Sunday, November 29, 2015

Growing my own Forest

All through the late summer and fall I've been collecting seeds: quaking aspen, sugar maple, hickory nuts, then red, white and scarlet oak acorns, and white pine and eastern hemlock samaras.

This began in the wonder of seeing my trees do things I'd long awaited.  But as little heaps of seeds began accumulating, they began to whisper: "plant me."  Before long I was trying in my mind to imagine planting a little forest.  A forest on less than half an acre.  Most of which is lawn.  In a city.  And of course the forest couldn't be allowed to shade my tiny vegetable patch.

So, of course, I've optimistically put aside enough seeds to plant a good acre of dense native forest.

I didn't collect every kind of seed, not quite--I did in fact have my reasons.  First, a tree needed to be one uncommon in my yard.  Hence the need for quaking aspen, red oak, scarlet oak, and especially white pine and--maybejustmaybe--tamarack.  (Tamarack is really in disguise here: a card-carrying member of the great boreal forest that rings the planet in the far north, that is pretending to be a landscape planting at the local VA hospital.)  A few species I had, but either these were too few or too old; so I collected white oak and black oak to replace the few aging trees on the property, and eastern hemlock to join my five-foot teenager.

Some trees have particular charms.  White pine makes a nice shelter for birds in the winter snows and wind.  White oak bears a rather sweet nut that squirrels love, and aren't bad snacks for people, either.  Quaking aspen is very animated in the slightest breeze, and, like white pine, grows quickly enough that I might live to see it attain adult stature.  Eastern hemlock is a slow-grower that, though common locally, eventually grows to a tree of dignity.  It, too, is shelter for birds.  Sugar maple makes the cut even though it is fairly common in the neighborhood: a hardwood of wild northern forests, the source of maple syrup and sugar, and the flame-colored foliage of fall all add up to a need to have one in my yard.

L-R top: Larch (Larix laricina) cone with a few tiny samaras, 
black oak (Quercus velutina) with small and large nuts, red oak (Q. rubra); 
middle: white pine (Pinus strobus), scarlet oak (Q. coccinea), quaking aspen (Populus tremuloides); bottom: white ash (Fraxinus americana) samaras, pignut hickory (Carya glabra) nuts, sugar maple (Acer saccharum) samaras.  

I might need a gray birch and a tuliptree from my parents yard just because.  And if I come upon pin oak acorns next year, I might try to squeeze one in. 
Next is to treat the seed so as to insure the best germination rate.  This treatment is known as "cold stratification."  This is a fancy term for doing what comes naturally: burying the seeds in moist sand in a place that will get cold enough to break seed dormancy, in due course triggering spring germination. 

Then I need to think about getting a bigger yard.  The little patch of woods at the back of our lot abuts the similar patches of three neighbors.  (I'll bet they won't even notice an extra tree or two.)

Saturday, November 21, 2015

Bittersweet Wreath

Oriental Bittersweet (Celastrus orbiculatus)--a robust, fast-growing vine with round leaves and buds sometimes mistaken for thorns--is a tough customer.   I remember finding maple trees with trunks turned to corkscrews by the vine's embrace.  In late fall, though, bittersweet comes into its glory, as yellow capsules split into fours to reveal bright orange seeds.  In autumns of my boyhood, I used to cut long vines of oriental bittersweet that hung over the stone wall that bordered the yard.  My mother would shape the vines into artful arrangements and sell them to a nearby handicraft shop. 

I was just reminded of this, seeing a bittersweet vine show that telltale orange, and it gave me an idea.  Oriental bittersweet would make a lovely addition to a holiday wreath, or could even be a wreath in itself.  And every bittersweet wreath hung on a door or gate would be a small gift to native plants: Celastrus orbiculatus is, after all, an alien invasive, probably doing more subtle harm to native ecosystems than just strangling the odd tree here and there.  And if your wreath-making habit became an annual tradition, so much the better!

 Oriental bittersweet, leaves gone, has begun opening its seed capsules.

Here's another alien invasive that is really lovely at this time of year: Japanese barberry (Berberis thunbergii).  Bright red fruit contrasts with the deep green leaves.  Make arrangements of these stems only with the heaviest leather gloves on--the thorns are needle-sharp!  As with bittersweet, you'll want pruning shears to cut the tough stems.

 Japanese barberry is deciduous, and its leaves have begun to fall.
But the stems are almost as pretty when leafless.

Friday, November 13, 2015

Acorn Mysteries

Before September was over, you couldn't walk under a red oak without crunching acorns underfoot.

A friend recently urged me to write a post on acorns.  "Why are there so many?" she wanted to know.  Indeed, after closely observing a number of oak trees and seeing none of the expected acorns last year, I was very pleased to see some of the same trees bearing heavily this year (I was ready to go nuts last winter!)  First, in September, a couple of red oaks of my acquaintance began covering the ground with stout, barrel-shaped acorns.  Other neighborhood oaks announced themselves to be red oaks by doing likewise.  Soon afterwards, white oaks with graceful long, tapering acorns began to weigh in with heavy crops of their own--so many acorns that, in a few walks, I filled my pockets with enough sound acorns to experiment on using them for food.  (Acorns were the staple food of a variety of North American tribes in the Pacific Northwest.)  The single scarlet oak I know nearby produced an admirable crop, as well, peaking in late October.  Black oaks, meanwhile, dropped acorns one tree at a time, with no pattern apparent to me.

This may even turn out to be a "mast year": one with many times the typical yield in tree nuts that are food for animals.  The random nature of mast years makes them an enduring mystery of their own.

Red Oak (Quercus rubra).

White Oak (Quercus alba) dropped its slender acorns so thickly I sometimes
avoided walking under the trees rather than murder them underfoot wholesale.

 White and black oak acorns compared.  White have warty caps, red, black, etc are scaly.

 Black oak (Quercus velutina) acorns may be as large as red, but are rounder, with deeper cups.

So why, then, was I left with the (ungrateful) question: why aren't there MORE acorns?  It turns out the most common of our oak species was almost a no-show.

Here's the census: 

The one scarlet oak I know finished dropping an impressive crop of nuts a couple of weeks ago.

Of the five red oaks I know, all dropped good crops.  (These I did not collect for food, because red oaks and their near relatives, black and scarlet, have two-year acorns that are very bitter.)  It's entirely possible that some red oaks didn't, but those I didn't know about.

White oaks are more common: I kept tabs on seventeen, of which about half had respectable crops.  (The two in my yard, among others, remain recalcitrant.)

Black oaks are commonest of all; I know of perhaps forty trees big enough to bear well.  (Some few of these may be the similar scarlet oak.)  I am only counting mature trees that overhang some pavement, making it easier to spot fallen acorns.  Yet only four black oaks out of the forty dropped any acorns worth mentioning!  And only one dropped a crop comparable to the better-bearers among the red and white oaks.  

Where are all the black oak acorns??

There are, of course, many factors that affect whether a particular tree will bear a good crop in any year.  A cold, wet spring could inhibit pollination.  A host of other environmental conditions including disease and insect predation could reduce yield.  And the trees themselves differ: oaks tend not to bear good crops under about age fifty, and drop off production when they become old; and some trees may simply be poor producers for genetic reasons.  Here in the city, other factors that occur to me include poor soil, or inadequate water due to pavement-covered tree roots.

All oaks, like other trees, produce flower buds in the summer or fall of one year and flower the next year.  But black oaks, like the related red and scarlet oaks, don't mature and drop their acorns until the fall of the year following the year they flower.  Thus any particular acorn on such a tree is vulnerable to the environment (late frosts, drought, extreme cold, and the like) for the better part of three years.  White oaks, by contrast, mature their acorns the same year they flower, and so have one less year of vulnerability.

I have made a point of watching bigger trees, so I think youth unlikely to be the problem.  And weather conditions should be similar in the local area.  So what are we left with?

The most useful explanation probably came from, and the above Illinois forestry extension agent.  White oaks and their near relatives tend to produce a regional crop: all trees in the region bearing about the same in a given year.  Black oaks and their relatives produce in individual patterns in which a good crop may be followed by two to four years of small crops.

Even so, in a five-year cycle we should expect good crops from about one-fifth the trees in any given year.  One-tenth seems awfully low.  And the red oaks--with similar vulnerabilities--had a bumper crop.

So, for black oaks at least, the mystery remains!

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. 

Wednesday, November 4, 2015

What color do oaks turn in fall?

Bit of a trick question--even if you keep the question to just one species! 

 Oddly, most oaks around here have color names.  But--except in the case of scarlet oak--it isn't fall colors that seem to be meant.  (Our one neighborhood scarlet oak hasn't turned yet, but I'm waiting!)  I've seen oak leaves turn everything from basic brown, to rust, to yellow to deep, deep scarlet--my favorite.  Of course, like most leaves, their color evolves over time.  

Weather also plays an important role, since the red color (anthocyanin) is generated by continuing photosynthesis in the dying leaf.  This is favored by bright sun and cool temperatures, and can be defeated by rain, which washes the soluble color away.

 A black oak (Quercus velutina) coloring up high; close-up below.

Black oak.

 Why is this called White Oak?  Beats me!  Maybe because the undersides of leaves (above)
are noticeably lighter than the tops--especially when green.

 White oaks (Quercus alba).  A flowering dogwood (Cornus florida) in the foreground above.

White oaks.
Going its own way.

Black oaks.  Why are the veins in the leaves below still green?

Swamp white oak (Quercus bicolor).

Black oak.

White oak.

Black oak.

All photos taken between 10/24 and 10/29