A hammock tied to two leafy branches, makeshift shelves to organize a few items of clothing and a large bottle of water make up the house in the air of this 35-year-old man.
"It was a new experience, I slept there in the park with the Venezuelans. They stole a lot and (because of) the danger ... I decided to get on this tree," he tells AFP.
Álvarez reflects on his situation. "The only ones that sleep in the trees are the animals," however, he adds, thus at least alleviating the sometimes infernal heat of Bucaramanga, capital of the department of Santander (northeast) with 528,000 inhabitants.
Two years ago he fled with his wife and three children from the crisis in Venezuela, where there was no longer a job for a butcher like him. In Colombia, he tried to earn a living as a recycler, but was unable to rent a room. His family is no longer with him.
"They are in Venezuela and they do not want to come, because it is not easy here. It is not easy in Venezuela, but it is better to war there, than to come to war harder, to come from scratch," says this urban Tarzan.
Ronal Rodríguez, an analyst at the Venezuela Observatory of the Colombian University of Rosario, assures that "housing occupies the first place" among the needs of migrants.
"The problem is that many of the responses remain at the humanitarian and emergency assistance stage ... because migration has been thought only in the short term," he says.
But since the exodus accelerated in 2015, the numbers have grown and there are already 4.5 million Venezuelans outside their country, according to the UN.