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I live in a volatile weather area and recently had lighning strike a tree within 10 feet of my home. I have gotten estimates from a few contractors for a lightning rod protection system but have found them expensive and somewhat of an eyesore. I am told that my home would need 15 or more lightning rods, no less than 20 feet apart. I have two chimneys which are the highest points of the home. Do I need all the associated metal and expensive of 15 lightning rods or can I just use the lightning rods on the highest points -- the chimneys?
If a lightning rod on each chimney will provide a "cone of protection" for all of the house, I would not spend much money for additional lightning rods. The radius of the protected horizontal distance is about two times the height of the object on which the terminal is mounted. I would spend some money for parts of the house not under the "cone of protection." I'm quite sure no lightning rod salesman will concur.
Don Pfost
Associate Professor Emeritus
Food Science and Engineering
My chain saw's chain has jumped its guidebar three times. It's a frightening experience with the chain flailing around. I'd be missing body parts if it weren't for the chain guard on the bottom of the saw. While cutting, I retension the chain every 5 minutes or so. What could be causing the chain to jump?
Have you had the bar and drive sprocket serviced? Sometimes the bar needs to be dressed and straightened after accidents in felling and bucking.
When you tighten the chain, are you keeping the nose of the bar elevated slightly? Nuts holding bar in place are just loose enough so that when you tighten the chain, the tip of the bar can fall down, You need to avoid that.
When all else fails, take it to a good saw shop and holler for help!
Bruce Cutter
Professor of Forestry
I have land near Laure, Mo. Can you tell me of any poision plants that I should look for in that area? I have small children that like to run the hills and I would like to educate them
We have a guide, G4970, Plants Poisonous to Livestock. If you would like a printed version, request it from your local MU Extension Center or contact MU publications at 800-292-0969.
Fred Fishel
Extension Associate Professor
IPM/PAT Coordinator
I love winter berries for Christmas decorating. How can I preserve them through the holiday season?
Certain winter berries (e.g. holly) have been identified as being toxic to humans resulting in symptoms of abdominal distress and diarrhea. While I am not certain of the stability of the offending toxins (triterpene compounds) when dried, I doubt that drying holly is something we should encourage because of the safety issue with children.
David Trinklein
Department of Horticulture
I just bought a tractor and understand the danger of tractor roll-over on slopes, but how steep is too steep -- 5 degrees, 25 degrees, 45 degrees?
All safety specialists caution against operating equipment on steep slopes. However, you are unlikely to find a specific number mentioned for deciding when a slope is too steep, because a situation and conditions which produce an unsafe operating condition are so variable and unpredictable. What might be a "safe" slope in one case, could be dangerous in another. The key is to recognize and assess key elements which contribute to the danger:
As you can see, this is truly a "judgement" kind of call. Certainly you should have protective equipment on the tractor to begin with, and assess the conditions carefully. Then ask yourself if you are personally comfortable with operating the tractor on the slope given your level of experience. Also, if at any time during operation of the tractor, you sense or observe any indications of instability, cease the operation until conditions change or some other approach can be found.
Finally, you mention 5, 25, and 45 degrees as decision points. I definitely would not operate a tractor on a 45 degree slope (one foot of elevation change for every foot of distance traveled). Also remember that slope as a percent, and slope as a ratio can be confusing. Many people talk about slope as percent slope, while others talk about it as degrees as you do. These are very different numbers. For example, the 45 degree slope you mention would be a 100 percent slope. The 5 degree slope you mention would be an 8.7 percent slope. For comparison, the maximum slope you would find on a mountain highway would probably be 10 percent or less, which is about 5.8 degrees. Service roads and fire roads in the forest are commonly 15 percent or less, which would be 8.5 degrees. A 30 degree slope would have a change of elevation of 1 foot in every 1.73 foot of horizontal distance, which would be a steep slope indeed. A change of 1 foot elevation for every 4 feet traveled, or a 25 percent slope would still be a pretty steep slope, but would only be 14 degrees. I have summarized these for you below: You can play around with a yardstick and create some of these "slopes" yourself to get a feel for what they look like, or alternatively, actually measure a few on your own property.
Thus, you can quickly see that even a relatively small degree of slope can be very steep. For the sake of thinking about operating on a slope, it is probably better to think in terms of how much the elevation of the terrain changes with horizontal distance.
There is no magic "safe" slope I can suggest to you. You'll have to weigh all these considerations, then carefully make a decision about when it is safe to use your tractor on a slope.
Willard Downs
Food Science and Engineering Unit
Updated 5/19/08