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
Sure, you may already know the answer to the question of how trees transport water up to such incredible heights. But this video from Veritasium is still worth it. It explains principles I didn’t even realize existed (water can only rise about 10 meters when sucked through a tube?) and makes a very compelling case… 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
Welcome to the club, Durham! The minimum-soil-volumes-for-street-trees club, that is. Durham’s recently released landscape manual now includes the following soil volume requirements for street trees:
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
Disturbance to pipes and sidewalks caused by roots is one of the most commonly cited complaints about trees. One of the many questions I get asked about is whether they penetrate and plug up drain pipes frequently. The answer – perhaps surprisingly – is no.
Here is this week’s “Ask Jim Urban” column. Jim Urban, FASLA is an expert on urban trees and soils and his recent book, Up By Roots, is the industry bible on these topics. Jim was also involved in the development and design of the Silva Cell system. In this column, which we’ve run for once a… More
I have been wanting to write about the history of street trees. When I sat down to begin my research, I started in the usual place: Google. Then, because I’m a landscape architect, I looked at my reference books on the history of landscape architecture, urban planning, street trees, and horticulture. I didn’t find much… More
A few weeks ago, non-profit American Forests released their list of the 10 Best Cities for Urban Forests. Many deserving cities made the list, but to me it seemed like something important was missing from the judging criteria.
Soil. Stormwater. Sustainable Infrastructure.
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