Trees in Israel’s cities are increasingly at risk due to a lack of suitable habitats, experts warn.
According to landscape architects, city paving and the construction of underground car parks and basements are restricting the ability of trees to spread their roots.
The Israeli Association of Landscape Architects has decided to make 2015 the year of the tree, during which it is focusing its efforts on protecting urban trees.
The architects say they are concerned not only by the felling of mature trees to make way for construction projects, but also over the disappearing underground habitat that is essential for trees’ survival.
“Today, we see lots of mature trees in cities like Tel Aviv. But in fact, we are enjoying the fruits of the past, when trees were planted in a way that allowed their roots to develop underground,” said Shachar Zur, who is leading the architect group’s arboreal activities this year.
According to Zur, in recent years safety regulations have required that urban paving be based on compacting and sealing the ground. In addition, more and more underground car parks and basements are being built.
Trees need several meters for their root systems in the upper soil. If they don’t have it, they cannot reach adulthood. Adult trees are the ones that provide most of the advantages of urban vegetation, first and foremost a green landscape and moderation of heat.
“Urban trees are adaptable, but only to a certain point,” said Zur, adding that sealing the ground prevents water and nutrients from reaching the roots.
Zur recently began a research project at the Technion – Israel Institute of Technology, Haifa, to assess the status of urban trees. He said he was finding more and more sites where trees were having trouble developing, including in Tel Aviv. However, he added that awareness on this issue was high in that local municipality.
He believes that municipalities should consider the available technologies for safe paving that also preserve the soil elements essential for root systems, although he conceded that some of these are costly. Urban tree surveys – common in big cities worldwide – are also needed, he said.
The Tel Aviv-Jaffa municipality responded, “We are working according to clear and strict principles for the planting of trees. The minimal size of openings for the planting of saplings and their soil depth are today significantly larger than in the past, and the trend is to work toward enlarging them. As the tree grows, the opening and depth of the pit are made larger. In lots where there are basements or underground parking that reach the edge of the lot, habitats will be prepared for the trees that are an inseparable part of the roof of the basement or the underground parking garage.”