Because the beaver isn't just an animal; it's an ecosystem!

Tag: Beavers chew trees


This has been a very BEAVERY week in the news. Yesterday the Gazette chimed in.

 At Home With Vivian: Vintage Beavers do Shakespeare

Yay for the Beaver Festival! The annual festival will feature live music, children’s activities, beaver tours and more than 40 ecological booths. Beavers in down town Martinez? Of course. Martinez has something for everyone.

 According to my friend Wikipedia, “Now protected, the beaver have transformed Alhambra Creek from a trickle into multiple dams and beaver ponds, which in turn, led to the return of steelhead and North American river otter in 2008 and mink in 2009. The Martinez beavers probably originated from the Sacramento-San Joaquin River Delta which once held the largest concentration of beaver in North America.”

Jeff and I enjoyed the Beaver Festival last year. There were lots of wildlife informational booths, many activities for children, and guided tours of the beaver habitat. It was a joyful place to be.

 So do something out of the ordinary. Come to the 8th annual Beaver Festival on Saturday, Aug. 1, 11 a.m. to 4 p.m., at Beaver Park (corner of Marina Vista and Castro streets). First 150 children attending will be able to collect 19 wildlife pins designed by Oakland artist Mark Poulin. The charms were purchased with a grant from the CCC Wildlife Commission. According to the Worth a Dam website (MartinezBeavers.org) “The activity will highlight the new wildlife seen in Alhambra Creek since the beavers arrived, and emphasize their role as a Keystone Species.”

To be honest, nothing makes me happier than when folks use Wikipedia to write about our beavers. Since our great friend Rickipedia is the one who wrote it, and he tells the story the exact same way I would. It’s a long column about cool things to do in Martinez and of course the peddler’s fair gets top billing, but never mind. It’s been a GRAND media week.

This morning I got an inquiry from the Martinez Tribune. Tribune? Apparently they saw a beaver near a wooden palate at Ward Street and wonder if we gave it to them to eat. (!) (Obviously they’re going to be another prescient media source in the metropolis.)  Here’s the Tribune’s fun photo which is on their Facebook page this morning.

palateFinally a big article in the National Wildlife Federation this week about the science involved in beaver chewing trees. This has caused a little debate in the beaver world and I was waiting until there were clearer answers from the author. But in the meantime, you might as well enjoy the icing on the cake of a beaverly week.

 Beavers: Masters of Downfall

Beavers-AS15-1.ashxHow do beavers fell trees in a preferred direction? A 10-year study reveals the answer.

For the past 10 years, I have come here every summer with my research team from the University of Arizona to study the beaver’s most iconic yet poorly understood behavior: tree felling. Studies have shown that more than 70 percent of all large felled trees crash in the direction of the water where a beaver’s lodge is located, which is to the animal’s advantage. But the question I hoped to answer was: How do beavers make the complex calculations required for such accuracy? After a decade of study, hundreds of tree measurements and thousands of hours of direct observations and camera recordings, we now know the answer.

In beavers’ work, just as in human logging, the directionality of a tree fall is produced by the “hinge”—uneven cuts on opposite sides of the trunk. A tree with a cut on just one side, no matter how wide, can collapse in any direction. But an additional small cut on the opposite side will make the fall strongly directional, with the direction depending on whether the second cut is above or below the initial cut. If it’s above the first cut, the tree will fall in the direction of the initial cut; if below, the tree will fall the opposite way.

 Making that second cut uneven in height to produce the hinge depends on changes in the beaver’s posture (sitting or standing) and the slope on which the tree is growing. On a tree that grows uphill from the water, for example, if a beaver starts cutting on the uphill side then simply circles the tree without changing its posture, it will produce a second cut below the first one—and a directional fall of the tree towards the water. Likewise, if the beaver starts its work on the downhill side of the tree and maintains its posture as it circles the tree, the tree will also fall toward the water.

We discovered that nearly all large trees in the area, especially those farther from water, had circular cuts of uneven heights and depths or directional hinges. In flat areas, beavers typically started their work on the side closest to water, gradually widening the cut over consecutive nights. Notably, as they circled the tree, they would rise on their hind legs, producing a second cut on the opposite side that was higher than the initial one. In just a few days, such trees would crash directly towards the water.

So beavers use directional cutting like loggers. Which surprises us not at all. But sparked a debate on whether trees fall towards the water naturally because they lean towards the open light. It seems to me that some trees don’t lean at all, and the research takes that into account in noting that they had directional cutting. Also that trees on the slope did NOT have it,  because they didn’t need it to fall towards the water. It’s an interesting article, you should go read the whole thing.

And if you want to JOIN the National Wildlife Federation and maybe sign up for a subscription to Ranger Rick, you can do that tomorrow because Beth Pratt of the California chapter will be exhibiting there.

You’re coming tomorrow, right?

Martinez Beaver Festival promo 2015 from Tensegrity Productions on Vimeo.

Join us Saturday, August 1st, 2015 for the 8th annual Martinez Beaver Festival!


Press Photo by Betsy Simon Dickinson resident Bradley Robertson surveys a tree in Jaycee Park on Friday, where beavers are blamed for damage to some of the trees.

“I was walking along the river two weeks ago when I noticed the trees and reported it to the person at the front desk at parks and recreation,” said Dickinson resident Bradley Robertson. “They said someone else had called before and that fencing would go up, but fencing isn’t going to be enough. They need to trap the beavers and set them loose somewhere else.

Clearly one of the limiting factors of maintaining a beaver website is plot variation. There isn’t any. Beavers build dams and cities get upset. Let’s call that Example A. Beavers block culverts and cities get upset. Let’s call that Example B. Beavers Chew trees and cities get upset.

Let’s call that example ‘C – for CHEW.

Residents and users of the area along Heart River near Jaycee Park are concerned that beavers may chew down all of the park’s trees if the Dickinson Parks and Recreation doesn’t step in.

“There’s not much I can do about it. They won’t let me shoot in the city limits,” he said. “And that it’s not my responsibility anyway. It’s the park board’s responsibility.”

“I’ve reported it to our staff operation manager, who will check it out and wrap with chain link, and we’ll contact the city forester to see if they will be salvageable,” he said.

Chain link? To give it that prison-yard look? I don’t suppose you’ll leave any space for the tree to grow? With their chain link tourniquets those trees should all be dead in NO time!

Maybe I should keep form letters for the three predictable solutions. I’ve been writing them all individually but why bother? They all require exactly the same advice. Get that man who wants to help but can’t “use his gun in the city” and put a paintbrush in his hand. Take some latex paint that matches the color of the bark and toss in some mason sand – (about 5 oz per quart of paint). Stir it up right before painting about three feet up the trunk on all sides. Voila! The gritty texture will discourage chewing and your trees will be safe. You’ll need to repeat it in about two years but visually it will look much less ‘penal’ than chain link.

If the trees are not salvageable, Kramer said they would be taken down but didn’t know how soon the issue would be resolved.  He said it has been two or three years since a trapper was called to the area around Jaycee’s Park and the baseball field.

“The thing is we can’t chain link or wire mesh around every tree,” he said. “Obviously, one of these trees is probably past the point of being salvageable, but we have some years where we go without any issues. It’s not like it is a problem we see coming. Typically, we don’t see activity until after the damage is done.”

Sigh. Example C – corollary 1. Don’t rush to take the trees out that the beavers cut down. The roots will still prevent erosion for a good long time – and depending on the species they’ll provide energy for the tree to recover its ‘root/shoot ratio’ by stimulating a natural coppicing effect when shoots grow back. Maybe you could put a little park sign to explain it to visitors. I know you’re in North Dakota but look what your next door neighbor is teaching today in Montana:

Home / News / Montana & Regional / Montana & Regional Montana tribes hold annual honoring of Flathead River Story Discussion Video Image (3) By VINCE DEVLIN of the Missoulian | Posted: Tuesday, May 8, 2012 9:30 pm | No Comments Posted Font Size: Default font size Larger font size buy this photo TOM BAUER/Missoulian Tim Ryan explains to fifth-graders from Ronan Middle School how a fish trap was made and used at the Confederated Salish and Kootenai Tribes’ annual River Honoring on Tuesday. The event brings hundreds of fourth- and fifth-graders to the lower Flathead River for two days of education.

When beavers take down willow trees to construct their dams and lodges, Ryan said, what is left eventually sprouts the fairly thin shoots that are the perfect material for fish traps.

Longer shoots were used to make the cone-like enclosure, while short ones were shaved into sharp points on one end and bound to the opening at an angle. Fish could enter unscathed, but would run into the sharp points if they tried to exit.

“Every time I do one, I thank the beaver for helping make my ribs for the fish trap,” Ryan said.

Well, I’m glad we had this little chat. Just remember example C – corollary 2: beaver chewed trees create ideal nesting habitat for migratory and songbirds. You like those things, right?

That’s why Kramer looks to users of and residents around the city’s parks to be additional eyes and ears for him and his staff.

Fair enough. Can we be the brains too?

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