Sunday, November 8, 2015

Looking Down: a good time to learn a few leaves

"Peak color" has passed, and the view aloft isn't quite as all-engrossing as it was a couple of weeks ago.  Sugar maples are entirely bare, and soon all deciduous trees will be, leaving only a few dried leaves rattling in some oaks.  Now--before Norway maples completely blanket all with a yellow coverlet--is a good time to see what's underfoot.

Fall color varies too much to rely on for identification.  A few colors are characteristic, en mass: the almost-neon orange of sugar maple is pretty reliable, but many sugar maple leaves remain a clear yellow.  A maple tree with yellow leaves still aloft very likely Norway maple.  Red maple is indeed typically red, but can be other colors or a mixture of them.  Individual red maple leaves are often a mottled combination that makes it seem the leaf couldn't make up its mind.

Oaks, as we have seen, can be many shades of red, yellow, tan or brown--even in the same species.

Leaf shape is a better guide to identity, if not perfect.

Nearly all maples have fan-lobed leaves: the parts of the leaf appear to radiate from a center (look at the veins).  Of these maples, one with smaller, toothed (jagged-edged) leaves is red maple.  The other two maples common hereabouts are sugar maple and Norway maple.  At a glance the leaves appear similar, having 3-5 smooth-edged lobes ending in points.  But sugar maple has graceful leaves as long or longer than broad, with each lobe ending in a long central point.  Norway maple has broader leaves, reliably yellow, and the points are nearly all the same length.

Sycamore is another tree with fan-lobed leaves; they are easy to distinguish from maples because their leaves are huge and heavily-veined, and their bark is a distinctive colored puzzle of peeling flakes. 

Red maple leaves, alone among local maples, have toothed edges.

Red maple is named not for its fall colors, but for its bright red flowers in spring.

 Flame-orange foliage pretty reliably marks sugar maple, but its leaves range into yellow, as well.
Norway maple loses its leaves mainly after sugar maple.  The yellow Norway maple (left) is broader, and without the gracefully-pointed lobe tips of sugar maple (right).

 Sycamore is an unrelated tree that has leaves somewhat similar to maple, but these leaves are much larger and coarser, and the bark of sycamore is a mottled patchwork of peeling flakes.

 Can you identify these leaves?  The orange, toothed leaves are 
red maple, while the larger yellow are Norway maple.

Oak leaves are also lobed, but, instead of coming from a common center as in maples, the lobes come from a central axis.

The easy oak is white oak: its leaves are reliably rounded, with no bristles.  Other than this, they can vary quite a bit.  White oak belongs to a larger group of oak species with similar leaves, but around this area the others are pretty rare.

Oaks with pointed lobes with bristle-tips are a bit trickier.   Of these, red oak has more lobes and the lobes are fuller, with rather small gaps between lobes.  Scarlet oak, by contrast, usually has fewer lobes and a leaf that is almost skeletal: "more hole than leaf."   The third, black oak, also has fewer lobes than red oak, but varies tremendously in it's fullness from "more leaf than hole" like red oak, to exactly as skeletal as scarlet oak.  If there is a low branch nearby, you will know black oak by its buds, which are large, strongly-five-sided tan/gray, and fuzzy.  (Scarlet oak has smaller buds with brown-edged scales and little fuzz.  All three species are found in the neighborhood, but one is overwhelmingly the most common; you can be pretty confident that any pointed-lobed oak leaf you aren't completely sure about is black oak.

White oak has rounded lobes.  (Fungi are at work recycling the one above--see the little bulls-eyes?)  Color varies from dusty rose to tan.  Amongst the white oak leaves below is one of black oak (center), with its bristle-tipped, pointed lobes.

The rounded lobes are the reliable trait of white oak--in other respects the shape sometimes varies.

Black oak can have a broader leaf like that in the middle two photos up, or one as skeletal as scarlet oak.  I would have taken these for scarlet, had it not been for the tree's fuzzy gray buds.

Buds of scarlet oak (above) have scales edged in brown and are smaller, less fuzzy, and less strongly-angular that those of black oak (below).  If you find acorns, those of scarlet oak have concentric rings around the tip, while those of black oak are smooth-tipped.  When in doubt, the tree is black oak!

Take the quiz and see how you do!  What are the nine leaves numbered below?

1 is Red maple, 2 is Norway maple, 3 is either sugar or Norway, 4-6 are black oak,
and 7-8 are white oak.  9 is some sort of imported maple (Japanese maple, perhaps?)

Correct your paper, and then try once more!  (No tricks this time.) And this time the answers will be a little farther down to make it a real test.

1-red maple, 2, 4, 6 are likely all black oak (though 4 & 6 might be scarlet), 3 & 7 are Norway maple, and 8 & 9 are white oak. 

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