I have experienced what happens when rows go down and it isnt fun. Most trees snap off at the graft union. And they take their neighbour with them for a couple of hundred feet up the row. By this time of course you have all of your annual costs into them but the harvest cost. Its a real mess.
That same block has other rows that lean and have to be propped every year. Thought I had got away from that years ago. Bringing rows back to the upright is nigh on impossible without snapping more unions. We are now placing in-line posts at 32 ft. The trick I think is not to let trees get top-heavy. Harold Schooley Schooley Orchards Simcoe, ON, Canada From: apple-crop-boun...@virtualorchard.net [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of David A. Rosenberger Sent: February-20-14 1:29 PM To: Apple-crop discussion list Subject: Re: [apple-crop] Tall spindle trellis In theory, trellis rows could be as long as you want them to be, but in reality there are almost certainly limits to the amount of tension the end-posts can handle without coming out of the ground. Consider the worst case scenario: Trees that have grown to 3-ft above the wire (i.e., 13 ft tall) with 2000 bushels/A evenly distributed over the upper 12 ft of the canopy (i.e., none within 1 ft of the ground). That could mean that 25% of the fruit are above the 10-ft top wire, and in my experience those upper limbs will tend to fall toward the leeward side of the tree due to wind effects. Lets assume that trees are on 10-ft row spacings and that 10% of the total crop is above the wire and off-center to the leeward side. If Ive done the math correctly so far, that means that every acre will have 4-tons of apples off-center and at least 10-ft above ground. At 10-ft between rows, it will require 4,356 ft to make an acre. Thus, with rows 1000-ft long, there will be roughly 1 ton of off-center apples 10-ft above the ground. Now add a 40 mph crosswind just before harvest, and (for those in the east) assume that you just had 10 inches of rain due to a hurricane coming up the coast. The line posts will provide some support, but ultimately the greatest stress will be on the end-posts, and that stress will increase with the total length of the trellis. Even on short rows of only 300 ft, I have gradually seen trellises go off-center with time (i.e., line posts begin to lean a bit) due to wind effects, uneven cropping on the two sides of the trees, and slope (which leads to uneven frost-heave effects). If the trellises are tilted just a bit under the scenarios outlined above, then the stresses on the end posts will be multiplied. Admittedly, my observations are mostly with wider trees and wider row spacings, and those planting systems probably was more prone to going off-center than a narrow tree wall. Nevertheless, the side-ways forces on trellises should not be ignored. You may quibble with some of my assumptions, but I really would like to see/hear an engineers perspective on how long rows can be given various soil types, diameter of both line posts and end posts, crop distribution in tops of trees, soil moisture levels, etc. Whatever the answers might be, I can guarantee that when a trellis goes over in a storm, the owner with shorter sections is likely to come out with smaller losses than the person with longer runs if one assumes that construction on shorter and longer sections was equivalent. **************************************************************** Dave Rosenberger, Plant Pathologist (retired) Cornell's Hudson Valley Lab, P.O. Box 727, Highland, NY 12528 Office: 845-691-7231 Cell: 845-594-3060 http://pppmb.cals.cornell.edu/people/dave-rosenberger **************************************************************** On Feb 20, 2014, at 12:43 PM, Hugh Thomas <hughthoma...@gmail.com> wrote: Seems to me, that they could basically be as long as you want them to be. I would calculate the fuel capacity of my tractors so that one doesn't run out of fuel before getting back... On Thu, Feb 20, 2014 at 7:27 AM, Fleming, William <w...@exchange.montana.edu> wrote: We had rows 2200 feet long between end anchors. 4 wires, 10 high with posts spaced at 42, 3 deep. End posts were a larger diameter, 4 deep at about a 45° angle. Wires and anchors were attached to a 4 long screw in steel anchor with 8 plate. Ground was basically flat. No problems holding a bumper crop. Bill Fleming Montana State University Western Ag Research Center 580 Quast Lane Corvallis, MT 59828 From: apple-crop-boun...@virtualorchard.net [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Arthur Kelly Sent: Thursday, February 20, 2014 6:24 AM To: Apple-Crop Subject: [apple-crop] Tall spindle trellis What is the longest length of trellis for tall spindle apple planting that growers have experience with? -- Art Kelly Kelly Orchards Acton, ME _______________________________________________ apple-crop mailing list apple-crop@virtualorchard.net http://virtualorchard.net/mailman/listinfo/apple-crop _______________________________________________ apple-crop mailing list apple-crop@virtualorchard.net http://virtualorchard.net/mailman/listinfo/apple-crop
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