"Norway maples should be banned from the United States." Bill Nierstedt, Plainfield tree guru and head of the City's Planning Division, made this xenophobic comment three years ago. I have waited in vain since then for him to be invited to repeat this hate speech for a national audience on Lou Dobbs' television program. Despairing after three years of ever seeing Bill on television, I decided to reprint his words here.
Bill is too late. The genie is out of the bottle. The horse is out of the barn. Norway maples are here. Norway maples are among the most common street trees in Plainfield. These European imports are perhaps the most numerous street trees in the eastern United States.
It has to be admitted that their bright yellow autumn foliage is quite attractive.
Some varieties have maroon foliage all season.
They're handsome trees. Arthur Plotnik's The Urban Tree Book describes their regular, lollipop form as looking like a tree drawn by a child.(1)
So what's the problem? Norway maples cast an inky shade in which very little can grow. They make a dense network of subsurface roots that quickly suck every bit of moisture from the soil and that lift sidewalks. Any gardener knows that to dig a hole near a Norway maple is to dig a hole in wood. Tight-angle crotches make the trees more susceptible than most to storm damage. Drive around Plainfield after a storm and take note of what kinds of limbs you see blocking the road. Mostly maples, many Norways.
But Norway maples' most egregious offense is that they breed faster than the natives (and I'm sure that it's this fact that most distresses Mr. Nierstedt). Norway maples are the most sucessful reproducers that I know. They put dandelions to shame. In a hospitable habitat like Plainfield, each tree manages to produce thousands of seedlings each year. The seedlings carpet the ground and are difficult to uproot. Those that grow in a lawn eventually succumb to repeated mowing, but what about the rest? They're extremely shade-tolerant and so have no trouble at all growing up in the middle of a mature hedge. They also have no trouble growing up in the middle of a mature forest. They leaf out earlier than most plants and hold their leaves later into the fall, giving them a longer growing season.(2) Norway maples are crowding native species out of our parks and forests.(3)
They're taking over the urban landscape as well. How many hedges have you seen that started out as privet and ended up as maple? Homeowners tire of struggling to uproot the very tenacious maple invaders and instead just shear the maples along with their hedging plants.
So what's the problem? Norway maples cast an inky shade in which very little can grow. They make a dense network of subsurface roots that quickly suck every bit of moisture from the soil and that lift sidewalks. Any gardener knows that to dig a hole near a Norway maple is to dig a hole in wood. Tight-angle crotches make the trees more susceptible than most to storm damage. Drive around Plainfield after a storm and take note of what kinds of limbs you see blocking the road. Mostly maples, many Norways.
But Norway maples' most egregious offense is that they breed faster than the natives (and I'm sure that it's this fact that most distresses Mr. Nierstedt). Norway maples are the most sucessful reproducers that I know. They put dandelions to shame. In a hospitable habitat like Plainfield, each tree manages to produce thousands of seedlings each year. The seedlings carpet the ground and are difficult to uproot. Those that grow in a lawn eventually succumb to repeated mowing, but what about the rest? They're extremely shade-tolerant and so have no trouble at all growing up in the middle of a mature hedge. They also have no trouble growing up in the middle of a mature forest. They leaf out earlier than most plants and hold their leaves later into the fall, giving them a longer growing season.(2) Norway maples are crowding native species out of our parks and forests.(3)
They're taking over the urban landscape as well. How many hedges have you seen that started out as privet and ended up as maple? Homeowners tire of struggling to uproot the very tenacious maple invaders and instead just shear the maples along with their hedging plants.
What happens if the maple seedlings are left to their own devices for a few years? They make a Norway maple jungle. Such jungles are easily found in Plainfield. The maple jungle pictured below is on Belvidere Avenue near Berkeley.
Don't mix up Norway maples with sugar maples. Although the leaves of the two species are quite similar, the trees are easily distinguished by their bark. Norway maple bark is brownish grey with shallow furrows.
Sugar maple bark is silvery grey and shaggy.
Found: a big, beautiful ginkgo.
955 Woodland Avenue has a mature ginkgo as beautiful as the hacked Netherwood Station ginkgo used to be.(4) It's worth a visit.
955 Woodland Avenue has a mature ginkgo as beautiful as the hacked Netherwood Station ginkgo used to be.(4) It's worth a visit.
Dan Damon sent photographs of a handsome ginkgo in the 900 block of Central Avenue. His photographs are below. Dan made the ultimate ginkgo sacrifice. He got up close and personal with the stinking ginkgo fruits and tracked some of them into his car. For his efforts he got great photographs of fruits that are adapted to fend off even dinosaurs with their odor.
(1) The Urban Tree Book, Arthur Plotnik, Three Rivers Press 2000, p. 95.
(3) To make the threat quite local, Professor Thomas Ombrello of Union County College observes that "There are numerous parks in our area where Norway Maples are displacing the native tree species." The Trees of Union County College, 2nd edition, Thomas M. Ombrello, Union County College 1997, p. 43.
An Overview of Nonindigenous Plant Species in New Jersey, (www.state.nj.us/dep/parksandforests/natural/InvasiveReport.pdf) published by the state Department of Environmental Protection in 2004, cites Norway maple among 29 "invasive nonindigenous plant species documented to aggressively invade...natural plant communities in New Jersey."
The Invasive Plant Council of New York State includes Norway maple on its list of the "Top 20 Invasive Plants in NYS" (http://counties.cce.cornell.edu/chenango/hortnr/other/weeds.htm#regular).
The Pennsylvania Dept. of Conservation and Natural Resources lists Norway maple among "serious threats to our native ecosystems" (http://www.dcnr.state.pa.us/forestry/wildplant/invasivelist.aspx).
(4) See April 19 Plainfield Trees post on Ginkgo biloba. http://plainfieldtrees.blogspot.com/2007_04_01_archive.html
Copyright Gregory Palermo
