Pine species have been naturalizing on East Maui for decades primarily via historical pine plantings at Haleakalā National Park and Kula Forest Reserve. A wildfire stimulated an accelerated invasion into the subalpine and alpine zones, causing concern among the three major conservation landowners: Haleakalā National Park, The Nature Conservancy, and The Department of Land and Natural Resources (DLNR). Two prominent species have spread more rapidly than most pines: Pinus radiata (Monterey pine), and Pinus patula (Mexican weeping pine). They now pose an extreme threat to Haleakalā’s subalpine habitat, which is recovering following the removal of ungulates.
Landowners and stakeholders have tried various methods to control pines for the past 20 years. The need to coordinate and combine the knowledge of fellow conservation landowners arose from this extensive spread into otherwise native dominant shrublands. The Maui Pine Working Group was formed in 2014 encompassing several state, non-profit and federal agencies in an effort to combine our knowledge and resources. By working and learning together, we will effectively increase our capacity to combat this threat into the future all while strengthening our conservation partnerships.
• 2-day event
• 12 agencies
• 115-person days
• 300 acres swept
• 1200 individuals treated
Historically, the Hosmer Grove plantation and the approximate 700 acre Lennox Plantation have allowed a constant dispersal of pine seed toward Haleakalā National Park due to the prevailing northeasterly tradewind direction. These two plantations have been the main seed source contributing to control efforts on the northern slope of Haleakalā for decades until the 2007 fire event.
The wildfire in the Polipoli area of Maui caused a dramatic seed-rain event dispersing over high elevation sites on the north and south slopes of Haleakalā and likely caused the increase of pine sightings outside of their normal ranges. Of the various species of pines found on Maui, Montery pine (Pinus radiata) has serotinous cones that release wind dipersed seeds following fire events and has been the dominant species found on the slopes of Haleakalā post fire event.
The threats to Haleakalā’s montane ecosystem due to the pine invasion are imminent if control efforts were to cease. The threat to native biodiversity comes through unfavorable changes in soil chemistry, displacement of native plants, interruption of food chains depended on by native birds and arthropods, and most severely, the potential of wildfires starting at Haleakalā’s high elevation subalpine sites and burning out of control down the mountain.
The Maui Pine Working Group was formed in response to this impending threat with the definitive goal of protecting Maui’s montane ecosystems. The aims of the working group include:
• Proposing how organizations will integrate management strategies in the short, medium and long term
• Encouraging and enabling members to work collaboratively to optimize their respective capabilities to minimize impacts
• Sharing of scientific and technical expertise of the parties related to pine management
• Developing a timeline showing the progress of management strategies and techniques
• Identifying opportunities and risks regarding a collaborative approach
• Identifying and aligning resources when possible
• Control efforts have been ongoing at Haleakalā National Park and The Nature Conservancy’s Waikamoi Preserve since the early 1990's with a focus on ground control efforts.
• With the influx of pines invading in more remote areas organizations have improved their control strategies to incorporate aerial applications. This method has significantly increased the treatment area and has allowed management teams to successfully target outliers and move toward the core plantations in a more focused approach to control.
• Over 20,000 acres have been treated by working group agencies to date.
• Data Collection - Both ground and via air
○ Need to standardize reporting data
• Funding - Long term funding necessary
• Retreatment intervals
○ Size classes
• Treatment methods
○ More research and trials needed
• Innovative Technologies – Spray rig with increased capacity and nozzle that allows for broader application.
• Recruit other stakeholders who are not currently involved in working group