What I've Been Up To

As I keep mentioning field work and related pitfalls on my blog, some of you may be wondering exactly what sort of research I've been working on.  It's fairly straightforward, as these things go:  The study is intended to investigate the relationship between social institutions and urban forest canopy cover/structure.  This is more exciting that it appears at first blush, I promise.

Two parts of that sentence may not make a great deal of sense to some folks.  So I'll explain precisely what is meant by "social institutions" and "urban forest", as the former may seem very broad, and the latter something of an oxymoron.

I have the excellent privilege of being loosely affiliated with the research institution run in part by Nobel Prize winner Elinor Ostrom, the Workshop in Political Theory and Policy Analysis.  Her work with IFRI informs this research project, and it is IFRI's definition of social institution that we are making use of: "institutions are defined as rules that constrain human behavior, either by encouraging people to do x or not to do x" (IFRI Manual, 2008).  That includes both formal--city ordinances--and informal--the approval or disapproval of your neighbor--rules.  This is may be broader than you might have guessed!  Our research group spent many, many hours devising a survey intended to probe the particular institutions we are interested in, primarily Neighborhood Associations (NAs) and Homeowner's Associations (HOAs).  We are also trying to investigate to what extent individuals are influenced by their neighbors and how much these things may impact land management decisions, particularly as those decisions relate to trees.

Now for the "Urban" bit of urban forest.  The word conjures up different mental images for different people, which is somewhat problematic. For some the word urban conjures images of Metropolis or Gotham; hundreds of thousands of people, the inner-city, concrete, high rise buildings, a lack of open space, etc.  To others it might mean anything bigger than a town of a few thousand.  There are official meanings, for particular purposes, of course.  The US census has a complex, somewhat arcane definition that can lead to odd outcomes at times. But it is a definition.



Functionally, urban environments are something that you know when you see them.  They are human dominated systems, with moderate to high population densities, little intact native flora and fauna, and significant amounts of impermeable surfaces (concrete, etc).  The astute reader will note that there in nary a single number in that definition.  This is intentional.  All of these variables together add up to create urbanity.  An unpaved shanty town will have few impermeable surfaces, but high population density, and only traces of the original ecosystem.  Conversely, many cities may have cores with comparably low population densities (in that very few people actually live there. Parts of lower Manhattan are like this, and turn into ghost towns after business hours), but close to 100% impermeable surfaces.  Both examples are human dominated systems.

So, what then is the Urban Forest?  For the purposes of our study, we consider the Urban Forest to be all the trees in the city of Bloomington, whether public, private, or commonly held.  A forester might be somewhat appalled by this, feeling that a forest should be mostly closed canopy, and properly has an understory, soil, topography, and hydrological systems, all of which play into the constantly changing state of the forest itself.   And those things are true, to some extent.  So while we are primarily focused on trees, we are also gathering data on two other aspects of the urban forest.  The first is a qualitative assessment of the shrub layer (including an assessment of invasive species), what might be considered the 'understory' in a nature forest.  The second is a very limited investigation into the soils under the trees, in particular how much carbon they contain.  A forester might also say that what we have in developed areas is more of an Urban Savannah, perhaps, or an Urban Parkland.  And they would again have something of a point; the urban forest rarely achieves the level of canopy cover you would see in a wild, natural forest.  However, urban areas can contain quite dense patches of trees, and it becomes cumbersome to try to segregate the diversity of tree cover contained in urban areas into discrete units.  So we adopt a broader, more inclusive and approachable term.

The city of Bloomington has conducted a full street tree inventory, and thus has a good sense of the state of the trees that belong to the city.  However, almost no data is available on the privately held trees within the city.  Our study allows us to take a small sample of those trees, and get some sense of what is out there.  Those wishing to purse the history and terminology of urban forestry a bit further might want to read this paper on the history of urban forestry, and the differences in terminology between Europe and North America (the lead author is Danish, so please forgive a few peculiarities in the English).

The parcel inventories that we have conducted have been as thorough as possible in counting and mapping the distribution of trees on each property.  We've made use of highly accurate GPS technology,  counted and identified every tree greater than an inch in diameter, and noted down detailed information about each.  This will enable us to produce a detailed snapshot of the state of the urban forest on these parcels, which we hope to combine with our social data (collected through the survey and interviews) into understanding how people relate to the trees in their environment.

It has been hard work, at times.  We've gotten innumerable chigger bites (particularly your intrepid author), and collected data on days when any sane person would have stayed indoors, due to the heat.  We've never had to work in the rain, but this week may change that.

It has also been a lot of fun, and wouldn't want to have spent my time doing anything else.