how high does a fence need to be to prevent European brown bear to climb it?

Question

An entrepreneur is planning a campsite-hotel in Romania, with a full outdoor gourmet restaurant attached, with an outdoor kitchen. There will be no cabins or other living structures, only tents and tepees. This campsite-hotel//restaurant should be attractive to people without much, if any, outdoor experience and allow them to live and eat outdoors without worrying about their safety from European brown bears. Living outdoors will be beyond the comfort level of many of the customers.

European brown bears are a danger in Romania, however docile they may be in other parts of Europe. See this article from Reuters and this article from Romanian Insider.com

I need to enclose an area at least 50 meters by 50 meters (164 feet by 164 feet) or 0.6 acre. For many reasons, I do not consider electric fencing as an option. It needs to be a physical concrete-pole fence. Metal will rust and/or will need to be painted regularly, and wood will be too weak probably. The area contains apple trees, and vegetables will be planted inside the area. There will be at least two enclosed areas, one for sleeping and one for eating. Parts of the fence will be behind bushes, so people will not feel confined, but they will know it is there for their protection.

What height does the fence need to be, and possibly any other parameters? Not sure if spikes at the top would be of any use? Likely the fence will need to be quite strong, with concrete poles smaller distance apart then the size of a bear, so he can't pass between by breaking the weaker material between the poles.

Is this feasible at all, or will bears break through anything, and climb over any fence?

Answers started going in the wrong direction, talking about locking away smelly food. Please focus on answering the question about parameters of the fence, not suggesting other solutions. There will be just too much smelly things inside to lock away: a large outdoor kitchen, restaurant, cafe, full-size freezer, not to mention growing vegetables and keeping chicken for eggs and goats for milk and meat.

To prevent obstructing the view and looking like a prison, I want to construct this as a ha-ha wall but on a slope, here is a cross section (1):

Answer 1

While caging animals is slightly different than keeping animals out, it probably provides the best evidence for specifications. Animal enclosures need to be secure, because animals frequently attempt to escape enclosed spaces. I have never heard of a large animal attempting to break into an enclosed space. Sure, bears try and steal food from cars and sheds etc, but jumping a fence to get to food that is 25 m away seems different.

The standard of care for large animals (including bears) says:

First, the upright members should be:

• at least 1-5/8 inch schedule 40 steel pipe (2-3/8 inch at the corners),
• at least 8 feet high (most of the LTB enclosures are 12 feet high),
• sunk in concrete to a depth of 18 inches, and
• no more than 10 feet apart.

Second, the chain link fencing should be:

• made of at least 9-gauge chain link (large animals are quite capable of destroying fencing weaker than that), including fasteners of the same gauge;
• with schedule 40 steel pipe placed horizontally at 4-foot intervals or where the animals are likely to exert pressure, beginning at ground level (so the fencing cannot be pushed out).

Third, unless the fencing is at least 16 feet high, it should have a chain-link roof with:

• cross-members of schedule 40 pipe, again at 4-foot intervals, or in the shape of a truss.

... Some sort of perimeter fencing is absolutely necessary as a back-up in case an animal escapes its enclosure.

... each perimeter fence should itself be at least 8 feet high, and built to the same standards as the interior fence.

There are some more details methods and alternatives listed in appendix b.

For those of us who use metric sizes, conversions approximately.
Upright members 1-5/8 inch (41 mm) schedule 40 pipe see this page 2-3/8 inch (60mm) at corners.
8 feet (2.44 meter), 12 feet (3.66 meter)
18 inches (460 mm)
Chain link fencing gauche 9 (wire 2.9 mm diameter) See this PDF file.
4 feet, (1.22 meter)
Unless the fence is 16 foot (4.88 meter)high it needs a roof.

Answer 2

When you look at zoos they have like 12-15 feet (4–5 metre) of cement. If you are going to lay that many poles might as well pour a fence but it will not be cheap. You could probably build a small log cabin for less money.

Answer 3

Lacking clear evidence/reports that the Eurasian Brown Bear is actually a problem anywhere I am issuing a frame challenge in suggesting just stop worrying about bears.

• If you want a passive bear-defence mechanism such as a non-electric fence it would need to be built exceptionally sturdy and rather high. This means a high initial investment and probably considerable maintenance costs.
• From my current experience in hiking/trekking/camping in Europe bear safety is not a topic that is often talked about. Even in some areas where the map you linked shows permanent bear populations (e.g. northern Sweden) bear safety is not an issue.

Last but not least, your outdoor-seeking campers might well not like it very much to spend their tranquil camping days behind a massive fence. So unless the area to be fenced off is very large - large enough for the fence to be somewhere out of site (meaning much higher costs!) - the presence of the fence could likely decrease the appeal of your camp ground instead of increasing it. This is especially true if the bear-safety aspect is not something that potential campers are worrying about (which in my experience is not the case in Europe).

If you are absolutely set on a fence, then I think the only viable option is an electric fence, similar to what is used for cattle/horse pastures. These come in different strengths/voltages and I can't tell you which you would need. But I know that electric fences are used regularly and successfully to protect camps in heavy bear areas.¹ Note that an electric fence is a deterrent rather than an impregnable barrier - but they are affordable, can be built (comparatively) low to the ground and the batteries last for months.

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¹: For example this guy spent months and months photographing the biggest species of brown bears on Kodiak island. He used electric fences to protect his camp sites.

Answer 4

Turn your fence into a cage. If you have a 50×50 m² area, surround it by a 4 metre high fence, and fence the roof as well. That's 4×50×4 m² = 800 m² of fencing for the walls and 50×50 m² = 2500 m² for the roof, 3300 m² of bear-proof fence in total.

If that sounds unpractical, rethink your business idea.

Answer 5

This question has changed quite a lot, so I will actually add another answer.

I can see the latest update for the planned Ha Ha wall as a workable idea, it seems to fit all the required parameters of your (updated) question.

However, the necessary height of it will essentially turn your outdoor campsite into a Vauban redoubt:

Here is a source for bear enclosures, including information on dimensions of housing/fencing:

• It mentions a minimum fence or wall height of 4.6m.

It also mentions that the top of a fence must be cantilevered to the inside (well, to the side where the bears are) to prevent bears from climbing over it. I'm assuming this wouldn't be needed if you can make sure that the walls are freshly poured, solid concrete that doesn't allow bears to climb it. The local bear zoo (recently built to modern standards) relies partly on concrete walls without additional climbing protection, see also the photo here (note the wall on the top right - the bears live on the green slope):

http://www.news.ch/Schluss+mit+Kaninchen+im+Grossen+Baerengraben+in+Bern/506841/detail.htm

Alternatively you could either pour a cantilevered concrete wall (probably more complicated and expensive) or add some additional anti-climbing barrier at the top.

Answer 6

Bee keepers in central B.C. will use old school busses as portable bee yards. Each hive base is bolted to the floor, and a tunnel leads outside. They use a solar electric fence charger to charge the skin of the bus. This allows them to either move them from crop to crop in the fruit areas, or follow the fireweed bloom up the mountain in burned areas.

I think your best bet would be two fold: Put up an 8 foot wooden fence, using surplus telephone poles as the posts (here available for 80 cents canadian per foot in 35 foot lengths) and conventionals rails and battens (vertical planks). This is to reassure the campers. Outside the wooden fence run wires at roughly 2 foot intervals, supported on insulators. Make the poles about 2 feet taller than the boards, and run a wire along the top of the posts.

Electric fences are easily shorted to ground. Even a grass stem is sufficient. A string trimmer is a quick way to trim the vegetation back away from the bottom wire.

Before committing to a full version of this, make a smaller one, and test it by putting something that that bears love. (Rotting fish, carrion, honey, shampoo, bacon...) and seeing if the bear is successful at getting inside. There is a risk that the bear associates your site with food and visits frequently, but if you are creating a 'safe haven' spot for campers, you create a spot that is attractive to bears anyway. Bears have large territories. You would need to run this test for months.

Bear response depends on local activity. In parks like Yellowstone, there are no bad consequences for bears that approach humans and their food. They become a nuisance. In regions that are hunted, they are very wary. In true wilderness situations (Canada's north) they are unfamiliar with people, and will challenge you. There you need to convince them that you are a threat. I recently took a trip in Willmore Wilderness. We saw bear tracks daily, but no scat. My dog however reacted to something, and was spooked. We were all eyes for that kilometer. Bears reek. I suspect he caught a whiff of one a km upwind or so.

In passing: the standard bear attack prevention/response was to wear bells and carry red pepper spray. The joke making the rounds was that you could tell grizzly bear scat from brown bear scat by the presence of undigested bells, and a whiff of cayenne...

Answer 7

The existing answers, should be considered. But given that the OP wants to know how high to build a fence.

I know from experience that bears can climb 20 feet (6 meters) without diffuclty in seconds.

I would say the lowest height to be safe is probably around 100 feet (30 meters) but that is just to get the bear bored from climbing. In which case they would probably just dig under it, if they really wanted in.

Said another way: There is NO max height that will keep a bear from climbing over.