Knowledge in Tree Pruning for Sustainable Practices in Urban Setting: Improving Our Quality of Life

Abstract

Pruning is one of the most important tree maintenance activities which gives a big impact on tree's health and structure. A well-pruned trees are not only able to maintain tree health, but also will provide a safe environment and enhance the aesthetic value. On the other hand, improper pruning will danger the public. The aim of this study is to assess pruning knowledge among Kuala Lumpur City Hall (DBKL) tree maintenance workers. Findings from this study will contribute to recommendations for changing knowledge for proper tree pruning which helps to raise the quality of tree management practices.

Full text

Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
Available online at www.sciencedirect.com
1877-0428 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the Association of Malaysian Environment-Behavior Researchers, AMER (ABRA malaysia)
doi: 10.1016/j.sbspro.2016.10.236
ScienceDirect
ASEAN-Turkey ASLI (Annual Serial Landmark International) Conferences on Quality of Life 2016
AMER International Conference on Quality of Life, AicQoL2016Medan
25 – 27 February 2016, Medan, Indonesia
Knowledge in Tree Pruning for Sustainable Practices in Urban
Setting: Improving our quality of life
Norainiratna Badrulhishamª
*
, Noriah Othmanᵇ
ªInstitute of Graduate Studies
ᵇCentre of Landscape Architecture Studies
Universiti Teknologi MARA, Shah Alam 40450, Malaysia
Abstract
Pruning is one of the most important tree maintenance activities which gives a big impact on tree's health and structure. A well-
pruned trees are not only able to maintain tree health, but also will provide a safe environment and enhance the aesthetic value.
On the other hand, improper pruning will danger the public. The aim of this study is to assess pruning knowledge among Kuala
Lumpur City Hall (DBKL) tree maintenance workers. Findings from this study will contribute to recommendations for changing
knowledge for proper tree pruning which helps to raise the quality of tree management practices.
© 2015 The Authors. Published by Elsevier Ltd.
Peer-review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers) and cE-Bs (Centre
for Environment-Behaviour Studies, Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.
Keywords: Knowledge; pruning; urban trees; sustainable practices
1. Introduction
Pruning is one of the most important tree maintenance practices that should not be ignored because it gives a big
impact on tree's health and structure (Clark and Matheny, 2010). By removing of diseased, broken, or dead branches
on mature trees and young trees, it will protect the trees by preventing decay-producing fungi from penetrating and
* Corresponding author. Tel.: +00000000; fax: +000000000.
E-mail address: onie_ratna@yahoo.com
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the Association of Malaysian Environment-Behavior Researchers, AMER (ABRA malaysia)

211
Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
infecting other areas of the tree (Gilman and Grabosky, 2006). Besides, pruning by thinning trees may help in
increase light penetration and air movement throughout the crown of a tree (Harris, 1994).
The benefits from pruning not only for trees but people and communities. Pruning will encourage trees to grow
with strong branch structure thus help in minimizing injury from hazard tree risk such as damage by dead, hanging
and detached twigs/branches falling from the tree (Ow, et.al. 2013). Trees in good structure and form will provide an
aesthetic visual which helping to improve human health (Tyrväinen, 1999). However, if pruning is not properly
done, it will not only give a poor appearance to the trees, but it can even lead to the occurrence of diseases that will
affect tree's health and weaken the physical strength of the wood which will lead it to breakage (Clark and Matheny,
2010). This situation may pose a danger to the public and personal injury or property damage (Harris et.al. 1999).
There are several tree assessment studies conducted in Malaysia showed tree failure caused by pruning that is
ignored or not done correctly. A study conducted by Murad (2000) on urban street trees in Kuala Lumpur showed
that 32.75% of the mature trees with hazardous risk and most of them suffered from various structural defects.
While a study conducted by Norainiratna (2013) on tree health of trees in Titiwangsa Recreational Park found that
most of the structural problems, crown imbalance and mechanical damage of trees are caused by improper and lack
of pruning works by the maintenance workers especially matured trees. While research by Sreetheran et.al. (2011)
found that 95.5% of the surveyed street trees in Kuala Lumpur were considered moderately hazard and majority of
the defects were from dead twigs/small branches not pruned.
Zakaria (2012) believes that this problem occurs due to pruning works run by employees who do not have
sufficient experience and knowledge in pruning. To perform the pruning job successfully, it is important for workers
to equipped themselves with the knowledge, skills and attitudes (Ainuddin, 2014). It is believed that when one's
knowledge increased, then the knowledge will inspire him to change his attitudes and the changes will result in
changes of behavior (Mahmud and Siarap, 2013). Some of the gaps of this research were there is no studies have
been published on knowledge of tree pruning practices in Malaysia cause of this study was conducted. The purpose
of this study is to create awareness of the importance of knowledge in tree pruning work. The objective of this
research is to investigate the level of pruning knowledge among tree pruning workers in urban settings.
2. Literature review
Pruning is a process of removing branches (or occasionally roots) from a tree or other plant using approved
practices to achieve a specified objective. Pruning is a regular part of the maintenance routine which helps to keep
trees healthy and attractive (Meade and Hensley, 1998). Interest in pruning research begins with Shigo and Larson's
(1969) photographic summary of the patterns of discoloration and decay in U.S hardwoods which discussed
discoloration and wounding on hardwoods. Then the research expands on modern research activity majorly on
pruning technique (Dujesiefsken and Stobbe's, 2002) and wound response (O'Hara, 2007). Based on a review of the
literature on pruning research by Clark and Matheny (2010), major topics in pruning research is on
compartmentalization, decay and wound dressing. However, there is less research done on human behavior which is
capable of affecting the effectiveness of pruning works.
Pruning strategies will influence the tree success (Vogt et.al., 2015). According to Sellmer et.al. (2004) and
Akmal and Noriah (2012), successful pruning begins with reason to do pruning, understanding how pruning affects
the tree, pruning at the proper time and following proper techniques and tools. All of these practices will not be
executed if there is no awareness of the importance of pruning. Knowledge is the basis of the conduct or behavior of
an individual. Without knowledge, one cannot act upon any information or issues that arose. Exposure to new
information can enhance knowledge. According to Schwartz (2012), behavioral changes occur when it increases
one's knowledge. It is also agreed by Valente et al. (1998), Cai (2007) and Mahadevan (2009) when a person's
knowledge increases, then this knowledge will provide the impetus for change their attitude. It is impossible to set
national standards and international best practice which aims to improve the health of the tree if there is lack of
knowledge on the physiological effects of pruning (Fini et. al., 2015). Trees in urban settings which receive properly
pruning will improve the view and provide clearance, reduce conflict with infrastructure and buildings, reduce wind
resistance and the risk of failure of the other trees such as broken branches, dead and others that could pose danger
to the public (Smiley and Kane, 2006). While improper pruning cuts will cause a large wound which will take a long
time to recover and will expose the tree to disease risk that may decrease tree vigor (Clark & Matheny, 2010).

212 Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
There is a few research of knowledge related with pruning. A study conducted by Kuhns and Reiter (2007) about
knowledge and attitudes of households towards utility pruning in six cities in the western United States found that
individuals who are exposed to knowledge will have a positive attitude toward acceptance of utility pruning. The
results of the study conducted were adapted from Close et al. (2001) research. While other studies are also carried
out by Kuhns and Reiter (2009) on knowledge and practices of topping towards household in the interior western
United States city found that majority of them who had not topped trees were significantly more knowledgeable
about topping. There are also studies that are not related to tree pruning carried out by Brunson and Reiter (1996)
and Jensen (2000) also noted the importance of knowledge as an educated person with knowledge will accepting
certain forest management practices.
3. Study area
Kuala Lumpur is chosen as the area of the research because it is the capital and largest city in Malaysia. It is also
the most urbanize state with 244 km² (94 sq. mi) of land area and has the highest population density (Department of
Statistics Malaysia, 2010). As an urbanized area, it is important to have a sustainable tree pruning practices as there
are many targets which will expose to risk if pruning tree was poorly done. Kuala Lumpur City Hall (DBKL) was
given the responsibility of maintaining and preserving the landscape around the city of Kuala Lumpur under a shade
tree management unit. This unit is carrying out maintenance on roadside trees only, excluding tree in a public park
and residential area. There are 11 parliamentary (Table 1) guarded by eight groups of assistant agricultural officers,
supervisors and laborers who do the pruning.
Table 1. Number of employees based on the parliament
Parliament
Number of employees
Segambut
10
Pusat bandar
10
Cheras
8
Kepong/Batu
10
Seputeh
8
Setiawangsa/Wangsamaju/Titiwangsa
10
Lembah Pantai
9
Bandar Tun Abd Razak
10
TOTAL
75
4. Research methodology
The study was conducted using a questionnaire as an instrument to obtain research data. A sample of respondents
were from all 75 Kuala Lumpur City Hall (DBKL) tree maintenance workers who perform roadside tree pruning.
However only 62 of workers who give feedback. The instrument used in this study involves two parts; Part A
contains worker's demographic information. Part B consists of 33 items of questions related to the knowledge of tree
pruning in the form of a 4-point Likert's rating scale statements that is 1 (strongly disagree), 2 (disagree), 3 (agree)
and 4 (strongly agree). 33 items contain 15 positive statements and 18 negative statements. For positive statements,
respondents who answered 3 (agree) and 4 (strongly agree) will be considered as the correct answer and will be
given 1 mark and 0 mark for the wrong answer. While for negative statements, 1 (strongly disagree) or 2 (disagree)
will be considered as the correct answer (1 mark) and 0 mark for the wrong answer.
The technique used in the production of the questionnaire to evaluate respondent's knowledge based on the
technique performed by Fazio and Krumpe (1999) which avoiding the feeling of taking a test by the questions
presented as seeking an "opinion". Questions made referred on manual of Pruning Trees Landscape Amenity by

213
Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
Malaysia's Country Landscape Department (JLN) and Best Management Practices of Tree Pruning manual by the
International Society of Arboriculture (ISA). The content of knowledge questions are:
x Objective or purpose of tree pruning
x Pruning methods (types)
x Pruning technique
x Impacts from pruning cuts
x Pruning equipment
x Pruning time/frequency
Apart from questions in a form of statements, the questions by using image were also included to help
respondents to ease them to understand the questions. It is because the majority of respondents were from among
those who have low education level. The data obtained then were analysed using Statistical Package for Social
Science Research (SPSS) version 20.0 according to research questions. Descriptive statistical analysis of frequency
and percentage were performed to analyse the details of the demographic characteristics of pruning workers. Then
knowledge level given based on knowledge score adapted from Abdolmaleki and Mohebi (2014).
5. Results and discussions
5.1. Demographic information
Table 2 shows the frequency and percentage of respondent’s demographic characteristics. All of the pruning
workers are male and the majority of them are between 31-40 years old (50%). There are only two nations which are
Malay (85.5%) and Indian (14.5%). For education level, most of them are SPM holders (58.1%), followed by PMR
(21.0) and standard 6 (16.1). This result indicates that majority of them had low levels of education. A total of 32
workers (51.7%) had served for more than 20 years shown that these people had a lot of experience with tree
pruning. Only 2 of them are contract workers. The results also found that 8 out of 62 of pruning workers did not
attend tree pruning course throughout their working period. It is important to follow the course so that workers'
skills and knowledge can be improve.
Table 2. Socio-demographic characteristics
Characteristics
Frequency
Percentage (%)
Gender
Male
Female
62
0
100.0
0
Age (Years)
21-30
31-40
41-50
51 and above
8
31
17
6
12.9
50.0
27.4
9.7
Nationality
Malay
Indian
Chinese
Others
53
9
0
0
85.5
14.5
0
0
Education level
Standard 6
PMR
SPM
STPM
Diploma
10
13
36
1
1
16.1
21.0
58.1
1.6
1.6

214 Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
Degree
1
1.6
Duration of service (Years)
Less than 1 year
1-5
6-10
11-15
16-20
21-25
More than 25 years
1
1
14
14
20
5
7
1.6
1.6
22.6
22.6
32.3
8.1
11.3
Job status
Permanent
Contract
60
2
96.8
3.2
Attend pruning course?
Yes
No
54
8
87.1
12.9
5.2. Knowledge level score
Table 3 shows frequency and percentage of the respondent who gave the correct answer for each item regarding
with pruning knowledge. For the purpose of pruning landscape tree, seems that majority of them understand the
purpose of doing pruning when the majority of them (above 92%) gave correct answers to 7 out of 9 questions. As
well as questions about pruning method when above 59 of them (95.2%) understand the types of pruning made on
trees. However, 60 (96.8%) of them gave the wrong answer when they agree that pruning can be made on trees
under stress. The next question asks respondents to choose which one of trees with correct pruning technique. A
total of 47 respondents does not know the bad consequences of doing flush cut on trees when only 15 (24.2%) of
them gave the correct answer. While 55 of them agreed that too much raising cut on the tree is fine, and only 7
(11.3%) of them gave the correct answer. Flush cut remove the branch collar which contain the protection zone.
Apart from causing a large wound, it will cause wounds to heal slowly and give a chance to any insect to infest the
wound or microorganism to invade quickly (Ow et. al., 2013). While too much crown raising only leave small
amount of foliage which will reduce photosynthesis process of trees.
For wound/pruning cut condition after pruning, the majority of workers do not know which is the good condition
of branches after pruning. Most of them do not know the good condition of wound closure when only 34 (54.8%) of
them gave the correct answer while 24 (38.8%) of them agreed that sprout growth as a result of improper pruning
are fine. Sprout growth occur as a result from flush cut pruning. Weak attachment from the sprout branches will
increase loading thus causing branch failure especially during severe wind or rain storms (Evans, 2000). Pruning
equipment question shows that majority of them did not know the use of secateurs in pruning works when 33 of
them define that secateurs can be used to prune small branches (diameter about 3cm length) and large (diameter
more than 3cm length). This is because secateurs may never be used in their pruning works. However, above 80.7%
gave the correct answer from 6 out of 7 questions of pruning equipment shows that workers understand the types
and good characteristics of pruning equipment. This shows that workers have the knowledge to choose the
appropriate equipment and using only equipment in good condition during pruning. For questions regarding with
pruning time, there are 3 questions with few correct answer. The majority of the workers agreed that pruning can be
done for trees in stress condition while 5 (8.1%) of them disagreed. Only 12 (29.3%) of them admit that pruning
should be done for the young tree and 42 (67.7) gave the correct answer to avoid pruning on drought season.

215
Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
Table 3. Frequency and percentage of respondent with the correct answer
Correct
Knowledge items
Frequency
Percentage
(%)
The purpose of pruning landscape tree
Maintaining public safety (risk of broken branches)
Maintain tree health
Maintain / improve tree appearance
Provide clearance from objects such as buildings, street lamps
or electric lamps, etc.
Encouraging the flowers / fruit growth
Reduce wind resistance
Promoting branches growth
Stop tree growth
Produce quality timber
62
62
60
62
57
61
60
16
24
100
100
96.8
100
92.0
98.4
96.8
25.8
38.8
Pruning is done on: (pruning method)
Diseased branches
Dead branches
Tree branches are obstructing objects such as buildings, street
lamps or electric lamps, etc.
Broken branches
Tree canopy that is too lush
Tree canopy that is too dense
Trees that lose their appearance
Criss-crossing branches
Trees that suffer from stress
62
62
62
62
61
61
59
60
2
100
100
100
100
98.4
98.4
95.2
96.8
3.2
Trees with correct pruning technique (Image questions)
Unsmooth pruning cut
Flush cut
Too much-raising cut
Topping
Stub left
Tree canopies were reduced by half
Proper pruning cut (outside collar)
Ragged cut
57
15
7
44
43
54
53
60
92.0
24.2
11.3
70.0
69.3
87.1
85.5
96.8
Wound/pruning cut condition after pruning (Image
questions)
Flush cut wound closure
Sprout growth
Good wound closure
Tearing bark wound closure
48
38
34
53
77.5
61.3
54.8
85.5
Pruning equipment
Secateurs can be used to prune small branches (diameter about
3cm length) and large (diameter more than 3cm length)
handsaw can be used to cut large branches (diameter more than
3cm length)
Pole pruner can be used to prune the branches of tall trees
Chainsaw can be used to prune large branches (diameter more
than 3cm length)
29
54
52
61
46.7
87.1
83.9
98.4

216 Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
Table 4 shows number and percentage of tree pruning workers' knowledge level score. The majority (88.7%) of
them are almost knowledgeable with scored between 18 and 26 correct answers. It is followed by 5 of them (8.1%)
with high knowledgeable and slightly knowledgeable (3.2%). None of them almost not knowledgeable. Based on the
result from Table 2, the majority of workers should be highly knowledgeable because majority of them had
experience in pruning job over 5 years and had followed the pruning course. This shows they still have no awareness
of the importance of doing proper pruning.
Table 4. Knowledge level score
Knowledge level
Number of
respondents
Percentage of
respondents
(%)
Highly knowledgeable
(Between 27 and 33 correct answers)
5
8.1
Almost knowledgeable
(Between 18 and 26 correct answers)
55
88.7
Slightly knowledgeable
(Between 9 and 17 correct answers)
2
3.2
Almost not knowledgeable
(Between 0 and 8 correct answers)
0
0
6. Conclusion and recommendation
Tree pruning practices should be emphasize and give attention to ensure the health and welfare of urban trees in
the long term. Higher knowledge in pruning practice will produce a sense of awareness and good attitude in doing
pruning work. Based on the result, the knowledge of the tree pruning workers especially on correct pruning
technique and wound/pruning cut condition after pruning is still needed to be improved. Based on demographic data,
it is recommended for Kuala Lumpur City Hall (DBKL) to expose all of their workers in the pruning course so that
they can increase their knowledge and awareness in tree pruning. By increasing pruning knowledge it is hope that
the quality of pruning practices will be improve to ensure the health of the trees and provide benefits to human’s
life.
Acknowledgements
Thanks are due to the shade tree management unit Kuala Lumpur City Hall (DBKL) for their support and
cooperation throughout the study. Authors also wish to acknowledge the financial support provided through
LESTARI Grant, Research Management Institute, Universiti Teknologi Mara (UiTM), Malaysia.
Pruning equipment must be sharp
Pruning equipment must be sterilize before/after use
Pruning equipment must be suitable with branches length
Pruning equipment must be blunt
59
50
58
95.2
80.7
93.6
Pruning can be done when:
Tree in worst condition (diseased branches, broken, etc.)
Trees that are in stress condition
Young tree
Newly planted tree
Drought season
59
5
12
57
42
95.2
8.1
29.3
92.0
67.7

217
Norainiratna Badrulhisham and Noriah Othman / Procedia - Social and Behavioral Sciences 234 ( 2016 ) 210 – 217
References
Abdul Kadir, M. A., & Othman, N. (2012). Towards a better tomorrow: Street trees and their values in urban areas. Procedia - Social and
Behavioral Sciences, 35, 267 – 274.
Abdolmaleki, M., & Mohebi, H. (2014). A diagnostic-remedial survey of Iranian EFL teachers’ knowledge and practice of suprasegmental
pronunciation features. Procedia - Social and Behavioral Sciences, 98, 36 – 43.
Ainuddin, N. (2014, June 18). Arborist in short supply. The Star Online.. Retrieved from
http://m.thestar.com.my/story.aspx?hl=Arborists+in+short+supply&sec=news&id=%7B79A499A4-17C6-4FB3 B272-
3AD921A0A0C1%7D
Brunson, M. W., & Reiter, D. K. (1996). Effects of ecological information on judgments about scenic impacts of timber harvest.. Journal of
Environmental Management, 46, 31–41.
Cai, W. J. (2007). People’s perception, reliability and utilization of Chinese medicine and its associated factors. Annual Report of Chinese
Medicine, 27(4), 153-224.
Clark, J., & Matheny, N. (2010). The research basis to pruning: A review of the literature. Arboriculture and Urban Forestry, 35(3), 110-120.
Clark, J. R., & Matheny, N. (2010). What does research tell us about the practice of pruning in arboriculture?. Arborist News, 19(1), pp.41-44.
Close, D. D., Groninger, J. W., Mangun, J. C., & Roth, P. L. (2001). Homeowners’ opinions on the practice and effects of topping trees. Journal
of Arboriculture, 27,160–165.
Dujesiefken, D., & Stobbe, H. (2002). The hamburg tree pruning system – A framework for pruning of individual trees. Urban Forestry & Urban
Greening, 1,75-82.
Evans, E. (2000). Trees damage. Retrieved on 2008, November 4, from
http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/treesnew/text/tree_damage.html).
Fini, A., Frangi, P., Faoro, M., Piatti, R., Amoroso. G., & Ferrini, F. (2015). Effects of different pruning methods on an urban tree species:A four-
year-experiment scaling down from the whole treeto the chloroplasts. Urban Forestry & Urban Greening, 14, 664–674.
Gilman, E. F., & Grabosky, J. C. (2006). Branch union morphology affects decay following pruning. Journal of Arboriculture, 32(2), 74-79.
Harris, R. W., Clark, J. R., & Matheny, N. P. (1999). Arboriculture: Integrated management of trees, shrubs and vines, 3rd ed. , Englewood
Cliffs, NJ : Prentice Hall.
Jensen, E. V. (2000). The effects of information on Danish forest visitors’ acceptance of various management actions. Forestry, 73,165–172.
Kuhns, M. R., & Reiter, D. K. (2007). Knowledge of and attitudes about utility pruning and how education can help. Journal of Arboriculture &
Urban Forestry, 33(4), 264–274.
Kuhns, M. R., & Reiter, D. K. (2009). Tree care and topping beliefs, knowledge, and practices in Six Western U.S. Cities. Journal of
Arboriculture & Urban Forestry, 35(3), 122–128.
Mahadevan, K. (2009). Knowledge, attitude and willingness to adopt environmentally responsible behaviours: A survey among students of
Universiti Sains Malaysia. MA tesis, School of Communication, Universiti Sains Malaysia.
Mahmud, M.H., & Siarap, K. (2013). Kempen pencegahan H1N1: Kajian tentang pengetahuan, sikap dan amalan penduduk di timur laut Pulau
Pinang. Malaysian Journal of Communication, 29(1), 127-140.
Meade, G., & Hensley. D. (1998).. Pruning landscape trees and shrubs. CTAHR CES L-8.
Murad, A. G. (2000).. Hazard evaluation of mature urban street trees in Kuala Lumpur. MSc thesis, Universiti Putra Malaysia.
Norainiratna, B. (2013). Tree health assessment and maintenance practices in Taman Tasik Titiwangsa, Kuala Lumpur. MSc thesis, Universiti
Putra Malaysia.
O’Hara, K. (2007). Pruning wounds and occlusion: A long-standing conundrum in forestry. Journal of Forestry, 105, 131-138.
Ow, L.F., Ghosh, S., Sim, E.K. (2013). Mechanical injury and occlusion: An urban, tropical perspective. Journal of Urban Forestry & Urban
Greening, 12, 255– 261.
Schwartz, S. H. (2012). An overview of the Schwartz Theory of Basic Values. Online Readings in Psychology and Culture, 2(1). Retrieved from
http://dx.doi.org/10.9707/2307-0919.1116
Sellmer, J. C., Cotrone, V. J., McGann, M., & Nuss, J. R. (2004). Pruning ornamental plants. The Pennsylvania State University Extension
Bulletin . #AGRS-95. pp28 .
Shigo, A. L., & Larson, E.H. (1969). A photo guide to the patterns of discoloration and decay in Living Northern Hardwood Trees; United States
of Department of Agriculture (USDA), Forest Service, Northeastern Forest Experimental Station: Upper Darby, PA, USA. pp. 1–100.
Smiley, T.D., Kane, B. (2006). The effects of pruning type on wind loading of Acerrubrum. Arboric. Urban For, 32, 33–40.
Sreetheran, M., Adnan, M., Azuar, A.K. (2011). Street Tree Inventory and Tree Risk Assessment of Selected Major Roads in Kuala Lumpur,
Malaysia. Journal of Arboriculture, 37(5), 226–235.
Tyrväinen L. (1999). Monetary valuation of urban forest amenities in Finland. Academic dissertation. Finnish Forest Research Institute,
Research papers 739. Finnish Forest Research Institute, Vantaa.
Valente, T., Paredes, P., & Poppe, P. (1998). Matching the message to the process: The relative ordering of knowledge, attitudes, and practices in
behavior change research, Human Communication Research, 24(3), 366–385.
Vogt, J.M., Watkins, S.L., Mincey, S.K., Patterson, S.M., Fischer, B.C. (2015). Explaining planted-tree survival and growth in urban
neighborhoods: A social–ecological approach to studying recently-planted trees in Indianapolis, Landscape and Urban Planning, 136, 130–
143.
Zakaria, A. Z. (2012). Fallen tree problems in the field of landscape architecture in Malaysia / Ahmad Zamil Zakaria. In: 1 st International
Conference on Innovation and Technology for Sustainable Built Environment 2012 (ICITSBE 2012), 16 – 17 April 2012, Perak, Malaysia.