Thursday, October 4, 2012

Oak Abuse: Progress - all the way to the drip line

I have told versions and parts of this story dozens of times on this blog, but I can't convey the importance of the photographs below without telling it again.

I got into this whole wacky oak caper back in the 80s.  I grew up in the northwest suburbs of Minneapolis and watched new housing development after new housing development roll over the oak woodlands where I used to hike, run, fish and (if we're being honest) blow things up and generally goof around.  In high school I worked at a local nursery and garden center loading up cars with the crushed landscape rock, plastic weed fabric and edging, seedless green ash trees and Crimson King Norway maples that replaced the oaks that were lost (oaks, of course, were far too "slow growing" and "messy" to plant back into the landscape).

I entered the Urban Forestry program at the University of Minnesota to learn how homes could be built in wooded areas with a minimum of damage.  I quickly learned that greater minds than mine (and I have yet to find another forester's mind that isn't) had already figured this out.  So I decided to be the guy who would bridge the gap between foresters and the rest of the world - developers, builders, homeowners - and bring that information to a wider audience.  My one and only attempt to make myself useful.

I started a non-profit organization called Lasting Woodlands, and put out a kind-of-sorta-when-I-had-the-time-and-money-bi-montly newsletter, put on seminars, spoke to builders and realtors groups and generally made a pompous nuisance of myself.  We're talking a lot of very late nights at Kinko's.

Lasting Woodlands was mostly famous for putting the non- in non-profit, and died a slow death in the 1990s as my other career - that of tree tube peddlar - demanded more and more of my time. Equally unprofitably.

But my interest in and passion for protecting construction zone oak trees has never abated, and I have continued to try to use every forum possible to spread the word - including some TV spots back in Minnesota a couple years ago (here's a link to the post with with that video - sorry for the glare off my forehead).

When speaking to builders I always found that the sarcastic approach worked best.  Actually, I don't know if the sarcastic approach worked best but since it's my default approach to everything it's what I went with.  I also knew that most times I was talking to builders or realtors it was a captive audience of folks getting continuing education credit toward their license renewals, so I could be pretty well assured they wouldn't get up and walk out on me.  I would tell builders, "Look, anyone can kill an oak tree the obvious ways - cut it down, bash into it with a bulldozer, snap off its branches in the middle of oak wilt season so that the tree dies by the 4th of July.  Those things don't take any skill at all.  But it takes a real expert to kill an oak tree so that it dies slowly over the course of several years, so that by the time it dies no one realizes the damage was done years before when the house was built."  The arboreal version of the perfect crime.

Then I would tell the assembled builders exactly how to kill an oak tree slowly.

First, you need to realize that the roots of an oak tree extend out away from the as far as - and usually much farther than - the longest branches.  The imaginary line from the longest branch tips to the ground is known as the drip line.  The circle created by tracing the drip line around the the entire tree is the root zone.

Second, you need to know that the vast majority of roots - especially the feeder roots that absorb moisture and nutrients - are in the top few inches of soil.

Third, you need to know that soil consists largely of air, and roots need that air to survive.

Fourth, you need to know how to kill those roots.  There are 4 time-honored methods of doing this:

1) Lower the grade of the ground in the root zone (thus scraping away and removing feeder roots)

2) Compact the soil in the root zone by driving construction vehicles underneath the branches - here's a tip: vehicles with tires are much more effective at compacting the soil as compared to vehicles with tracks

3) Raise the grade of the ground in the root zone (thus suffocating feeder roots under tons of fill)

4) Severe the roots to install utilities, sprinkler systems, etc.

The two great things about damaging the roots are a) it really takes very little damage to send the tree into a downward health spiral, and b) that downward spiral can occur over the course of several years.  By the time the tree dies no one will attribute its demise to construction activities that happened a decade ago, and instead will blame its death on whatever insects or diseases secondarily attacked a stressed tree already in decline.  Like I said, it's the perfect crime.

The only downside to this perfect crime is that - on the off chance anyone is actually concerned about saving the trees - it is equally easy to prevent.  Just put up a fence around the drip line - better yet a bit beyond the drip line - and don't allow any changes of grade or construction traffic in that area. 

No, you won't get the thrill of knowing you committed a tree murder that will never be solved, but you will get the less exciting but nonetheless palpable satisfaction of having done the right thing.

In the last two plus decades I have seen a dramatic increase in the use of protective fencing on construction sites.  Sadly it generally is set up to protect only the trunks - and not the root zones - of mature trees, a further twist on the perfect crime that is as sinister as it is brilliant:  The trunk protection fence makes it look like you care about saving the tree, while giving free access to do the root zone damage that won't show up for years.  Brilliant!

But more recently I have been seeing protective fencing on construction sites that is actually, well, protective. 
There are two sights that fill my forester's heart to bursting:  Seeing a newly planted oak tree reach its (astounding) growth potential, and seeing a properly installed drip line fence.

So, without further adieu (because this post has already included way more adieu that anyone could be expected to read), I applaud the California Department of Transportation - Caltrans - for exemplary use of the drip line fence during a renovation of Hwy 101 near the Santa Margarita exit.

Even younger oaks are worthy of drip line protection
(since young oaks are generally where old oaks come from)
Even better: Fence the drip line of a stand of trees;
you might end up accidentally saving some non-oaks
in the process, but that can't be helped.
That last caption was a bit of sarcasm just to see if you're still with me.

If you are ever out and about and see either construction damage in progress, or in the wildly unlikely event that you actually see well-deployed construction fencing, please let me know and send pictures!

1 comment:

  1. Hahahaha, I loved the snippet at the end. Very funny. You're putting a hell of a lot of effort into saving them, extremely honorable. Thank you for doing a huge part for our ecosystems and environment, every step counts.

    -Tony Salmeron
    Tree Service Hendersonville NC