With the end of summer in Istanbul, the risk of autumn rains, strong winds and storms came to the fore again, and all eyes turned to the old and large trees in the city. In Şişli, the internal structure of trees that appeared healthy from the outside began to be systematically “rested” for the first time. Approximately 200 large and old trees will be scanned with sound waves, hidden rots on the trunks will be visualized in three dimensions and the possible risk of falling over will be calculated. The starting point of the study was the trees, which appeared to be rotting from the inside, although they appeared healthy from the outside. This scanning, which started in Şişli, also raised the question of how many of the thousands of old and protected trees in Istanbul were at real risk of falling before the storm.
THE INTERIOR OF THE TREES IS ROTTEN
The alarming incident took place in Teşvikiye last month. A large plane tree, which looked quite healthy from the outside, fell over. When the tree was examined, it was revealed that the rot started from the roots and progressed into the trunk. Şişli Municipality and Istanbul University-Cerrahpaşa Faculty of Forestry then examined the large and old trees in the district, and approximately 200 trees were identified in the first stage.
SENSOR IS INSTALLED
The method is similar to tomography applied to humans. So much so that, while sensors are placed on the trunk of the tree at certain intervals, how fast the sound waves sent to the trunk travel is measured. While sound travels faster in healthy tissue, it changes direction and slows down when it reaches the bruised or hollow area. The computer processes these differences and displays the internal structure of the body. If a suspicious section is found, the measurement is repeated at different heights. Thus, not only the existence of decay, but also where it starts and how far it progresses, is revealed in three dimensions.
MONUMENTAL TREE STATUS
Just because the inside of a tree is rotten does not automatically mean that it will be cut down. Experts also take into account the tree’s height, trunk thickness, crown width, slope, branching and wind load of the location. The study in Şişli has also revealed another fact. There are many more old trees in the district than thought. Assoc. Prof. from Istanbul University-Cerrahpaşa. Dr. According to the information provided by Serhun Sağlam, especially among plane trees, there are specimens that are over 100 years old and even reach 130-150 years old. Some of them have registered monument tree status.
MORE THAN 5 THOUSAND SPECIAL TREES
According to the data in IMM’s Istanbul Open and Green Area Approach document, there are 517 monumental trees and 4 thousand 561 trees worth protecting in the city. Thus, the number of monuments and trees worth protecting in Istanbul reaches 5 thousand 78. However, the storms experienced in recent years have made it more important to closely monitor the condition of especially large and old trees. As a matter of fact, in one of the strong southwest wind events in 2025, 39 trees fell in just a few hours, while trees and their broken pieces damaged 11 vehicles. During the storm in July 2026, fallen trees in different parts of the city disrupted transportation. In August 2026, due to the expectation of strong winds, 12 large green areas, including Emirgan, Yıldız, Gülhane, Fethipaşa, Beykoz and Çamlıca groves, were temporarily closed against the risk of branch breakage and tree fall.
