A Giant from Thailand - Tamarind Tree Transplanted within Hortpark

Tamarindus indica (Tamarind) somewhere in the middle of Hortpark, which was transplanted from the entrance of Hortpark.

Tamarind Road in Yishun is named after this tree. The fruit is known locally as "assam".

The area immediately around the trunk was sunken, as compared to the outer ring of the compost circle. This is possibly due to the root ball of the tree sinking, as it was transplanted when it was already a large tree.

Fungal fruiting bodies a.k.a. mushrooms observed at the root flare of the tree, presumably exacerbated by the compost that is piled around it.

Before being transplanted to the middle of Hortpark. Compare this root flare with the one above, the buttress roots were more apparent. Photo taken approximately 7 years ago (Feb 2010).

Somehow in the trenching process the rootball was raised, and the root flare was covered. Hence, resulting in the tree being planted at grade or lower than grade, even though it was thought to be planted higher than grade by using the top of the rootball as a guide.

 

Tamarindus indica (Tamarind) was located at the carpark entrance of Hortpark at Hyderabad Road. This tree was first brought in from Thailand. At the time when it was being transplanted to the middle of Hortpark, it had been there for 2 years (since 2008). Girth was 1.5m (DBH 0.48m or 18.78 inches) and height just under 10m.

The tree after its second transplanting.

Generally, this species has low chances of success when transplanted, which is in stark contrast to the other species in the same family (Leguminosae). It was being transplanted without trenching beforehand, and waiting a few weeks to encourage new fine roots*, and that would further lower transplant success. Trenching more than 10 weeks before moving the tree may reduce the advantage of root pruning, as regenerated roots will quickly grow outside of the rootball.

A rule of thumb was that transplanted trees would take one year to recover for every inch in diameter. Recovery was defined as being able to resume growth in girth, not just putting out new foliage. The tree would need, in "theory" (again, rule of thumb), almost 19 years to recover, based on a DBH of 18.78 inches. Hence, the tree would need 12 more years from today in order to increase in girth. That is, if it manages to overcome a possible basal decay as indicated by the fungal fruiting bodies.

*Fine roots refers to roots (0.05 - 2.0mm dia.) that are colonised by mycorrhizae, and both of them are responsible for the entry of water and nutrients into the plant from the soil.

Accumulation of years of leaves and debris covering root collar

Somewhere adjacent to the M+S building along Beach Road.

North-east facing heap approx. 0.5m height

 South-west facing heap approx. 0.3m height. One large surface root damaged.

Recent soil disturbance due to construction of the M+S building. Distance from edge of trunk to "heap cut" is 0.8m for both sides. The accumulated material was hard but a bit spongy. Width of planter 2.0m.

Peltophorum pterocarpum (Yellow flame tree) - 2.0m girth, 9m height, 12m spread. 

Recently crown thinned and topped.

Reminded me of some years ago, I spent nearly two hours breaking and clearing the accumulated material at the tree base of a Gymnostoma nobile (Bornean Rhu) with a hand hoe (see photo below). In this photo, my colleague Eina is putting on the finishing touches by filling up the depressions with a good soil mix and contouring. On the right was a tree that still had a compacted tree base.

Hand hoe

 The area where the bark did not develop fully the bark was decayed was the height of the accumulated material.

What seemed like a before-and-after photo but its not. The tree on the right, which was doing better to begin with had its accumulated material removed, and the tree on the left had not been worked on. This photo was taken just 4 days after the accumulated material was removed.

The root collar excavation should have been done on the tree on the left as the leaf density is lower than that of the tree on the right, which indicated a possible defect in the root collar.

Taken on 26 Mar 2016

Tree Branch Falls on Car at Cairnhill Road on 12 May 2017

Opposite of The Laurels @ 38 & 40 Cairnhill Road. The branch was so large I thought it was a whole tree at first. Photo: Stomp

Turned out to be one of the co-dominant branches. Photo: Stomp

View of the tree trunk and crotch taken on Aug 2016. Note the branch bark ridge. Photo: Google Maps Streetview

Overall view of tree taken on Aug 2016. Photo: Google Maps Streetview

Mr. Mattheck said that co-dominant branches are not bonded together like a branch-stem attachment and hence weaker, but they rarely fail because the branches rise vertically, as compared to a branch that hangs perpendicular to the stem.

Bogstadveien 19, Oslo, Norway

Continuation of the second part of this blogpost: http://openplants.blogspot.sg/2017/05/monitoring-at-risk-trees-using-spectral.html

Figure 1. Google Maps screenshots - the left photo was presumably from an earlier date, as compared to the right photo that has a tree missing in the middle.

Figure 2. A gap in the middle where a tree could have been. Credit: Google Maps.

Figure 3. Another angle of where a tree could have been. Note the house with orange window frames and the house with white walls in the background of the red ellipse. Credit: Google Maps.

Figure 4. Google Streetview taken on August 2014 screengrab. Could that tree be mislabelled as Alive Tree #2? That period was somewhere in summer, so that was maybe why the trees were having lush growth. Note the construction material laid on the area in front of the tree.

Figure 5. Google Streetview taken on May 2016 screengrab. Could that tree be mislabelled as Alive Tree #2? That period was somewhere in late spring, so that was maybe why the trees were still putting out leaves. Hence, hard to tell whether the reduced leaf density was due to stress. Note the slight difference in foliage colour between the two tallest trees. May have to wait till 2018 for the Google Streetview car to go past that park to see whether the fallen tree was mislabelled or not [if the tree is not there anymore, then its mislabelled].

Figure 6. Photo from Aftenposten (The Evening Post) 10 Aug 2016, taken by Rolf Øhman. Several other trees around the city fell in the same night, so presumably there was a short storm event? Note the house with orange window frames and the house with white walls in the background, as mentioned in Figure 3.

Is the tree fall related to the construction activity of converting soccer pitch surface from loose asphalt to paved asphalt? Fertilisation on the lawn behind the tree causing the tree to develop a smaller root system? Dutch elm disease? Leaching of heavy metals and PAHs from the paved asphalt?

Excerpt of News - Botanic Gardens Safe for Visit: NParks

Comprehensive tree management scheme in place and more checks will be done, it says.
Samantha Boh The Straits Times 13 Feb 2017

...
Singaporean plant expert Jean Yong, an eco-physiologist at the Australian Research Centre for Mine Site Restoration, said...

"Issues relating to urban trees are challenging and require good scientific allometric assessment to better predict tree stability when the soil is very wet, and when encountering a seasonal microburst of strong gale-force winds," Dr Yong said.

Besides tree health, which routine inspections now focus on, constraints to root space volume should also be recognised and documented, he added.

Monitoring At-Risk Trees Using Spectral Reflectance Data from Satellites

A desktop early warning method for arborists and tree management to carry out migitating actions.
Uses data from two commercial satellites: WorldView-2 and WorldView-3.
Satellite data processed by remote-sensing software to generate spectral reflectance of individual trees, and compared with the data of previous year(s).
Have to be using cloud-free images, although software could compensate for other atmospheric effect on images.
Spectral reflectance relates to chlorophyll content and leaf cellular structure, which correlates to tree stress and/or structural stability. These symptoms could not be readily observed by the naked eye.

For the following analysis, data of the spectral bands of red, red edge, and near-infrared 1 and 2 on 25 May 2010 and 17 April 2015 (five years apart) were acquired from WorldView2 satellite.
- Three Banyan trees (Ficus microcarpa) in Hong Kong.

Over the five years, the drop in the spectral reflectance of the near-infrared band for Tree #1 was 4%, Tree #2 was 3.5%, and Tree #3 was over 7%.
The author believes that there is a direct correlection between the drop in spectral reflectance and the closeness to the date of collapse.
Based on the indicators, all three trees were stressed and structurally unstable, leading to their failure after 96, 94 and 2 days, respectively.

In a back-dated analysis for a tree that has already fallen on 10 August 2016, data dated 2 September 2014 and 8 September 2015 (one year apart) were acquired from WorldView2 satellite.
- Three Elm trees (Ulmus sp.) in Oslo, Norway.

In just one year, the drop in the spectral reflectance of the near-infrared band for Fallen Tree #1 was 5%. There was not much variation in spectral reflectance in the adjacent Alive Tree #2 and Alive Tree #3.

Conclusion:
This method is not meant to diagnose the cause of stress and structural instability.
Presents more objective and quantitative means to measure the health of trees.
Could be combined with field inspection to enhance the management of trees by implementing timely mitigating actions.

Reference:
International Society of Arboriculture's Arborist News, Volume 26, Number 2, April 2017

Terrarium Basin/Sink Countertop

 A basin/sink countertop with a terrarium, which can be accessed from the doors in front.

Can be used from both sides with a swivel tap. LED light strip illustrates how the waste water would flow, obviously.

The tap was not connected to a water source here, but this is a working model that can function as designed.

My attempt in instructing the fabrication of this countertop. Using a CAD software that is not Autocad.

 Maybe a rectangular basin like this would be more suitable?

A fish tank sink that was a inspiration to the above design.

Alternatively, it can be used to contain a Zen garden.