Thursday, June 30, 2016

Time and Chance Happeneth to Them All

 I returned, and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all.   Ecclesiastes 9.11  KJV

To maintain a stable population, an individual needs to have, on, average, one child.  This is no less true for oak trees than for humans.  But it is an axiom of nature that individuals of every species have more offspring than that--very often enormously more.  The house sparrows nesting in the old maple in my front yard will have a little brood in their nest by now--and house sparrows can have several broods per year.  A female mosquito can lay hundred of eggs at a time, and thousands over her life.  And an oak tree?

A big oak tree can pave the ground so thickly with acorns that your feet won't touch the ground as you walk.  Though the tree will have lean years as well, it will produce crops like this many times over its long life.  All of this takes enormous expenditure of resources.  And why?

Life's a crap shoot.  Any given offspring faces very long odds of surviving to have its own brood.  Predators,** disease, competition, starvation, drought, cold--there are any number of dangers and forces at work.  We forget this sometimes because we have so modified our environment* that nearly all of our children (in the first world, at least) grow to adulthood.  But for every other species enormous fecundity is necessary for most individuals just to get a foot in the door of the next generation.  

(And any genetic trait that increases your ability to survive and get more offspring to adulthood will subtly change the genetic make-up of that next generation--which is natural selection, the chief mechanism of evolution!)

 Gray birch seeds (light brown with translucent wings), the scales that 
accompany them (dark brown fleur-di-lis), and sprouts (top left, bottom right)

 More gray birch sprouts.

Pitch pine sprouts.

I had special reason to ponder this chanciness after my little winter project.  Having collected seeds of many native trees last fall, it occurred to me to plant some in my yard in the spring.  I carefully wrapped seeds of nearly a dozen species in moist paper towels, bagged them in plastic, and kept them cold over the winter to break their dormancy.***  Those that had not gotten moldy I planted in various places around the yard back in late March.  At least some were alive, since they had sprouted.  I didn't keep track, but must have planted over a hundred seeds.  Soon after, we had a little snow, and then a hard freeze.  I didn't worry too much, figuring that, such wild species could take a little weather on their own.  Then I got very busy and forgot about them.  A very dry spring followed.  I finally sought out the little patches I had planted, and found not a single shoot.  No survivors.  I had forgotten for awhile that plants succeed at least as much from their numbers as their toughness.  Yet another lesson in the hard facts of life.

This year's crop of black oak young-in's is coming along nicely.

*That modification has come at the expense of most of the ten million-odd species sharing the earth.

**Although, weirdly enough, an oak tree can put predators to work!

***In a process called "cold stratification."  Actually, I tossed them into the trunk of my car, to be exposed to something like natural temperatures, but not to predators.

Tuesday, June 21, 2016

Sassafras in the City

I was delighted and a little surprised to find a few sassafras trees at the middle school just down the street.  Sassafras is famous for its three leaf shapes: "mitten," double-mitten", and just plain normal.  I like that it hangs out in wilder areas like Blue Hill Reservation--although one of the biggest trees I know is actually in a suburban yard near my mother's house.  And, of course, I love it for the aroma it gives off.  Like many plants, sassafras generates aromatic compounds that defend it from insects.  And--like many plants--these defensive chemicals smell very nice to humans!  In fact, our culinary herbs and spices come from plants that use them as weapons ("Those humans: using our poisons, they make pizza!  Go figure.")

The leaves have some insect damage right now; of course, insects evolve as well as trees--and faster, since they have a shorter generation time--so the arms race continues. 

Sassafras root was an original flavoring in root beer.  Sassafras was an important medicinal export in colonial times, second only to tobacco, at one point.  Many years ago when I worked at a Boy Scout camp, we used to put a few twigs into hot water to make a nice tea.  We stopped when we learned  one ingredient might be harmful, and even carcinogenic.  But the leaves are still powdered to make the file that flavors, for example, New Orleans' file gumbo.  (And that same toxic oil, safrole, is the main ingredient in the designer drug, Ecstasy.)    

I still remember when some construction work knocked a small sassafras tree down, leaving its roots exposed.  Walking downwind of that tree, the the overpowering smell would always stop me in my tracks.  I couldn't go on without first inhaling a deep lungful.  

So you don't have to ingest sassafras to enjoy it.  If you spot a tree, there is no harm in breaking off a leaf or a tiny twig now and then and enjoying the fragrance!

 The trees flowered late in April.

 By mid-May it was clear that none of the flowers I could see would set fruit
--I don't know why, since several nearby trees also flowered.

The variable leaf shape makes this perhaps the easiest of all trees to identify!
In winter, the green twigs are a clue.

 Some critters can apparently eat the leaves and survive.
But this is much less damage than most other trees are suffering, right now.

Friday, June 17, 2016

Grasses in Flower

I have watched as one species of tree after another has flowered and unleashed its pollen on unsuspecting humans.  The last of these was white pine, which made up in sheer volume for its lateness.  But only in the last week or so have gotten noticeably congested--after the trees were finished.  The real summer allergy culprit?  Grasses.

But it's worth it to take your allergy meds so you can enjoy their beauty close-up!  Here are some June-flowering grasses around my yard and neighborhood.  And here are other posts on grass ID and grass sex.

English ryegrass (Lolium perenne) dangles yellow stamens laden with pollen.

Orchard Grass (Dactylis glomerata) has a bunchy appearance, especially before and after flowering when the flower clusters are more contracted.

Red fescue (Festuca rubra) is often a good guess as a typical lawn grass.

Timothy (Phleum pratense), a European pasture grass, is not yet flowering.

Deertongue can begin flowering even before the flowers completely emerge, 
as befits its Latin name, Panicum clandestinum.

Deertongue flowers are very pretty--even though grass flowers have no petals:
the stigmas (female parts that receive pollen) are a lovely shade of blue.

A luxurious stand of quackgrass (Agropyron repens) at the middle school.  Breathe that pollen!

Possibly Redtop (Agrostis alba)

Smooth brome (Bromus inermis), I think.

Possibly Red Fescue (Festuca rubra), a popular and shade-tolerant lawn grass.

The fescue grass above shows both yellow stamens and also feathery, pollen-accepting stigmas of a most delicate blue.  (To appreciate beauty in flowers so small takes close observation.)

Quackgrass (Agropyron repens) has flower clusters a bit like English Ryegrass,
but they are flat to the stem instead of edge-on to it.

The "prairie garden" beside my house hosts a beautiful stand of Switchgrass
(Panicum virgatum) and Big Bluestem (Andropogon gerardii) that will flower
late in summer, waving their flowers as high as six feet in the air.

Saturday, June 11, 2016

A good year for caterpillars--


--means a bad year for trees.  And a bad year for sitting in the shade, with frass* raining on your head.

I first noticed the caterpillars in early spring.   I'm in the habit of plucking twigs of trees that interest me on my walks, and putting them in water at home to see how they turn out.  (Kind of a waste of time actually: even in the best of circumstances, these developing twigs need resources from the rest of the tree to do much growing.)  But not only did my twigs not develop, the leaves would rapidly be eaten by caterpillars that, unnoticed, had ridden home with me.  In the beginning, these caterpillars were more varied, but as spring progressed the dreaded gypsy moth caterpillar dominated overwhelmingly.  

Gypsy moths would be kind of pretty if not so frightening.  They prefer oaks, and will even eat young pine needs--both well-equipped with chemical defenses against most herbivores.  If the infestation is bad enough, the trees will spend so much in resources to continue producing leaves that they starve to death, or or so weakened that they succumb to secondary diseases.  I remember doing field work  in an oak forest as a college student doing field work in the early 80's.  It was a bizarre experience: the rain-like patter of frass falling on the dry leaf litter contrasted weirdly with the sunlight streaming in through the leafless crowns.  This year is bad, though not nearly as bad as that.  

Gypsy moths were deliberately imported into Massachusetts from Europe in 1868 by a French scientist who wanted to breed them to produce silk.  Like many such introductions before and since, this did not go according to plan, and an outbreak occurred  only a decade later.  Lawns and smaller plants of the forest floor will likely see a fertilizer effect from the caterpillar droppings.  The caterpillars are a food source for many birds and small mammals such as mice and squirrels, which should see their own population booms.  At high population densities the insects suffer from epidemics of fungi and a virus.  (I have seen many dead caterpillars hanging from twigs.)  But the fungus, in particular, needs moist conditions to spread, and this has been a dry spring.  

It's too late to do anything about this year's infestation, although trees could be sprayed early next spring to avoid a repeat performance.  Then we could get back to business as usual: battling periodic outbreaks of winter moth caterpillars--another alien invasive.

Red oak, alder (tiny caterpillar), ash-leaved maple, and witchhazel with caterpillars in early spring.

Maples like this red maple have seen a lot of damage.

 Black oak seems to be a favorite--and is the most common tree in the neighborhood.

Swamp white oak is tasty, too, but a pretty rare tree hereabouts: first sign of trouble, then later on.

 Both paper birch (above) and gray birch (below) are nice snacks.

Witchhazel is good, but rare.

 I'm not sure about white oaks; many seem to go almost unscathed, but not all.

Sand-grain-sized frass is good fertilizer, but makes a mess of cars, lawn furniture, etc.

*Insect poop.

Monday, June 6, 2016

Blue Jay Beauty

When I saw this bird out of the corner of my eye, perched in a paper birch, I didn't know what it was.  In the next few seconds he (she?) turned every which way and showed a different appearance each time--like a runway model.  I can hardly imagine a more fetching combination of colors than this.  

Blue jays eat practically everything from seeds to nuts to insects to small animals (rarely eggs or nestlings).  They are intelligent.  Males & females share nest-making responsibility, and they seem to pair-bond for life.  They are not aggressive around bird feeders.  Although known for their harsh, raucous call, they also have a variety of songs, and do a very fair imitation of the red-tailed hawk's cry that used to fool me regularly.

That both males and females are colored like this may tell us something about them, and us.  In general, one sex (most often the female) chooses their mate.  The choosier is most often the female because the female has the biggest investment in offspring, and the most to lose if she chooses poorly.  Since both are colored, perhaps blue jays choose each other?  In any event, the colors that so entrance me must also entrance them--otherwise blue jays wouldn't find their mates so attractive, and by their choices drive natural selection to generate such a palette.  So, in a sense, the blue jays and I have common tastes.

Blue jays are common enough around here, but this one gave me enough of a start to look at them again, and appreciate beauty I had taken for granted.