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Evan McDivitt

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since Aug 18, 2013
Elkland, PA
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Recent posts by Evan McDivitt

Yes the live crown ratio is crown length (the vertical part) to total tree height (http://dictionaryofforestry.org/dict/term/live_crown_ratio). The live crown is: "of a standing tree the vertical distance from the tip of the leader to the base of the crown, measured to the lowest live whorl (upper crown length) or to the lowest live branch, excluding epicormics (lower crown length) or to a point halfway between (mean crown length) - {from http://dictionaryofforestry.org/dict/term/crown_length_(live_crown) }

So, you have it correct the way you described your math! So, in a ten foot tall black walnut tree, you'd measure from the tip of the leader way up high down to the lowest live branch (you're talking about the original branches as the tree was developing). Epicormic branches are a shoot arising spontaneously from an adventitious or dormant bud on the stem of a woody plant often following exposure to increased light levels or fire so disregard them in measuring the live crown ratio. If after measuring your ten foot tall tree (down to the lowest live branch) you found you had 8 feet of live crown, your live crown ratio would be 8 / 10 *100 = 80 percent. As a rule of thumb you could safely remove the lowest 20% which would be from the lowest live branch up 2ft. along the stem.

As a general rule of thumb I think you'd be safe doing it this way. I think pruning works best in younger trees. If you had a 100 foot tree, chances are the lower branches would be getting pretty large and even with pruning along the "veneer" part of the tree, the quality of the butt log would be in pretty poor shape. Although if you DID prune the lowest 20% of the 100 foot tree, I don't think it would be enough stress to kill the tree. However, if you are growing a black walnut / black cherry plantation starting with young seedlings, you have the best opportunity to influence the tree's straightness and quality of form.

Here's a PDF about "Managing Stand Quality" It discusses pruning and Live Crown Ratio more in depth.

Here may be some helpful links for you (you may have already seen them but I like them):

Corrective Pruning Of Black Walnut: http://www.extension.purdue.edu/extmedia/FNR/FNR-76.html

Black Walnut Plantation Management: http://www.extension.purdue.edu/extmedia/FNR/FNR-119.html

Black Walnut Management Slides: http://www.extension.umn.edu/distribution/naturalresources/DD6713.html

Growing Black Walnut: http://www.extension.umn.edu/distribution/naturalresources/dd0505.html
5 years ago
Regarding the quality of timber in widely spaced trees, the lower boles (the first 16 or so feet of the timber tree from stump up) will have a lot of sunlight shining on them if they are widely spaced. In hardwoods like black cherry and walnut, they will produce many epicormic sprouts in such a high-sun environment. These sprouts will become branches low on the tree. Since you will want the first 16 + feet to be free of branches (if you are growing trees for lumber / veneer), you will have to prune them early on. There's been a lot of research in silviculture on pruning trees. I learned if you look at a trees total canopy (or live crown) and look at the live crown ratio (in percent). This live crown ratio is the percent of the tree's total height that is in canopy. If you figure out a tree's live crown ratio, you can safely prune back 20% of its crown as long as you don't go below a total live crown ratio of 40%. So, if a young walnut is ten feet tall and has a canopy that encompasses six of those ten feet, you could prune the lowest two feet of branches resulting in a ten foot tree having a canopy that encompasses four of those ten feet. This is just a rule of thumb I learned in forestry school - I'm sure it doesn't always work so pretty in reality. Since hardwoods grow so slow, you could even just prune back the lower branches every 5 years or so to give the tree enough leaves to continually promote height growth and not outward growth. Also important, secure that first 16 feet of clear bole as quickly as possible without harming the tree's vigor. If you can secure a clear 16 to 20 ft bole as soon as possible then you will be on your way to hopefully producing some quality veneer trees.
5 years ago
Could it be some kind of quince? Have you looked at Identification Keys for different quinces?
6 years ago
I've been reading about the concept of Energy Return on Energy Invested and have learned that the easy access oil used to bring a 24 to 1 energy return on energy invested. Nowadays its closer to 11:1 (harder and more energy intensive to produce). I've also learned that oil sands production drops to anywhere from 7:1 to 3:1. I've heard corn ethanol is also quite low (similar to oil sands). I'm wondering if anyone has heard of some reliable sources that calculate an EROI for agrarian-based societies? I'm sure "agrarian-based" societies are as diverse as anything but there's got to be a generally accepted range for energy input versus output. I read some of the comments on this article( http://www.theoildrum.com/node/8625 ) and got a "sort-of" idea of what such an EROI might be but I'd like to hear where permaculture might fit into this subject? See attached PDF for a "libertarian" view on Fossil Fuels. Again I would be interested in learning how permaculture fits in with this type of view? Thanks.
6 years ago
I've read about the Spanish dehesa agrosilvopastoral system and was wondering if anyone has attempted a parallel version in the eastern U.S. oak-dominated woodlands? Has anyone produced Iberian pigs? I'm assuming they are a special breed with special considerations?
6 years ago
Has anyone had success incorporating black cherry and black walnut (both widely spaced) as timber trees, mixed in with some sort of agroforestry / agricultural crop production? Just wondering if there are any lessons learned? Do widely spaced timber trees actually grow up to produce a high-quality sawtimber tree? Even if they are pruned?
6 years ago
Can anyone give me some information about how they have used hackberry fruit? I have seen it grow as far north as Syracuse, NY and have eaten it and it is not bad (not much per fruit). Has anyone experimented with processing methods or efficiencies?
6 years ago
Has anyone had any success incorporating birch syrup production into a permacultural system? I'm wondering how is it different / how is it similar to maple syrup production in terms of yields per tree; sap to syrup ratio; tree spacing in a productive bush; tapping and tubing; evaporation / processing?
6 years ago
Long term, try growing moss? Not sure how to grow moss but it grows well on rotten and moist logs. It might help make wet logs less slippery.
6 years ago