Friend or Foe? Cottonwood Poplar, Populus nigra
By: Shari Jones
Populus nigra, the black poplar (also known as the Lombardy Poplar), is a species of cottonwood poplar, the type of species of section Aigeiros of the genus Populus, native to Europe, southwest and central Asia, and northwest Africa. Source: Wikipedia
Metropolitan landscapes are not easy places for trees, yet trees are extremely important to the quality of life of people and animals that live around them.
Before the first Spanish incursions into California in 1769 the dominant trees were oaks, pines and other conifers. There are naturally occurring 300 types of trees in California. Starting in the mid nineteenth century, nurseries started producing other species and homeowners and cities started planting non-native species - for ornamentation, shade or agriculture.
The Poplar has many positive qualities. The species is fast growing and narrow. I imagine these were planted in San Francisco because earlier homeowners appreciated that they would get results quickly and in theory, they wouldn’t take up too much space on the sidewalk.
Unfortunately, as non-native to San Francisco, they are susceptible to pests and diseases. They also require a lot of water. Several of these trees have had to be removed along this street due to disease and the risk that they would fall in a big wind storm.
Having said that, I really appreciate the leaves and the sound of the wind through them as I walk down the street. I am curious about the decisions that the city made long ago to plant these trees on this street. I wonder if they would make the same choice today.
It’s clear that the Poplar wants to spread its roots! Surface roots seek water and in doing so, they tend to lift up and crack the sidewalk. It has created some issues as it can be difficult for pedestrians to navigate the sidewalk.
These trees are doing their best to survive in a metropolitan landscape but they are knocking up against the desire for people to create a safe and tidy cityscape. It’s interesting to me how these trees illustrate the tension between nature and urbanization, and the impact that short-term decisions on tree planting can cause knock-on consequences down the line.