Tippy trees.

Some trees lean.  Leaning trees are a natural phenomenon in nature.  While there are many reasons why trees lean, most of the time the reason involves the search for light.  This is called a phototropic growth response.  Trees growing in this manor put on adaptive growth and reaction wood to maintain stability.

Once a tree has grown to a point where there is a clear view of the sky the lean will 'self correct,' and new growth will begin to grow with a more vertical orientation.  At this stage the stem lean should be at its maximum, and if the tree remains structurally sound the angle of the lean should remain constant.

Look carefully at the pictures below.  The picture on the left is a screen shot from Google Street View of a post oak taken in 2011.  The 2nd picture is of the same tree taken in December of 2013.

2011                                                                                       December 2013

Notice the difference in orientation of the lean.  The root collar of this tree is not well exposed.  The homeowner indicated she noticed a change in the lean of the tree in July of 2013, and was aware of at least one 3- to 4-inch diameter root that was severed to install the brick walkway earlier that same year.  After some peripheral probing with a soil knife to about 6-inches deep, no structural roots were detected on the tension side of the lean. 

Could this tree be actively failing, albeit slowly?

Well that's something

While looking at some storm damage a few weeks ago I happened upon this pear.  Like many pears it was cursed with multiple co-dominate stems that tore from the tree during high winds and rain.  While there is nothing special about a flowering pear breaking in a storm event, what's cool about this tree is what was exposed after the tree failed.  The limbs that failed pealed down the trunk to expose branches pruned in the past.

This pear offered a rare glimpse of how trees create new wood around the stem and branches, from the inside.  If only we could dissect some more pears for the greater good, enjoy the pictures below.

You can clearly see the remnants of past pruning.

Another view of past pruning wounds exposed when a portion of this tree failed.

Not to Kick You when You're Down, but another Incredible Tree Failure

I always hate seeing a tree fall, but sometimes there is no better way to learn about the way trees grow than from a post failure forensic investigation.  And while I know our last post was about a fantastic large tree failure, this was too good to pass up.

Our subject is a large mature willow oak that suffered a tremendous root plate failure.  This tree was growing in a known flood plain, and was one of the tallest trees on the block.

Notice the amount of standing water in hole left behind when the roots pulled from the soil.  Keeping the size of the root plate in mind, and the proximity to the camellia in the picture below, notice how the wet conditions allowed the roots to be pulled from underneath soil like a magician pulling the table cloth from a fully set table.

The only indication of decay at time of failure was a cavity along the lower trunk/root flare of the tree.

Now, here is a part of the tree we don't get to see often.  With the root flare up ended we can see the structure and arrangement of the structural root system, and associated decay.

The decay column moving upward in to the stem is a common occurrence in many tree species.  It is a result of the original tap root dying off and allowing a path for decay to move into the stem.  This is a process that can take years, if not decades.  In species that compartmentalize well it is just a peripheral event, but for poor compartmentalizers, it may the defining defect in their demise.

Good thing the Jeep was insured.