We have big trees and small ones, short ones and tall ones...what more could we want?  For extremists, we have giant sequoias and tiny dwarf willows (Salix herbacea). We also have a few blue whales and tons of Tardigrades for any animal lovers impressed by size. Everyone is impressed by something. 

Urban street trees can't be really big or really small if they are to be useful. Mature broad leaved street trees make a huge difference to the livability of a city. It doesn't work very well to try to plant them on the spur of the moment when you notice you need some shade - it takes decades worth of foresight to ensure the trees are in position when they are needed. Maintaining the continuous beneficial effects of that leafy cover also takes considerable planning and adjustment to address the ever-changing conflicting goals of urban renovation and expansion. Urbanised areas are constantly changing and, like the rest of the world, are not what they once were. For many city dwellers, street trees can be the closest they normally come to "nature", but changes to buildings and infrastructure take precedence over trees.

Street trees provide an obvious moderation of daytime high temperatures as well as aesthetic values for anyone who takes the time to notice. (If the trees have blossoms in the spring, that can be even more pleasing.) The cooling effect of urban street trees is instructive. Similarly, a natural forest floor can be significantly cooler and moister than adjacent non-treed areas. The aerosols emitted from mature forest canopies can influence the amount of precipitation that is available for a wide area beyond. The biodiversity and general health of many natural ecosystems depends on the effects of extensive mature forests that may actually be far away.

Pursuing trophy trees - tall or tiny - is actually missing the point, or a lot of points. The geographic extent and mix of species matters; size alone is irrelevant. A city with a well-chosen and well-maintained mix of street tree species will benefit greatly from their presence, even as they can only hint at the importance of natural forests in undisturbed nature. (There might be an unintended metaphor lurking in there somewhere, but if you spot one, just ignore it. Metaphors are untrustworthy.)

The photo above shows a bonsai plantation of Ginkgo trees (Ginkgo biloba). We don't have to worry about "not seeing the forest" for these trees...or do we? Ginkgo species have lived for hundreds of millions of years, and were widespread in what is now North America until a few million years ago, when they disappeared. During the last few centuries, populations of surviving Ginkgos were planted throughout southeast Asia, and seeds and seedlings eventually exported to the rest of the world. The trees can live thousands of years, are extremely resilient, and can grow to more than 40m in height - and apparently can be pruned and kept to less than 40cm, judging by the photo.

I started thinking and writing about the giant sequoias in Victoria, B.C. more than a year ago because their presence in that urban setting seemed to suggest some interesting questions about human relationships with nature. There are also Ginkgo trees in Victoria - planted as street trees and in parks, providing welcome shade and bright yellow fall foliage. They are very interesting trees, and aesthetically pleasing to look at - for those who haven't already decided that they are "bad" because their fruit can sometimes be foul smelling. The trees' resilience apparently allows them to survive the stressful environment provided by extensive surrounding pavement, but they are far from unique in their ability to survive the stresses of bonsai confinement. A large number of tree species that naturally grow to great heights have been displayed as miniature bonsai specimens in many gardens - maybe in one there is even the oldest smallest giant sequoia in the world.

There seems to be an almost endless number of ways for humans to "use" aspects of nature, but far fewer ways to appreciate its complexity. Appreciating the welcome shade of street-planted Ginkgo trees on a hot, sunny day and knowing something about their complex origins might be a mix of both. The bonsai Ginkgos would obviously not be useful for shade, but might precipitate additional contemplation.

"We can't see the forest for the trees" is a well-known metaphor, most often applied to non-forested locations and circumstances. As I have noted, we also have trouble seeing the trees for their size and age - and of course their market value. And if we get past that, we have to consider that most of the non-metaphorical tree is invisible to us. We can't really "see" a tree, let alone a forest, because so much of it is underground or microscopic. Of course, with the aid of all the studies that have been done, we are better able to "visualise" a tree. We can imagine some of the parts we cannot see directly. To a much lesser extent, we might be able to do some of that with forests too. To what extent can we "see" nature?

Okay, perhaps the word "see" is a bit fuzzy in this context: often it implies some degree of understanding whichever object it is focused on. Everyone assumes they know what a tree is when they look at one, even if they only "understand" it a little - or don't even know what species it is. What they may be "seeing" are leaves, branches, trunk, bark, and maybe height and girth. That might be enough for a painting or a photograph - a static image - but it is not actually a tree. I'm not suggesting that you need to know everything possible about trees in order to see them, but that the more you have learned, the more you will be able to "see".

Of course, those who want to see less can easily do so, aided by a surfeit of distractions and social incentives. But I think increased knowledge and understanding of natural processes can lead to a sense of perspective that results in unique pleasures, partly because it counteracts the on-going stresses of human preoccupations. Nature isn't hiding. It's out in the open. We just have to learn how to see it.

Above is a photo of a ground squirrel, just below timberline in the Canadian Rockies, eating an almond someone has thoughtfully provided. It is a long way from the nearest almond tree grove, but the squirrel seems to know how to handle the nut. In fact, since it is along a popular, scenic, hiking route, this squirrel has probably handled plenty of nuts and other high-energy snack food commonly carried by hikers. The fact that this squirrel sat right by the side of the trail completely un-bothered by passing hikers as it munched on the nut, suggests that it was very familiar with humans and their odd handouts. While this might be wilderness in winter, during the height of summer tourist season it becomes something else.

I could say that the setting was natural, if not wilderness, but that the squirrel feeding was unnatural, and just leave it at that. But it seems remarkable that some individuals of various species have developed novel feeding behaviours that depend on the transient activities of human visitors. In addition to the squirrels, some ravens patrol parking lots in search of insects recently squashed on automobile front bumpers. Canada Jays hang out at picnic areas and campgrounds looking for discarded leftovers or handouts. And bears...well bears are actively discouraged from sharing our snacks, but often know where and how to look for them.

The vast majority of each of these types of creatures in the Rocky Mountains still never (or very rarely) encounter humans and their foods, so they pursue their traditional foraging methods in traditional ways. It seems that whenever humans introduce a potential energy source (a food) to a location, there are likely soon to be some other organisms attracted to it. You can fence a garden or orchard to keep deer, and rabbits and raccoons out, but not birds and voles, and certainly not insects. None of those creatures know what a garden is, just as a squirrel could not know where almonds come from - such things are unnatural. And yet it seems quite natural for creatures to adapt to such unnatural, transient feeding opportunities. Or is there another way to think about it?

While other creatures can sometimes seem surprisingly adaptable, there are also serious limitations to those abilities. It is important to remember that impressive small scale accommodation to some changes can easily be overwhelmed by more disruptive, major change.