Reply to post by Russ Carlson, on August 27, 1999 at 07:07:49:

A few years ago we had a summer windstorm blow throughand a client called because of broken limbs. ON eo the trees, a green ash, blech!!!, that I had pruned in late winter had a broken limb. The limb was typical of the nursery cultivars inthat it had turned inot a lion's tail. I saved the splintered part to do an autopsy. After ripping it with my bandsaw and sanding it with my random orbital sander, (That is how I justify buying tools) I studied the splinter. What I found was that the year before we had an ice storm and this limb had a very small fracture. The fracture only went through three growth increments. The tree actually had formed one layer of callous tissue at the fracture. When I wet the sample it is very visible. But this was enough to present a weak spot the next year when the wind came through.

At first I was embarassed that the limb had broken since I had just pruned it. But after doing the investigation I realized that there would be no ay to have seen the crack.

IN this case, I paid the bill for the woodworking. Since then I have used the sample in several classes and seminars taht I have taught. I use it to illustrate how small wounds can lead to failure

Reply to post by Scott, on July 26, 1999 at 08:49:28:

Same tree. 2nd branch dropped this morning. A light breeze, but nothing severe. 2" dia @ break. Can't see where it came from in canopy so can't see lenght of remaining stub. Branch about 10-12 feet long. Not acorn weight. No external water weight, dry today.b No obvious defect in branch, but one streak of discoloration. When I have time I'll take a closer look.

Reply to post by Scott, on August 26, 1999 at 20:10:31:

Yikes Scott, it sounds like its time to sit under a different tree!! *G*

Ive done some dissecting but unfortunately I havent got easy access to a bandsaw now, and if Russ is right that looking at this thing from macro and micro levels is needed then someone else would have to do the slicing.

It sure is interesting however, we had a limb drop from a sweetgum on Saturday here at NYBG. Rained like mad then when it stopped and the foliage dried, bingo, off it came. Same pattern as before, but not so hot after the rain. May be something to do with a relative weight gain over time. If the wood is only moderately dry it may take a temp spike to 'insure' that the tree tanks up to maximum weight. If the tree is dry enough, it may just require retanking up to normal levels and a temp spike is not required for branch failure.

Now there's a batch of armchair arboriculture!! Think we need someone with a bandsaw....... I have a good microscope

Wayne

Reply to post by Wayne, on August 30, 1999 at 10:08:47:

If you can't afford, or justify, a bandsaw, think about looking at the DeWalt 18 volt cordless tools. I bought a kit that has a snake light, circular saw, reciprocating saw, and drill. I have used all of them on the job too. The recipricating saw does a pretty good job of ripping open limbs for disection. A client had a wood deck surrounding a tree and I used the saw to cut away some of the decking. When I do any bolting I use the saw to cut off threaded rod instead of the "Go To-Come From" saw.

Maybe this post belong's in Tools but it was more relevant here.

Tom

Reply to post by Tom Dunlap, on August 30, 1999 at 14:22:27:

Tom,

Thanks, good idea. I have a very nice manual miter saw that does a great job on small to medium cross sections, but is useless for a longitudinal cut. And in the interest of multi-use..... the miter saw does a very nice job on baseboard and window frames on the weekends......

Reply to post by Scott, on July 26, 1999 at 08:49:28:

That 1st one I reported 8/26 which was wedged in the tree came down in last night's heavy rain. (Whew, I don't have to climb up there to get it!) I'll take a closer look and report. If nothing grossly unusual I'll take a sample mark it up and see about future disscection.

Reply to post by Scott, on August 26, 1999 at 20:10:31:

Hey Scott, I like the ones that fall all the way down!! Interested in knowing what it looks like inside. According to Russ, we need the stub end too

Wayne

Reply to post by Wayne, on September 06, 1999 at 07:34:34:

Russ can come up and climb to both of these, each about 60-70' up and out about 30' from center (about 180 degrees apart!). Oh, and the cables in this tree will prevent a clean swing from a central crotch. The larger one I saw, the smaller one not. I'll even buy him lunch.
The smaller one appears to have a small "punky area" around top center which may have propagated the failure, not real soft just not real hard and glossy. The larger one appears to have had a pre-existing split or delamination side to side about middle extending out from the fracture. About 4" dia. with 23' of tip beyond and only 2' or so back to parent. We'll be getting together probably next week so I'll bring them along.

Reply to post by Wayne Cahilly, on July 26, 1999 at 08:49:28:

WAYNE: Thanks for accepting the butt ends of SLD #'s 1 & 2 with the environmental data I was able to accumulate. You've got the good microscope and better understanding than I of wood structure. Looking forward to results of your dissections as time permits.

RUSS: Wayne was closer for delivery purposes and undercut your bid! Sorry. But don't feel left out, see following.

BOB W: 100% of samples to Wayne. 100% of results of dissection may be posted here for review and comment by all.

Reply to post by Scott, on July 26, 1999 at 08:49:28:

Hopefully, Wayne also has more time right now to look at that stuff...... (scrambling fast and going backwards)

Reply to post by Russ Carlson, on September 16, 1999 at 17:44:44:

Yes, I've had that problem too. It took me a while to find the instructions for shifting out of reverse, they're on p. 397. Really crummy documentation.

Reply to post by Wayne Cahilly, on July 26, 1999 at 08:49:28:

I've just picked up a case of SLD concerning a Cedrus libani in August 2000. Nice clean break from a limb about 20 feet up, approximately 16" in diameter, from a mature tree showing 100mm of shoot extension. How do we maintain for this phenomena? Short of fencing off every tree of a certain size, what is the answer?