"Thanks for your query. These are a variety of cypress tree (possibly Italian) but I’m not 100% sure. The effect is unusual and has likely come about as a result of damage (vandalism) when the trees were young, forcing the trees to produce new leaders, which is what we see in the strange shapes. Ironic that vandalism can result in something visually creative sometimes!"
When I thanked him he added this:
"It was an educated guess that this is what happened to them, based on their form. It is possible that the result is genetic but I would still argue that damage at the formative stage was the most likely cause."