Winter Tree ID 2020

This winter, I worked with the NYC Parks Department* to prune young street trees in Queens. We prune trees between 2 and 4 inch caliper (diameter of tree trunk), and between 2 and 4 years after planting. Any tree that had been planted less than 2 years ago, we left alone: these are taken care of by city contractors. Any tree that has been planted for longer than 4 years, we typically left for forestry. We had a lot of fun and I learned a lot of new tree species and developed a new understanding and appreciation for the trees I had already known.

These links are helpful for identifying NYC street trees in your area. The maps and list
s are not perfect but they are generally accurate.

*A disclaimer: This website and the images and ideas posted are expressly my own (unless otherwise noted) and in no way represent the NYC Parks Department.

Sample of area map with trees

Sample images of street tree leaves from the NYC Parks Tree Map website

The distinguished and deeply furrowed bark of Celtis occidentalis, or Hackberry.

Twigs, buds and desiccated fruit capsules of Prunus virginiana (Choke Cherry), Prunus serrulata (Flowering Cherry), Syringa reticulata (Tree Lilac) and Celtis occidentalis (Hackberry). Note the difference in bud shape and size from the Prunus virginiana and the Prunus serrulata. Also note the small, opposite buds of the Syringa reticulata as opposed to the alternating buds of the Prunus species. One of my favorite ID features of Syringa reticulata is the banana-shaped dehiscent (rupturing) capsule arranged in panicles towards the top of the tree canopy.

Here are the leaf shapes of the above-pictured cherry trees: Prunus virginiana (Choke Cherry) and Prunus serrulata (Japanese Flowering Cherry)

This season I enjoyed taking twigs of cherry and dogwood home and forcing them (to bloom).

The magnificent vase-shaped Carpinus betulus 'Fastigiata' - Fastigiate European Hornbeam
Often, NYC Parks selects fastigiate (narrow, or upward sloping) cultivars of common trees. Narrow street trees are less likely to disrupt sidewalk or vehicular traffic. However, they can be tough to prune, especially when the cultivar is so fastigiate that the branches run nearly parallel to the central leader. 

Contrasting the tightly held, conical buds of the Carpinus betulus 'Fastigiata' with the globular (rounded) evenly held buds of Acer rubrum (Red Maple)

A closer look at the buds, lenticels and leaves of Carpinus Betulus 'Fastigiata' - Fastigiate European Hornbeam

Quercus acutissima - Sawtooth Oak
Oaks tend to hold onto their leaves during the winter. The Sawtooth Oak has distinct oblong leaves with parallel veins and little bristles lining the leaf edge. This tree is native to China, Korea and Japan and is considered semi-invasive by some, as it naturalizes. So don't plant it in a native plant garden but I doubt that it will naturalize in a New York street.

Close up of Quercus acutissima foliage.

The distinctive acorns and juvenile form of Quercus acutissima. 

Gymnocladus dioicus - Kentucky Coffee Tree 
Gymnocladus dioicus has an unmistakable architecture once its leaves have fallen; the tree looks nearly dead. The hint is in the name, as Gymnos means "naked" and klados means branch. There are a few oddly-arranged branches and often you can spot the remaining wisps of leaf rachis (stalk of a compound leaf).  

Bark of Gymnocladus dioicus 

This is a new tree for me: Parrotia persica, or Persian Ironwood
Native to Northern Iran and named after F.W. Parrot, a 19th century naturalist, this small deciduous tree reaches 20-40 feet tall. The flowers are apetalus (no petals) and appear in spring before the foliage. Oval leaves emerge reddish-purple in the spring and mature to a shiny deep green. Great fall colors of yellow, red and orange. 

Flower buds of Parrotia persica. You can see hints of the crimson-red blooms which emerge March-April.

Leaf of Parrotia persica, Persian Ironwood

Comparing twigs of Fagus sylvatica (European Beech), 
Quercus palustris (Pin Oak) and Parrotia persica (Persian Ironwood). Note the graceful, elongated buds and slender stems of Fagus sylvatica as compared to the chunky and clunky stems of Quercus palustris. Parrotia persica has a silver-grey stem.

Close up of Fagus sylvatica twig. Note the elongated buds and the undulating leaf with 5-7 parallel veins (as opposed to Fagus grandifolia, whose leaves feature small serrations along the edge, and 11-15 pairs of parallel veins).

Buds and dehiscent (exploding) fruit of Liquidambar styraciflua, or Sweet Gum. Many people dislike this tree because they tire of cleaning the fruit, which fall to the ground from December to April, but I find this tree to have the most beautiful, upward arching structure. These trees rarely need corrective pruning when young. This tree is called Sweet Gum because the resin from the tree has been used for chewing gum, medicines and perfumes!

Comparing twigs of Liquidambar styraciflua (Sweet Gum) to Ginkgo biloba (Ginkgo) and Syringa vulgaris (Tree Lilac). Note the swollen, resinous buds of the Liquidambar as compared to the stubby nobs of the Ginkgo twig. Syringa has opposite buds, with two joined at the apex of the twig.

Attractive peeling bark of Acer griseum, Paperbark Maple

Vertical silver stripes on the bark of Amelanchier canadensis, called Serviceberry or Shadblow

The blush-colored pointy buds of Amelanchier canadensis are reminiscent of the Betulus sylvatica, or European Beech. But they differ in color and in size. 

The greenish-yellow twigs of Styphnolobium (Sophora) japonica, or Japanese Pagoda Tree. Some trees retain the bean-like fruit pods all winter long.

Bill Logan & Urban Arborists planted and care for these Platanus x acerifolia (London Plane Tree) at the Metropolitan Museum of Art. In order to contain the height and width of the tree canopies, Urban Arborists pollard the trees every winter. When you pollard a tree, you cut the branches of the tree at a specific point, to encourage new growth. At the end of the season, you cut back to this same point, thus constraining the canopy. Trees that are regularly pollarded form calluses (thick nubs) at the pruned point.

This looks like a Wisteria floribunda, or Japanese Wisteria snaking around a tree in someone's yard.

Graceful Salix babylonica (Weeping Willow) in Morningside Park, Manhattan.

I had to look this tree up on the NYC Street Tree Map: it is an Albizia julibrissin, Mimosa, or Silk Tree. The tips of the branches have a unique zig-zag shape and the remaining fruit capsules look like dried pea-pods. The Mimosa tree was planted in the US as an ornamental (the flowers are fragrant, soft pink and silky) but it has escaped cultivation. If you ever had to take care of a garden next to an Albizia julibrissin, you will understand why- they seed everywhere!

Not a street tree or a tree at all! I admire the upright stems of Pycnanthemum muticum, or Mountain Mint. I love the soft smell of this native mint plant. I read that a tea made from its leaves can be used for medicinal purposes. If you look closely, you can see the emerging foliage at its base.

Cornus mas, or Cornelian Cherry Dogwood
A small multi-stemmed tree that flowers mid-February to early March. In the winter, you can identify a Cornus mas by its globular-shaped buds, which held oppositely on the branch and are yellow-green in color. Small yellow flowers are held in umbels, which open to reveal 4-petaled bracts. Fruit is a bright red drupe. I have come to appreciate this tree as it is one of the first to bloom in this region.

Detail of Cornus mas flowers emerging from buds, early March. 

Forcing Cornus mas twigs to bloom in my kitchen


Popular Posts