Another Pine Thinning

Gary_C · February 21, 2012, 01:13:57 PM

I just finished a job here in SE MN for a private landowner. I'm not sure of the acres but there were two tracts of mostly red pine with some fairly good scotch pine in some spots. From what I was told, the two tracts were planted in 1956 and had been thinned once some years ago, though I did not see any evidence of thinning.

The trees were pretty consistently 70 feet tall as I was getting eight 8'4" sticks per tree. The trees had pretty well self pruned, even the scotch pine which is normally a problem in this part of the state and probably everywhere else for that matter.

The planting was rather unusual and did cause a problem. I was told the stands were planted with two guys sitting in a wagon behind a tractor. So there was two rows spaced about 3-4 feet apart and then about a nine foot space between the double rows. And in many places the trees were planted less than two feet apart in the rows. That made for a lot of 2-3 inch pecker poles that were doing nothing. However it may have contributed to good height and good self pruning.

The double rows.

The wide spacing.

The growth rings.

After I took the job, the landowner decided to make a clearcut straight off the end of the dead end road that ran into one tract. You can see the road in the distance and the road runs into a main highway just beyond what you can see of the road.

From that view, the trees on the west side had been thinned. the rows actually came into the clearcut at an angle and you can see one of my tracks thru the stand.

The trees on the east side had yet to be thinned at the time I took the pictures.

Here is a pdf of part of the printout from the computer on my harvester showing the two major species on this job. The aspen was not mixed in the pine but in a separate part of the private land.

SwampDonkey · February 21, 2012, 01:53:34 PM

Those are some nice looking pines from what I can see. Your trail work looks good to. Nice site to work to. Flat, no water, no boulders. The knot wood is beginning to heal over, some a few years beyond. ;D

Gary_C · February 21, 2012, 02:29:22 PM

I don't know if it was good or bad to have the trees in the double rows so close together. If you look at the diameter distribution, there was a very high amount of sticks in the 3 inch size. It doesn't seem to follow the normal distribution pattern. About a third of the volume was in the 6 inch diameter size with the largest being in the 13.75 diameter size. But there were as many pieces in the 3 inch size as there was in the 5 inch size. I don't think that's normal.

The total cords of pine as shown on the computer accumulation was higher than what was sold, but that can be due to too many conversions and slight differences in the diameter calibration. Not only can the sensors be slightly off, but then the machine keeps track of volumes in cubic meters and then converts to cords and the wood was sold by the ton so there's another conversion.

terry f · February 21, 2012, 02:36:14 PM

Nice job. Whats more important, letting them self prune and put a little extra height, or thin early and go for diameter? They look like they could of used it 40 years ago from the rings.

SwampDonkey · February 21, 2012, 05:31:24 PM

Volume wise, the peek of the bell curve should be the average piece size. Now note I said volume not stem count. Do you have volume by diameter class? 25 years of age seems to be the time to thin after planting or after PCT spacing even with spruce and fir, to keep the volume growth going. Pine might be 5 years sooner. Always seems to fall right around that time up in the northern US states and eastern Canada non-the-less. Normal I think is what you would expect with optimal spacing, this seems more random like you said earlier. More like wild growth.

WDH · February 21, 2012, 08:49:09 PM

Looking at the cross-section, you can see where the tree responded after the first thinning. However, they thinned it way too late the first time, in my opinion. If you are going to grow pulpwood, you may as well grow big pulpwood.

semologger · February 23, 2012, 11:03:04 PM

i would love to have a tract like that coming into my peeling yard. I have to go look at a tract of pine saturday but he wants it clear cut. we will see. What were you skidding with or using a forwarder? Nice job

Clark · February 23, 2012, 11:40:32 PM

As usual, great information Gary. That planting regime is unusual, I can't see any benefit of doing it that way, especially in hardwood country where you would want the canopy closed ASAP after planting.

I would tend to agree with you, that stand was never thinned. The cross-section shows typical growth for pine up here. The good growth seems to stop after about 10 years of age, planted correctly it would have continued to grow well until about 15 which is more "normal".

Quote from: terry f on February 21, 2012, 02:36:14 PMNice job. Whats more important, letting them self prune and put a little extra height, or thin early and go for diameter? They look like they could of used it 40 years ago from the rings.

For red pine they typically leave them thicker and let them self-prune to a higher height. The final market they are aiming for is telephone/utility poles. I would say there is benefit to thinning heavy and growing a bigger log but no one around here does that. In a managed stand at 50 years average dbh is ~12", I think we could manage them a little differently and bump that up to 16". And now I'm just rambling. ;D

Clark

SwampDonkey · February 24, 2012, 06:02:50 AM

I didn't see any thinning evidence in that particular log. But if the thinning was as "interesting" as the planting it probably didn't accomplish much. I think there are quite few rings around the pith there you can't see. A seedling doesn't grow that quick up north. However, in 10 years a red pine should be about 5" on the but. They are around here and quit bushy. Hard to thin (PCT) around red pine plantation because of the stiff long limbs and big buts if you let it get ahead.

WDH · February 24, 2012, 08:37:38 PM

Surely there is evidence of prior thinning in that cross-section!! Look again

. After the first 20 years of pretty good growth, the rings get very tight as the diameter growth slows to a crawl. Then, amazingly, the rings suddenly get wider and there is more vigorous diameter growth. That is not simply coincidence. It indicates that this tree was released.

SwampDonkey · February 24, 2012, 10:21:18 PM

After 20-25 years (I can't see too good around the pith) all I see is uniform ring width from then on out. There's always a 4-6 year stretch or so that the rings half and then go real tight when not thinned. When you fertilize you find that the codoms take 3 or 4 years to respond. This tree I suspect is a codominant. There should be a few in the plantation above the rest, the largest diameters. Even with even-age there are some that express dominance where conditions give them an advantage.

WDH · February 24, 2012, 10:26:09 PM

No. It definitely slows way down, then picks back up.

SwampDonkey · February 24, 2012, 10:34:32 PM

I think what your seeing is edge effect, that 1/4 of the log, close to half maybe, is quite a bit wider than the rest of the cross section.

WDH · February 24, 2012, 10:43:26 PM

OK, maybe. But the growth rings seem wider on the outside than in the middle. That would indicate release or it might indicate that I need to go to the Eye Doctor

.

SwampDonkey · February 24, 2012, 10:58:44 PM

Yes, it certainly would. ;) Funny Gary never found any old stumps, they would persist for 2 -3 decades. They do on any thinning we do with brush saws (softwood).

Gary_C · February 25, 2012, 12:06:55 AM

Not only were there no visible stumps, but in many places in the rows, the trees were 2 feet apart and not doing well. And there were a lot of 3 inch diameter and 70 feet tall pecker poles. If some one did thin the stand many years ago, they sure did a poor job of spacing the trees out.

WDH · February 25, 2012, 07:34:33 AM

The tree in the pic could have been released naturally by mortality of adjacent trees.

SwampDonkey · February 25, 2012, 07:44:34 AM

Yes, that's certainly a possibility and now may be dominant.

Corley5 · February 25, 2012, 11:47:47 AM

There will be no evidence of stumps in red pine thinnings in 10-15 years in this area. I thinned a few from the stand by my house in 1994 and most of those stumps are long gone. The only ones that persist and you have to look for them are on the hill where the wind blows the duff away so they are exposed and stay drier. A light kick to them and what's left crumbles.

SwampDonkey · February 25, 2012, 02:25:58 PM

Seen lots of sites the brush is long gone to soil and the stumps are still there. 2"-3" stumps and the leave trees are now 8-10" some bigger if they were scattered oversize stems when the thinning was done. 10 years usually takes care of all the brush, hardwood or softwood. ;D

I'm with Gary, if it was thinned they were just playing because they didn't accomplish a thing.