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?