Forest Sciences Commons^™

Tremblings, February 2025, Western Aspen Alliance

Tremblings

Bridging Conservation Science With Native Meaning

James Calabaza, Indigenous Lands Director; Trees, Water & People

Last fall, I had the privilege of collaborating with the Western Aspen Alliance and other partners to carry out a 3-day workshop focused on quaking aspen genetics, fire ecology, and co-stewardship. Held at Rocky Mountain Biological Laboratory (Gothic, Colorado), the workshop brought together academics, NGOs, federal agencies, and Tribal members to share diverse perspectives on aspen's significance and management futures.

Climate Change Aggravates Bird Mortality In Pristine Tropical Forests, Jared Wolfe, David A. Luther, Vitek Jirinec, Jeremy Collings, Erik I. Johnson, Robert O. Bierregaard, Philip C. Stouffer

Michigan Tech Publications

Stable understory microclimates within undisturbed rainforests are often considered refugia against climate change. However, this assumption contrasts with emerging evidence of Neotropical bird population declines in intact rainforests. We assessed the vulnerability of resident rainforest birds to climatic variability, focusing on dry season severity characterized by hotter temperatures and reduced rainfall. Analyzing 4264 individual bird captures over 27 years, we found that harsher Amazonian dry seasons significantly reduced apparent survival for 24 of 29 species, with longer-lived species being more strongly affected. Our model predicted that a 1°C increase in average dry season temperature would reduce the mean apparent survival …

Humination Modification: A Green Approach To Improve The Material Properties Of Scots Pine (Pinus Sylvestris L.) Sapwood, Amir Ghavidel, Arantxa Eceiza, Xinfeng Xie, Reza Hosseinpourpia

Michigan Tech Publications

Recently, wood modification with environmentally friendly modification agents has received special attention. To this end, this study was conducted to use humin fractions, in combination with citric acid (CA) and succinic acid (SA), as reaction catalysts for the modification of Scots pine (Pinus sylvestris L.) sapwood. The effects of humination modification were evaluated by means of dimensional stability, static and dynamic mechanical properties, thermal stability, crystalline structure, and biological durability tests on modified samples and compared with the unmodified reference ones. According to the results, the dimensional stability of the huminated samples significantly increased, and this increase with the presence …

Timber Harvesting Was The Most Important Factor Driving Changes In Vegetation Composition, As Compared To Climate And Fire Regime Shifts, In The Mixedwood Temperate Forests Of Temiscamingue Since Ad 1830, Daniela Robles, Yan Boulanger, Jesus Pascual, Victor Danneyrolles, Yves Bergeron, Igor Drobyshev

Aspen Bibliography

Context The vegetation composition of northeastern North American forests has significantly changed since pre-settlement times, with a marked reduction in conifer-dominated stands, taxonomic and functional diversity. These changes have been attributed to fire regime shifts, logging, and climate change.

Methods In this study, we disentangled the individual effects of these drivers on the forest composition in southwestern Quebec from 1830 to 2000 by conducting retrospective modelling using the LANDIS-II forest landscape model. The model was run based on pre-settlement forest composition and fire history reconstructions, historical timber harvest records, and climate reanalysis data. We compared counterfactual scenarios excluding individual factors …

A Climatically Significant Abiotic Mechanism Driving Carbon Loss And Nitrogen Limitation In Peat Bogs, Alexandra B. Cory, Rachel M. Wilson, M. Elizabeth Holmes, William J. Riley, Yueh Fen Li, Malak M. Tfaily, Sarah C. Bagby, Darya Anderson, Robert M. Jones, Gareth Trubl, Nicole Irwin-Raab, Sky Dominguez, Moira Hough, Virginia I. Rich, Matthew B. Sullivan, Maria F. Fahnestock, Suzanne B. Hodgkins, Ruth K. Varner, Michael Ibba, Regis Ferriere, Ahmed Zayed, Patrick M. Crill, Jessica G. Ernakovich, Jeffrey P. Chanton

Michigan Tech Publications

Sphagnum-dominated bogs are climatically impactful systems that exhibit two puzzling characteristics: CO2:CH4 ratios are greater than those predicted by electron balance models and C decomposition rates are enigmatically slow. We hypothesized that Maillard reactions partially explain both phenomena by increasing apparent CO2 production via eliminative decarboxylation and sequestering bioavailable nitrogen (N). We tested this hypothesis using incubations of sterilized Maillard reactants, and live and sterilized bog peat. Consistent with our hypotheses, CO2 production in the sterilized peat was equivalent to 8–13% of CO2 production in unsterilized peat, and the increased formation of aromatic N compounds decreased N-availability. Numerous sterility assessments …

Managing Usda Wildfire Crisis Strategy Landscapes In The Intermountain West (Region 4): A Program For Training Future Forest Managers, Justin Derose

Funded Research Records

No abstract provided.

Supporting Wildlife Restoration In Eastern States Via State Wildlife Action Plans, L. Mark Elbroch, John Vucetich, Christa Rose, Jeremy T. Bruskotter

Michigan Tech Publications

The biodiversity crisis is driven by extinction at two scales: the global extinction of species and the local extirpation of populations (i.e., range contraction). Local extirpations are especially acute in the eastern United States, which has lost a substantial portion of its native mammalian fauna. Species restoration in the U.S., therefore, should be utilised more to revitalise and restore degraded systems. State wildlife agencies can elevate discussions about species restoration and facilitate internal capacity to conduct restoration projects by including locally extirpated species in State Wildlife Action Plans, which are currently under revision, and will guide state conservation programs for …

Evaluating Elk Distribution And Conflict Under Proposed Management Alternatives At The National Elk Refuge In Jackson, Wyoming, Gavin G. Cotterill, Paul C. Cross, Eric K. Cole, Jonathan D. Cook, Margaret C. Mceachran, Tabitha A. Graves

Aspen Bibliography

We evaluated measurable attributes describing the current and future distribution of Cervus elaphus canadensis (elk) across a region surrounding Jackson, Wyoming, for five feedground management alternatives proposed by the U.S. Fish and Wildlife Service as a revision to 2007 "Bison and Elk Management Plan" of the National Elk Refuge. A resource selection function evaluated measurable attributes of interest to managers, including elk use of private property and sensitive habitat types at monthly timesteps and varying winter conditions. The study area boundaries were created through an expert elicitation process and consist of the Jackson Elk Herd Unit, Grand Teton National Park, …

Increased Positive Tree Species Mixture Effects On The Abundance And Richness Of Collembola With Stand Development In Canadian Boreal Forests, Yakun Zhang, Sai Peng, Zilong Ma, Chen Chen, Bilei Gao, Xinli Chen, Han Y.H. Chen

Aspen Bibliography

It is well established that species mixtures could enhance ecosystem functioning in diverse ecosystem types, with these benefits increasing over time. However, the impact of tree mixtures on Collembola communities following stand development in natural forests remains unclear, despite the critical roles Collembola plays in litter decomposition and nutrient cycling. We investigated the effects of tree species mixtures on Collembola abundance, diversity, and community structure by sampling pure and mixed jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) of 15-year-old and 41-year-old stands in natural boreal forest. In total, 6,620 individuals of Collembola were identified …

Land-Use Effects On Soil Organic Matter And Related Soil Properties In A Mixed Agricultural–Forest Landscape Of Central Wisconsin, Usa, Kathryn L. Hofmeister, Gwen Feitl, Kaylee Tackett, Leah Fleury, Lucas E. Nave

Michigan Tech Publications

Soil organic matter (SOM) influences a wide range of ecosystem processes, including nutrient cycling, water movement, plant productivity, and biodiversity. In agricultural landscapes, adjacent land uses often differ in SOM contents and related soil properties, such as soil organic carbon (SOC) stocks, but the direction and magnitude of these effects are inconsistent across studies. We assessed how land uses differed in SOM and related properties in a representative US Midwest agricultural–forest landscape to support land-use and management decisions by local landowners and producers. We measured SOM, bulk density (Db), root biomass, and pH, and estimated SOC stocks, in a Typic …

Forest Above-Ground Biomass Estimation Using Nasa Gedi Lidar Waveforms And Global Tree Allometry, Ian Grant

Theses and Dissertations

Above-ground forest biomass plays a crucial role in global carbon cycles, yet accurately estimating biomass at global scales remains challenging. This thesis addresses two key challenges in processing NASA’s Global Ecosystem Dynamics Investigation (GEDI) space-borne lidar data to estimate above-ground biomass density (AGBD): accounting for global variation in forest structure and developing robust physical interpretations of lidar returns. The first component of the thesis analyzes global patterns of tree allometry using the Tallo tree allometry dataset, examining relationships between tree dimensions across biomes, continents, and plant functional types. This analysis reveals consistent allometry across continents for some biomes (e.g., tropical …

Soil Amendments Alter Tree Growth And Wood Decay After Forest Thinning, Deborah S. Page-Dumroese, Martin Jurgensen, Chris Miller, Joanne M. Tirocke, Derek N. Pierson, Cole Mayn, Mark J. Kimsey, Haley C. Anderson

Michigan Tech Publications

Forest soil amendments are increasingly used in western US forests to dispose of unmerchantable woody residues, reduce wildfire risk, and improve soil properties. Our objective was to determine the effect of fertilizer and organic amendments on tree growth and organic matter decomposition after thinning. Treatments were a control, three single soil amendments (wood chips, fertilizer, and biochar), and one combined soil amendment (biochar + fertilizer), each applied after thinning a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) stand. After 10 years, amendment treatments had no effect on tree diameter increment (p = 0.600), but the biochar + fertilizer and wood …

Coffee Farmgate Price And Post-Harvest Processing In Honduras., Isaac Desouza

Theses and Dissertations--Agricultural Economics

Volatile commodity markets and changing climate expose coffee farmers to price and production risk. Proponents recommend specialty coffee as a strategy to combat price risk, because its unique attributes differentiate it from commodity coffee. Extrinsic and intrinsic attributes define specialty coffee and affect prices at many levels of the supply chain. Despite much work on extrinsic attributes, little is known about how intrinsic attributes relate to farmgate price. Post-harvest processing is itself an intrinsic trait and driver of coffee quality. In 2024 we surveyed 261 coffee farmers from La Paz, Honduras, to uncover relationships between capital, post-harvest processing, and farmgate …

Timber Talk, Vol. 63, No. 3, July 2025 (Special)

Timber Talk: Nebraska Forest Industry Newsletter

Timber Talk, Vol. 63, No. 3, July 2025 (Special)

2025 Annual Report, Tennessee. Division Of Forestry And Tennessee. Department Of Agriculture

Forestry Annual Reports

This annual report presents an overview of Tennessee Forestry Commission programs and management.

Feasibility Of Producing Non-Structural Wood Products Using Trembling Aspen Lumber, Mengyuan Zhang

Aspen Bibliography

Trembling aspen (Populus tremuloides) is abundant in Canada but underutilized in non-structural solid wood products.This study was aimed at evaluating the feasibility of using aspen lumber to produce flooring, moulding, and siding. The shrinkage, surface roughness, and wettability of aspen wood were tested. The surface hardness, screw withdrawal resistance, colour change, and dimensional stability of there products fabricated were examined. The wood yield of each product was analyzed. It was found that aspen showed superior machinability and wettability to silver maple and yellow poplar. Aspen flooring had a Brinell hardness of 13.47 MPa, 60% lower than silver maple. …

Assessing Understory Along The Elk River (Hikshari') In Headwaters Forest Reserve, Humboldt County, California, Julie R. Meyers, Aliyah M. Ingram, Caleb N. Larkin, Joshua L. Carpenter

Environmental Science & Management Senior Capstones

Northern California’s extensive logging history and lack of forest management has altered old-growth coast redwood (Sequoia sempervirens) forests, leaving dense, homogenous second and third-growth forest stands. This has led to the use of modern restoration techniques such as variable density thinning (VDT) which aims to rehabilitate old-growth forest conditions by improving stand heterogeneity and light availability for understory species. Our study was done in Headwaters Forest Reserve (HFR) along the Elk River (Hikshari’) Trail in Humboldt County, California. Initially, the project was supervised by the Bureau of Land Management (BLM) Arcata Field Office. However, the 2025 U.S. government …

Six Rivers National Forest Hazardous Fuels And Fire Management Project 2025 Orleans Complex Fire Effects From 9/13/25 - 9/14/25, James L. Parr, Nosheen Maung, Darby J. Lewis, Javier E. Margarito, Giancarlo Golloti

Environmental Science & Management Senior Capstones

The 2025 Orleans Complex affected the Klamath National Priority Landscape, designated by Congress as a priority to reduce fuel load and mitigate wildfire risk near rural, at-risk communities. To address the threat of large destructive wildfires, the 2023 Six Rivers Hazardous Fuels and Fire Management Project identified desired ecological conditions, using the right type of fire at the right time and place.

An Assessment Of The California Logging Workforce, Kendra Jean Gerstenberg

Cal Poly Humboldt theses and projects

There is limited literature describing the capacity and capabilities of the logging workforce in California. This study examines the logging workforce in California to quantify the number of logging crews, assess demographic diversity, and evaluate capacity and capabilities. The target population was California Licensed Timber Operators (LTOs) who have the legal right to harvest timber. A survey was developed and distributed to LTOs on the CAL FIRE database. Surveys were also distributed at regional logging conferences or collected by phone. Data were analyzed using Statistical Package for the Social Sciences (SPSS) and emergent coding for follow-up interviews was conducted. There …

An Evaluation Of Fuel Model Accuracy And Multi-Scale Mitigation Strategies In The Wildland-Urban Interface Of Southern Humboldt County, Julia I. Cavalli

Cal Poly Humboldt theses and projects

Strategic placement of fuel treatments is critical for mitigating wildfire risk and reducing potential structure losses in wildland-urban interface (WUI) communities. As wildfire activity accelerates across the western United States, the need to identify high-impact fuel treatment locations grows increasingly urgent. Concurrently, housing development in the WUI is expanding, intensifying the exposure of homes and infrastructure to wildfire threats. In response, many communities are looking to mitigate the likelihood and severity of losses during wildfire events. The success of these efforts depends, in part, on robust data to support strategic placement of effective treatments that reduce fuel availability.

This study …