After the Rain

Late last week we experienced four separate storms that produced a total of 1.5 inches of rain over a two day period.  The first storm arrived in the early evening, so there was plenty of light for me to sit on the porch and enjoy the action.  The rain quickly filled the Water Garden to overflowing.

The storm lasted a total of 20 minutes and five minutes of that was a straight downpour that gave us 0.5 inches.  That’s a rate of six inches per hour.  I think we could have soaked up a full hours worth. 

Following the heavy stuff was a gentle rain and a lot of lightning.  This bolt struck in the woods across the road.

Even though the rain did nothing to recharge our ground water supply, it did rehydrate all of the plants.  The most noticeable change was the Rose Pink once again producing fragrance. 

There was no overland flow associated with these storms, but the water that fell in the creek bed made its way to the low points and filled most of the pools.  This will ease the stress on animals that need an open source of water.

Without additional rain, this water won’t last more than about three weeks.  It’s nice and clear now, but that will change with increased animal usage.  As pools are lost, those that remain become cloudy with sediment stirred up by animal visitors.

The newly filled pools are without fish.  Only those aquatic animals capable of surviving periods without water were around to take advantage of the restored aquatic environment.

Drifts of cedar leaves and berries at the downstream edge show that the pools were just at the point of breaking out and temporarily restoring stream flow.  It seems that each storm we have is violent enough to remove fruit and nuts from the trees.  Those cedar berries are supposed to be attached to the trees to act as food for the overwintering Bluebird population.  The amount of fruit lost to the effects of storms and drought make me think this is going to be a tough winter for many species.

The gravel beds that hold water in the pools are not water tight and allow a trickle of water to move through.  This nearly imperceptible flow can only be seen in those areas of the creek where solid bedrock is exposed.  Under normal conditions, this water would be replaced by water moving into the creek from the groundwater reservoir.  Because of the extended drought, that water is not available.

Where the creek bottom is composed of loose gravel, the moving water is hidden from sight.  The rain necessary to end this drought is still somewhere in the future.  There’s still time for this year of weather extremes to amaze us with more unexpected developments.

Fresh Lightning Strike

Evidence of storm damage fills the woods. It would surely have been exciting to witness the lightning strike that left its mark on this Tuliptree.

At 50 feet from the tree, the shards of tree bark are easy to find. There were some pieces as far as 125 feet from the tree and they probably would have gone farther had there not been such a clutter of understory branches in the way.

I’ve read that the passage of the lightning through the tree causes the water and sap in the tree to make a rapid transition from liquid to gas. The sudden formation of gas produces pressure that explodes the bark from the tree. The result is a scar that runs from top of tree to the ground.

In the cartoons, a lightning strike always leaves things charred and smoking. Nothing like that is evident on the tree. If I had taken hold of the bark and ripped a section free, it would have made a wound much like this. This wound can heal, but it can also let in a host of insect and disease pests.

The visible damage ends at ground level. This doesn’t mean that there’s no damage below ground. Intense heat often causes cell damage in the shallow roots. This produces additional stress on the tree and depending on the nature of the damage, can leave the tree with a less stable foundation.

In the tree world there are hazards associated with rising above the others. Tuliptrees grow rapidly and produce a tall, straight, moisture laden trunk that is very attractive to lightning. Tuliptrees make up about two-thirds of the obviously lightning struck trees at Blue Jay Barrens.

Leaves are still green and healthy, despite being the apparent hosts to a hoard of leaf eating insects. If the tree was wounded beyond repair, it may take a couple of years before that fact becomes obvious. A healthy forest is not hurt by a few storm damaged trees. The storms just sprinkle the spice of diversity over the woodland landscape and increase the numbers of organisms that can live there.

Lightning Tree

There are hundreds of trees at Blue Jay Barrens that display enough unique characteristics to be individually recognized anywhere. In a forest without a stressful past, the trees would probably have more uniformity. I search these odd trees for clues to their history that would help explain why there are as they are today.

The top of this Tuliptree was lost so long ago that its remnants have long since vanished into the forest floor. Given the time involved, you would think that growth from the lateral branches would be much more extensive. A healthy tree could have put on that much growth in just a few years.

A look at the base shows the tree to be in less than perfect health. Loose bark hangs all around the tree and it’s hard to find any living material at all. The living top is evidence that there is still a functioning cambium layer somewhere on this trunk, but it must be a minimal amount that can only support a greatly reduced top.

Here’s the signature curve displayed by so many of Blue Jay Barrens’ large trees. Following the curve down the trunk is a scar from an old lightning strike. While most of the bark is partially detached from the trunk, the area along the scar appears to be alive and well. This may well be the lifeline to the tree top.

It’s hard to predict how lightning will impact a tree. Exterior moisture on the bark, extent of sap flow through the cambium, and wetness of the soil can all influence whether the electrical surge passes through or along the exterior surface of the tree. Some of this bark appears healthy and some is just draped over the trunk. Sap may have to follow a maze to reach the top of the tree.

On another side is some more serious lightning damage. Under certain conditions, a lightning strike will superheat the moisture within the tree, causing it to turn to steam. The pressure resulting from this sudden transformation from liquid to gas can cause the bark to explode from the tree. This is the type of strike that causes the greatest visible damage to a tree.

I witnessed a strike like this when I was in High School. I’d been out fishing and was hurrying across a field, trying to get home before a storm arrived, when lightning struck a large fence row tree about 70 yards from me. When the lightning hit the tree, I hit the ground. Pieces of bark made it out to where I was and I felt a heat flash on my face and arms. I just stayed there and let the storm roll on over me. I had plenty of time to think while I was laying there and what I thought was that if I had to ride out a storm in the open, I should have just stayed at the lake where I could still be fishing. Since then I’ve become much more adept at judging the speed of approaching storms and haven’t found myself accidentally out in a storm since then.

Dead Ash

There are always some new dead trees in the woods. Sometimes it’s a wonder that the woods can persist given the annual numbers of newly dead trees. I found a clump of dead and dying ash trees along one ridge top. The cause of the tree deaths usually remains a mystery. That’s partially due to the multiple factors that constantly put stress on the trees. Insects, disease, shallow soil, weather, air quality, impurities in rain water, lightning strikes and various other factors combine to weaken the health of a tree, making it very difficult to assign one factor as the cause of death.

These days, when any ash tree dies, people automatically assume that the Emerald Ash Borer got it. I gave this Blue Ash a careful going over and could find no evidence of any borer damage. That crooked trunk suggests that this tree has seen some stressful moments during its life.

The exposed wood seems free of borer damage. Emerald Ash Borer would have left distinctive tracks from the larvae that feed just below the bark.

The inner side of the bark is also clean. It’s nice to know that the trees aren’t being killed by an exotic borer, but it’s little consolation to avoid borer infestation by having the ash trees die before they can become infested.

Some of the trees are showing dead tops, but have new branches emerging lower down on the trunk. When trees react in this fashion, they are not likely to recover. There is often a temporary period of increased vigor which is followed by a dramatic decline. This sequence may occur several times, but the final outcome is death of the tree.

The dying trees are located around the perimeter of a small opening in the tree canopy. It’s possible that these trees are suffering from a cloud-to-ground lightning strike to this clearing. From the house, I’ve watched so many lightning strikes to this ridge that it’s a wonder there are any trees left. Many of the trees bear the scars of their lightning encounters. It’s not hard to believe that a well placed bolt of lightning could mean the end of a few of these trees.