Thank you for the telephone message you had recently left in response to my inquiry regarding suggestions for a choice of tree for my back yard in Queens.
The new tree will replace a 60+ year old anjou pear tree that was removed last fall. A new tree should be smaller than the pear tree and of course not bear fruit, which becomes problematic. It should grow mainly upward but not much higher than the power lines that you may see in the pictures I had provided of our back yard. Neither should it extend too far laterally so as not to damage the neighbors' garage roofs if only by dripping early morning condensate. The tree will be planted approximately 8 to 10 feet from the two nearest garages. It should be deciduous, hardy, and, ideally, flower in the spring. The tree in the foreground seen in one or more pictures is a blossoming Kwanzan cherry tree but this type of tree seems already too large to put also in the rear of the yard. There should be a single main trunk that will become tall enough to allow a person of average height to walk underneath the crown or at least allow access with a lawn mower unlike, e.g. a Japanese maple that often branches closer to the ground.
I would much appreciate any suggestions you might be able to provide.
Thank you for writing. In fact before I turned on my computer today I was revisiting those pictures you had sent and was contemplating the options. Thank you for the greater detail about the site and your specifications. Here are a few small trees that typically mature no larger than 30' that might be appropriate choices for the space. If you feel as though you really need something that is going to remain much smaller you might be forced to consider some shrub options as well. In any event, here are some of my favorite small trees:
Acer palmatum 'Bloodgood' (Bloodgood Japanese Maple) - I know you are concerned about low branches of the proposed tree being problematic, but Bloodgood Japanese maples do have much more of an upright growth habit. They do not put out a flashy flower, but the rich red foliage all summer long I think is stunning. They are moderate growers so over time you can easily prune the tree up to be able to walk or sit underneath it. The drawback is that these trees, because so popular in the trade, may be more expensive than some of these other options.
Amelanchier (serviceberry) - This shrub or small tree is praised for it's year round interest in the garden. Small white blossoms are among the earliest to bloom in April, they have a nice leaf and texture during the summer, the fall fruit is attractive but not too messy, and the charcoal bark provides interest all through the winter. Even though it naturally grows more like a shrub, I have been able to find single-trunked specimens for sale at large nurseries and retailers.
Cercis canadensis (eastern redbud) - One of my absolute favorite native trees, this might be a perfect option. Eastern redbuds like a protected site so your back yard sounds like a perfect spot. Bright magenta flowers bloom right along the dark stems in spring, eventually pushing out a delicate heart-shaped leaf for summer. Like the maple, as this tree matures you can slowly prune it up so that one can easily pass underneath it. The canopy of mature redbuds is also fairly airy and open and it does allow a little dappled light through which helps with whatever plantings you may have underneath the tree. There is also a white-flowered cultivar of eastern redbud that is becoming more popular and available at garden centers.
Cornus Kousa (Japanese flowering dogwood) - Japanese dogwoods have gained popularity in American landscapes because they do not fall victim to anthracnose like the native flowering dogwoods (Cornus florida). They have fabulous dark green foliage and a white flower that comes out early summer. Their growth habit is also rather upright so you should not have to prune too much as time goes on. Eventually, however, these trees can get to be a good size, so if it is to be planted right under power lines you might think otherwise. The summer flower is prolific and a selling point of the tree. They also have rich fall color, but the mature 1" orange seeds drop in the fall and some consider them too messy for small spaces.
Laburnum x watereri (goldenchain tree) - Unique because of its flower, this small tree produced large yellow cascades of blossoms from May into June. Growers are now raising forms of goldenchain tree that have a denser canopy of leaves while still putting out a strong flower. The tips of the branches do weep slightly, but you should be able to find this tree for sale with a tall, single trunk. You should know that the blossoms do attract bees during June. Some do not like that because there may be small children present - I think it's fabulous for promoting natural habitats within the city limits.
Styrax japonicus (Japanese snowbell) - The 'snowbells' refer to the delicate little white flower buds that form and hang in the springtime. They open to a fragrant flower in late May to June that I adore. This tree left to its own devices can get rather wide, but new varieties are being bred to grow more upright and narrow. It does not get to be too large, and I have used it on a number of different jobs with great success. There is also a native version, but that definitely fits more in the category of a shrub.
A last note about crabapples (Malus sp.), cherries (Prunus sp.) and Magnolias (Magnolia sp.). There are small varieties of each of these different kinds of tree and they all sound like they would fit into the space you are trying to fill. However, as you have already mentioned, low branching can become really frustrating. Others listed above will still put out low branches that will have to be pruned in time, but many apples, cherries, and magnolias want to naturally grow from low points on the trunk so it is best to steer clear of them.