We were once told by an MSU Extension agent it is OK to prune after it has gotten 20 degrees or below twice.
On Dec 1, 2011, at 12:13 PM, Kushad, Mosbah M wrote: > I recall a discussion in a class that I took from the Guru of plant stress > physiology Dr. C.J. (Bud) Weiser, at Oregon State University in the early > 80's about pruning in late fall/early winter compared to middle and late > winter. The answer can be summarized in how fast the plants enter deep > dormancy and how quickly they get out of it. Dormancy relates to how > quickly the water moves out of the cells and their surroundings and how much > dormancy hormone(s) (abscisic acid +??) they accumulate. In general, as the > days get shorter, plants enter a holding pattern state called quiescence/rest > before they become deep dormant. If the weather is warm in late fall and > early winter, the trees can remain in the rest/quiescence state for a longer > time, but if the weather is cold then they move into deep dormancy much > faster. Trees are much more susceptible to injury during the rest state than > during deep dormancy (it relates to the water in and around the cells) > > The general belief is that older trees tend to enter deep dormancy earlier > (no scientific evidence to back this up) than younger trees. Understandably, > because younger trees tend to have more free water in their cells because > their tissues are more succulent and that will require longer time for the > free water to move outside of the cells/and or become less free. When free > water freezes, icicles can puncture the cells causing injury that can lead to > tree death. > > Here are my two cents on the pruning. If the weather in late fall and early > winter is warm and/or you expect it to become warm >60 to 70F (>16 to 21C) > for several days (more than 4 to 5 days), then I will be hesitant to prune > any trees, regardless of their age. However, if the weather stays in the > low 30 to 40F then I would prune older trees and keep the younger ones for > later, as Bill suggested, to make sure that they have entered deep dormancy. > Best of luck, Mosbah Kushad, university of Illinois > > > > From: apple-crop-boun...@virtualorchard.net > [apple-crop-boun...@virtualorchard.net] on behalf of Fleming, William > [w...@montana.edu] > Sent: Thursday, December 01, 2011 10:13 AM > To: Apple-crop discussion list > Subject: Re: [apple-crop] Best time to start apple pruning after harvest > > I always start pruning after leafs fall mainly because the branches fall to > the ground more easily. No leafs allow a more accurate cut and avoid cutting > trellis wires also. Have always started pruning as early as possible to > utilize a year round workforce. I always heard but have never seen any > documentation that it’s not a good idea to make big cuts close to a central > leader if sub zero F weather is anticipated. Have always saved the youngest > trees for last when the coldest part of winter has passed. > It seems like anymore pruning has become almost a year round activity. Some > years we haven’t finished winter pruning until long after bloom without any > apparent ill effects but the workers hate it. > They call it “cutting bees.” > > Bill Fleming > Montana State University > Western Ag Research Center > Corvallis, Montana > From: apple-crop-boun...@virtualorchard.net > [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Jose Manuel > Pereira Cardoso > Sent: Thursday, December 01, 2011 4:56 AM > To: Apple-Crop > Subject: [apple-crop] Best time to start apple prunning after harvest > > Hi don't know the best time to start prunning appIe trees, and if is > cientific consistent that i suggest that pruning the apple tree should be > always start when the is 100% dormant, because if not dormant the plant is > mobilizing the reservesI don´t know if is any inconvenient to carry out > pruning just afterthe leaves fall because it coincides with the maximum > translocation of reserves (given the scarcity of labor, which has many > hectares has already started to prune pruning). In the latter case when you > start pruning early on the one hand we are to reduce the reserves in buds and > in some ways to help the plant to respond with vegetative buds and increase > alternance, and we are exposing the plant to external agents that can cause > fungal infections and by bacteria. When you start pruning early apple wood > still not well "hard" it needstimely, and then gain more strength. As for > which variety to get there. Can still be considered that the parcels located > in areas of higher risk andlower the occurrence of frost can be made as close > to the bud ...This year in September and October were too hot, and this > heatkept the vegetation greener longer, sometimes causing a delay inentry > into dormancy of apple trees that can be advanced with the application of > copper, to force the plant to go dormant.Greetings > -- > > JMP CARDOSO > SOMA MAÇÃS MAIS > > > _______________________________________________ > apple-crop mailing list > apple-crop@virtualorchard.net > http://virtualorchard.net/mailman/listinfo/apple-crop
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