2024 Forest Ecosystem Monitoring Cooperative Conference

Authors: Joshua Syverson, Saint Michael's College

The species area relation has often been referred to as ecology's one true law. As area of habitat, island, or simply area of habitat sampled increases, ecologists commonly find that the number of species also increases. This relationship has been demonstrated, for example, with birds in the Galapagos, mammals in National Parks, the herptofauna of the West Indies, and beetles in reserves in Italy. Explanations of the pattern include the habitat diversity hypothesis, increased resistance to disturbance in larger areas, and increased probability of detecting species with larger sample sizes. The pattern has implications for ecological reserve design and the design of appropriate community sampling protocols. Despite the ubiquitous nature of the pattern, it has rarely been tested using freshwater macroinvertebrates. We sampled macroinvertebrates from a series of sixteen cobbles and small boulders collected from Lake Champlain in Vermont at Oakledge Park. We scrubbed the surface of each substrate thoroughly in basins of lake water before sieving the macroinvertebrates for preservation and subsequent identification. We then measured the surface area and thickness of each substrate to rank them from smallest to largest. We detected a strong trend of increasing total abundance of macroinvertebrates as substrate size increased. The response of macroinvertebrate species richness to area was less strong but did trend toward more species on larger substrates. We will use rarefaction of the community samples to separate mathematical sampling bias from other potential impacts on species diversity. Loose substrates in wave-washed rocky shore lines offer a promising system for biodiversity studies because increased water flow creates somewhat river-like conditions allowing for the occurrence of several typically lotic species in addition to the expected lentic species. Our results represent an expansion of species area studies using lake macroinvertebrates.

Authors: Jay Wason, University of Maine
Shawn Fraver, University of Maine
Colby Bosley-Smith, University of Maine
Rachel Poppe, University of Maine
Kathryn Miller, National Park Service

Climate change will have impacts on forested ecosystems worldwide, with increasing severity and frequency of extreme climate events causing unprecedented stress to many tree species. Despite evidence for a rapidly changing climate, there is still a need for research on how the physiology and growth of vulnerable tree species such as red spruce (Picea rubens) will be impacted. Red spruce is an important species economically, ecologically, and culturally in the northeast region of North America, making it crucial to make better predictions for how spruce forests will be impacted by extreme climate conditions. In addition, spruce forests along the coast of Maine are existing in coastal climate refugia south of their typical range, and it is unclear if the coast will continue to be a refugium as ocean temperatures continue to rise. The goal of this study is to determine how red spruce growth and water status responds to climate extremes in both inland and coastal climate conditions across Maine. To determine the physiology underpinning growth responses to climate in mature red spruce, we deployed automated point dendrometers on 100 canopy spruce trees across 10 coastal and inland sites representing a broad range of climatic conditions. With these data we tested: (i) the climate conditions that lead to tree water stress through measurements of daily stem shrinkage and tree hydraulics to better understand the mechanisms that lead to drought stress and (ii) the daily weather conditions correlated with daily radial growth. Our results indicate that red spruce daily growth is strongly driven by climate, in particular atmospheric and soil moisture. Importantly, our work shows that prolonged periods of dry soil and high vapor pressure deficit lead to periods of shrinkage that may become more common in the future. These results provide managers with a finer scale understanding of tree growth responses to climate that can be used to identify locations and climate factors that govern growth and the physiological processes that underpin them.

Authors: Jordon Tourville, AMC
Georgia Murray, AMC
Sarah Nelson, AMC

The northeastern United States is experiencing some of the greatest shifts in climate in the US, with warming winters, increased frequency of extreme precipitation events, and severe droughts. For instance, annual mean temperatures across the northeast have risen ~1.7 ?F since the 1930s. Currently, we are lacking adequate information to connect potential montane tree growth and productivity trends across the broader context of the Northern Appalachian region, which is critical to understand adaptation under future climate scenarios. Broad-scale study of tree growth is limited in feasibility due to the cost-restrictive band dendrometer instruments (devices that measure the radial, or outward growth of tree stems) required to reliably measure these characteristics. In this project, we captured variation in tree radial growth as measured by traditional and low-cost dendrometers across climate and edaphic gradients linked to elevation, and between different age classes of trees and tree species within Tuckerman's Ravine (White Mountain National Forest) in New Hampshire. Our project provided valuable comparative data for the performance of traditional band and point dendrometers, priced at approximately $400 (Ecomatik, Germany), to the performance of low-cost point dendrometers, priced at approximately $100 (TOMST, Czechia), to determine the accuracy of low-cost dendrometers for the study of tree growth dynamics. Overall, we find that, in addition to better ease-of-access, simpler installation and maintenance, and better durability, our low-cost dendrometers have comparable measurement accuracy to more expensive traditional band dendrometers. This study will expand our understanding of the viability of using low-cost dendrometers to measure tree response to climate warming in environments across the northeastern US. Additionally, we anticipate that our work will lay the foundation to establish a robust monitoring network to aid in gathering data to understand the effects of a warming climate as well as make inferences about the future character and health of tree species in the northeastern region.

Authors: Paige Cormier, University of Maine School of Forest Resources
Melissa Cullina, Coastal Maine Botanical Gardens Plant Science and Collections
Bryan Peterson, University of Maine School of Food and Agriculture
Jay Wason, University of Maine School of Forest Resources

Climate change threatens the continued presence of forest trees in their historical ranges which may lead to shifts in species composition. In the northeastern United States, seasonally high temperatures combined with altered precipitation regimes are already impacting forests. However, we have a limited understanding of how these stressors impact the growth and survival of first-year seedlings, which are generally thought to be the most climate-sensitive life stage of trees. Without a better understanding of how first-year seedlings respond to these changes, we cannot predict how forest compositions may change with continued climate warming. In this study, we tested how extreme temperature and drought conditions reduce growth and survival of first-year seedlings. We exposed over 700 containerized seedlings of eight northeastern tree species to three temperature and three precipitation treatments (and their interactions) for three months. We measured the height, vigor, and survival of all seedlings and compared them to species-level drought tolerance traits. Overall, compared to the warming treatments, we found stronger effects of the drought treatments on growth and survival of most seedlings. However, in some cases, the effect of drought was worsened when combined with heat. Generally, angiosperms grew more quickly and had larger leaf areas than gymnosperms, causing them to use available water more quickly during droughts. These results suggest that forest managers planning for increased heat and drought impacts should carefully consider how management actions impact risk to first-year seedlings by limiting exposure or targeting less vulnerable species.

Authors: Radka Wildova, Ecological Research Institute

Lingering ash are chemically untreated mature trees that retain healthy crowns through peak EAB invasion. They are not trees that merely survive peak invasion nor are they trees that reached maturity after peak infestation onset (ingrowth). Lingering ash have been found for all three widespread Northeastern species: white (Fraxinus americana), green (F. pennsylvanica), and black (F. nigra). Although lingering ash display some resistance, it often is not complete, meaning that even these trees will likely eventually decline. Thus, lingering ash must be found once ash mortality is high enough to reveal them, but not too long after.

Lingering ash can play important roles in ash conservation. One is providing scion for resistance breeding. The USFS EAB Resistance Breeding Project has shown that for green ash, scion (twigs) collected from lingering trees can be grafted to yield replicates used for selective breeding, yielding highly resistant trees. In the Northeast, for all three species, scion have already been collected in New York from lingering ash detected by the Monitoring and Managing Ash (MaMA) program and used to create clone banks at Cornell, which can be used for selective (within-species) breeding. As the area long-invaded by EAB increases, so too will opportunities to find lingering ash.

Seed collection can also benefit from lingering ash detection. In contrast to untargeted seed collection (especially in areas not yet at high mortality), to the extent that resistance is heritable, seed collection targeting lingering ash can in some circumstances take advantage of the natural selection that sets them apart from more susceptible trees. However, the resistance of seedlings produced by even targeted seed collection will likely be lower than those produced in a seed orchard of confirmed resistant parents.

Lingering ash detection needs to be incorporated into ash management. One way to enable detection is to monitor EAB-induced mortality (through plot establishment or Rapid Ash Mortality Assessments) to determine when it is high enough to reveal lingering ash. Also, aside from designating some trees for mortality monitoring, enough healthy trees should be left untreated and uncut for there to be a reasonable likelihood of detecting some as lingering ash.

If lingering ash are found, they should be reported through the MaMA Lingering Ash Search project and protected from cutting, at least until scion are collected from them. Additionally, because their resistance typically is partial, once they are reported and validated, they can be chemically treated to prolong their health. Finally, resistance breeding complements other tools. For example, increasing resistance through breeding and reducing pest pressure via biocontrol can combine to reduce EAB's impacts.

For more information on MaMA, please see the poster "Monitoring and Managing Ash (MaMA): a program that enables lingering (resilient) ash detection".

Authors: Colby Bosley-Smith, University of Maine, School of Forest Resources
Rose Gellman, University of Maine, School of Forest Resources
Megan Grega, University of Maine, School of Forest Resources
Emily MacDonald, University of Maine, School of Forest Resources
Gregory McHale, University of Maine, School of Forest Resources
Camilla Seirup, Northeast Temperate Network
Jay Wason, University of Maine, School of Forest Resources
Shawn Fraver, University of Maine, School of Forest Resources
Daniel Hayes, University of Maine, School of Forest Resources
Nicole Rogers, Maine Forest Service
Peter Nelson, Laboratory of Ecological Spectroscopy

Coastal spruce forests are one of the most understudied and climate sensitive forest types in the northeastern US. Historically, the coast of Maine served as a climate refugia for spruce forests. Today, the Gulf of Maine is warming faster than 99% of global ocean bodies, and climate models suggest nearly a complete loss of coastal spruce habitat by 2060. We hypothesize that coastal spruce forests are particularly vulnerable to climate change due to low species diversity, limited active management and red spruce's requirement for cool and moist microclimate conditions. The overall objective of our project is to identify the factors that promote coastal spruce forests, assess the risks posed by climate change, and develop tools to manage for resilience. One year into this project, our team has begun producing the first fine-scale maps of the current distribution of coastal spruce forests, identified locations for conservation, management and restoration and developed new data on stand dynamics and climate sensitivity to inform management and conservation decisions.

Authors: Jonathan Rosenthal, Ecological Research Institute
Radka Wildova, Ecological Research Institute

Monitoring and Managing Ash (MaMA) is a program of the Ecological Research Institute that enables widespread detection of strictly defined lingering ("resilient") ash, chemically untreated mature trees that retain healthy crowns through peak EAB invasion. These trees can be used to enable long-term ash conservation, especially through resistance breeding, as shown by the USFS EAB Resistance Breeding Project. Developed in 2017 in consultation with USFS researchers, MaMA has been implemented in Vermont and New York since 2018 and now features prominently in the Tree Species in Peril initiative led by The Nature Conservancy in collaboration with the USFS, enabling it to expand throughout New England.

In long-invaded areas of New York, MaMA has already detected over 140 lingering ash, including representatives of all three widespread Northeastern species; some of these have furnished scion for resistance breeding at Cornell. MaMA's ability to find lingering ash is based on large-scale data collection along with the integration of lingering ash detection into ash management. Both components are enabled by MaMA's partnerships with agencies, conservation NGOs, researchers, managers, and community scientists.

For a tree to qualify as a lingering ash, it must be a chemically untreated, mature tree (at the time of peak EAB pressure) that retains a healthy crown for >= 2years after >= 95% of the mature ash in the area were killed by EAB. Thus, finding lingering ash depends upon searching in areas in which this mortality threshold has been reached. Searching before then can produce false positives (i.e., trees that haven't yet been tested enough by EAB), whereas searching too late is also problematic, because: 1) even lingering ash can eventually succumb to EAB or other causes; and also 2) ingrowth (trees that reached maturity after peak invasion levels) can occur. MaMA's "action maps", yielded by data from its data collection projects and other sources, enable looking for lingering ash at the right places and times.

These maps are initially created using EAB detection history data and standard mortality trajectories and spread rates to project where/when 95% mortality will be reached. They are refined using data from three of MaMA's research projects, all of which rely upon widespread participation: MaMA Monitoring Plots Network, MaMA Rapid Ash Mortality Assessments (MAMA RAMAs), and MaMA Ash/EAB Surveys, enabling its fourth project, MaMA Lingering Ash Search to be appropriately targeted. Participants can choose which project to participate in based on their interests and capabilities and the EAB status in their area.

Authors: Peter Howe, University of Maine

The Northern Forest Historical Atlas Project is bringing to life the University of Maine's Sewall Collection of over 700,000 historical aerial photographs covering Northern New England and dating back to the 1940's. These aerial photos-remarkable for their age, detail, and geographic extent-represent a sweeping landscape record that remains undigitized and largely inaccessible to the research community and the broader public. With recent advances in photogrammetry technology, we are stitching together historical photos into spatially accurate orthomosaic images to map landscape level change across the Northern Forest from the 1940's to present-day. Using machine learning models and historical forest inventory data to train and validate models, we are generating novel land use-land change and forest disturbance maps from historical orthomosaics across the last 80 years. User-friendly web maps make this historical archive accessible to the research community, land managers, educators, and the broader public. By using photogrammetry to generate historical geospatial data with spatial accuracies and resolutions comparable to modern imagery, the Historical Atlas project is extending the remote sensing record of the northern forest by decades and offers powerful new perspectives on the past.

Authors: Rachel Swanwick, Forest Stewards Guild

The Sustaining Ash Partners Network (SAP-Ne) builds off ongoing efforts to protect ash across Tribal Nations, government agencies, academia, private organizations, and diverse forest stewards (e.g., private landowners, Indigenous knowledge keepers, forestry contractors, municipalities, youth) in the Northeast. Led by the Forest Stewards Guild in collaboration with a growing network of partners, SAP-Ne engages in training, treatment, and outreach across the region's states (i.e., Maine, New Hampshire, Vermont, New York, and Massachusetts) and lands of federally recognized sovereign Tribal Nations throughout this region. Our objectives are to 1) elevate the importance of stewardship approaches that honor the cultural values of ash, 2) offer regional workshops and webinars, 3) establish a network of demonstration areas that highlight ash stewardship and 4) monitor the efficacy of the network, its proposed actions, and outreach. SAP-Ne encourages landscape level actions to sustain ash, share stories of hope for ash preservation, and amplify the cultural significance of ash among Indigenous peoples.