Monday, March 30, 2015

Bald eagles!!

I got your Spring showers right here, chump
My favorite fact about that capricious whistlepig, Punxsutawney Phil is that, as with most progrnosticating animals, he is wrong over half the time. And that's with a 50/50 shot of being right. Today my mom and I spotted this beefy white-chinned woodchuck fiercely defending its cozy little drain pipe.

On my way home from CCV today I decided to drop in at Salmon Hole and see what avifauna all that open water might have brought out. And boy was I delighted! After watching the gulls hunting fish, I spotted a mature eagle hanging out on the ice down stream. I went home to get my camera and convince my mom to come out and join us. When we got back to Salmon Hole the eagle had left already. In its stead was a beautiful assortment of water loving birds. Bonus challenge: Spot (and name) all four species in the photo below?

Can you spot four different species in the above photo?
After hanging out for about 20 minutes, the gulls just went berserk and all those standing around chittering with each other burst up into flight. Sure enough, flying straight towards them from downstream was the eagle! The gulls scattered and circle around until the eagle disappeared in the distance (it flew over My Web Grocer towards St Mikes). 

(Dichotomous key interlude) Time lapse of cherry blossom

About 3 weeks ago I pruned some of the fruit trees in my backyard. I took branches from peach, cherry, and plum inside to force. The first cherry blossoms opened as soon as I got to DC! I set out a camera to try and catch a time lapse of the second set of flower buds opening. The branch had three sets of flower buds on it and they opened in sequence from outer most (distal) to the buds closest to the trunk (proximal).

Here's what I learned from my first attempt at capturing a time lapse of a flower opening:

  • Get your framing right! I should have left space on either side of the flower and then used a batch edit to crop all the photos. Instead the bottom flower opened and exited the frame!
  • Use an artificial light source and block outside light as much as possible. The street lights kept going on and off and altering the lighting on the flower. Also, as the sun came up it threw off the lighting even more. 
  • Use the manual aperture and shutter speed settings on the camera to get the exposure constant. The flickering in the video was from minor adjustments because the light meter kept vacillating at f11 between 1/20 and1/25.
  • Time intervals. I set the camera to take images at 5 minute intervals and that seemed to work just fine. I used Microsoft Movie Maker to piece them together and set the image timing at 1/10 second. 
  • Use a tripod. I didn't bring mine with me so I wound up having to jerryrig one out of an old olive oil container. It shifted slightly and had I needed to replace the batteries it would have thrown the framing off. 

Thursday, March 26, 2015

Dichotomous key (V) - Bud scars

Leaf scars have personality. No doubt about it. With a nice little bonnet, top hat, or beehive hair do to cap off a gnomish face, each monster marches a terrifying procession along the length of their twigs. These tiny monsters grin out at the unsuspecting world. And lo, a peripatetic naturalist pauses to discover their intricate world. Sam and I spent some time asking these trees what their names were and boy were we discovered. Each face is a leaf scar, the outline of where the stalk of a leaf connects to twig. The dots and features that give the face its facey-ness collectively form the vascular bundles, which are composed of xylem and phloem (imagine cutting a celery stalk in cross section). 

(Black locust) Marrowzodufia Blugly the Dwarf

(Butternut) Pompuzador the bonnet keeper of spiggetiezi

(Yellow birch) Joy Doom Happy Stacks

(Cottonwood) Mark Buntly of the Broofing Haws

(Common buckthorn) Ronald the Masked Parasitic Jubilee

(Slippery elm) Squirky Bunkles

(Staghorn sumac) Salwall Dimlar the Jay Slorper

(Sugar maple) Starky Cusperbun

(Lilac) Ralphez the woggly-eyed lime top

(Black cherry) ZanKiffle Waffletragedy, aka ZK Waffles in the forests of Burlington

(American beech) Qwayzar Dalooskie

(Bitternut hickory) Ahab Dilbous-Bannister, Purveyor of Simple Fun

(Quaking aspen) Emperor Mewslies of Nostralias
(White ash) The Honorable Wide Collared Professor Kitten Anderson
(Witch-hazel) Slippy Ghoul Grin aka Barbara Butterfields aka Babs Buttfiel

Monday, March 23, 2015

Dichotomous key (IV) - Pith

Pith is one of my favorite things for some reason. I think its substance remained elusive to me for a long time - I couldn't seem to track down a good answer as to what it was and why it looks the way it does for different species. Over the years, primarily through carving, I've become much more acquainted with pith. Pith is essentially the undifferentiated, highly moldable ingredient of new growth. Also called medulla (which means middle), it also stores starches and water.

Classification of plant cells narrowing down to pith (I didn't subdivide alternate branches of the classification)
  • Vascular tissue (transport water, nutrients)
  • Dermal tissue (protection, prevent water loss)
  • Ground tissue (photosynthesis, food storage, growth/regeneration, structure, protection)
    • Sclerenchyma (main structural support of plants)
    • Collenchyma (structural, provides extra strength in areas of new growth - think, the long fibrous strands in celery)
    • Parenchyma (play a large role in synthesized food and water storage)
      • Chlorenchyma (photosynthesis, home of chloroplasts)
      • Aerenchyma (large intercellular spaces that hold air for buoyancy and respiration)
      • Prosenchyma, or Palisade parenchyma
      • Vascular parenchyma (forms either the xylem or phloem)
      • Medullary or ray parenchyma
      • Conjunctive parenchyma (root parenchyma)
      • PITH!

Pith changes in a variety of ways over time, the most obvious of which is color. Most pith starts as whitish in color and changes as it dies and ages to a yellowish or brown. The above photo shows this years growth of staghorn sumac on the left. Note the single growth ring of white adjacent to the egg yolk yellow spongy pith. On the right, below the bundle scars from the previous year, is a two year old section of the branch showing the darker brown aged pith. Note here the white ring of sap wood and the previous year of woody growth in the single ring of yellowish wood.

Turtle-like pattern of poplars

Cottonwood showing fluted ridges that correspond to the vascular bundles connecting to the leaves
Pith doesn't have a ton of variability in terms of shape in cross-section, so this isn't often a helpful tool for identifying the species. But some are beautifully non-circular. The Populus genus has five-pointed stars in cross section. The above photo shows a cottonwood (Populus tremuloides) twig in cross-section. The five-pointedness of the pith on cottonwoods corresponds quite nicely to the five ridges running parallel lines on outside of the twig.

Chambered pith of white walnut - or butternut (Juglans cinerea) above and black walnut (Juglans nigra) below
The walnuts have perhaps my favorite pith. Above is both black and white walnut pith side by side. For others the pith disintegrates completely (one way to distinguish between native and non-native honeysuckles is to crack open a twig; non-native honeysuckles are hollow, as shown in the photo at the top of the posting).

From top to bottom, Staghorn sumac, catalpa, elderberry, white ash

Some species have fantastically huge pith. Particularly great examples of these include elderberry, ash, staghorn sumac, catalpa, boxelder are among these species. Other species have nearly invisible pith.

Wednesday, March 18, 2015

Dichotomous key (III) - Of twigs both stout and thin

White ash on left surrounded mostly by red maple in the background, note the ashes much stouter branches
Leaves have typically fallen off the tree in the fall (except on trees that died before the fall or marcescent  trees or evergreen trees), so we can't see if they're simple or compound. But looking at the twig can give us some indication of what they might have been. I know I said that relative characteristics aren't the best, but they can be helpful with gestalt (recognizing something on a subconscious level) and I'll try and add numbers in to support this. 

Stand of staghorn sumacs showing thick twigs (also support the heavy fruit stalks that are persistent)

Compound leaves can be thought of "cheap disposable branches" (Peter Thomas's description in the incredible Trees: their natural history). This allows the trees to put more investment into quick vertical growth rather than into developing energy intensive branches lower down the bole. A somewhat contradictory result is that compound leaves are bigger and therefore weigh more, and so need a more robust twig to support them. Therefore, we might ascertain from looking at a twig if it's simple or compound. While I'm focusing on opposite twigs here, some of the thickest twigs are the alternate compound leaves of sumac.

Butternut on left, staghorn sumac on right. Both have compound leaves attached to stout twigs
Below I've broken down which of the MAD Capped Bucking Horse species are simple and which are compound:

  • Maples (except boxelder)
  • Dogwoods
  • Caprifoliaceae (except elderberry)
    • e.g. Viburnums, Honeysuckles
    • Boxelder (Ash-leaf maple)
    • Ashes
    • Elderberry
    • Horse chestnut 

    I went ahead and did some homework and gathered twigs from most of these species. I arranged them in order of increasing diameter, and wouldn't you know it, this corresponds to relative leaf size! In the photo above, from L to R, we have honeysuckle, buckthorn, dogwood, red maple, sugar maple, norway maple, boxelder, white ash, elderberry. This wasn't exactly a perfect sample, but I did try to find "average" twigs.

    Okay, so in a rough estimate, we have the following:

    Relative twig diameter
    (1=smallest, 9=largest)
    (s=simple, c=compound)
    Leaf size
    (from Peterson's Eastern Trees)
    Honeysuckle (s)
    Glossy buckthorn (s)
    Red-osier dogwood (s)
    Red maple (s)
    Sugar maple (s)
    Norway maple (s)
    Boxelder (c)
    White ash (c)
    Common elderberry (c)
      It works out quite nicely, at least in my minimum little experiment. I'll be it would be more instructive to measure twig diameter in the summer and measure the weight of all the leaves attached to that twig. But for now, I'm satisfied with the results. 

      Thursday, March 12, 2015

      Dichotomous key (II) - opposite (and sub-opposite)

      Decussate opposite branching - each pair offset 90deg in sugar maple (Acer saccharum).

      This post is mostly a reiteration and expansion of some of the notes from the previous post on branching patterns. There are relatively few trees/shrubs that have opposite branches. If we have an opposite or subopposite species we can use the mnemonic MAD Capped Bucking Horse. Usually it's just MAD Cap Horse, but since we're using shrubs here too, I called it a MAD Capped Bucking Horse.

      Horse chestnut

      Boxelder (Acer negundo) with branches offset at about 90degrees
      Both alternate and opposite branches can have the nodes arranged around the stem in another pattern. The first, and far more common, is called decussate. Decussate branches have nodes at right angles to the pair above and/or below. By alternating placement, the tree maximizes the amount of light each branch receives.

      Winged euonymus (Euonymus alatus) branch tending towards distichous branching
      Distichous branches, on the other hand, run in two parallel lines up the branch. We don't have any distichous opposite branched trees in Vermont. It's a common growth pattern in understory trees that tend to arc out and flatten at the top, like musclewood or hophornbeam, in order to maximize access to sunlight. If you're growing vertically it doesn't make a whole lot of sense as this would shade out the leaves/branches below.

      If you're growing mostly vertical, it makes sense to be decussate (branches offset 90deg), but for branches that flatten out, reaching to the sides of the bole, or trunk, for sunlight, a distichous pattern makes a whole lot of sense. While out today I noticed that the lowest branches on sugar maples are showed a functional distichous pattern. That is, for the most part, they had cut off growth of branches that grew along a vertical plane. I noticed on white ash that I looked at afterwards that the branches were mostly following this pattern, and in places where the vertical branches were still growing, the one away from the sun tended to be significantly longer. That way it could still harness sunlight while not shading out leaves adjacent to it.

      Here in Vermont, we only find pronounced sub-opposite branching in buckthorns (common buckthorn, as shown above, and glossy buckthorn shown on the previous post). The faster a twig grows, the more offset are its paired buds. This can even be seen in species other than buckthorns. Once I started looking I noticed this on ash, though the distance they're offset was at most negligible. Glossy buckthorn appears primarily alternate. 

      Tuesday, March 10, 2015

      Dichotomous key (I) - Branch pattern (phyllotaxis)

      Opposite apical buds on winged euonymous (Euonymous alatus)

      Dichotomous: Dikho (Greek: two, apart) + -tomia (Greek: cutting)

      Given my familiarity with the gross anatomical features of twigs, I was ready to dive into identification by learning the specifics. It would be in my ability to discern variation in the different features that would allow me to use a dichotomous key and identify the twig of concern. A good dichotomous key is indeed a rare thing. Many field guides (most tree ID books) lack them because they often require highly technical language, making them difficult for neophytes (pun intended) to use. But they are incredibly useful as they force the observer to look and look again. Making good dichotomous keys (for anything) requires the following:
      1. Finding categories that you can use to lump the things you're studying into the largest groups possible. These categories will have to be binary. For humans, you might start with something like gender, or eye color. You wouldn't start with obscure characteristics, like has four fingers since this would give you two very uneven sized groups.
      2. Avoid relative characteristics (like big, frail, etc.) and be specific with numbers where possible
      3. Come up with characteristics that have only two answers. Essentially, you're creating two groups repeatedly until there's only one item in each group. So blond and not blond, male and not male
      4. Start with easy to observe characteristics. Things get harder to split into groups the more specific you get, so start with things that are simply and easily observed
      Remember too that a dichotomous key is only as good as the person who made it. These are some of the potential hazards of a dichotomous key:
      1. It relies on a characteristic not present on your specimen (mature bark deeply furrowed when you only have a sapling)
      2. It uses something clear to the author not clear to the user (e.g. too technical of language)
      3. Lack of clear contrast in characteristics (flowers red vs flowers pink)
      4. Uses relative or subjective characteristics (e.g. plants tall)
      5. One group is a clump of multiple characteristics (flowers yellow vs flowers white, red, or absent)
      6. The plant you have is not in the key! Plant ranges have changed over the years and an old manual may say your plant only grows south of Massachusetts. 
      Rather than rewrite a dichotomous key, I wanted to focus in on the attributes of some of the key features used to identify plants by their twigs. A common way to start with our trees is evergreens vs deciduous trees but I skipped that since for now I'm just focusing on hardwoods (synonymous with deciduous and broad-leafed). The next most common way of lumping them is to look at branching patterns. For our broad-leaved trees, branches can be arranged in one of four different ways.

      Witch-hazel (Hamamelis virginiana) bud showing exagerrated zig-zag of alternate branching

      Each node - part of the stem where the buds originate/leaves attach (the internode, the space between two nodes, is nearly absent on spur branches) - only contains one lateral bud.

      Opposite branching in white ash (Fraxinus americana)

      Each node contains a pair of lateral buds.

      Sub-opposite branching in glossy buckthorn (Frangula alnifolia),
       buds are paired, but not directly opposite one another

      Each node contains a pair of buds, though they are not directly opposite one another on the stem. This often will occur on rapid growth of plants that are typically opposite. 

      Catalpa (Catalpa sp.) branch showing two shoots and leaf scar coming out from same node

      Each node contains three or more buds. The least common branching pattern. We only have two species of hardwood trees/shrubs in Vermont with whorled branches. Catalpa and buttonbush. 

      Sunday, March 8, 2015


      The end of winter is rapidly approaching and before it does, I wanted to take a last minute inventory of twigs. In identifying twigs, I've found dichotomous keys to be extremely helpful, but rarely use them while out in the field. When identifying species in the woods I also typically don't use the same thinking to identify twigs that I would while using a key at home, perhaps because I'm not as skilled as a botanist and don't have the familiarity with the technical aspects of twig ID to call it up in my head. This became more obvious while out at the LaPlatte River in Shelburne.

      To start, since I've got some familiarity with twig anatomy, I wanted to photograph the different anatomical parts then create my own dichotomous key to some of the most common in the area. Below are the different aspects of a twig shown on various species moving from the stem of the plant out to the tip. A twig, by the way, is technically all the current year's growth (i.e. everything produced by the tree since bud burst in the most recent spring).

      Spur branch on common buckthorn (Rhamnus cathartica)

      Spur branch
      Spur branches are tiny branches formed from lateral buds and can be several years old. They tend to be found on more shade tolerant species. These species don't put on a lot of growth each year and retain leaves in roughly the same position on the plant year after year (great examples can be found on yellow birch). These are not monophyletic (found on one evolutionary branch), and show up in some conifers (e.g. tamaracks) as well as broad-leafed trees. 

      Bud scale scar on red-osier dogwood (Cornus sericea)

      Annular scar or bud scale scar
      A bud is essentially a mini branch hording tini little leaves and/or flowers flowers inside. Where the bud covering of the terminal bud falls off, it leaves a scar fully encircling the branch. This can often be discerned by finding a clear change in color from the older to the more current year. Depending on the species, this color is apparent going back four to six years.

      Spongy pith of white ash (Fraxinus americana)
      Pith is parenchyma tissue. Parenchyma is basically just undifferentiated cells with thin cell walls. You find parenchyma cells in highly active growth areas (like the tips of twigs). In twigs, pith is the origination site of buds. It is typically white and spongy when young, though as it ages it will discolor and break. Depending on how it ages, pith can be solid, spongy, chambered, or hollow.

      My fingerprint on whitish bloom protective covering on twigs and 2-year-old growth on boxelder (Acer negundo)

      Bark coverings
      Some first year twigs are coated in hairs (pubescent), others have a white bloom to them. I still don't know what this white bloom is, but it's the same stuff found on raspberry twigs, grapes, and lots of other fruits like apricots.

      Lenticels of boxelder (Acer negundo)
      The mouth holes of the tree that open in the cork of tree (cork is the protective outer tissue of the bark). This is where gas exchange happens on the stem of the plant (occurs on the stomata of leaves). Many species have adaptations within the bark to protect the tree from fire, predators, damage from flooding, etc. The thicker bark on these species blocks off gas exchange. Look for lenticels on younger, thinner barked parts of trees. 

      Lateral buds off a red maple (Acer rubrum)

      Lateral buds
      Running up the branch of the tree, these are all the buds that aren't at the tip of the twig. They can be arranged alternately, opposite, sub-opposite, or whorled. Our only deciduous whorled tree here in Vermont is the catalpa (I think). The vast majority are alternate. This is largely a characteristic shared by all members of a given genus. MAD Cap Horse works as a mnemonic to remember the opposite branched trees (Maples Ashes Dogwoods Caprifoliacea - the honeysuckle, viburnum family Horse chestnut).

      Bundle scar (black) and Leaf scar (grayish) looking monkey face of a butternut (Juglans cinerea)

      Leaf scar + Bundle scar
      A petiole connects the leaf to the branch. Petioles come in a wide range of shapes from the u-shape of celery stalks to the flattened wagging stems of aspen leaves. Nutrients are fed into the leaf (and siphoned back down to the roots) via vascular tissue in bundles. When the leaf falls off it exposes bundle scars - the parts where the tubes flow from the stem into the leaf - illuminating the arrangement of these bundles, which is unique to each species. Butternut scars have the appearance of a funny little monkey face.

      Terminal Bud
      The terminal bud is the apex of the shoot (also called an apical bud). It usually points directly out and is larger than the lateral buds. As with lateral buds, it contains miniature leafs and flowers.

      Over the coming weeks I'll be drawing out a dichotomous key by drawing attention to these features and others of some of the more common wild and naturalized species found in my part of Vermont.

      Friday, March 6, 2015

      Birds along the Winooski River

      Male and female Common goldeneyes
      Zac asked me if I had a name for the spot we went today, and I don't, but perhaps I should. Turkey's Respite? Willow Wonka and the Tangled Edge? It's an old largely forgotten stretch bordered sharply by the Winooski River, the Interstate, and Patchen Rd. It's quite a few acres (about 40) and seems to be major habitat for quite a few species. Over the years, I've spotted otters, beavers, muskrats, red and gray foxes, deer, turkey, and lots more making use of it - and only very seldom do I ever see people.

      2 male (bottom), 2 female (top) goldeneyes

      With eager anticipation to see what ducks were in the open water, we crept up to the edge. The mallards seem largely indifferent to my approach, but I'd spooked off the other ducks the two previous times and hadn't gotten a good luck at them. Today, we wound up getting a good look at some goldeneyes hunting along the edge of the ice. There were about 25 in total. 

      Flock of goldeneyes flying over
      Waterfowl aren't a specialty of mine, so it was great to get to spend some time looking at the difference between the males and females. The males have significantly more white on their throats and bellies. The females are much grayer and have just a thin collar of white between their brownish heads and grayish chests.

      Female (immature?) buffleheads
      Initially, we supposed that they were all goldeneyes. When I got home and was looking at the images, I realized that the drab birds I assumed were female or juveniles were actually another species - note the white patch behind the eyes. Turns out these little gals were females buffleheads. It makes sense in retrospect. When we finally spooked the birds, three of the four drab birds flew upstream, the forth ambled slowly to where two male goldeneyes were feeding.

      Three female buffleheads. No males around...
      Besides wanting to check out the open water and see what was utilizing it, I wanted to show Zac a patch that'd been cratered by deer. Shortly after looking at that section we spotted a turkey. We eventually saw three turkeys in total.

      Wid Turkey

      Other notable birds, were a couple birds of prey. In our field trip to Addison last week I realized that I'd always thought red-tailed hawk wings to be much lighter on top, but I keep seeing red-tails with really dark tops to the wings. 

      Red-tailed hawk soaring overhead