2008-05-07 P & R Packet - Laserfiche WebLink

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Page 1 of 4 Teresa Bender From: Gregg Thompson [gregg@metroswcd.org] Sent: Monday, April 21, 2008 6:02 PM To: Statz, Mark R Cc: Gregg Thompson Subject: Re: Centerville Lake Mark, 1. Regarding the soil issue - I am proposing that the 91blft. 16" diameter biolog be wrapped in a turf-reinforcement mat (synthetic) that will never go away. I am also recommending that the biolog be planted with specific plugs that do well in biologs (blue flag iris, lake sedge, etc.). The plugs I'm suggesting using in the actual soil backfill area (lake sedge - strongly rhizomatous), and redosier dogwood live-staking, have a track-record of establishing quickly. Although the biolog fiber should break down in about 6-8 years, the TRM & root systems should be there for many years into the future. The biologs that were put into Centerville Lake last year were shredded from being too low -I believe that setting them (and achoring them) on the mini-gabion, sitting a little higher, will extend the life of the biologs to what we are seeing typically for a life-span, while the plantings in and behind them get established. 2. Regarding the live-staking, it is not too late to harvest those, although if they are cut and then stored for too long, they will dry out and die. One of the best ways to do live-staking, is to harvest them on the same day (or day before) they are going to be staked. With the dogwoods, especially, their lower 2/3 of the stems should be soaked in water before placing as live-stakes (softens the bark skin and gives a higher chance of sending out roots). Also, the stakes should not be "pounded in" - a pilot hole should be made first (with a diameter of similar size), then put in the live-stake. Pounding them in can strip the bark off, as its going into the soil (depending on soil- compaction level, soil-type, rock presence, etc.). Dogwoods have an approximate 60% chance of survival as live- stakes (willow are around 90%), so any advantages you can give them will be useful in giving them a good chance. Also, I do not suggest lopping off the top of the dogwood live-stakes (adds another end that can dry out and die) - I suggest leaving on the branch tips, but clipping off the side-branches so it can slide into the pilot hole with minimum air-pockets. Also, the live-stakes need to extend down to the water table to access consistent moisture that helps them sprout roots - no soil-moisture, no sustainable re-sprouting. The stake length needed will be dependent on the depth from the soil-surface to the water-table. Live-staking (and harvesting) of dogwood in mid-July can be done, but great care is needed with the dogwood cut-ends, to keep them from drying out and giving them a 12-hour soaking before placement, if the bottom 2/3 of the live-stake isn't going to be sitting in consistently moist soils. Regarding live-staking of shrubs at Centerville Lake, although I wouldn't suggest willows (sometimes people freakout at the mention of willows), I do think that much of that site would benefit from the reintroduction of the great soil-holding root capacity of redosier dogwood. Herbaceous roots can only do so much on steep lakeshore areas - a matrix of root-types (both herbaceous, shrubs and trees) has the greatest chance of being a sustainable stabilization method. Shrub clearing is often what ultimately gets steeper lakeshore banks into a whole lotta trouble. There is another shrub that would work (False Indigo - Amorhpa fruticosa) but it doesn't work as live- staking - and one can now only get it as bare-root (seasonal availability) and potted. I bought some through a bare-root sale at the Anoka Conservation District, for planting at the lake I live on, but I could donate 25 of them to Centerville's project if you were interested. otherwise, I could push the parks folks a little harder on the need for at least some redosier dogwood. Hope this is helpful. If you guys aren't comfortable with my toe proposal, I would be open to some more discussion and possible revision, but I feel quite comfortable with it. 4/28/2008