In the world of Low Impact Design (LID), the terms raingarden and bioretention are often used interchangeably. However, there are some inferred differences between these two LID practices. These differences were highlighted during recent work with the Washington Department of Ecology, which designated Silva Cell as functionally equivalent to a bioretention facility.
(Read “Rise of the Curb Cut: Part 1 here). The fundamental behavior of stormwater in curbs and street design is simple. Each creature, each inanimate object, each molecule of everything functions and abides by its simple and powerful law every day: gravity. From this basic concept, direct parallels can be drawn between the design elements… More
Before anyone is lost to their thoughts or misgivings about the title of this post, this is not a piece on Germany in World War II or military strategies. Rather, this is about how odd parallels can be drawn between streets and nature, the built environment and natural one, and how an understanding of history… More
There are lots of ecological arguments for creating more green roofs, particularly in urban environments. Until now, though, I had never considered one additional benefit – certifying them as wildlife habitats. I started thinking about this after reading an item on the S.W.I.M. Coalition website about the Christian Reformed Church in North America (CRCNA) of Grand… More
Alex Shigo, one of the most famous plant biologists and fathers of arboriculture, is widely credited with making huge improvements to standard industry practices. One of his famous sayings was an exhortation to “touch trees.” I’ve adapted this to my own related specialty, urban trees and soils, which is why I often tell landscape architects and other… More
A couple of years ago, I wrote hopefully about the City of San Francisco’s plans to revamp our main thoroughfare, Market Street. The project, which began in 2009 and planned to improve transit, pedestrian spaces, and business opportunities, represented a tremendous opportunity for Market Street to meet the grandness of its proportions. I hoped for… More
What do trees really need? Sunlight, surely. Water, and nutrients from the soil. But do they need pruning? Some trees are said to be self-pruning, shedding dead limbs or even overly heavy live limbs. Trees and plants have evolved for millennia without our intervention.
Earlier this year, I wrote about a study by Dr. Jessica Sanders, Director of Technical Services and Research at Casey Trees, that concluded that “apparent available soil” was a good predictor of ultimate tree size. Now, Dr. Sanders and two co-authors, Jason Grabosky and Paul Cowie, have published a complete version of their study in the… More
My generation, the millennials, has been described as politically apathetic many times and by many people. I’m not sure it’s an entirely fair characterization, but I do relate to a feeling of powerlessness when it comes to influencing policies and other types of fundamental changes. When I was a kid, my parents and teachers would… More
Read Part I of The History of Street Trees here. In the United States we have hockey season, football season, etc. Well, in the Middle Ages of Europe there was a war season. It was after the fields were sowed and through the summer until harvest. Lords (i.e., kings) would round up farm boys and… More
Need a lively discussion topic for the dinner table, a road trip, or a hot date? How about stormwater credits for trees?! A group of us started discussing the intricacies of how to set up a stormwater credit system for trees two summers ago, only to discover that the subject was even more “interesting” (both… More
Silva Cells were originally developed to provide adequate tree rooting volumes even in areas dominated by pavement. They do this by extending rootable soil volume under HS20 load bearing surfaces. These rootable tree volumes and the large trees that root in them are also an efficient sustainable stormwater management system. Sometimes people ask us if… More
Soil. Stormwater. Sustainable Infrastructure.
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