Roadside Oscar Malapitan led the planting of D.

Roadside trees reduce air pollution (Rai, 2015), noise pollution
and water logging; moderate effect of wind and incoming radiation; and provide shade,
aesthetics, and ornamentation (National Highways Authority of India, n.d.).
Firetree (Delonix regia) is a
roadside tree (Rai, 2015; Suhane et al, 2016) mainly valued as a decorative
tree (Orwa et al, 2009). Unfortunately, D.
regia was deemed dangerous in Puerto Princesa City, especially along Sta
Monica National Highway after a firetree fell down a driver resting in his
tricycle (TV Patrol Palawan, 2014).

According to Ziyou
Tian (2016), D. regia is a popular
tree that provides shade to the urban environment in Hong Kong. Dr. Allen Zhang, assistant
professor at the Faculty of Design and Environment at the Technological and
Higher Educational Institute of Hong Kong (THEi) claimed “the flame tree could
adapt to Hong Kong’s environment very well in urban parks, public housing
estates, and public spaces, but not as a roadside tree. Limited space results
in oxygen deficiency, malnutrition and conflict with pavement” (qtd. in Tian,
2016). This is due to branches growing horizontally (Orwa et al, 2009). Thus,
Hong Kong cannot plant the tree in crowded areas where space is scarce yet it
is still widely planted in less densely populated areas (Tian, 2016) for its
aesthetic purpose. Whereas in Australia, D.
regia is considered an environment weed for having invasive roots that
damage sidewalks (Queensland Government, n.d.).

Meanwhile, D. regia
falling has caused two deaths in India in 2017, with falling trees claiming 17
fatalities in the last six years. Assistant Municipal Commissioner and local
(M-West) Ward Officer Harshad Kale said “the tree looked strong from outside,
but its roots were weak” pertaining to the D.
regia roots not appreciating moisture due to the continuous rain (qtd. in
Singh, 2017).

On the other hand, under the ‘Replace your Tree Program’ in 2014,
the Metropolitan Manila Development (MMDA)
gave around 1,000 D. regia saplings
to the residents who lost a tree/trees due to Typhoon Glenda. The Department of
Environment and Natural Resources provided the saplings.  As mentioned by MMDA Chair Francis Tolentino,
D regia is pleasing to the eye and is
not hard to take care of; they are good replacement for the uprooted trees
(qtd. in Brizuela, 2014). Following this, Caloocan City Mayor Oscar Malapitan
led the planting of D. regia along
Saranay Road, Caloocan (David, 2017) as part of his environment-friendly
solutions in providing oxygen, shade, and adding aesthetics to the streets
(Politics, 2017).

Similarly, Palawan has D.
regia as roadside trees in Puerto Princesa City and Culion (PCSDS, 2006).
Usually planted for ornamental purposes, D.
regia has gained attention from tourists visiting the province, as
mentioned in several blogspots (Mikem, 2011; Mae, 2017; Kathryn, 2017).

However, despite gaining popularity for its beauty, D. regia has been deemed dangerous by
the residents living beside Sta. Monica National Highway due to the increasing
fatalities of D. regia falling (TV
Patrol Palawan, 2014). As such, falling of
trees along highways and roads were filed as the main reason for the public to
complain, followed by brittle and thick branches, and leaning tree trunk,
relative to roadside trees (Hasan et al, 2016).

Citing this,
the researchers will aim to identify fracture properties of D. regia in relation to the climate, air temperature, and soil of the
city, thus determining its appropriateness to be planted as a roadside tree
along Sta. Monica National Highway, Puerto Princesa City.