Weed Management UpdateBased on recommendations from our lake management partners, we have made changes to how we manage the weed growth that impacts our boat lanes. We outline the strategy and results below and recognize it was a tough summer of weeds on Pine Lake. Weed control challenges stemmed from a few things:
-New EGLE regulations restricting what we can treat
-Late developing Milfoil that pushed back harvesting
-Native weeds were denser and covered more area than many of us have ever seen on the lake. This is the first time we’ve faced the above challenges and recognize the need to improve the process next year. We will be working with Progressive on a plan across the winter. Weed Management Plan Overview
This season was the first season where we faced the EGLE restrictions and we have learned a lot about timing and process that will help this be improved next year. Our focus for weed management is different for invasive weeds than it is for native weeds:
Invasive Weeds
-Milfoil and Curly Leaf pond weeds are the two invasives that we are managing on the lake via treatments with Savin
-Milfoil has prevented harvesting in recent years as it spreads when cut, but it is now significantly more controlled after 4 years of clearing large beds
-We still have new “pop ups” of Milfoil and we can treat spot treat them
Nuisance Natives
-Generally, native weeds are healthy for our lake, and we have many areas of natives that are never treated
-However, when native weeds make up 50% or more of the water column in boat lanes, it creates challenges navigating our lake – hence the term “nuisance natives”
-EGLE closely regulates treating natives and Progressive ensures we follow all rules when treating nuisance natives in our boat lanes
-EGLE has begun restricting the areas where we are allowed to treat. We were able to get a special permit approved in 2024 for some areas of the lake, but the weeds this year are bad outside of these permitted areas Progressive and Savin advise us to use weed harvesting for several reasons:
-Nuisance natives have been a consistent issue in the boat lanes and are particularly bad going into July this year
-Milfoil is now under control (no concern about cutting fragments and spreading the invasive)
-EGLE is limiting our ability to manage boat lanes with application
-Harvesting removes plants from the lake which reduces the phosphorus loading on the lake when those weeds decompose at the end of the season
-Oakland Harvesters was selected not just for price, but also the quality/age of their harvesters to minimize debris as well as technology to report the amount and areas harvested The plan for our summer weed management was to conduct treatment in two steps, one a spot treatment for Milfoil and the next for harvesting nuisance natives approximately three weeks after the milfoil treatment. Unfortunately, we had new Milfoil beds grow late, and we needed to treat those areas prior to harvesting (as harvesting when Milfoil is in the beds will cause the milfoil to spread), which delayed harvesting to late July. Harvesting Results While harvesting was later than planned, we felt that Oakland Harvesters did a nice job on the lake. While we all picked up weeds on our shoreline across the summer from either boats or harvesters, their equipment was much more efficient at cutting and collecting weeds than prior vendors. Oakland Harvesters were on the lake from July 15th through July 25th and they removed 366 cubic yards of weeds (Ai estimates this is between 180,000 to 366,000 pounds removed!). They commented that the number of weeds removed was more than they expected from the acreage they cut, another indication about how dense the weeds were. See image below for the GPS track picture which shows the areas covered by the machines, which was recommended and managed by Progressive. The color references speed, where red is ‘slow’ and green is ‘fast’. Their maximum speed is 3 mph with a strong wind at their back, so the actual speed variations are not drastic and it heavily dependent on wind and waves. Nuisance Native Volume Across the summer, Progressive conducts several biovolume mappings which determine plant density in the lake. Below are biovolume maps that show the difference between weed volumes from June 25th compared to the most recent biovolume from September 5th. The board and Progressive use these maps to assess the lake and determine treatment strategies. In addition, Progressive and several members of the board do visual surveys as well. The Dark Blue color on the map representing 10% or less would indicate very few weeds or low weeds growing in each area where Orange and Red colors indicate dense weeds that are approaching or at the top of the water, taking up 80-100% of the water column. These maps show the aggressive growth that we’ve had across the summer. Summary We will be working with Progressive on a game plan for next summer that will more aggressively address the conditions we faced this summer. We have also received many requests from riparians about treating dock areas. Several of the associations on the lake privately hire Savin to treat their swim and dock areas, leveraging the permits the PLPOA files with EGLE. It may be possible to streamline a process for individual riparians to privately hire and treat their shorelines. Not all riparians have issues with weeds close to shore (see above map), but we recognize that those that do would like a more turn-key solution. Thank You for Contributing to Our Success: A huge factor of the weed treatment success is members stayed off the lake that resulted in calm water and no wave action to move treated areas. Thank you for your help and cooperation! More to come in the spring for next year!
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