Even after the timely discussion of "green lie" this week, I am still unsure of the best method to eliminate grassy vegetation around the pine, cedar and oak seedlings we are putting in this spring. I feel this is very important because we lost a whole planting to voles in 2013.
• Parameters: about 50 pine/cedar/oak seedlings
• Setting: 18 acres of what will be grazed pasture with borders of trees at the margins.
• Location: Monroe County NY --- moist to wet loam with heavy deer pressure
2013 all trees wiped out by voles --- had heavy snow and the critters ate thru the plastic tubes and maybe deer helped by knocking stakes over. When the snow melted there was nothing left of the seedlings. They were planted into grassy pasture with no clearing around.
2014 all seedlings survived (20 oaks) they were protected by 1/4" hardware cloth sleeves, 2' staked and had a plastic tube over them with wood pallets for protection (we went crazy on this, it was time consuming and costly to make the hardware cloth sleeves)
2015 so far: 50 pine seedlings staked (not sure what protection we will give them over the winter we feel we need to keep the area around the seedlings clear of grassy vegetation because of the voles and other rodents.)
A family member does not want to use chemical sprays. I suggested a propane heat gun but he seemed to think this was going to be costly. He also seems to think we were just unlucky that first year and we need not clear the grass from around the trees. Using a shovel seems to me to be very time consuming and something that will just not be done. What would you use? Joanne
"What would you use?"
I would use the family member that does not want to use chemical sprays to do all the work! : )
It looks like the hardware cloth and pallets helped protect the seedlings. And, to help reduce the grassy vegetation around the seedlings you could define a 5' diameter circle around the seedlings, clear that area, perhaps lay down some ground cloth and top with a mulch. Then add......hardware cloth and pallets....
Now why did I not think of that! I will get my magic wand out and make it so.
Seriously though, I read that weed mat does not discourage, and may even encourage ground critters like voles to take cover under them. To be fair, we did not have the depth of snow in 2015 winter as we did in 2014.
I do think the pallets provided shelter from the deer. The pallets may have spooked them -- no tracks in the area.
In another area where we used 3' unenergized portable fence there were tracks
Looking up a propane torch, I find that this will require repeated treatments. That means that I will have to skulk about with it several times to get this done.
What chemicals are recommended for this purpose? We are talking about 100 new plantings overall.
Mechanical (AKA organic) treatments can be effective but sometimes at the cost of labor, time and repeated entry. As Dean notes, some people who favor organic treatments often re-assess their perspective when they get involved in the effort.
I too have heard that the weed mats can provide cover for rodents. I suspect they have utility when you have a tree tube that is buried an inch or so into the soil. Rodents won't chew through 0.25 inch hardware cloth, but that doesn't offer the greenhouse advantage of the tree tubes. Tree tubes, if you go with herbicides, also protect the seedlings from overspray.
Flame weeding might be an option. The seedlings will be very sensitive to heat, so perhaps flame a 3 ft diameter patch at each planting site before planting. You can plant immediately. If you have already planted, you might find a double or triple walled wood stove chimney pipe you could use to insulate the seedling while you flame. After flame (or another mechanical sterilization technique), use 3 to 4 inches of sawdust. Sawdust offers weed protection because of high C:N ratio and helps retain moisture. Don't incorporate the sawdust into the soil as it will bind N and slow tree growth.
If you want to go the herbicide route, use a glyphosate based product such as Accord XRT II or Round-up. I treated about 150 seedlings last week and used about 600 ml of 52% concentrate in 6 gallons of water (just to give you some rough numbers). This was about a 4% active ingredient concentration (I don't recall the exact concentration of the mixture). A different starting concentration would have a different mixing ratio. i have a column in the latest issue of NY Forest Owner on mixing ratios. www.nyfoa.org and that I'll post to www.ForestConnect.info in a couple weeks.
The seedlings I treated are part of a reforestation experiment. The competing grasses are sprayed twice a year (takes about three hours per treatment). The grass between the rows is mowed 3x/summer to limit the suitability of the habitat for rodents and make them easier targets for predators. Thus we use a combination of organic (mowing) and chemical (foliar spray at each seedling) to control herbaceous weeds. As you noted the weeds both compete with the seedlings and provide habitat for rodents.
If this is your only use of glyphosate, you could find a likely find a quart or two at a local farm/garden store and mix according to the details on the label. If you want to use for other projects, you could get 2.5 gallons of concentrate, for about the cost of a couple quarts, via www.arborchem.com and if you're a NYFOA member i believe you get the contractor's price.
There is good information on site preparation and planting in our bulletin on Northeast Tree Planting and Reforestation here.
Thanks Peter, That's everything I wanted to know. Joanne
...some people who favor organic treatments often re-assess their perspective when they get involved in the effort.
That's exactly what happened!
Joanne: there is a product you can get called "Avenger Weed Killer". It does kill weeds and grass. The active ingredient is d-limonene 70% which is extracted from citrus fruit such as oranges, lemons, and limes. It comes as a RTU product and in various sizes of concentrates such as 1/2 gallon, one gallon, and 2.5 gallon packages. Its about $25 for the 1/2 gallon and $55 for the gallon size. You should be able to see results after a couple of hours and it is ORMI listed.
You may have to use sprays to keep the deer away too especially if you don't want to make hardware cloth sleeves and pallets. Repellants based on putrescent egg solids seem to do the best.
The voles you have seem like they are mutants from a horror film! Eating plastic? Sesh!