Nelda Matheny
Planting and managing trees in engineered soils and constructed spaces
Tuesday 11th September 14:35pm
As part of the afternoon session which focuses on engineered solutions for constrained environments, soil quality specialist Nelda Matheny will impart her experience in the San Francisco Bay Area with planting and maintaining trees in engineered soils, modified pavement treatments, planting areas over structure, and in storm water management areas.
Nelda has been instrumental in developing tree management programs for a variety of public agencies and private companies. During a decorated career in arboriculture Nelda has won the ISA President’s Award, the Alex Shigo Award for Arboricultural Education, to name just a few. As well as soils, she specializes in water quality assessment, plant problem diagnosis, landscape management, tree risk assessment and tree preservation during construction.
Speaking on her passion for arboriculture she said “What’s fascinating to me is that trees are influenced by a myriad of factors even though they’re a static organism. Because trees don’t talk, it sometimes takes a Sherlock Holmes kind of effort to try and figure out what is wrong with them. In the 25 years that I've been in business there has been an incredible revolution in concerns about tree safety and how we approach evaluations”
The mixed uses of urban trees are often dealt with by engineering the spaces in ways that may compromise efforts to increase canopy cover and maximize benefits they provide; Nelda will offer us insights and solutions that utilise engineered soils based on her experience since founding the California consultancy ‘Hortscience’ in 1983.
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Björn Embren
The search for the indestructible urban soil: Stockholm black skeletal soils with biochar
Tuesday 11th September 15:40pm
Björn Embren has been a Tree Officer in Stockholm since 2001 and a driving force in the city’s development of plant beds for trees in paved areas.
The Stockholm Biochar Project converts plant waste into biochar, which is used to encourage plant growth. The process sequesters carbon from the atmosphere (equivalent to emissions from 3500 cars) and will deliver a return, within 8 years, on the city’s investment of just over $1 million.
After winning the Mayors Challenge in 2014, the City of Stockholm built its own plant in 2016, to produce biochar from garden waste submitted to the city's recycling facilities. The produced biochar is used in Stockholm plant beds.
Björn said that they were using biochar before it became a buzzword “We actually started using biochar with the city’s trees six months before we knew its name. We just thought it was simply charcoal, nothing else. It wasn’t until 2009, when I read a journal article about biochar, that I realized our “charcoal” was something special with many benefits we hadn’t ever considered. Having a name for it allowed us to learn more about biochar, both online and through academic contacts, and in 2011 we identified the potential to connect biochar with the existing recycling facilities in Stockholm.”
“When you give people the extra information about how to use biochar, it’s simple for them to understand the benefits. Plus, biochar gives people hope. It’s a way that you, through your individual effort, can do something about climate change. And that’s a nice thing.”
Bjorn will explain the science behind his solution as well as its numerous positive impacts. Including how it avoids damage on soils both during the construction phase and during the expected life of the plant beds by using sorted stable materials as supporting elements, which result in a substrate that almost becomes an indestructible soil mixture.
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