Arboriculture's Transition into a Profession

The August 2019 edition of Arborist News had an article on the history of arboriculture and how it became a profession for arborists, but I am not going to summarise the part on history. But I do want to touch on the character below.

John Evelyn, an Englishman, published  "Sylva or, a Discourse of Forest Trees" in 1664 and called for increased tree planting and restoration of woodlands to ensure the nation's economic wellbeing. So just you know that certain country leaders were not the first to have that idea. Mr Evelyn at that time observed that tree pruning practices are poor and thus trees were full of defects. He advocated that pruning to "avoid the bark and branch tearing" and "avoid cuts close to the bole".

The author of that article (Shane A Lanigan, Chartered Arboriculturist) recalled in the 1971 being taught to make flush-cuts in order to "prevent fungal infection" and facilitate "fast and complete wound occlusion". It took Alex Shigo with books published in the 1990s and early 2000s to teach modern arborists to cease flush-cutting.

This recommendation was often forgotten, and it seemed that our industry education and standards have advanced and regressed at the same time.

Flush-cuts of tree, photo taken on Jan 2012.

Another angle of the same flush-cuts, photo taken on Jan 2012.

Back to the USA. From the early 1920s, the practice of arboriculture florished and in 1924, scientists and practitioners came together for the first 'Shade Tree Conference'. Shade tree is a "code name" for ornamental trees. An organisation not unlike a society was formed and named National Shade Tree Conference (NSTC) in 1928. In 1946 the NSTC created a fund for research and members presumably benefitted from the research. In 1961, the organisation changed its name to the "International Shade Tree Conference" and in 1976, it became the International Society of Arboriculture (ISA). Certification of arborists was first offered in the USA in 1992.

The "Certified Arborist" programme was made available in Singapore I believe in 2005, which was facilitated by the National Parks Board (NParks). After almost 15 years of seeking scientific knowledge from this esteemed society and scientists from elsewhere, I think that NParks and its arborists had made a positive impact in general on the trees under their care.

Getting the Point of Ceiba speciosa and Ceiba pentandra

Dendro the detective decided to visit a friend who was managing a rather tropical garden. The friend is an arborist and he planned to climb up a Ceiba speciosa (Brazilian silk floss tree) to do crown cleaning of some deadwood for aesthetics. The detective looked up the crown with his binoculars and handed it to his friend to have a look too. There were thorns on the branches and upper trunk, but no thorns from ground level to about 12 meters up. If the arborist had anchored his climbing line on one of the thorny branches, it could be disastrous. Thorns seemed to be an adaptive feature in Ceiba speciosa to deter damage by browsing animals when the trees are in juvenile stage. As the tree gets older, the thorns could weather off. The arborist made a note to himself to take some time to look at the upper scaffold branches with binoculars before deciding to climb or not. In this case, he decided to rent an aerial lift.

Ceiba speciosa (Brazilian silk floss tree)

Silk Floss Sky View. Photo by www.flickr.com/photos/tinyfroglet

Silk Floss Tree. Photo by www.flickr.com/photos/tinyfroglet

Ceiba pentandra (Variegated), Variegated Kapok tree at Gardens by the Bay - The lower trunk on the left seemed to be devoid of thorns but the right still have some thorns.

 Same variegated species at Hortpark - thorns still present on lower trunk.

On the upper trunk and branches as well.

Signage of the tree at Hortpark.

 Some species of Ceiba in the Flower Dome of Gardens by the Bay.

A non-variegated Ceiba pentandra (Kapok tree) at Gardens by the Bay. Appeared to have no thorns anywhere but some bumps though.

 

 A Ceiba of unknown species with menacing thorns on the lower trunk at Singapore Botanic Gardens. In the vicinity of the dry/cactus garden.

Changi Airport Interior Trees

 Interior landscape like the above gets changed from time to time according to the holidays or themes. The plants and trees would get some time in an outdoor nursery to take up natural sunlight when they are not on display.

 But how about trees that are permanently planted indoors like this Heteropanax fragrans (Fragrant Aralia). Taken on 12 Nov 2017 at T4 presumably shortly after opening.

Same tree after almost two years. Taken on 19 Sep 2019.

 Another tree of the same species looking deprived of sunlight. It had some artificial lighting to help it, although its not much help.

 Ficus benghalensis (Indian Banyan) looking balanced even though one side is facing natural sunlight.

 Ficus maclellandii (Alii Fig), which I mistakened for Ficus celebensis (Weeping Fig) initially. One side of the tree seemed to have more leaves than the side facing away from the natural sunlight.

 The tree was topped at some point to prevent the apex from hitting the false celling.

I did not get the name of this tree despite the name tag being on the tree. Does not look like Heteropanax fragrans or Ficus species. Still looking good presumably due to the natural sunlight from the clear roof.