Sinkholes

Walking along the Main SW Trail about 200 ft NE of the Grandfather Cottonwood,  I noticed a small depression, the size of a couple of cottonwood leaves. Thinking that it could turn an ankle I thought I'd fill the depression with a bit of weathered wood. I selected a 4 foot long 2 inch diameter dead elm branch and pushed it into the soft soil. It went all the way down - disappeared into the soil. Some sort of mostly hidden remarkable subterranean cavity. I shoved two more sticks in before quitting; and left wondering what had caused and maintained the deep cavity. In the killing heat of the very dry summer, the soil there was broken into irregular polygons with deep fissures between. I wondered then about the fissures as potential refuges or hiding places for smaller fauna. How much more so to have substantial four foot deep cavities in the soil. Refuges for hidden life.

I remember 10-15 years ago walking a quarter mile west from this point, on the same kind of dried wetland soil in the Woods during another La Nina winter like this one, as a substantial rain was pushing fingers of inch deep water through the area. At 2-3 fascinating places the water was sinking, flowing into the soil with a constant boiling of bubbles of subterranean atmosphere pushed out of subterranean chambers. The bubbling went on for a full day. Evidence of hidden worlds beneath the surface of the soil.

Three white-tailed deer running north into the Woods from the Dune trail. They may know they are safe there as hunting season begins.

Leaves

 Thursday walk in the Woods from the southeast gate. Last few days of gentle breezes have brought down more leaves. From the upper canopy seventy percent are down. Tall elms, green ash, pecan are mostly bare. But in the lower canopy seventy percent remain. Sugarberry, walnut, hickory, mulberry, are still in full leaf. I watched golden leaves trickling down in the still, warm air under the cloudy sky. After Friday's storm front many more (most) leaves will be down.

Last two years, dozens of understory trees, mostly mulberry and younger elm in the southeast quarter, re-flushed fresh new leaves in the early autumn. This autumn I see only three trees that have done this. Perhaps the tough summer drought and heat suppressed this.

Walking along the trails they are carpeted in gold.

Scores of robins through the Woods are 'flighty', busy foraging, I think the cloudy skies and sullen heavy moist air must tell them a storm is coming. There are many gathered around the East Pond. Some are dipping for a drink from small teacup-size depressions filled with water in the bottom of the otherwise empty pond. Woodpeckers are flying too, downy and flickers.

One full grown white-tailed deer dashes away. In two weeks, deer hunting season begins on the 19th. I expect to see small herds of deer move into the Woods for protection until early December.

Walking to the Northwest Pond I pass by the fallen Carpenter cottonwood. Its massive upper branches smashed against other large trees, green ash, box elder and locked upright against them. They stand there now like giants locked in combat, a testament to the destructive power of falling canopy trees and the huge weight of their crowns. Elsewhere below the big tree grove, three large trees have fallen together, as if uprooted by some giant's breath, one striking another and that one bringing down the third like dominoes.

I stop to turn over a small rotten log and see the colonies of busy small ants scurrying on the underside. I break off the top third of the spongy rotten log and open the interior where there are three Mesodon snails taking shelter. I imagine they have crawled into the log to find an insulated shelter, safe from the colder weather coming. I wonder why the ants do not bother them. With just a tinge of guilt I put the log back together rebuilding the snails' refuge.

Light rains the past two weeks have started the growth of new agaric mushrooms, two clusters of perfectly formed gray brown agarics with white stems from the base of a half-dead elm and two patches of much smaller golden orange agarics through the bark of a down box elder. Along the Barney's cutoff trail there are a hundred perfect small parasol mushrooms in one cluster. Only good for a day or two, a few have already begun to deliquesce, their caps melting with their spores.

I see new steps built in the Woods. Engineers providing a help on two of the steeper trail sections.

A peaceful golden few hours in the Woods. I will have to return after the storm Friday to see what leaves remain.

Changes

 It is the golden time in the Woods again. Yesterday afternoon I went to the Woods' NE Gate to see how the Woods have changed. We have now had some good 1-2 inch rains. The ground is no longer parched. Daytime temps have fallen to pleasant 50's-70's - a favorite time of the year. Fifty feet inside the NE Gate there stands a young black hickory with beautiful rich, butter yellow leaves. There are a half dozen of these in the Woods. They light up the under story in late October.

 Along the trails a diverse carpet of yellow leaves light the way. Yellow from the green ash, and elm, and sugarberry. Red from persimmon and haw and Virginia creeper. Beautiful sight and fresh autumn smell of fallen leaves. Later leaf drop species like bur, pin and blackjack oak, most of the cottonwoods, and willows still hold green leaves.

 To my surprise, the light rains have resuscitated some wilted shrubs like the Callicarpa beautyberry. In August, all of these had leaves that were dry as paper, wilted or shriveled. They looked beyond the point of survival. But rains saved the leaves of half or more of the beautyberry. They will get in one more shot of photosynthesis to feed the roots, stem and new buds for next year before increasing cold induces leaf drop.

Other species did not do as well. There were three of the Euonymus spindle trees in the Woods (that I knew of). I enjoyed one nearest the second largest cottonwood tree in the Woods. It held its green leaves later than others, but it did not survive. A larger spindle tree on the SW side of the East Pond is better and producing its distinctive decorative seeds.

Some trees and shrubs are maturing their fruit: the soft red berries of Symphoricarpos buckbrush, the red rose hips of multiflora rose, the large incongruous grapefruit-sized bright green fruit of the one Osage orange, or bois d'arc in the Woods. Squirrels have chiseled down some of the nuts from the large pecans, but most of the pecans are still holding on.

There is work needed with some large pecan tree tops down, massively blocking trails and requiring a saw to clear. I will wait until after first frosts put the ticks and chiggers to bed for the year.

I stopped to investigate under the bark of a large log and found a gathering of beetles that I did not recognize. Flat, the size of two grains of rice, cordovan color with black eyes, antennae that looked like darkling beetles. A half dozen were feeding with some smaller saw-tooth grain beetles on fungi beneath the bark. Exciting to find new species in the Woods.

And the greatest new change in the Woods is a new bridge across Island Crossing. Looks well designed and well built, with a set of log steps down the steep bank. This is a great addition and will be helpful for wet days and winter.

Drought, Apical dominance and Invasive shrubs

Mesonet this morning reports that this 30 day period just finished, is the driest period across these dates in the past 100 years. However one views the data, it is clear the Woods are in an unusually dry period. I entered the SW Gate at 10 AM to walk through the southern Woods and to see what may have changed. The canopy of the Woods is still green. Few leaves have fallen or begun to change color. Many box elder along the trail had stump sprouts or growth of green shoots and leaves from axillary buds along the stem. I wondered if this could be a response to inadequate auxin from poor growth at the top of the tree, resulting from the heat and summer drought. Need to check with tree physiologists.

As I was contemplating this, another form of 'dominance' erupted - mobbing. Five crows, sounding like 50, began raucous calling and harassment, likely of some hapless predator they'd found. A sleepy barred owl or young hawk. The uproar continued for several minutes until the whole flock of noise flew west.

I walked the South Boundary Trail of the SW loop. West of the Beaver dam, small lines and patches of light fine sand were accumulating on the bare dry cracked earth along the Main SW trail. I've seen this before in other dry, hot La Nina years. This looks like the result of the process OU professor Asa Weese described as the potential source of the sand dune in Oliver's Woods. Prevailing SW dry winds carrying sand from the South Canadian River and depositing it in Oliver's Woods. An extensive dry period five thousand years ago may have been the time of the growth of the dune. [Weese was a distinguished academic, President of the Ecological Society 1931, Ecologist of the Oklahoma Biological Survey, President of the Oklahoma Academy of Science 1931-1933. ]

https://www.esa.org/wp-content/uploads/sites/94/2022/02/Weese_AO.pdf

Walking along the NW side of the dune, I enjoyed seeing a monarch butterfly out in the sunshine. Their migration south is continuing. The sunny patch was an opening produced by die back of several large invasive Ligustrum privet shrubs. Privet all through the Woods was killed by extreme February cold 2021. Now dead stems of privet carry small patches of a white decay fungus, likely turkey tails, Trametes versicolor. 

Crossing the dune on the West Dune trail there are several invasive Amur honeysuckle Lonicera maackii that should be removed before they can start to take over the Woods as they have in other local preserves (e.g Riley Park Noble OK).

Monarchs and Beaver

 This last day of September I went early to the Woods to see what the change of season might have brought. With southward-migrating monarchs flying over the Northeast Gate, I started along the Tree Loop. 

The Woods are parched. The still-green leaves of the Callicarpa beautyberry are drooped in a full wilt. The leaf litter crackles underfoot. Some early leaf drop has started, mainly stressed leaves of elm and sugarberry. No significant rain since 1.5-2 inch at the start of September. But most of canopy of leaves remains, and is still a weathered green.

With drought and heat, it is notable that the western wash is still full at Island Crossing, and at Elm Bridge. I was startled (and delighted) to see fresh beaver activity in the Wash. A young elm along the Wash, near the south end of the Tree Loop, had been cut down and its bark chewed partly off. It has been over a decade since I last saw beaver in the Wash. The water is something of a mystery - its been flowing for a few weeks. None of it is from recent rain. It is coming from the OU campus, perhaps along Timberdell somewhere, a pipe break? I want to know if it is dilute wastewater, irrigation water or something else.

The flow has been sustained for enough weeks that minnows and aquatic surface insects are present; and now, beaver. At Island Crossing a small garter snake appears to have adopted the area and swam away before I could snap some pictures.

Walking west, I surprised three or four whitetail deer. As they romped away I lost sight of them beyond the shrubby undergrowth. I heard several snorts of the doe calling the yearlings back.

Trees along the trails have sustained some breakage. Up on the North Rim trail, a large sugarberry crown has been torn down and blocks the trail. But trails I walked on were mostly clear. The earth along the Main Wash by the Grandfather cottonwood is cracked dry and broken into irregular polygons, waiting for rain.

The Northwest and East Ponds are both dried across their basins. Pushing a rod into the damp soil near the water depth post, there is water visible about 6 inches below the surface. Most of the annual wildflowers, Elephantopus Elephant's foot, Verbesina Frostweed and Crownbeard and others along the trails have wilted, drooped leaves. Not sure what a rain might do to restore. The season is probably complete for them.

Armadillos have been plowing through the leaf litter searching for a meal, beetles, snails, other invertebrates. They've left their characteristic furrows in the dried leaves.

Although very dry, the Woods have become pleasant again for walking and exploring. The highest heat of summer is gone.

Late summer turtles

 Returned to the Woods Tuesday to clear two large fallen trees from trails. I was interested to see what changes late summer had brought after unusually dry hot July-August and recent 2 + inch rain Sept 1.

Entering via the NW there was a nice display of yellow asters and white Verbesina crownbeard with a Three-toed box turtle Terrapene carolina beneath them. I found 3 box turtles on the trails I walked today. I did not see any of the ornate box turtle Terrapene ornata. Charles Carpenter did extensive work with turtles in the Woods in the 1950's. I wonder if he found the ornate box turtle to be common seventy years ago. Did the 2017-2018 illegal collection of a thousand box turtles from Oklahoma for export sale include turtles from Oliver's Woods?

The Sept 1 rain and subsequent small shower of a third of an inch have not refilled the NW or East Ponds. They are both empty with only a bathtub-sized area of wet mud near the center. The hundreds of small young leopard frogs that were in both drying ponds a month ago are all gone. 

There is a substantial flow of turbid water in the West Wash. At Island Crossing there was one small young garter snake swimming and all along the Wash there were small fish (minnows?) feeding. Did these migrate up from the long connection down to the South Canadian? 

I wondered if the flow of unnaturally turbid water might be from a broken pipe or part of the OU water system, as was the case for a week or more in early August. But following the water upstream, it remained in a regular watercourse west of Lloyd Noble, west of the Museum of Natural History and east along Timberdell. I did not find a break.

The Beaver Dam crossing was dry with no water or mud anywhere west of there, although it was clear water had recently flowed 'upstream' pushing sticks and debris westward, probably during the 2 inch rain when the Western Wash flooded from southeast to the southwest.

One armadillo ran away (15-20 m) as I walked the northwestern side of the Tree Loop. I often wonder how they survive with such an ineffective escape run.

Snake in the Woods

 I rarely ever see a snake in Oliver's Woods. This morning I encountered a slender garter snake, skimming away from me on the drying mud shore of the East Pond. It may have been attracted there by the scores of small young leopard frogs sitting on the soft damp soil, all that is left of the East Pond. The Northwest Pond is in a similar condition with a bit more soupy mud remaining in the center. The fish that were in the ponds (mosquito fish?) must have been scooped up by predators as they became stranded.

Oddly, the West Wash was still moderately well-filled with water flowing past Island Crossing at perhaps 2 gallons or 10 liters/ minute. The water in the wash was turbid and I am thinking it must be from a anthropogenic source. Maybe a burst water line? I should check this out.

I had gone to the Woods to see how the trees and other plants were responding to the heat and drought. Nothing catastrophic. The forest is under stress. Blackjack oak Quercus marilandica, Pecan Carya illinoinensis and red elm Ulmus rubra had some premature yellowing of (only some specific) leaves. Like a form of programmed self-pruning or programmed death of select units. The crowns remain green, not yellowing generally all over.

Taller mulberries and elms are now starting to drop a large number of leaves on the forest floor, enough to make the forest floor begin to look like early autumn east of East Pond. Happy to see this, as that means trees are forming natural abscission layers after setting buds for next years growth; rather than leaves simply dying and turning brown, hanging on dead branches.

In the under story, many/ most plants have wilted leaves. The leaves of the beautyberry shrubs Callicarpa are still a dry green, but they are shriveled and probably beyond resuscitation.

Trailside forbs, elephant's foot Elephantopus and lady's thumb Persicaria have drooping leaves but look they could return to life with a good rain.

There were two Three-Toed Box Turtles, probably, Terrapene carolina triunguis west of Island Crossing on the

trail. I did not disturb them. They reminded me to check on the upside down box turtle I righted - and hoped I had rescued a few weeks ago. I went to look for it, not there, so I am hopeful it survived.

Around the shore of the Northwest Pond fresh green pecan nuts were down, and some chewed open. Likely squirrels getting a jump start on autumn harvest. A few green walnuts had fallen but nothing feeding on them, the pungent smell of the green husk. On the same damp mud of the NW Pond a fresh Red-spotted purple butterfly and large yellow Tiger Swallowtail were 'puddling' taking up mineral nutrients, mostly sodium, dabbing their mouthparts on the soft mud.

There were two beautiful large Underwing noctuid moths that flew and landed on big bur oak and large pecan. Now late summer is good time to find these showy moths. As I was leaving, I looked at my jeans and noticed that the season of weed seeds is beginning. I snapped a few photos of the drying NW Pond to contrast with the days after first good autumn rains.

I imagine the snapping turtle that feeds there, has retreated under the shelf of roots on the south shore. Interesting to see the germinating seedlings on the drying East Pond bed. Wild grape, lady's thumb, other bits of green scrambling to start life on the bare wet soil. They will almost certainly be drowned when rains return but may have an ecological part to play before then.