I was recently looking at a pine stand that had been thinned in the last two years and I made a comment that it looked like it had been thinned from the top down, ie. largest first. Reason I thought that was I had looked at the stand before it had been thinned and I thought the trees were somewhat larger than they now appeared.
To my surprise the forester said there was some studies that said it may be beneficial in at least Red (Norway) Pine to thin from the top down. It may have been a USFS study the forester was refering to at the time.
Anyone else heard this?
Needles grow wood. Trees with the best crowns grow faster than trees with poor crowns. Seems like a rationalization to me. I don't buy it.
I'm wondering if it's worked out from an economics perspective. Getting a more profitable harvest from an early thinning offsets the reduced income from the final crop. 1/2 return now, 1/2 in 20 years. Re-invest the first return for the next 20 years, and you are better off than waiting for one big harvest? Even though the overall harvest may be less, getting a significant payment from the stand earlier offsets the reduced final crop.
For example, earn $100 now, and $1,000 in 20 years. Or earn $500 now (invest that) and another $500 in 20 years. Which option is a better return?
Conventional wisdom is to thin the worst trees, and let the best ones grow to maturity. Around here the thinning is done early (5-7 years) and usually just left to rot as it's not worth hauling out. Everything left after that is a final crop tree. But different locations and species, you might manage things different.
So if the smaller tress in the stand were a species that responded well to being released, then maybe you would come out ahead financially at the end?
Ian
The Classic French Silvicultural system, while not utilizing a severe thinning from above, favored leaving co- dominant and intermediate crown class trees over leaving dominant crown class and suppressed trees after the first commercial entry. Part of the reason is, as you surmise, economic - getting a quicker return on your investment. However, on the softwood species on which they applied it (I don't know if they still do), the co-dominants and intermediates respond better to thinning than dominants do ( even if they can't produce as much growth as the dominants can) and since they didn't have as aggressive a pruning regime as you folks do, the fewer and smaller limbs on the boles of the co-dominants and intermediates meant that those classes would produce higher quality wood as they grow.
Gary it depends on the health of the leave trees and the remaining basal area. If it's a bunch of thin stemmed trees with small crowns and opened up with less than 70 or 80 ft2/acre..... then just wait for the next wind and/or ice storm. Usually when leaving codoms the affect is not immediate, but 3 to 5 years from now. I have seen these types of rationalizations end up in disaster and as mentioned it's more about the economics than anything. Plain and simple.
Around here, we call that diameter limit cutting. They cut the best and the biggest leaving the rest to grow. Its also an economic clearcut, as the leave trees have a lot less value. Its a useful tool if you have a lot of wolf trees in the stand.
I've always looked at it as killing your best milkers. Farmers generally understand that. Bankers don't.
Top down would be different from diameter limit cutting as you would still take worst first, but when it came to a choice in a space where there is one or more dominant trees, you would take the larger trees to release the smaller ones. Apparently from what little the forester told me, taking some of the larger trees in a crowded space enables more growth from the many smaller ones. Overall it just might be a net gain.
And it may be different in milkers as there is a limit on food available for the trees but there should not be limited amounts of food for good milkers. But even then, I've seen where one boss cow can hog the feed and prevent others from giving full production.
That's an odd one Gary. Like everyone else I'm not buying their rationalization. If they are interested in simply the economics of it all and taking the biggest ones sooner is better, why not just take them all? If they don't think there is value in increased size then why not plant and clearcut every 30 years?
Quote from: Ron Wenrich on October 13, 2011, 05:49:31 AMI've always looked at it as killing your best milkers. Farmers generally understand that. Bankers don't.
I like that saying but I think with bankers you have to tell them you are borrowing from the principal.
Clark
Here is a fact. Needles and leaves grow wood. They are the factory. The more needles and leaves, the more wood gets grown. It is that simple.
I would hope that my trees are growing at a better rate than money in the bank. :-\
Up here crown wood stumpage suppresses the price for private wood, so I'm not so sure. :-\
Quote from: Magicman on October 15, 2011, 09:14:40 AM
I would hope that my trees are growing at a better rate than money in the bank. :-\
Unless they're shrinking, at least they're growing at a better rate than money in the stock market...
Hardwood stumpage has typically outstripped inflation by about 3%. That hasn't been the case in recent years. Seems like we're doing boom or bust right now. Market timing is hard, and its not one of those things you can manage for effectively.
Depending on the stand age, you might expect to see growth rates in the 3 to 6% range with SYP. 5% might be a decent average, however, if the stand is in the tweens, then it will be growing much more than that.
I talked to another forester and he gave another explanation. Says that Red Pine has so little genetic variation that growth rates are almost exclusively determined by the growing environment. So theoretically if you take out the largest or dominant tree in a group, you may get more growth in your stand by releasing the many smaller ones.
But he also said it's probably six of one and a half dozen of another.
Does the results vary by species? Sounds like red pine might fair better than white pine. We don't have much of either in my area.
As far as genetic variation in red pine, your forester in right. I've worked with tree improvement and they came to that conclusion years ago. But suppression and dominance plays another role, but they are not exclusive. So your last line has some merit also Gary. The only species here in NB that the suppression and dominance can be over come is red spruce. It will respond to release even after long suppression. It's a tough tree.
White pine will do "ok" in suppression until pole size and then needs to be released. Up here it needs to be grown in shade or the weevils keep killing the leader and if too tight a spacing the blister rust becomes a problem due to damp environment, which can be alleviated with intensive pruning. Most all my white pines are either damaged by wildlife and insects or blister rust is on it. I'll be lucky to get 50 trees to any size before they are ruined. And I have about 3000 I hand planted a few years ago. Hare and moose have white pine radar, but I am now realizing I have ribies everywhere and they even can take a lot of shade it seems. They like damp ground. On crown land they told us to not even bother trying to save them when brushing, they're going to grow into cabbage trees anyway. I've even found ribies in the back yard, so the one white pine I have left will likely be doomed. I lost one other from rust. Grows like weeds around here and several species of it including stuff introduced like gooseberry. Impossible and expensive to control.