed data into a coupled land surface-atmosphere model. The basic concepts and underlying theory behind this proposed approach are presented with the intent that this will guide, facilitate, and stimulate future research focused on its practical implementation when appropriate data from the Earth Observing System (EOS) become available. The theoretical concepts that underlie the approach are derived from relationships between the values of parameters which control surface exchanges at pixel (or patch) scale and the area-average value of equivalent parameters applicable at larger, grid scale. A three-step implementation method is proposed which involves (a) estimating grid-average surface radiation fluxes from appropriate remotely sensed data; (b) absorbing these radiation flux estimates into a four-dimensional data assimilation model in which grid-average values of vegetation-related parameters are calculated from pertinent remotely sensed data using the equations that link pixel and grid scales; and (c) improving the resulting estimate of the surface energy balance-again using scale-linking equations by estimating the effect of soil-moisture availability, perhaps assuming that cloud-free pixels are an unbiased subsample of all the pixels in the grid square.

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ARBOR: A new framework for assessing the accuracy of individual tree crown delineation from remotely-sensed data

Remote Sensing of Environment ◽

10.1016/j.rse.2019.111256 ◽

2019 ◽

Vol 231 ◽

pp. 111256

Author(s):

Jon Murray ◽

David Gullick ◽

George Alan Blackburn ◽

James Duncan Whyatt ◽

Christopher Edwards

Keyword(s):

Remotely Sensed ◽

Tree Crown ◽

Remotely Sensed Data ◽

Individual Tree ◽

Crown Delineation ◽

Tree Crown Delineation ◽

New Framework

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Long-Term Validation and Governance Role in Contemporary Urban Tree Monitoring: A Review

Sustainability ◽

10.3390/su12145589 ◽

2020 ◽

Vol 12 (14) ◽

pp. 5589

Author(s):

Blaz Klobucar ◽

Johan Östberg ◽

Märit Jansson ◽

Thomas Barfoed Randrup

Keyword(s):

Urban Areas ◽

Sampling Design ◽

Lateral Approach ◽

Urban Trees ◽

Limited Attention ◽

Governance Arrangement ◽

Urban Tree ◽

Primary Focus ◽

Longitudinal Sampling

Urban trees provide important ecosystem services, across ownership and governance structures, and tree inventories are an important tool enabling urban foresters and green space managers to monitor and perform the sustainable management of urban trees. For optimal management of urban trees, a better understanding is needed concerning how urban tree inventories can provide long-term monitoring overviews across administrative borders, and how inventory protocols should be adapted to address specific practitioner issues. In this review, 98 articles on urban tree inventories were examined, the primary focus being sampling design. A governance arrangement approach was applied to identify the policy-making arrangements behind the inventories. Stratification is commonly used in the sampling design, despite being problematic for long-term representativeness. Only 10% of the stratification sampling designs identified were considered as having long-term validity. The studies frequently relied on an individual sampling design aimed at a particular issue, as opposed to using an existing longitudinal sampling network. Although private trees can constitute over 50% of the urban tree population, 41% of the studies reviewed did not include private trees at all. Urban tree inventories focused primarily on tree data on a local scale. Users or private tree owners are commonly not included in these studies, and limited attention is paid to economic, cultural or social factors. A long-term validation of sampling methods in urban areas, and a multi-lateral approach to tree inventories, are needed to maintain long-term operational value for local managers in securing ecosystem service provisions for entire urban forests.

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Urban Trees and Human Health: A Scoping Review

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17124371 ◽

2020 ◽

Vol 17 (12) ◽

pp. 4371 ◽

Cited By ~ 3

Author(s):

Kathleen L. Wolf ◽

Sharon T. Lam ◽

Jennifer K. McKeen ◽

Gregory R.A. Richardson ◽

Matilda van den Bosch ◽

...

Keyword(s):

Public Health ◽

Human Health ◽

Green Infrastructure ◽

Weight Status ◽

Urban Forest ◽

Research Policy ◽

Urban Forestry ◽

Urban Trees ◽

Environmental Benefits ◽

Future Research

The urban forest is a green infrastructure system that delivers multiple environmental, economic, social and health services, and functions in cities. Environmental benefits of urban trees are well understood, but no review to date has examined how urban trees affect human health. This review provides a comprehensive summary of existing literature on the health impacts of urban trees that can inform future research, policy, and nature-based public health interventions. A systematic search used keywords representing human health, environmental health, and urban forestry. Following screening and appraisal of several thousand articles, 201 studies were conceptually sorted into a three-part framework. Reducing Harm, representing 41% of studies, includes topics such as air pollution, ultraviolet radiation, heat exposure, and pollen. Restoring Capacities, at 31%, includes attention restoration, mental health, stress reduction, and clinical outcomes. Building Capacities, at 28%, includes topics such as birth outcomes, active living, and weight status. The studies that were reviewed show substantial heterogeneity in purpose and method yet indicate important health outcomes associated with people’s exposure to trees. This review will help inform future research and practice, and demonstrates why urban forest planning and management should strategically promote trees as a social determinant of public health.

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