Budworm in Maine: ‘Intensifying and expanding’
As the spruce budworm strategy comes into focus, so will the results of this year’s monitoring of the population. The SBW task teams have completed their reports, which have been assembled into a draft by Dr. Robert Wagner of the University of Maine, who is director of the Center for Research on Sustainable Forests (CRSF) and Cooperative Forestry Research Unit (CFRU). The effort to develop risk assessment and response strategies is led by Wagner; Doug Denico, Maine state forester, and Patrick Strauch, MFPC executive director.
State Entomologist Dave Struble gave a preliminary report on this year’s budworm trapping at the annual meeting based on a quick survey of results from about 20 of the 80 sites where pheremone traps had been place in previous years. This year, the number of areas where pheromone traps were placed increased from about 80 sites in 2013 to about 400 in 2014, with three traps at each site. There still is no defoliation in either Maine or in New Brunswick, Struble said. Nor their been any flights of budworm moths from the infested areas in Quebec.
“As near as we know, we’re seeing just an upwelling of the native population,” Struble said. “I haven’t heard that they saw it either up in the Gaspe or in New Brunswick either. So this cold wet summer may have kind of depressed the moth activity or something did.”
Analysis of the trapping results is ongoing and the trend he outlined at the meeting has continued. This week Struble emailed an update, which is included in its entirety below.
“Preliminary Spruce Budworm Report
With results in and counted from 35 of the previously measured sites, populations on average are up approximately two-fold from 2013. Highest catches at Cross Lake, 11R14 and Big Twenty ( 211, 162 and 115, respectively). Overall average on the trend plots went from 19.2 to 33.7.
Although the average increase is less than seen last year, it is consistent with a general intensifying and expanding regional infestation. Catches in the northern tier are significantly heavier than further south (but we haven’t yet mapped the results). The population increase appears to be an the result of- of native populations (vs in-flights from the current Quebec outbreak).
We have logged in (but not yet analyzed) 245 samples from 16 of 21 cooperators. Cursory review of these samples suggests similar numbers to that seen in the 35 long-term trend plots. (above).
More samples are in hand but not yet been logged in, and some of the 16 cooperators have sent only some of their sites.
And there are 5 cooperators who have not yet sent in any samples.
Overall it appears that the cooperative monitoring effort is a success.”
Meanwhile, the SBW task teams are reviewing the draft now and making comments or suggestions. In November, the report will be presented to Keeping Maine’s Forests, a coalition of large forest landowners, forest-dependent businesses, recreation interests, Maine tribes, education and advocacy groups, land conservation and wildlife interests, and government agencies. Presentations also will be made to other groups, Strauch said, “So there won’t be any major surprises as we head to the Legislature with some changes that are needed.
“Bob Wagner’s theory is that Maine’s forestry policy is set by the biology of the spruce budworm,” Strauch said. “The last outbreak in the 1970s led to the Forest Practices Act and then three statewide referendums on clearcutting. This time we’re trying to break that cycle and raise awareness before the infestatation.”
Wagner, who could not be present because he was teaching classes, prepared an overview of SBW draft report, which was presented by Strauch.
Two recent studies ( Hennigar et al. 2013 – CFRU and Legaard et al. 2013 – NSRC) have concluded that Maine could see an annual reduction of 15 percent to 30 percent reduction in spruce-fir volume or biomass in a moderate to severe SBW outbreak and that the recovery would take about 40 years.
“The good news is that nearly all the spruce-fir volume losses can be prevented by using all of these techniques at once,” Strauch said. “You just have to decide if that makes sense to you. We’ve coined this term adaptive harvesting, which is really reducing the high-risk stands ahead of the outbreak. Knowing where the susceptible stands are and working in them to remove the species is what was modeled.
“Foliage protection is spraying, high-risk and valuable stands,” Strauch said. “The models show that if you’re going to use this strategy, only 20 percent of the area affected needs to be treated in order to kind of match the loss in inventory. And then salvage logging, is, of course, capturing that mortality.
“Here’s how the models played out. As you add adaptive harvesting with planning and spraying, you get another bump in saving the inventory or matching that inventory. Theoretically, you can bump the line back up over the top. If you do nothing, you’re going to lose somewhere around 500,000 cords per year and you can begin to use the various scenarios to affect that loss going forward.
“Another factor to consider is that in the 1970-80s outbreak, spraying cost about $5 an acre.,” Strauch said. “Now for two applications – this is all published information in Quebec – we are looking at closer to $45 a acre. So there’s a financial change that’s taken place on the landscape as well.”
Strauch also noted other changes since the 1970s outbreak ended in the mid 1980s.
“Certainly there’s less of a spruce fir forest, there’s a younger forest, the connection to the mills is different, a better road system, better forest management technology etc.,” Strauch said. The days of the B52s going across the horizon spraying everybody’s land and the landowner paying half and the government paying the other half, are just not there anymore. There is a more sensitive political environment and less entomology expertise. So the challenges during the coming outbreak will be different.”
Strauch said he is hopeful that the budworm effort under way now will help Maine be better prepared for the infestation that is coming.
“We’ve actually got a great success story here in that the landowners have stepped up and are working with the Maine Forest Service,” he said. “I think we’ve got a trap in every township in the affected area, so that’s been an indication of the kind of collaboration I think we can expect going forward.”