Last winter lots of our local reservoirs froze and caused hungry goosander and cormorants to look further afield for food. To make sure a sufficient proportion of your adult fish and juveniles survive the winter - you need some refuges. Many rivers don't have enough emergent marginal vegetation or dead-fallen trees to do the job.

This sort of thing helps immensely:




More here:
Goosander and/or Cormorants eating your adult fish and parr?

Would last 10 seconds in big winter flood on my rivers!
regards
bert

Perhaps - and perhaps not.

Have installed them on the Wharfe at Huby (OK it isn't the Tweed) which gets 15' plus high spate flows pretty frequently.

Still there after a couple of years...


The only thing that will shift them will be another tree or a boulder hitting them (or something that would uproot the anchor structure itself - like a bank washing away).

....Oh......

and I should have mentioned



They put them in rivers that have ice flow down them in North America......

Or EAW, citing it as a possible obstruction were it to be dislodged during a flood. Unfortunately preserving fish stocks tends to play second fiddle to flood prevention in some parts.

As drawn, the spruce tree is like a down stream parachute, and the force of a flood on a few of the rivers i fish would either uproot the anchor post or snap the wire.
Dont get me wrong, sitca or norway spruce placed tip upstream, and pinned to bank is an excellent way of reducing bank erosion on same rivers i frequent, has been done, but the visual as drawn, wont work as cover on the same rivers. I can see however, how it would work on rivers with less aggresive flows in high water.
regards
bert

Ah, ye of little faith. The cable is 12-mm braided steel - you could hang an oil rig off it (for comparison, 10-mm braided steel cable has a breaking strain of over 5,500kg).

Also - if those cr@ppy bits of tubular netting that dodgy geezers use to wrap Xmas trees in in the supermarket carpark can manage to bend the little side branches upwards into a tight funnel; I'm sure the force of a river doing 2 to 3 metres per second would manage it no problem.


Rather than a piddling little Xmas tree; here's a mature (8-m ish tall) tree weighing somewhere around a ton with a full crown of branches being held in dropping spate flows (in the picture there is about 2 and a half feet on normal level, two days earlier it had been over 10 feet of water on and there was a full grown fallen tree washed up about 3 times the size just upstream of the bridge on Station Road on the Goyt at New Mills). It is still there now, 2 years on as Ennio can confirm.



As I say, the Yanks and Canucks put MASSIVE trees in BIG rivers on steel cable and they anchor them using buried "earth anchors" made from boulders and such like and they withstand spate flows that carry chunks of melting/broken off ice down them. Are you saying our cousins across the pond are more able and more confident in their river management/engineering than the Scots?
e.g. here:
http://el.erdc.usace.army.mil/elpubs/pdf/sr13.pdf

Sorry - I don't mean to jump all over your comment just for the sake of it; but I can't have people wondering if I know what the hell I'm talking about in my professional capacity

aint your professional capacity my comment was aimed at.
was capacity of river related to diagrams.
just seen a river rip out 5 foot of reinforced concrete and 4" tubular steel safety barriers at height of flood.
buried on "earth anchors" and tied down with 25mm cable!
river is three times wider than the one with your roped willow, and moves 5 ton boulders at will.
hence my comment that it will work on slower moving rivers, but not some of the faster flowing rivers i fish.
Lets just shoot the goosanders!
regards
bert

Where as our wee brook is more sedate and in times of flood, if it rises more than 4' its topped the banks and over the fields.

So for us smaller streams this kind of things ideal, especialy where the canopies too dense and we can dropp a tree to thin out, or the winters storms recruit some naturally.

We dropped a large hawthorn last week in a rather wide area of water with little cover or variety of current, which had previously been straightened.

Unfortunatly Photo bucket is up the stuff tonight so i can't show the steel rope system i have used. But it is platypus fittings.
Used by tree surgeons and landscapers to anchor mature tress that have been transplanted.
I like these as there is a sturdy fibre sling to go round the tree. or post. My worry is that, especially with augered holes, a tree swinging around in a current is liable to cut in where the rope is stressed into the green wood.
(though I have never seen this happen.... it's a hunch).

photos will follow paul as i get chance to upload them.

Cheers for the debate to and fro guys,

I'd like to sum up my position that, this technique is absolutely suitable for spate rivers (and not just something for benign chalkstreams)

In areas where goosanders are likely to make a significant impact (i.e. where depth, flow and dimensions of channel are low enough for them to hunt with their famous very high efficiency) - you are also likely to be able to successfully install cabled tree "kicker" cover to at least always prevent a total wipeout of local grayling populations for example.

Finally, even on rivers that sometimes rip banks out (and angular concrete is incredibly susceptible to the river working slowly behind/under it and prising it away from the "true" bank) - there will be reaches where it will be possible to anchor them well enough to give you several years' benefit. Co-incidentally, these slightly more sheltered areas would tend to be the most severely predated (because the pace of the current would be more favourable to the birds in those areas).

Now - I'm not saying that these kind of things can be put indiscriminately anywhere on a raging wild Scottish/Alaskan river; but that on balance, there will be spots in every river system where tipping the balance of odds between survival and mortality due to predation by birds (and everything else) will have massive benefits to wild trout, salmon and grayling populations.

In fact, I would go so far as to say that there is not a single river SYSTEM where (if there was a deficiency in the amount of marginal brashy cover - if it ain't broke don't fix it) tree kickers could not be installed at strategic points.

The danger for anyone reading an initial response along the lines of "all very well but wouldn't work on a big, steep river" could go away thinking that this approach is totally irrelevant to their local fishing. Whereas, in fact, it will almost always be possible in the appropriate site, using the appropriate anchoring.

N.B. re willow photo - that is just one that I happen to have where there is a bit of water going down. Coincidentally, the river Wharfe (site of another much larger tree kicker) at Huby is probably 3 x the width of the Goyt at this point (see photos on sheet 11 and sheet 13 out of 24 in this section of the upland rivers habitat manual: http://www.wildtrout.org/images/PDFs...s_section5.pdf
-photos taken during absolute low flow condition and sheet 13 photo shows the width more accurately because it avoids the foreshortening evident on sheet 11 (PS the guy with the white hair is professional yorkshireman Ollie Edwards )

Although, speaking of width actually, once the channel width exceeds the width of the tree kicker sufficiently to prevent "edge effects" of the opposite bank (i.e. friction causing turbulence from the opposite bank that affects the near bank structure) - it doesn't matter at all whether the river is a mile wide; it just depends on the reach mean velocity of water (a function of discharge, cross sectional area, bed slope and hydrological "roughness"). In the classic case, the flow velocity will, of course, be much greater in narrow "pinch points" of the channel.

I take the point that, generally, the larger the width of river, the larger the discharge; but there are a lot of other things that determine the shear velocity experienced by the structure hanging in the water.

Basically, I could have shortened the above essay to "If you have a predation problem, give the WTT a call and we can assess where/if cover can be installed. There will be very few instances where this will prove impossible"



N.B. Edit - I do, of course, accept that in specific reaches where 5-ton boulders are moved on an annual/sub-annual timescale, it will be difficult to find suitable spots!