Willow Oak Exposed to Fire

Steve Connally

Well-Known Member
#1
I looked at a tree today that had been exposed to a house fire last spring. Half of the canopy has healthy looking limbs and the leaves are dropping normally for this time of year. The half exposed to the fire last spring has most of the leaves still on it, brown and shriveled. So the fire was in april before the leaves had sprouted. Sometime in the spring the leaves set and then within weeks they turned brown but didn't drop. A few branches have cracked bark I assume from the heat. What I found in the canopy was a full bud set for next season and the branches were still green and flexible. They are asking the survivability. I'm thinking if its set buds for next year it should come back. However, it leafed out then they dies this past spring. Do any of the super arborists have any experience with this situation and could provide some additional insight?
 

JD3000

Well-Known Member
#2
Not with oak but I take care of some driveway arbs that got cooked by a car fire. They refoliated the following season and actually look pretty good two season later.

The problem you will be facing is how extensive the cambial damage was and how the tree is reacting since. Doesnt sound great since one side defoliated and didnt seem to refoliate this season. Did you do a scratch test up in the canopy to look for live wood or take apart some buds? Examine the trunk, branches, bark, sapwood, etc?
 

Steve Connally

Well-Known Member
#3
I didn't do a full canopy inspection or take apart any buds. I didn't do anything invasive I did examine the trunk, branches, and bark. I didn't find any charring or discoloration of the bark. Just a few branches with split and cracked bark. The funny thing in it leafed out then the leaves died this year within about 2 weeks
 

JD3000

Well-Known Member
#4
Hmmmm...closer look and pics necessary. Looking at some cut stems in cross section, perhaps an iodine test to cut wood
 

KTSmith

Well-Known Member
#7
Thanks JD for the plug.

Steve, I've done some work on compartmentalization and closure of fire wounds that resulted in scarring. Check out the Publications and Products tab at: https://www.nrs.fs.fed.us/people/ktsmith
That has most of my published stuff listed since the late 1990's (mostly), though you'll have to wade through some storm injury and dendrochronology stuff as well. Drop me a line if you need direct links.
I'm not an expert on willow oak. If the leaves are usually off by now, and they are off on the healthy side and not on the side in question...That tells me that that side is either dead or way low in reserves. Sounds funny, but normal leaf shedding is an energy-requiring process. I am curious that there is no obvious scorching. In mature oak with a well-developed bark (rhytidome), you can get quite a bit of scorch and even bark char before the vascular cambium is zapped. Might the fire have overheated the root system. That happens sometimes in intense wildfires, but I have no experience with house fires. I have another couple of oak wood fire scar anatomy papers yet to be written...Siempre mas.

As for the iodine test, JD is referring to the use of a stain that darkens in the presence of starch. So some folks would take a branch cross-section or increment core and test the sapwood. Will not show anything with heartwood or dead sapwood. So a few drops on a freshly cut, smooth surface of sapwood will go from white/cream color to rust to brown to even dark purple depending on quantity of starch therein. I usually suggest folks unfamiliar with the color change to try a drop or two on a freshly cut potato tuber, just to get your eyes calibrated. And the stain itself is iodine dissolved in a saturated aqueous solution of potassium iodide (I2KI). Straight tincture of iodine (what my mom used to disinfect small cuts) doesn't really work well. The drugstore tincture is made with alcohol. Elemental iodine (a volatile grey-silver metal, oddly enough) isn't water soluble, but the potassium salt is soluble and the dissociated I anion complexes with the elemental I2, bringing it into solution as I3- anion. That little structure binds to starch grains and colors 'em right up

A recipe is towards the end of Shigo's Modern Arboriculture. The same components are in Lugol's Solution, sold in some drugstores to treat thyroidism, as a disinfectant, and a few other things. Problem is, the over-the-counter preparations, made for human contact or consumption, may be diluted below the level that we need for the starch test. Oh yeah, the solution does break down over time. Ok, Ok, more than you wanted to know.
 

Steve Connally

Well-Known Member
#8
Wow, thanks for the amazing amount of information. I will do some reading tomorrow for sure. There was no effect on the trunk or root system other than runoff from the firefighting water. The chemistry lesson was interesting as well! I'm headed to be but will reread your post in the morning. Thank you
 

Steve Connally

Well-Known Member
#9
Sooooo..... After rereading the reply and the study I have come to a very important conclusion. I may be an arborist however I am truly just a tree cutter. I am always amazed by the amount of knowledge I didn't even know I didn't have in this industry. I'd have a tough time making it in the industry if I had to actually employ some serious arboricultural skills.

The research was very interesting to read as well as the chemistry lesson from Kevin. I had to brush up on it a little since it's been some years since my HAZMAT chemistry class.

I think I'll leave this up to the boss to work out with the property manager. The testing would be interesting and I'd love to do it, however it may be more than they want to sink into a tree they want me to say is dead anyway.

What I find interesting is how the tree didn't have the energy to drop the leaves but there are fresh terminal buds on the very same branches. I guess in some amazing way the tree channeled what energy it did have to ensure survival for next season instead of discarding the leaves from this season. Pretty darn smart. However, the OCD in me thinks the tree still needs to get rid of those leaves. No job unfinished rite? I'm glad trees aren't OCD also.

Thank you guys so much. This small exposure has been a great learning experience as well as a reality check as to how little I know about what I'm doing. I appreciate the information. You guys are absolute professionals. Lots of respect for you and your knowledge.
 

Treetopflyer

Well-Known Member
#12
@KTSmith little off topic although we briefly touched on some fire talk during the veteran tree care course at Brooklyn botanical gardens last year, as this maybe just a plug for that workshop in which I thoroughly enjoyed. Any word on that happening again? If it does take place @Steve Connally I'm sure you would enjoy. I always am very amazed how much there is out there to know if one is looking to know about something. The father you go the deeper it gets. I think Kevin shows us a good example of that in his post above. Hope to meet again in Brooklyn. Thanks all for the thought provoking in this thread
 

KTSmith

Well-Known Member
#13
Thanks Treetop, yes the Brooklyn Botanical Garden two-day session was great fun for me and folks seemed to get pretty engaged. I'm sure some folks were thinking in advance "could it still be interesting after two days?" As it was, it was just a taste. Immediately afterward, my contacts at BBG and Green-Wood Cemetery were all fired up about a session this spring. I haven't heard anything lately. I'll check with them, just to get the schedule committed. In January, I will be doing simple lectures at a Landscape Disease Symposium hosted by Univ. California Extension folks and the Midwestern Chapter ISA conference in Overland Park, KS. I'm committed to the FL ISA chapter conference in June, but I'm not sure exactly what form my part will take. Folks generally need to experience one of the longer-format events before they commit to putting one on themselves. Understandably so!
 

guymayor

Well-Known Member
#15
I'm committed to the FL ISA chapter conference in June, but I'm not sure exactly what form my part will take. Folks generally need to experience one of the longer-format events before they commit to putting one on themselves. Understandably so!
FLISA typically has a half-day "academy" session on the first day. I led one in Key west a few years back.
 
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