Sunday, March 30, 2014

Red-stained Box Elder Wood




It was recently pointed out to me that the wood of Box Elder trees (Acer negundo) often exhibits a reddish stain.  I was curious to find out what caused it.  After some research, I learned that typically, the stain has been attributed to the fungus Fusarium reticulatum, but that research done at the U of MN has shown that the stain is not associated with any particular species of fungus.  Instead the stain is likely a result of some compound produced by the tree to protect tissue after it is compromised in some fashion.
What actually causes the stain was undetermined by the study; the compound is broken down quickly after it is produced (the authors of the study speculate that it is a phenol that oxidizes to produce the stain, but that detail will be left to the distracted chemist to explain further).

The above picture shows a box elder stump with the red stain along with a network of black lines.  This is know as spalting, and is attributed to fungal decay, though as far as I know, not any particular species.

Box Elder wood is not widely used since it is a relatively weak and rot-prone wood.  But wood with  the red stain is used by wood workers to make smaller, ornamental objects.

Tuesday, March 18, 2014

Life In A Sap Bucket - Springtails

The Sugar Maple sap started running today, not a lot, but enough to attract these minute Spingtails (class Collembola) to the buckets.  I almost overlooked them; they initially registered in my brain as woody junk that fell into the bucket from the tree.

I was surprised to learn after observing these today that springtails are not insects, they are in their own taxonomic class.  They share some similarities with insects: three body parts, six legs, two antenna.  But they don't have compound eyes, but instead feature a cluster of eye spots on their head.  And two notable structures that are unique to springtails is the furcula, an appendage on the end of their abdomen that allows them to "spring" when flexed.  And the collophore, a tube located at the front of their abdomen that aids in moisture uptake and excretion.  And please note, that this description is very simplistic, and probably contains some inaccuracies due to it's brevity.

Springtails are usually found in damp places, and are omnivorous, feeding on a wide range of organic matter.  Though mostly unknown to the majority of us, it seems they can be found anywhere there's moisture and organic matter, often in large numbers.  In MN, you can sometimes observe springtails on the snow during warmer weather.  They are commonly called snow fleas - but of course aren't fleas at all, because fleas are insects.

And oddly enough, this my second run in with springtails within a week.  I toured the Cave of the Mounds in WI with my family this weekend, and it was mentioned on the tour that the only creature living in the cave were springtails. 

Wednesday, March 5, 2014

An Illustrated Life List: Canada Goose



A bitter cold walk from somewhere, I don't remember where, in North Minneapolis to my home on the other side of the river.  I crossed along of the Lowry Ave bridge.  This was a few years back before the bridge was rebuilt; when it was a criss cross of old iron girders.  It was the piece that tied two ugly and depressing sides of the river together; giant piles of scrap metal, derelict structures stretching into the river, and dilapidated buildings jumbled together along a forgotten stretch of the Mississippi.  The area has changed a fair amount in the past few years, with redevelopment, new river front parks, and a new bridge (which is pretty cool looking, and lights up).

The bridge usually has some open water under it and attracts Canada Geese, Branta canadensis under it during the winter.  It's also a good spot to find Common Golden-eyes, Bucephela clangula during the winter.  And usually a Greylag Goose, Anser anser - domestic goose.  I'm not sure if it's been the same one, and I don't think I've seen it every year, but it's been there more than one winter, mixed in with the Canada Geese.  The first time I saw it, on the aforementioned cold walk home I got really excited.  I didn't have binoculars and thought it was a rare goose of some sort; a new entry for my life list!  I hurried home, and returned with binoculars, scope and a field guide.  The discovery that it was a domestic goose was disappointing, but only briefly, because their was still the joy of discovery, and in the long run, a place in my neighborhood to bird watch during the winter; I look here for Barrow's Golden-eyes in the winter, so perhaps birding here will eventually yield a new life list entry (though this winter the river did freeze over completely under the bridge, so no geese or ducks).

You might wonder why this post isn't titled "An Illustrated Life List: Greylag Goose".  It's because I didn't add the bird to my list.  Everyone has slightly different criteria for adding birds to their lists, but I believe it's fairly common practice to not add domesticated birds to a life list.  It strongly resembled a wild Greylag Goose, but one has never been recorded in Minnesota, and it's much more likely that it escaped, or is the hybrid offspring of a Canada Goose and a domestic goose on a farm.  I do look here for Barrow's Golden-eyes in the winter, so perhaps birding here will eventually yield a new life list entry.

Sunday, March 2, 2014

A Quick Guide to Poison Ivy Look Alikes


As a professional naturalist, if I had to pick one most frequently asked "nature" question it would be how to identify Poison Ivy.  So of course, I point out the three leaves per stem (leaves of three, let it be), which works . . . to a point.

Because as soon as you start really looking, a lot of plants have three leaves and sort of look like poison ivy, and poison ivy itself is variable enough that it can be hard to pin point other identifing features that seperate it from these look alikes.  So I've been thinking for awhile of a quick, nontechnical guide to separate Poison Ivy's look a likes from the plant itself.

The plants pictured below are prime candidates for Poison Ivy look alike status.  Under the plant's name is a one word or short phrase description of the plant; one feature that distinguishes these three-leaved plants from Poison Ivy.  Then after the picture is a short discussion of that feature.  Note these are not complete ID guides for these plants.

Box Elder - Acer negundo
Opposite
 
When Box Elders first sprout, they look remarkably like Poison Ivy.  As the they grow, it assumes a more definitive shrub-like appearance and is less likely to be confused for Poison Ivy.  A quick, but not nescessarily easy way to tell a young Box Elder apart from a Poison Ivy plant is to note the arrangement of the leaves; they are opposite in Box Elders or side by side along the stem.  I say not easy because sometimes stems and leaves break off making an opposite arrangement of leaves look like an alternate arrangement  (which Poison Ivy has), and the arrangement isn't always the clearest in smaller and young plants.  Overall, it's hard to find an easy feature that definitively separates the two, though in my opinion, if you let go of the more analytical, detail oriented aspect of your brain, you'll notice Box Elder always has a certain shrubby je ne sais quoi to it.

Raspberry - Rubus sp.
Thorns
Fairly easy to distinguish from Poison Ivy once you notice the thorns.

Virginia Creeper - Parthenocissus quinquefolia
Five leaves
Despite the five leaves instead of three, Virginia Creeper does resemble Poison Ivy.  They are both found in similar habitats.  They both have similar growth forms; they can both assume either a ground cover habit or grow as a climbing vine.  And they both often turn a bright red in the fall.

Hog Peanut - Amphicarpa bracteata
Smooth leaves
No teeth, bumps or serrations along the leaf edges separate this plant from Poison Ivy.  It spreads out along the ground in the woods, sometimes climbing up other plants.  In my opinion it has a much more dainty appearance compared to Poison Ivy.

Jack-in-the-Pulpit - Arisaema triphyllum
Stemless leaves
The three leaves are joined together in the middle, with no stems.  Trilliums (Trillium spp) also have three leaves and strongly resemble Jack-in-the-Pulpits, if no flowers are present.  It doesn't seem to get confused with Poison Ivy all that often in my experience, maybe because it is a spring ephemeral that comes and goes before Poison Ivy is in full swing.

Note: the five plants included here may not be definitive, since most of my experience with the plant is from MN.  I'm curious to know what other plants you know of that look like Poison Ivy.