Showing posts with label Aristida purpurascens. Show all posts
Showing posts with label Aristida purpurascens. Show all posts

Friday, March 13, 2015

The Almost Final Last of the Season Cedar Maintenance

This aerial map shows the roughly three acre field in which I am currently completing cedar maintenance.  Red outlines indicate the areas of the field that have so far been completed.  A small area to the right is yet to be done.  The portions labeled B-2 and C were completed back in early February.  Work was then halted when a series of storms buried the field in snow.  Snow exited the field a couple of days ago, but it wasn’t until yesterday that the soil dried out enough for me to resume work.  Section D was completed yesterday afternoon and E is what I could get done this morning before heavy rain moved in.  I would not normally be doing this type of work in March, but I just couldn’t leave the field partially completed.  If the rain ends tomorrow as predicted, it will probably be the middle of next week before the soil will be dry enough for me to finish the last bit of this field.

The aerial view makes it appear that this field is heavily occupied by large Eastern Red Cedars.  The view from ground level shows that the cedars are spaced widely enough apart to allow plenty of sunlight to reach the ground.  Where soil conditions allow, a thick grass cover is present.

The slope steepens rapidly at the south end of the field.  The last 15 feet are an almost vertical plunge into the creek.  The last of the snow is still holding on along the top of the creek bank.

Field blends with woods at the steep north end of the field.  One October, about 20 years ago, I mowed a path through the tall grass.  The deer, which always seem to take the easiest option while walking, immediately began following the mowed path.  They still follow the same path and are responsible for it becoming a muddy trail.  As deer numbers increased through the years, they developed paths in other directions through the field and now this is just one in an expanding network of deer highways.

This is considered to be a south facing field.  Unlike the previous field I discussed, this one is dissected by a network of surface depressions that drain water in many different directions.  While the field is still generally south facing, there is a wide variation in slope steepness and direction.  This gives the field an interesting collection of microclimates within its boundary.

Saturated soil is still releasing water into the center of the drains.  The presence of water on the surface is short lived, but a gradual movement of subsurface water along this same route may persist for a couple more months.

Small cedars thrive in these areas of increased water availability.  This eroded area was practically bare when I bought this property.  Prairie grasses are slowly stabilizing the soil.

Between each drain is a ridge.  There is a drastic difference in the amount of water available to plants on the ridges as opposed to the drains.

This section of the field suffered soil slips that resulted in a stair step arrangement of bare patches on the slope.  The slipping stopped long ago, but the poor quality of soil exposed in each step is making it difficult for vegetation to become established.

Lichens are the pioneer species in these bare areas.  In time, grasses take root in the soil stabilized by the lichens.

Lichens become established on any stable surface.  Here they have encrusted an old cedar stump left from my initial clearing of the field.

The deep snow mashed down the fine grasses, making it more difficult to find the small cedars.  Even in the best of conditions I miss a few, but there were probably many more like this that escaped my search this time.

I found several patches of the uncommon Purple Triple-awned Grass, Aristida purpurascens, scattered about the field.  This grass was represented by only a few small clumps at the time this field was originally cleared.

The grass gets its name from the three long filaments, known as awns, projecting from the end of the seed.

I found collections of Blue Jay feathers beneath three different cedars, evidently the work of a Blue Jay predator.  I couldn’t tell if the feather piles represented three different birds, of if the predator moved the bird a couple of times while dining.  This batch included a section of leg bone.  I’m guessing this was the work of a Cooper’s Hawk.  The Cooper’s Hawks around here seem partial to Blue Jays and Mourning Doves.  It’s not unusual to find piles of feathers from these two species.  Even with the hawk whittling down their numbers, the Blue Jays seem just as abundant as ever.

Monday, December 21, 2009

Purple Triple-Awn

Noticing differences allows you to discover new components of an ecosystem. The golden-brown patch of grass in the middle of a predominately reddish-brown landscape indicates the presence of an unusual type of grass. In this case, the unusual grass is a rarity known as Purple Triple-awn, Aristida purpurascens.

This grass has a thin stem and extremely narrow leaves. When in a clump, the result looks like a wad of Easter grass supporting a mass of long pins. Once you’ve seen it, it becomes an easy species to pick out.

The flower spikes always look a bit scraggly. This specimen has lost very few of its seeds and is typical of what will be found at the time of seed maturity.

The long, thin projections are the awns. Each floret bears a set of three awns, hence the name Triple-awn. Nature programs like to show a species of grass that has the seed planted by a corkscrew motion of the awns. I haven’t seen that action with this species, but the awns do support the seed so one end is held away from the soil surface. This may make it more likely for the seed to fall into a crack formed by the frost heaving of soil during the winter.

I’ve been picking some of the seed and scattering it around this immediate area. I’m now seeing Purple Triple-awn 50 feet away from the original cluster I found about ten years ago. Next I’ll try moving the grass to some other locations in this same field.