April 2008 student forum ramblings
STUDENTS ON GREEN ROOFS
 

"Green Roofs on the Curve"

By Christine Thuring, Student Editor (Download as a PDF)
 

Hello green roof enthusiasts!

If you’re coming to Baltimore, for the 6th annual Greening Rooftops for Sustainable Communities Conference, Awards and Trade Show, please stop by the Greenroofs.com booth (#108) to say hello! In the meantime, I’d like to share with you a little bit about what I’ve been up to and what this conference holds.

I’ve been very busy the last few months organizing North American’s first green roof tours to Europe: Green Roof Safari! This 6 day tour runs from Frankfurt to Zürich and features a diversity of green roof projects and conversations with local policy-makers, designers and researchers. Offered from Sept. 8 – 13 and Sept. 21 – 28th, the tours sandwich the World Green Roof Congress (Sept. 17 – 18) in London UK. Visit www.greenroofsafari.com.

Left: Municipal, residential, commercial, industrial, institutional green roofs; Right:  Vetsch Earth Houses; Hundertwasser, living roofs: Big and small, we will visit them all!

At the GRHC trade show, you can find postcards and brochures about Green Roof Safari at the Greenroofs.com booth (#108). My colleague and co-founder of the tours, Jörg Breuning, can tell you more, too, at the Green Roof Service booth (#318).

Since coming to Vancouver in 2006, I’ve been intrigued by the extensive moss communities that dominate this bioregion. The mossy roofscape seems to me to embody everything that extensive green roofs are meant to be. Resilient, regenerative, and self sustaining, these spontaneous communities do not require human inputs, remaining green and functional year round.

If we relieve ourselves of aesthetic conditioning (i.e. “unwanted plants are weeds”), might these moss roofs have lessons for us? Do they express a genius loci – spirit of the place – in a way that we’ve never considered? From a plant ecological perspective, what can we take from the patterns of colonization, the conditions for establishment, and the processes of natural succession? From an economic point of view, what place do mosses truly hold within the chronology of roof degradation? Do these diminutive organisms (which lack roots and vascular tissue) really cause roofing products to deteriorate? Or are mosses just indicators that the roof is degrading, as they take advantage of pre-existing puddles and cracks?

The old tar & gravel roofs of Granville Island are extensively covered with moss, as seen from the Granville St. Bridge (Fig. 3). With a couple roofs in mind, I tracked down the property manager and was granted access for a vegetation survey. With the help of a maintenance personnel (and a scissor lift) and bryologist colleagues (people who know their mosses), two inventories of 3 roofs were conducted in 2007 and 2008.

Left: If Granville Island’s green roofscape were intentional, this part of Vancouver could rival European cities for surface area covered by green roofs. Right: Licorice fern (Polypodium glycerrhiza) is a native fern which occurs in protected corners of mossy communities, whether the crotch of a tree or the protected corner of a roof.

The diversity on some of the roofs we surveyed was variable, depending on location, microclimate or other factors we are attempting to determine. For example, the roof of Waterfront Theatre supports 3 species (2 mosses and one grass), while the roof of the Parking Garage supports over 30 species, including both native and non-native grasses, ferns, herbs and Sedums.

As Granville Island begins a major renovation project for its infrastructure and many of the buildings, green roofs will likely be included in the plans. When initially approached, the property manager wondered if it would be possible to transplant these well-established moss communities onto “intentional” green roofs. Hurrah! This could represent the next phase for this study.

If you have any thoughts, ideas or opinion, please email me.

Hope to see you in Baltimore!

Truly,

Christine

Christine E. Thuring, Greenroofs.com Student Editor
StudentEditor@greenroofs.com
MSc 2005, Centre for Green Roof Research, Penn State University

Publisher's Note:  If you wish to get on Christine's mailing list, send her an email: StudentEditor@greenroofs.com.
 

September 2007 student forum ramblings
STUDENTS ON GREEN ROOFS
 

"Green Roofs on the Curve"

By Christine Thuring, Student Editor (Download as a PDF)
 

Like the Spring 2007 Students on Green Roofs Ramble, this one again contemplates how the green roof industry can stay ahead of the curve. Having a sense that this theme will persist, I’ve made this concept an entity of its own, “GREEN ROOFS ON THE CURVE.” I’d love to know your thoughts, ideas and comments on any of the content discussed; email me!

Have you heard the term “Peak Oil” lately? A ground-breaking model, the Hubbert Peak Theory, gained wide acceptance in its time, then died down in the societal cycling of ideas. This ramble will revisit the theory and attempt to draw connections between Peak Oil and green roofs, as a way of presenting challenges for the green roof community to stay ahead of the curve. By weaving lessons from the past into our current endeavours, through dialogue and practice, we can each contribute towards the realization of a healthy vision of the future.

The Hubbert Peak Theory refers to a singular event in history: the peak of the entire planet's oil production. After Peak Oil, the rate of oil production on Earth will enter a terminal decline. Without getting into the details of the model, I’ll defer to George W. Bush’s January 2006 State of the Union address, in which he admitted to “a serious problem: America is addicted to oil.”

What does this mean for the green roof industry? Just as Peak Oil will be a major test for our society, it also represents a challenge for the green roof industry. As individuals and “dirty” industries begin to ask themselves how they can reduce their dependence on oil, the green roof industry, too, should examine its relationship to fossil fuels.

First of all, green roofs must become better known for the many solutions they offer. A major barrier to green roof implementation and acceptance is that they are poorly understood. I recently saw “Escape from Suburbia,” which featured many great people and projects engaged with their understanding of Peak Oil. The importance of food security received considerable air time, but not a single mention was made of rooftop gardens. Were green roofs absent from the discussion on urban agriculture because the film-makers weren’t aware of them, or did they simply not make the cut?

In addition to better representation in the media, the benefits of rooftop greening need to be more fully explored. For example, is it valid to think about green roofs as significant carbon sinks? Will the roofs we’re designing and building today support our cities in bumpy times of oil shortage? Do they truly support the triple-bottom line of local economies in their function? Do their embodied energies vindicate their value? And beyond their environmental benefits, will green roofs help to lead the way towards urban resilience? If so, how will this collaborative role be established and managed?

On the topic of urban agriculture, some developments require a certain percentage of built space to be offset with garden plots. In Vancouver, the new Olympic Village for the 2010 Games will allot 30% of the surface area to garden plots. The Vancouver Green Strategy, due in the near future, is also anticipated to devote a certain percentage to urban agriculture.

As far as economic value goes, we know that rooftops can generate revenue by growing herbs for restaurants, but what about growing cash crops, like cut flowers? If oil really becomes scarce and expensive, then at least the infrastructure would be in place for food production. In the meantime, locally grown flowers would be nice! Certainly the design would be dramatically different from that of an extensive Sedum roof, but many of the benefits could still be maintained and measures taken to deal with anticipated issues, like fertilizer and water use.

Ecologically, if we decide to re-instate ecosystem services and functions to our urban areas, wet roofs could not only close the loop on building water use, but also create valuable habitat and improve the urban climate through greater cooling benefits. Keep your eyes open for the next issue of Green Roofs for Healthy Cities’ “Green Roof Infrastructure Monitor” for an article about wet roofscapes. Whatever the system or design on top, connecting a building to its immediate environment through biofiltration can dramatically reduce its ecological footprint.

Peak oil is well underway, and prices will likely continue to rise. The extraction that continues today has a very low ‘energy return on energy investment,’ and represents the greed of annihilist petrol giants suffering from social and environmental myopia. The green roof community can take the higher path. By integrating sustainability principles into the practical needs of this emerging industry, we can reduce urban dependency on oil. With intent and collaborative genius, green roofs can contribute to a prosperous and secure future for all.

Please email me with any ideas, comments, concerns or questions that this column inspires, or post them on the Forums page!

Christine

Spring 2007 student forum ramblings
STUDENTS ON GREEN ROOFS