When Gov. Jerry Brown pronounced an end to the drought emergency last month — but not to the possibility of another drought — it would have been just like him to quote another eminent Californian, the naturalist John Muir, who said that “we all travel the Milky Way together, trees and men.” Not enough trees, though, which is why making “urban forests” come true truly matters. That’s where Igor Lacan can help out. He’s an expert tree advisor with the University of California’s cooperative extension, a kind of Johnny Appleseed of urban forestry, planting the seeds of knowledge about what trees can do for us. And it’s high time for us to ask what we can do for our trees. What is your reaction when people say, ‘Yay, the drought is over’? My reaction is to say, yay, the drought is over. We now need to get back to maintaining our urban trees, which I think we’ve neglected a bit during the drought. We’re witnessing the end of the old paradigm where we’re just trying to remove the water from our urban surfaces, and we are slowly beginning to transition into the new paradigm where we try to use that storm water as a resource. Trees are regarded as a luxury by some who say, ‘Well, trees, after all, don’t grow in the desert.’ No. 1, trees are not a luxury. Urban trees are an absolute necessity. Trees improve lives in cities, from improvement in health to reduction in crime to increases in property values. All of these things are dependent on living healthy urban trees. Now, I’ve lived in Southern California for a few years myself, and Los Angeles is not actually a desert. There is a small but important difference between not a desert and a desert. Not only that, Los Angeles is an artificial ecosystem at this point, so we really should think very hard about what we want an artificial ecosystem to look like. When you talk about the benefits of trees, you cite many things, first of all trees as a benefit to public health. There was a famous study that showed that patients who were coming from surgery and had a view of trees required less painkiller than those who had a view of just a brick wall. And this act influenced hospital design to a certain degree. But, unfortunately, it hasn’t trickled into the broader field of architectural design quite yet. Humans have a preference for a view or nature in general. Having trees as part of your landscape, as something you look out on when you lift your gaze from the computer, makes a pretty substantial difference. I also wonder whether it has to do with the fact that our forebears of many hundreds of thousands of years past lived in trees as a safety measure, and trees give you a sense of security. There are theories in landscape architecture, and one of them is this thing called the prospect refuge theory, that says we prefer these landscapes that have some open space and some trees. It perhaps reminds of us of our very, very, very distant ancestors. It’s not surprising when you look at a lot of classically designed landscape: It’s not just a dense forest but also not plain open spaces — it’s a mix of trees, open space and paths leading somewhere. There’s another study about how having trees around a house influences babies’ birth weights. Babies are less likely to be underweight if the mother lived in a place surrounded by trees. That’s very important when you talk about support funding for urban forestry, because if we think of urban forestry as part of our health infrastructure — even as a very small part of our health infrastructure — it suddenly becomes very cost-effective to have healthy, living urban trees. What kind of numbers are we talking about with low-birth weight babies and women who live surrounded by trees? The actual number in the problematical birth weight was very small, but when you think…