Street Tree Structure, Function, and Value: A Review of Scholarly Research (1997–2020)

Round 1

Reviewer 1 Report

Thank you for possibility to revise the manuscript.  The manuscript deals with scholarity review of structure, function and value of street trees. Authors analyzed a broad range of scientific papers across natural and social disciplines.

I am completely aware about the difficulty of description of such complex problem. Overall the manuscript is rather interesting, but there are few issues which need to be addressed.

I miss the aims of the research clearly stated and relevant questions asked or hypotheses formulated.

I miss the concepts defined. What do you mean by street tree / street trees/ urban forests? What are the differences between them? The structural differences you can “easily” describe, the functional differences you should searched by the review. I wasn’t sure if your results focus on urban trees or urban forests. The key words you searched in the scientific papers doesn’t contain urban forests. What about shrubs, were they included?

Interesting question should be what the functional differences between single trees, group of trees, or urban forests are. If there are some concerning the research topic.

I really like the overview of classification in the table 1. It should be mentioned how the table was created.

You summarized methods used for street tree inventory, in the Table 3. My question is, what is monitored by the each method?

Units are missing in the Figure 3.

Author Response

Thank you for the detailed review of our article. Our responses (unitalicized) follow your point-by-point comments (italicized) below:

I miss the aims of the research clearly stated and relevant questions asked or hypotheses formulated.

Thank you for this request. Near the end of the introduction, on page 3, we have now more directly articulated the aims of this paper: “The aims of this literature review were to identify the scope of street tree literature across academic disciplines (by literature database and journal subject matter), to identify where (geographically) and when (by year) this research was published, and to call attention to discrete, yet inevitably overlapping, street tree research topics in recent decades.”

I miss the concepts defined. What do you mean by street tree / street trees/ urban forests? What are the differences between them? The structural differences you can “easily” describe, the functional differences you should searched by the review. I wasn’t sure if your results focus on urban trees or urban forests. The key words you searched in the scientific papers doesn’t contain urban forests. What about shrubs, were they included?

We understand your comment and agree with the need for clarification. In section 2.1 Record Identification, on page 4, we have now added the following: “This review narrowed articles specifically to street trees, or the trees located in sidewalk cut-outs, street-side planting strips, and medians (Roman et al. 2013) and did not explicitly seek to include articles on other urban trees (like park trees, residential trees, or woodland trees) or other plant communities (like shrubs, herbaceous plants, and mosses) that comprise an urban forest (Morgenroth and Östberg 2017).”

Morgenroth, Justin, and Johan Östberg. 2017. “Measuring and Monitoring Urban Trees and Urban Forests.” In Routledge Handbook of Urban Forestry, 16. New York, NY: Routledge.

Roman, Lara A., John J. Battles, and Joe R. McBride. 2013. “The Balance of Planting and Mortality in a Street Tree Population.” Urban Ecosystems 17 (2): 387–404. https://doi.org/10.1007/s11252-013-0320-5.

Interesting question should be what the functional differences between single trees, group of trees, or urban forests are. If there are some concerning the research topic.

Thank you for commenting on the ways in which this literature review can foster additional research opportunities. We agree that future research directions could focus on the functional differences between single street trees, groups or patches of street trees (and adjacency to other planting areas, like parks or private yards, and varied environmental conditions), and street trees as a discrete and pervasive component across urban forests writ large. In the Discussion section, on page 17, we have edited the text to elaborate on this as a specific opportunity for future research: “In terms of the physical qualities of urban street tree populations, this review identified that there is a widespread, baseline interest in assessing street trees as a component of the urban forest. Not surprisingly, our review anecdotally found that street trees are studied at the scale of individual trees, groups of street trees, a single tree planted amongst a matrix of other tree planting locations, or as a discrete component across an urban forest. This literature review did not assess the ways in which the position or placement of street trees is related to other planting locations in cities, however this is a worthwhile inquiry for future literature reviews or empirical research.”

I really like the overview of classification in the table 1. It should be mentioned how the table was created.

Thank you for complimenting Table 1. On page 5, we have more clearly stated how Table 1 was generated. “Table 1 was created to outline operating definitions and examples (from related literature), emergent themes, and key challenges identified by the authors from the review process.”

You summarized methods used for street tree inventory, in the Table 3. My question is, what is monitored by the each method?

These inventory methods were an emergent pattern from the review process. On page 10, we have now noted “ Street tree inventory methods have been used to aggregate the spatial location of individual or collections of trees, above or below-ground components of the trees, or the overall “greenness” of a street.”

Units are missing in the Figure 3.

Thank you for this observation, an additional label was added to the y-axis.

Reviewer 2 Report

Comments for author File: Comments.doc

Author Response

Thank you for the detailed review of our article. Our responses to your comments are below:

1. To improve the Conclusion part: Need for correlation between Discussion and Conclusion part. When reading the Conclusion part, the reader feels different tone of the author (try to be consistent). The third paragraph from Conclusion (cooling) should be previously discussed or presented (in Discussion).

Thank you for this request. We added several additional sections of writing to pages 16-17 in order to better connect the Discussion with the Conclusion.

 

2. Present the importance of your ideas and the subject matter in one closer way for the reader (heuristic?). Finally, you need to summarized and reiterate the main points in same way during the all text. Also try to avoid repeating p.15 “…Of the 429 records collected as part of this review, approximately half were identified across three primary scholarly journals in urban forestry, with the remainder being distributed across 110 cross-disciplinary journals.” More or less the same sentence on p.13 in Disucsion part, in paragraph 2 of 4.1 The Multidimensionality of urban street trees.

We went through the article to consistently frame several main points and removed inconsistent references (e.g 429 articles versus over 400 articles).

 

Other Detailed comments  

- Please check the citation role according to the author guidelines (in numbers not in alphabet order), Please check all reference e.g. Lawrence in text 2005 (p.1 Introduction) in reference list 2006 – check carefully all references.

Thank you for the thorough attention to detail. These citation mismatches will be corrected in formatting the final manuscript (per journal guidelines, they will be numbered by order of appearance).

 

- Although you defined the street urban trees in Introduction part it is useful to put certain frame(work) of urban street trees (definition) in 2. Materials and methods for justification for utilization of the keywords.

We understand your comment and agree with the need for clarification. In section 2.1 Record Identification, on page 4, we have now added the following: “This review narrowed articles specifically to street trees, or the trees located in sidewalk cut-outs, street-side planting strips, and medians (Roman et al. 2013) and did not explicitly seek to include articles pertaining to other urban trees (like park trees, residential trees, or woodland trees) or other plant communities (like shrubs, herbaceous plants, and mosses) that comprise an urban forest (Morgenroth and Östberg 2017).”

Morgenroth, Justin, and Johan Östberg. 2017. “Measuring and Monitoring Urban Trees and Urban Forests.” In Routledge Handbook of Urban Forestry, 16. New York, NY: Routledge.

Roman, Lara A., John J. Battles, and Joe R. McBride. 2013. “The Balance of Planting and Mortality in a Street Tree Population.” Urban Ecosystems 17 (2): 387–404. https://doi.org/10.1007/s11252-013-0320-5.

 

- The focus for the published papers 1997-2020 is unusual (23 years).  Personally I do not have nothing against but as reader I expected to read/find why did you choose 1997 as starting year (something happen, …or..)

Thank you for this request. A statement justifying this date range is included on page 4.

"A precedential article was published in 1997 (McPherson et al.) that has served as a benchmark in relation to mapping the trajectory of street tree scholarship over time. Additionally, the 1997 – mid 2020 date range corresponds with the commencement of the “digital age” which ensures that searches are replicable between archives (Xiao and Watson 2019), through to the point at which disrupted patterns of publications ensued due to the onset of the COVID-19 pandemic."

McPherson, E Gregory, David J Nowak, Gordon Heisler, Catherine Souch, Rich Grant, and Rowan A. Rowntree. 1997. “Quantifying Urban Forest Structure, Function, and Value: The Chicago Urban Forest Climate Project,” Urban Ecosystems 1, 49–61.https://doi.org/10.1023/A:1014350822458

Xiao, Yu, and Maria Watson. 2019. “Guidance on Conducting a Systematic Literature Review.” Journal of Planning Education and Research 39 (1): 93–112. https://doi.org/10.1177/0739456X17723971.

 

- Follow the structure and categorization of Figure 3 for the 3.3.1 Structure the using order is Tree inventory, Establishment and Growth, Survival and mortality and Disease and pest management and in Figure 3 you use different order (Disease and pest management, Survival and mortality, Establishment and Growth, Tree inventory). Because the order for 3.3.2 Function and 3.3.3 Value is identical with the Figure 3 order/categorization.

Thank you for pointing out this oversight, the order of the text now follows the order of Figure 3.

 

- The supplementary document is full with very interesting and useful data. Most of the them are not used in the Result part 3.3. I’m encouraging you to add additional analyses.

e.g. the papers dealing with Economic valuation appear first in North America, and there are no papers from Europe before 2010.

Some topics are more relevant for some continent compared to others and in some continent certain topics were invented. This will add you extra value on your paper. 

Thank you for this useful suggestion. We reviewed our data again in order to emphasize the study areas (by continent and across time) throughout the Results section 3.3 (pages 9-16)

 

Reviewer 3 Report

Thank you very much for reading this text. The text is additions, but additions.

The article is good methodologically and technically. The research is exploratory. Work manage, check, the topic of city trees.

The outline of the topic is presented, which introduces changes in the approach to problem analysis. Results This study synthesized more than 400 scientific articles on street trees. Summary of the results with the characteristics of the literature and the methods of calculating the structure and function of the street tree. Sampling for research by other authors Conclusions contained in the paper refer and achieve the results.

Retreats also to make suggestions about the possibilities of the studied range.

Research opportunities include street research and the possibility to apply for access to the survey through a meta-analysis performed by many experts from a given zone, the scope of value studies and an overview of the structure and function of trees in city streets.

Author Response

Thank you for the detailed review of our article.