The sound of birds in trees is so ubiquitous we may not think about the strong connections these organisms have with one another. Birds need urban trees for food, nesting and protection. Those who work with trees may not be aware that certain tree pruning activities can endanger nests and remove habitat for our feathered… More
You’ve done your site analysis and ensured enough rooting volume for the tree. You spent time carefully selecting the right species and cultivar. You’ve even inspected nursery stock and rejected specimens with uncorrectable root defects. In other words, you tried to do everything right. Yet six months later, the trees don’t look so good. What… More
The other day, I passed a dead street tree in San Francisco Not an uncommon occurrence unfortunately, but this tree had once been on TV. The tree, a Paradox walnut, had been planted along with a second tree next to it as part of an art/science project called OneTrees designed by Natalie Jeremijenko. Jeremijenko cloned… More
This article tells the story in words and pictures about the evolution of a sidewalk on a single block in San Francisco. The 20th Street Biophilic Landscape is on 20th Street between Alabama and Florida Streets. This block is a flat area that was on the edge of or part of a tidal marsh. In… More
Quick – name three important types of urban open spaces…public parks, community gardens, umm…roof gardens…how about cemeteries? While making space for the living invariably involves destruction of open space, the space we make for the dead can be a uniquely important part of the urban forest. We owe our historical cemeteries a great deal in… More
Nature vs. nurture is an old debate in human psychology: are we the way we are because of our genetics or our environment? Plant people know that both environment and genetics play a role in plant development. Perhaps one of the most dramatic examples can be found in the Coast Live Oak (Quercus agrifolia) in… More
Someone thought this was a good idea: plant street trees that are already “limbed up” to provide clearance for cars, keep signs visible. No need for follow-up maintenance for the next 10 years….right?…
Ever wonder what kind of questions are asked at the “Ask An Arborist” booth at the local street fair? I spent a lovely afternoon recently with two colleagues at the Castro Street Fair in San Francisco. We handed out literature, shared reference books, and fielded questions like these.
The research has been out for a while now: circling, girdling, diving and kinked roots in the nursery pot lead to poor health, blown-down trees and shorter lifespans. With budgets for greenery shrinking, every tree or shrub has to last for a while.