Our current inventory showed us having 9,500 acres located on 208 stands of non-merchantable aspen and paper birch cover type. We had photography flown for storm damage in the St. Croix State Forest the fall of 2011. Using the newly flown aerial photography, we were able to pare down stands to be surveyed to 38 stands for 2,000 acres that needed to be checked for damage.
In setting up the site prep project, we used a helicopter to aerially survey approximately 2,000 acres on 38 stands for storm damage. Initially the stands were assigned in blocks individually to be field checked on the ground, which we were finding we didn’t have the time or resources to complete.
After the stands were aerial surveyed, we came back to the office, and made a determination based on a percentage of the stand that was damaged, whether the stand would be treated by roller chopping or not. We combined the damage stands into geographically local project working groups for contract. We had 10 projects covering 22 stands for 1,000 acres planned to be roller chopped.
The treatment occurred over three winters. The first winter, we did a trial test of a 100 acres on 5 stands, as there wasn’t enough funding to cover the 1,000 acres that were set up. We had ideal frozen ground conditions (winter of 2012-13). We treated the first tracts in February of 2012. This provided us an idea of what the equipment and operators abilities were to treat the damaged stands.
The following winter 2013-2014, we had heavy snow, but no frost in the ground. A contract was bid out for the next 900 acres. We were unable to see the treatment performed due to the lack of frost in the ground. We had the contract extended for one more year due to adverse weather conditions.
The winter of 2014-2015 found ideal conditions to treat these stands, and we began operations in mid-January. We ended up ground-truthing the stands as the contract got under way. This should have been done earlier in the process, prior to setting up the contract. There were areas of regen that were damaged, but untreatable due to the amount of merchantable timber which had fallen impacting, this and some topography issues as well. We ended up treating 13 stands for 353 acres.
The timing of using the roller chopper on frozen ground with little snow cover was effective. The roller typically is used to inhibit aspen regeneration when used in the spring and summer. The use of a roller chopper was found to be an effective method to regenerate aspen when used in the winter on frozen ground.
Funding, suitable weather conditions, experience, timing, all play a part of the whether the contract will be successful or not.