Thursday, February 25, 2010

not so light and fluffy...

Having greenery in a winter landscape is refreshing, especially when winter starts to get dreary. After the last couple snows, I appreciated it even more: I had never realized that evergreens were sticking their necks out by keeping their leaves all year round.

I used to see pines like this one with only a muffin top of foliage and wonder why all the lower branches were broken off.

During the last snow a friend explained to me that snow loads snap branches, especially when the snow is wet.

He pointed out this pine skirted with broken branches.

Close by there was another with damage.

It had only been snowing for a few hours.

Snow can help prune dead branches from a tree, but it can also take huge healthy limbs.

The new losses made the old ones more obvious. To prevent disease, broken branches will be cut back to the branch collar.

Although the pines seemed to be the most affected, no evergreen species in the cemetery was immune. There was damage to arborvitae, pine, spruce, holly... Here's a blue atlas cedar with a snapped limb. There was even a tree that was entirely uprooted by the big snow we had.

Sometimes snow weight will simply bend braches without causing any breakage. It can also splay the more shrub-like evergreens. When the snow melts, some branches will spring back to their former position. (Thanks for the photo, Art.) As another wet snow falls today, I'm thinking of my favorite evergreens in the cemetery. There are some ways to prevent damage, but with the number of big trees in Green-Wood, there's nothing to do but let nature have its way.

Tuesday, February 23, 2010

Thursday, February 18, 2010

Paper Birch

Here's one of the younger paper birches in the cemetery. Betula papyrifera usually has several stems and can have either a conical or an irregular crown. This specimen has a single stem with branches starting low on the trunk.

The white bark peels in papery sheets. At first the bark underneath is orange, but it whitens with time. Harriet Keeler, in Our Native Trees, says that the paper birch "possesses the most wonderful bark of any of our native trees." Personally, I would make an argument for beech bark, but paper birch bark comes in a close second. Although it's papery, it's quite strong. Native Americans used it to make canoes. It can also be written and painted on.

This accumulation of exfoliated bark looks like burnt newspaper.

The long horizontal lenticels in the bark allow for the exchange of gases.

Here are the pre-formed male catkins. The female catkins will emerge in the spring as the male catkins elongate. If you click on the photo, you can see that twigs are reddish-brown and dotted with small lenticels.

Trees Near You

If you're interested in learning about the street trees in your neighborhood and you have an iPhone, check out the new Trees Near You app.

Each tree on the map is represented by a circle. When you click on a "tree" you can see the species and trunk size. The app also links to the wikipedia entry on the species in case you want to learn more.

For the moment, this app only covers New York City trees. This could be fun in Green-Wood... Thanks, Tibor.

Sunday, February 7, 2010

Saucer Magnolia

Here's a saucer magnolia after Tuesday night's snowfall.

When it's leafed out, it looks like a giant shrub. Now that the leaves are gone, you can see that it's multi-stemmed.

The large hirsute (fuzzy) floral buds give this tree an interesting winter texture. You can see the crescent-shaped leaf scars directly below the buds.

Here is an infructescence from last summer minus the red seeds. Most of these empty fruiting bodies have fallen to the ground by now.

The saucer magnolia is one of the earliest blooming trees in the spring (which unfortunately makes the flowers susceptible to frost damage). The pink or purple and white flowers emerge before the leaves. The saucer magnolia was hybridized around 1820 by Etienne Soulange-Bodin, a French horticulturist. Hundreds of varieties of this hybrid exist today.