Why did Ljubljana plant trees in subzero temperatures?

Apparently, it has something to do with being a youth-oriented city

Normally, we don’t think of December as a prime time for horticulture and gardening, yet this is when public workers from the Slovenian capital Ljubljana planted some 80 trees in the city – often when temperatures dropped below zero.

City officials, however, explained that this is in fact perfectly normal and not bizarre, plus it gives the trees the chance to show off their green foliage by the time summer comes.

In addition, one of the trees, a linden sapling, was planted as a celebration of the tenth anniversary of the city being declared a Youth Friendly Municipality, for which it received a certificate back in 2012.

Ljubljana got more than 1000 new trees in 2021

The young tree was a gift from the programme. It confirms that the city remains at the forefront of youth empowerment with its policies.

It was planted on the grounds near the Cukrarna Palace, an ex-sugar factory converted into a cultural centre for youth activities. Still, many wondered what’s the point of planting a tree in snowy conditions and will that tree even survive?

Nejc Praznik, an arborist who takes care of arranging green areas in the City of Ljubljana, offered an expert explanation: “Autumn-winter is actually the best time to plant trees. We start digging up trees from the nurseries only when they drop their leaves and go into the period of dormancy. This time varies a little from year to year, this year it was in the first half of November. Trees with a root bale are transported to our warehouse, where they are protected from low winter temperatures until planting with straw bedding and jute coatings.”

However, he added that temperatures below minus 10°C could be potentially harmful, but the reality is that the cold air doesn’t translate to cold soil. At depth of 40 cm underground (where the roots lie), it stays 10 degrees warmer than the exterior.  

Ljubljana usually plants between 300 and 600 new saplings per year but last year was a record one with the number exceeding 1000!