Naturalization

[Ivor Davies]

Oakville, Ontario, Canada completed a UFORE project and published results in October 2006. Our Parks and Open Space Department now drives for naturalization of the Parks system. Within this drive we have a small sub-set of residents who cry for more native species: I gather, as near as possible, total naturalization. The top 6 best tree species for Air Quality Improvement (AQI) in Oakville (trees suitable for hardiness) range from an index value of 100 down to 94.3, include 4 non-native species. Within this group 2 native species and 2 non-native species were found in the UFORE sample of Oakville's trees.

With a background in agriculture worldwide, from seed development to commercial crops and well aware of the benefit trees convey, I am intrigued by this drive for naturalization: with a small sub-set driving for ever more are we, with changing weather patterns, existing non-native tree species that do not out-compete and displace native species and are preferred for AQI going in the right direction?

[Jerry]

with a small sub-set driving for ever more are we, with changing weather patterns, existing non-native tree species that do not out-compete and displace native species and are preferred for AQI going in the right direction?

My $0.02: Tree selection is not a value-free problem: you always have to select for some particular goal you want to attain. Furthermore, if you want to get something in the plant world, you usually have to give up something.

Thus your question can be restated this way: whose goal is more valid, that of people wanting native species or that of people concerned with air quality? We could even expand it by adding other groups and their goals: low maintenance, beauty, longevity, etc.

For me, this problem of conflicting goals in urban forestry reinforces one of the few basic principles that promises a long-term solution: species diversity. I happen to be a great fan of native trees and shrubs, but at the population level for an urban domain I would nonetheless urge that the principle of diversity be upheld to accommodate a community's natural desire for mutually competing goals.

[Ivor Davies]

with a small sub-set driving for ever more are we, with changing weather patterns, existing non-native tree species that do not out-compete and displace native species and are preferred for AQI going in the right direction?

My $0.02: Tree selection is not a value-free problem: you always have to select for some particular goal you want to attain. Furthermore, if you want to get something in the plant world, you usually have to give up something.

Thus your question can be restated this way: whose goal is more valid, that of people wanting native species or that of people concerned with air quality? We could even expand it by adding other groups and their goals: low maintenance, beauty, longevity, etc.



For me, this problem of conflicting goals in urban forestry reinforces one of the few basic principles that promises a long-term solution: species diversity. I happen to be a great fan of native trees and shrubs, but at the population level for an urban domain I would nonetheless urge that the principle of diversity be upheld to accommodate a community's natural desire for mutually competing goals.

Thanks Jerry. My concern, you will note I mention a small sub-set imbued with a drive for native trees, is the increasing clout they have in the municipality. To my mind it is a possible distortion in the drive for the major benefit trees convey that is somewhat supported by a majority of residents: allowing for other goals such as low maintenence, beauty, longevity etc.,