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Rain, Wind and Your Orchards - Updates from Rob Crassweller and Jim Schupp

Posted: September 9, 2011

In July we couldn’t buy a drop of rain. August wasn’t too bad but September has been a real soaker—first Irene and then Lee. The eastern part of Pennsylvania was hit the hardest but nearly everyone had some rain from the two storms. Some growers are reporting support systems that collapsed under the weight of the tree and crop with all the rain. If you have some trees that went over and did not break off at the union you can rectify the problem but you must act fast. (The most recent weather forecast calls for the rain to finally end on Monday).
Dr. Rob Crassweller, Penn State Extension Pomologist

Trees can be righted utilizing a rope or chain attached to a tractor. Attach a padded chain or rope well up the trunk. Gradually straighten up the tree being careful not to twist the trunk or break off any more roots. Attach the tree to a post or metal or wood stakes driven in the ground as shown in the drawing if you are dealing with individual trees. If you are dealing with a support system failure, notice what part failed, e.g., were the posts not driven in deep enough? Did the system fail because the wire staples pulled out? Was the crop load too much for the system? If any of these were the reason resolve to correct them. Immediately after you have pulled the tree upright, tamp soil down around any exposed roots. Reduce any stress to the trees next spring. This includes weeds, voles, drought and heavy cropping.

Besides trees falling over there have also been reports of trees succumbing to excess moisture resulting in a lack of oxygen to the roots. Jerry Frecon showed pictures of peach trees being underwater after Irene. He indicated that if stone fruit trees are underwater for 24 hours they will generally die due to a condition called anoxia (oxygen deficiency). Later, symptoms in the trees appear as wilting and yellowing of the leaves similar to what happens to nitrogen deficient trees. Be on the lookout for signs of collar rot in these trees.

Dr. Jim Schupp made the following observations of trellis failures in a planting at the Penn State Fruit Research and Extension Center in Biglerville:

Irene’s damage has taught some hard lessons that should be applied to future plantings:

1.      Four wire trellises held up to storm winds better than vertical axis systems with a single wire supporting a conduit.

2.       Vertical axis trellis systems in which the wire was attached by running it through a hole drilled through the top of the post held up much better than those in which the wire was attached to the post by staples.

3.      Trellis systems that were held by an angled end post wired to a vertical anchor post were more likely to loosen than were trellis systems with a vertical end post attached to a vertical anchor post by an “h” brace.

The bottom line is that the most economical trellis system is the one still standing after a catastrophic event.