Sunday, May 4, 2008

A Tale of Two Trees

The two trees that were planted on my street in March leafed out over the last three weeks, and emerged as beautiful young Zelkova trees, most likely Japanese Zelkova, (Zelkova serrata) as these are a species listed on the NYC Department of Parks and Recreation list of approved trees for street tree planting. The majority of the existing trees on the block are Callery Pear (Pyrus calleryana), but there already is a mixture of a few other species that the two new Zelkovas are joining, including Ginko, European Hornbeam, Green Ash, and a few older Zelkovas.

Although they were planted on the same street, on the same day, these two trees have had very different experiences. The tree on the southern side of the street has had a much rougher go of it. A branch was torn off of the south side tree in early April, leaving a jagged wound. Coming home from work one day, I saw the damage done, and was afraid that this wound would provide an entry for insects and fungus to attack my new neighbor, stunt its growth, and possibly kill it. Luckily, another neighbor also realized the danger to the young tree, as the torn branch was pruned within a week.

To add insult to injury, the tree on the south side of the street remains shaded by neighboring buildings much more of the day than the tree on the north side of the street. This may not seem like such a big deal to us who can walk to the grocery store to get our food, but the Zelkova is stuck waiting for the sun to bring food to it, so building shadows can really get in the way of a good meal. In fact, the south side tree leafed out a few weeks later and continues to lag behind the north side tree in foliage growth. There undoubtedly were other factors effecting the slower growth rate of the south side tree (the wound, perhaps differential treatment at the nursery or during planting), but the southern exposure that the north side tree experienced certainly gave it a leaf up. Further down the street, the Callery Pear trees on the south side and at the corners (where they were able to get more sunlight) also flowered sooner and more this spring. Most people do not realize just how much of an impact building shadows have not only on what can or cannot grow, but also on the size, shape, and speed of growth of whatever is planted there.

North Side Zelkova

South Side Zelkova

Wednesday, April 2, 2008

Spring has sprung and I have been surprised by the speed with which bulbs, pansies, and other cold hardy flowers have begun appearing in tree pits across the city. The emergence of buds, leaves, and flowers on trees and woody plants is also amazing and wonderful. The weather is still tempestuous, varying from the 50s to 20s, but the brave new leaves and buds have come forth and are keeping their own.

In my neighborhood, the crocuses emerged first. Then the dwarf irises. Pansies were planted. And then all sorts of cold hardy plants began emerging on windowsills, stoops, and shop fronts. One interesting thing I've noticed is the different ways in which flowering bulbs have been appearing in tree pits around the city. In many neighborhoods bulbs were planted last season and have sprouted and flowered on their own schedule (such as the purple irises below). In other neighborhoods they do not allow their bulbs to overwinter on the street, but grow their bulbs in greenhouses and then bring in plants that have already sprouted and developed flowers to bring instant color to their tree pits (such as the yellow tulips below). Two different methods. One is certainly more expensive than the other. Another difference is an aesthetic one between a more naturalized planting, bringing a bit of natural woodland into the city, verses filling in the tree pit as if it were a flower box, to be kept to optimize seasonal color. Tree pit plantings are always contrived, cultivated areas. However, there remain different approaches to the aesthetic of a tree pit, and decisions to be made on whether it is to be treated as a bit of nature in the city, or a controlled flower box to be filled with the monoculture of the season.

Tuesday, March 25, 2008

Spring Trees

I requested a street tree be planted in 2 empty tree pits down the street from me last fall... and last week 2 trees were planted by the NYC Parks Department! With Mayor Bloomberg's initiative to plant a million trees in NYC, getting a street tree planted is faster than you can say spring has sprung. I think the trees planted down the block are a cherry species because of the lenticels in the bark, but I'm waiting for the leaves and flowers for a definite I.D.

I was happy to see that there was not a mulch volcano around the base of the young tree. However, they clearly did not skimp on the mulch, as the pit is practically overflowing, as you can see below. Also note that the new tree pit quickly attracted dog droppings and garbage piling. One can see that a tree guard, even a small one, is needed to protect soil around the tree, as well as the tree itself.

April is MillionTreesNYC Month. There is more information about how to request a tree and other ways to get involved (such as planting a tree on private property!) on the MillionTreesNYC web site.

Monday, February 4, 2008

mystical mulches

A variety of stones can create a mulch that has an elegant yet rustic look in all seasons. Here is an example from the Village.

Some tree pits are better left unplanted...

I came across this beautiful Willow Oak (Quercos Phellos) on Hudson Street, and was struck by the beauty of the bare roots (pictured below). Proof that given a large enough tree pit, enough water, not too much vandalism from pedestrians, dogs, or parked cars, and a bit of luck, street trees can mature to a ripe old age. Older people have longer ears, and older trees have larger roots. Large roots can take over a tree pit to create a beautiful, sculptural element on the sidewalk that has interest in and of itself.

The large roots of the Willow Oak also support a large canopy (pictured below in winter). The tree canopy provides shade, cleans the air, cools the climate, and provides beauty and interest year round. Larger trees may not have room in the tree pit for additional plantings, but large specimens are so majestic they don't need any adornment to make a beautiful statement on the street.

Saturday, January 19, 2008

winter color

These west village tree pits show how pine cones, faux berries, and red dogwood branches can add color to evergreen branches. These decorative touches add spice and texture to the healthy evergreen mulch. These tree pits wisely used faux berries, as real berries may attract (and be eaten by) birds, or worse, rats! Some berries are not attractive to birds or rats, such as juniper berries. Although these tend to be less showy than edible berries, they still add interesting shapes and textures to the winter mulch. Juniper berries have the added bonus that they can be used to make gin when the season is over! :)

Thursday, January 3, 2008

winter branches

It is winter in the city, and the streets are cold and gray. Tree pits that have been planted with evergreens, such as the buxus plants shown below, seem particularly attractive at this time of year. However, woody plants need more root space than annuals and so can be difficult to plant in small tree pits. New Yorkers are used to addressing confined space issues by building up, but this can be treacherous to do in a tree pit. Building up the soil in a tree pit more than 2-3 inches is not recommended because it can cause the tree bark to rot and fall away, exposing the trunk to disease. In addition, the additional soil can become compacted and prevent water and oxygen from getting to the roots below. So although the evergreen buxus shown below are vibrant green even in the dead of winter, this is at the expense of damaging the trees they are surrounding. The Parks Department does not recommend installing any solid walls around the tree pit that will retain soil; metal guards that keep dogs away but allow water and soil to drain are best.

A better way to bring color to winter tree pits is to lay evergreen branches over the tree pit. Evergreen branches can look and smell lovely without building up the tree pit and damaging the tree. Branches are easy to get and easier to "plant," and can actually be good for the tree. Evergreen branches make a good winter mulch, protecting the soil from the worst of the cold and road salts that can be damaging to trees in winter. Branches should be removed in the spring, but then there are probably more interesting things to done in tree pits as weather warms.