TOPOGRAPHY

Unlike the rest of the Back Bay, what is now known as Kenmore has always been on solid land. In fact, Beacon St. mimics the path of the old mill dam that used to enclose all of Back Bay. Not coincidentally, from at least as early as 1852, the Boston & Worcester Railroad also ran from the Boston to peninsula to the Kenmore area, at which point it split into the Boston & Worcester and the Brookline Railroads. (Rumsey) Kenmore was bound to become a central intersection from the start because it is the shortest distance across the "Railroad Basin," what is now Back Bay, from downtown Boston. From Kenmore, one could access the rest of the greater Boston area without crossing any bodies of water or navigating narrow peninsulas. In a time where engineering techniques were limited, and steam powered engines were used mostly in trains and some heavy digging tools, this would have been a vital crossroads in mass transportation of goods to Boston via land. In 1856, however, developments in engineering allowed the city of Boston to fill entirely the Back Bay with sand and gravel from Needham, nine miles away using massive steam shovels and loading up trains all day and all night for forty years. (Spirn, 18) Still, the filling of Back Bay didn't reduce Kenmore's importance at all as a major intersection, rather it increased it. Once the filling of the Back Bay was complete, Kenmore was a direct link between Boston and the Brookline and Brighton areas. Almost anyone traveling west by car would have driven through Kenmore, encouraging commercial development along that route.

WINDS

The first thing you notice walking west down Commonwealth Avenue is the wind. All day and night huge walls of wind fly all the way from Boston Common down past Boston University and on to Brighton. The trees that have lined Comm Ave for a century and a half still keep the wind in check during the first part of its journey, but as soon as it hits Kenmore Square it sees miles of straight flat, hard concrete with buildings on either side encouraging it along. This funnel of wind is not exclusive to Kenmore; it is mocked by the Massachusetts Turnpike just a block south. Walking over the Beacon and Brookline Street overpasses, it's easy to see why. The highway is set 15 feet below street level with concrete walls lining either side, giving it the same urban topography as Kenmore. Both of these funnel type situations affect airflow much in the same way that urban sewage and storm drain systems increase the speed of water flow during rains and decrease the time for which this water flows. (Spirn, 131) While the effect of faster and higher water flows is readily noticeable in times of heavy rains and flooding, evidence of similarly fast and high volume wind currents can be seen everyday in the trees and plants that are subject to these winds. In extreme cases, the entire upwind side of a tree could be torn bare of bark and branch from constant abuse, leaving branches only on the lee side pointing like a weather vane in the direction of the wind. In more moderate cases, such as we see in Kenmore, trees may appear comparatively normal, but branches will tend to be distinctly more bare, and the growth of the trees stunted.

Winds also kick up dust, disturbing not only pedestrians, but plant life as well. Seeds are blown around, but in this urban landscape many of them can't find a suitable place to take root. Looking in the central median on Comm Ave, the soil is packed and hard without a healthy upper layer of biomass to help absorb water and oxygen and provide nutrients to the trees. On the western end dirt and sand has been blown on to Comm Ave as an example of just how unforgiving these winds can be. Just one block north along Bay State Road many of the trees, while the deeper soil is packed as on Comm Ave, have been afforded the luxury of a soft upper layer of mulch that is often set a few inches below the protective brick walls that surround it. Another key difference between the Comm Ave and Bay State trees is that Bay State trees are all privately owned and tended. They are all in separate plots which also support various shrubs and grasses. These secondary plants help keep the soil loose, and deposit biomass that aids in growth, as mention earlier. The trees on Bay State are generally healthier than those on Comm Ave which acts as a positive feedback loop, further reducing wind speeds and promoting growth.

MICROCLIMATES

When I walked behind the southern block of Kenmore, I didn't expect to find much plant life. It's noisy and windy there, the air is full of pollutants from constant Mass Pike traffic. But I was shocked to find front yards on almost all the apartment buildings along Newbury Street. At this time of year there wasn't much to see, but it was clear that the owners of the building had been taking measures to ensure plant life during the spring summer and fall. Like their northern neighbors on Bay State Rd., these gardens were topped with mulch that was surprisingly moist just an inch or two down. One of the larger building complexes had a healthy looking strip of trees and shrubs along the sidewalk, again with a nice moist layer of mulch.

Yet in spite of this, some plants weren't doing as well as others. One of the trees on the street was about 8 feet tall and looked like it might have been 4 or 5 years old, but when I examined a twig I counted 10 nodes, each about an inch apart, indicating that the tree was in fact ten years old and struggling to grow. Stunted growth is often caused by oxygen and water deprivation, too much or too little sunlight, hard packed soil, shallow soil depth, polluted air, and root competition with underground gas, electric, and sewer lines. (Spirn, 175-176) While most of these evils are surely at play, the poor growth of this particular tree is probably a result of poor air quality from the tens thousands of cars that pass every day, the utility lines that pass underground from street to basement, and excessive sunlight. Since the building behind it faces south, it absorbs a lot of solar radiation throughout the morning and mid-afternoon which it then emits later in the evening and early night. This changes the temperature spectrum that a tree in the wild might experience on any given day. Temperatures are both higher and last longer, thereby catalyzing evaporation by excessive heating of the leaves and bark..

This process is very prevalent in the gardens along Bay State Rd. Ice and snow on the entire south facing side of the block is completely melted, while all of the gardens on the north facing side are covered in thick sheets of ice. The detrimental effect of the buildings on the trees there is now twofold: trees can't reach sunlight unless it's directly overhead, and the grass and dirt that usually surround it are now unable to absorb any water or oxygen to feed the tree. In trying to fight against the influence of nearby buildings, a lot of the trees lean towards the street, sometimes at quite large angles. A common problem that might arise then is that their branches become more susceptible to passing buses and vans that might damage them or tear them right off. Almost as though they expected this, the branches grow almost exclusively upwards, both reaching for the sun and avoiding the dangerous vehicles below.

City planners must have also recognized that the sun hits south facing buildings, because the entire north side of Comm Ave is residential, and the entire south side commercial. All of the residential buildings have little gardens out front, while on the south side these gardens have been replaced with stairways for access to basements restaurants and small businesses.

In general, large open grassy areas near and around trees allow them to grow healthily. Grass roots hold down soil, retain water, and tend to keep the earth light and airy. When grass is replaced with concrete, or even ice, all of these benefits are eliminated, and trees must rely entirely upon their branches and leaves to provide them with nutrients. Comm Ave. shows prime examples of both situations. In the center median, where grass and dirt cover much of the surface area, the trees are large and fairly healthy. Judging by nodes on their twigs and branches, they seem to be growing 6-8 inches a year. Their branches are full and radiate outward as well as upward, indicating that they are not fighting for sunlight. Their trunks are maybe a little thin, but still a good two or three feet in diameter. The soil around their roots isn't as fertile as they would prefer, but still fertile enough that they've survived a few decades. The trees along either sidewalk, however, are not faring as well. Many of them are young, planted sometime within the past decade, indicating that the former trees weren't able to survive there. And it's no surprise. With nothing but sidewalk in all directions, these trees have no healthy soil from which to draw nutrients. Many are surrounded by protective steel fences, which I can only imagine sit deep in the soil, giving the tree's roots more competition for space. Their thin branches point almost exclusively upward, begging for sunlight, and their trunks are only a few inches in diameter. It's clear to see that these trees wont last another ten years before they are removed and replaced again.

The open space under the Storrow Drive overpass has a wide range of plant life and soil conditions. (This area is not part of my original site, and is defined by Beacon St on the north, Comm Ave on the south, and Charles Gates East and West, respectively.) Some areas have dense shrubbery, some have massive trees, some have grass coverage, and some are bare. Near Beacon St there are two large trees and down towards Comm Ave a few trees have been recently planted, judging by the slight mounds of darker dirt around their trunks. Based on how the rest of this area of Boston is landscaped, I would guess that some array of trees had been planted along the surrounding roads, but all that's left of that now is two trees on the corner of Beacon and Charles Gate West, and three or four at Beacon and Charles Gate East. My hypothesis as to why these trees survived and the others didn't--and why I don't think the newly planted trees will grow terribly well--is because of their proximity to the waterway connecting the Back Bay Fens to the Charles River. All of the older trees are within 20 feet of the water's edge, and their closest roots are probably no more than 5 feet away. Since the waterway was built party to serve as a floodwater control system, I would say that some of the water is allowed to seep through the great stone slabs that comprise the banks, thus vitalizing the soil. This is a luxury that none of the other trees in Kenmore have. The reason this type of groundwater access is more beneficial than natural seepage from surface water is that surface water just can't permeate the dense urban soil very well.

Evidence that there is at least a minimal groundwater supply is growing along the eastern bank of the waterway. The bank is quite steep, and it looks as though it has been heavily planted to help prevent erosion. While the shrubs and grasses look somewhat bleak now, it seems as though the area is surviving fairly well. Clumps of dirt are collecting in the cracks between the stones in the wall, and grasses are taking root there. A few trees right near the edge have been cut down in what looks like an attempt to eliminate competition for the smaller shrubs that are there now. And for the time being it seems to have worked.

The land just past the western bank, however, isn't even given a chance. The line separating grassy lawn from chalky dirt falls directly under the edge of the overpass, showing how a lack of sunlight can overwhelm any other favorable conditions that might be present. The rest of the open is space is indeed covered with grass, which may seem expected, but no grass grows twenty feet away on the Comm Ave median. The conditions in this area are indeed more suited to plant-life. And if the ground seems hard now, we can imagine what it might be like if the entire area were chalky and hard instead of covered with grass. There would be almost no water retention during rainfall and garbage and pollutants would be carried from the field into the waterway to then be swept out into the Charles.

ANOMALIES

Going back to Newbury St, south of Kenmore, I noticed an odd cluster of trees abutting the cement wall along Mass Pike. I couldn't see any reason why they might have been planted there, nor any evidence that someone had been tending them. All but one of the six or seven trees seemed as healthy as any of the other trees in Kenmore, and the one that wasn't had been cut about three feet up and now has three branch clusters growing from the stump. This goes to show that even under the harshest of conditions, some species are able to grow and regrow, while others that have constant care and attention can still fail, reminding us that Mother Nature still holds the trump card for any hand we play.

CONCLUSIONS

Though numerous examples we've seen the effects of topography, wind, and microclimates on plant growth in Kenmore Square, and almost always, urban conditions detriment growth. Oftentimes designers will consider natural advantages of certain locales end exploit them, as in the case of the south facing block on Newbury, Comm Ave, and Bay State Rd. At the same time, however, certain factors are ignored, particularly in terms of providing a large enough open space around trees. So what can we learn from this? If we look at the city as a large-scale version of the microclimates we find in city gardens, we can imagine that a healthy city requires as much attention to its surroundings as it does to itself. Just as trees require a sustainable environment--open space, grass coverage, etc.-- a city needs to grow in a way that meshes with the environment, rather than one that tries to muscle its way through it. Consider the most basic example of the sidewalk tree. It is doomed to die as soon as it is planted. There is no room for it grow! The same principle applies to any city, and it is important to consider the city as a living, evolving form in order to ensure its health and longevity.

Ryan Luersen, 2007. 4.211J/11.016J, The City

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