Exploring The Relationship Between Tree Dbh And Lichen Cover On Coast Redwood, Grace M. Personeus, Sierra Gittleman, Alisa A. Zarattini

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

We investigated the relationship between Diameter at Breast Height (DBH) and lichen cover on coast redwood (Sequoia sempervirens) to see if larger trees had higher percentages of cover. We measured cover using 10 cover classes on the southeastern and southwestern sides of trees in a secondary growth forest. We found a significant relationship between DBH and cover, yet no significant difference between the two sides measured. We suggest that further research with a larger sample size and more varied age classes will provide further insight into the relationship.

Following The Water: Tree Water Sources In Coastal Northern California Forests, Kaitlyn Briggs

Cal Poly Humboldt theses and projects

Increasing drought intensity and declining summer water availability in Mediterranean- climate forests raise concerns about forest resilience and streamflow persistence. This study evaluated how tree water sources vary with hillslope position, season, species, and watershed context across three coastal northern California forests. Stable isotopes of hydrogen (δD) and oxygen (δ18O), soil moisture time series, linear mixed-effects models, and site-specific Bayesian mixing models (MixSIAR) were used to estimate proportional contributions of shallow soil, deep soil, stream-associated, and fog water to tree xylem water. Across sites, xylem water isotopic signatures overlapped primarily with soil water, indicating dominant reliance on subsurface sources, while …

Effects Of Conifer Encroachment On Oregon White Oak Crown Structure And Nonvascular Epiphyte Communities, Courtney Jonell Copper

Cal Poly Humboldt theses and projects

Oregon white oak (Quercus garryana, QUGA) is an ecologically and culturally important broadleaf tree species native to northern California and the Pacific Northwest. Fire suppression and subsequent encroachment by Douglas-fir (Pseudotsuga menziesii, PSME) and other conifers have made QUGA woodlands among the most threatened habitat types in the region. This study examines the influence of conifer encroachment on QUGA crown structure and nonvascular epiphyte (NVE) communities using ground- and crown-based sampling techniques.

Twenty-four trees were sampled across four sites in northern California along a gradient of conifer encroachment that was quantified as PSME basal area (BA). A …

Long-Term Relationships Between Tree Growth And Climate In The Trinity Alps Wilderness, Klamath Mountains, California, Usa, Emma R. Knepp

Cal Poly Humboldt theses and projects

The Trinity Alps Wilderness is a unique setting for evaluating late-Holocene climate variability because former glaciers occupied comparatively low elevations in a region influenced by both coastal and interior climate patterns. Tree-ring chronologies were developed from four conifer species—Shasta red fir (Abies magnifica var. shastensis), western white pine (Pinus monticola), Brewer’s spruce (Picea breweriana), and mountain hemlock (Tsuga mertensiana)—sampled at high elevations (1950 - 2300 m) near Emerald and Grizzly Lakes in the Trinity Alps Wilderness in northern California. The final chronologies included 12 Shasta red fir trees, 12 western white pine …

Factors Influencing Tree Vigor And Structural Failure Along Powerline Corridors In Northern California: A Multi-Species Analysis, David Justin Dorval

Cal Poly Humboldt theses and projects

Tree failures (e.g., stem breakage, uprooting, or branch drop) can pose significant risks to public safety, particularly along powerline corridors for the risk of power outages and wildfire ignitions. In California, tree-related powerline failures have led to severe ecological and human costs in recent years. Despite extensive research on tree failure in urban environments and post-disturbance contexts, comparatively little empirical work has examined where powerlines intersect largely unmanaged stands. This study evaluates tree failure trends across multiple forest types in Northern California by examining how tree-level characteristics influence recent growth and failure occurrence in regionally dominant tree species. Specifically, the …

Assessing The Potential For Bigleaf Maple Syrup Production In Humboldt County, Ca, David A. Reinhart, Juan A. Ramos-Cool, Liam H. Richardson

Undergraduate Scholarship

The bigleaf maple (Acer macrophyllum, Pursh) is the largest maple of the Pacific Northwest. While it has generally been treated as a nuisance in timber harvesting operations, a small amount of research has been conducted on its sugaring ability in Oregon, Washington, and British Columbia. This research has yet to reach further south in the species' range. This study aims to help a California landowner understand which maple trees on his property produce the most maple sap, to gauge what environmental factors contribute to maple sap production, and to find greater implications for the production of maple sap …

Modeling Forest Stewardship In Goukdi’N: An Assessment Of Carbon, Wildlife Habitat, And Fire Resilience In A University Forest, Benjamin Stock

Cal Poly Humboldt theses and projects

This thesis presents a forest management plan for Goukdi’n (also known as the Jacoby Creek Forest University Tract), a coast redwood–tanoak–Douglas-fir forest within the ancestral homelands of the Wiyot Tribe. This project addresses the need for a forest stewardship approach that supports ecological resilience, cultural values, and long-term forest health in a landscape shaped by industrial logging, fire exclusion, and decades of under-management. To evaluate potential management pathways, forest growth modeling was conducted using the USFS Forest Vegetation Simulator (FVS) to compare three management prescriptions focused on carbon storage, fire resilience, and structural heterogeneity and a no-action alternative. Model outputs …

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 …

Sense Of Place In Natural Resource Recreation And Tourism: An Evaluation And Assessment Of Research Findings.

The International Journal of Ecopsychology (IJE)

No abstract provided.

Longevity Of Prescribed Fire Effectiveness In Mixed-Evergreen Forests Of The Klamath Mountains, Kaily M. Fineran

Cal Poly Humboldt theses and projects

Prescribed fire is a common management tool used across the western United States to create wildfire-resilient ecosystems and communities. The Klamath Mountains of northern California, USA has experienced numerous, large wildfires in recent years. This is due in part to a combination of highly flammable fuels, uncharacteristic weather events, and high fuel accumulations as a result of fire exclusion and forest management practices. Within the last decade, local land management organizations and the Karuk Tribe have begun re-introducing prescribed fire in low elevation, mixed evergreen forests. While the long-term effects of fuel treatments are not well-known, these efforts provided a …

Post-Fire Persistance Of Sequoia Semperviens In A Secondary Forest: Examining Drivers Of Basal Resprouting Response, Jackson T. Carrasco

Cal Poly Humboldt theses and projects

Historically frequent-fire forest ecosystems are now facing increased size, frequency, and severity of fires attributed to climate change, intensive forest management, and fire exclusion. Understanding post-fire resilience in forest ecosystems is critical amidst escalating challenges posed by recent increases in fire activity. This study examined the basal resprouting response of coast redwood (Sequoia sempervirens) in a secondary forest two years after the CZU Lightning Complex fire on the central coast of California. Robust allometric equations were developed to quantify redwood resprout biomass and leaf area, revealing strong explanatory power for biomass equations (R² > 0.85). Probability of …

Knobcone Pine Response To Shading From Competing Chaparral Shrubs Following Stand-Replacing Wildfire, Sean T. Lindley

Cal Poly Humboldt theses and projects

In northern California, fire regimes are shifting towards more frequent and larger severe wildfire. There is growing concern that this shift poses a threat to biodiversity in the form of cover type change at the landscape scale, resulting in the extirpation of some species in favor of +AD617:AD649well-adapted ones. In northern California, mature serotinous conifers, such as knobcone pine (Pinus attenuata), and resprouting shrub species easily regenerate in severe patches of any size. There is no general consensus regarding the effects of shrub competition on conifer recruitment; conifer response varies with shade tolerance and other abiotic factors. Knobcone …

Investigating Tribal Co-Management Of Caifornia’S Public Lands, Zachary Joseph Erickson

Cal Poly Humboldt theses and projects

Collaborative management with Indigenous groups is becoming increasingly common as many Indigenous communities continue to assert their inherent rights to self-determination. Due to the removal from and dispossession of lands, tribes often rely on access to public properties for various uses including ceremonies and gathering of culturally important plants. Some believe that the absence of indigenous involvement has also led to a decline in both the quality and abundance of culturally important resources, as well as limited the intergenerational transfer of traditional ecological knowledge, or TEK. There is increasing momentum toward re-engaging tribes as stewards of their ancestral lands through …

Factors Contributing To Legacy Hardwood Mortality Following Prescribed Fire, Heather D. Rickard

Cal Poly Humboldt theses and projects

Interruption of Indigenous stewardship has resulted in hardwood decline along what is now known as the middle Klamath River in northern California related to adverse effects to Tribal food sovereignty and community wellbeing. The survivors of a “legacy” of Indigenous stewardship are highly valued by the Karuk and neighboring Tribes for a myriad of culturally beneficial ecological associations and sources of traditional staple foods. Prescribed fire, following a century of fire exclusion, has resulted in unanticipated mortality of legacy tanoak (Notholithocarpus densiflorus), California black oak (Quercus kelloggii), and madrone (Arbutus menziesii), warranting further investigation. …

Assessing The Recovery Of Forest Understory Vegetation After Clearcut Logging Across A 445-Year Chronosequence, Molly Smith Metok

Cal Poly Humboldt theses and projects

The conversion of natural forested lands to managed forests has reduced the amount of older, structurally diverse forests worldwide. In conifer forests of the Pacific Northwest (USA) – where the understory plant communities comprise only 1% of forest biomass but represent 90% of the plant species richness – the long-term impacts of timber harvesting are not fully understood. I used a chronosequence of forests in southwestern Oregon that ranged from 25 to 445 years of age to compare changes in plant communities in logged (i.e., managed) stands with that of stands in late succession and old growth conditions. The chronosequence …

Drought, Tree Mortality, And Regeneration In Northen California, Sophia Lb Lemmo

Cal Poly Humboldt theses and projects

The 2012-2016 California drought was the most severe in the state’s recorded history, contributing to the death of millions of trees. While the effects of this drought on forests are relatively well studied in the central and southern Sierra Nevada, less is known about its effects on the heavily timbered and diverse forests of northern California. Through sampling 54 0.25 ha plots in northern California, this study compared tree mortality and regeneration patterns before, during, and after California’s most recent record-setting drought. This study evaluated 1) the influence of habitat and competitive covariates on mortality and regeneration trends using ridge …

Assessing Soil Disturbance From Tethered Logging On Steep Slopes In Northern California, Karolyn Marie Fagundes

Cal Poly Humboldt theses and projects

The implementation of tethered harvesting allows for the expansion of mechanized logging onto steeper slopes. Recent updates to the California Forest Practice Rules have explicitly removed the slope limitation for logging equipment, provided it’s tethered. California is now witnessing the reintroduction of ground-based logging equipment on steep slopes. Previously, operating equipment on steep slopes was considered detrimental due to the potential for soil disturbance. However, tethered equipment interacts with the soil in a new way due to the use of a winch. Relatively few studies have attempted to quantify soil disturbance with this new practice. The goal of this study …

Comparison Of Low-Cost Commercial Unpiloted Digital Aerial Photogrammetry To Airborne Laser Scanning Across Multiple Forest Types In California, James Edward Lamping

Cal Poly Humboldt theses and projects

Science-based forest management requires quantitative information about forest attributes traditionally collected via sampled field plots in a forest inventory program. Remote sensing tools, such as active three-dimensional (3D) Light Detection and Ranging (lidar), are increasingly utilized to supplement and even replace field-based forest inventories. However, lidar remains cost prohibitive for smaller areas and repeat measurement, often limiting its use to single acquisitions of large contiguous areas. Recent advancements in unpiloted aerial systems (UAS), digital aerial photogrammetry (DAP) and high precision global positioning systems (HPGPS) have the potential to provide low-cost time and place flexible 3D data to support forest inventory …

In-Flux: Economic And Community Adaptations Of Former Timber Mill-Towns In The American West, Cherilyn P. Ashmead

Cal Poly Humboldt theses and projects

Once built around natural resource extractive industries, rural communities’ economies are changing as the United States is transitioning away from its industrial past. While much research has focused on rural economic shifts from natural resource production toward amenity-driven economies (Morzillo et al., 2015; Winkler et al, 2007), less research has explored the economic and demographic trends in areas pursuing new modes of production. This two-part study focuses on an understudied region with historic ties to timber in dry mixed-conifer forests, much of which are under federal land management. With few natural amenity draws, the region has largely maintained production-based sectors. …

Aspen Growth Response In The Presence Of Inter-Annual Climate Fluctuation And Disturbance In The Lake Tahoe Basin, Keath K. Sakihara

Cal Poly Humboldt theses and projects

In the western US, aspen forests tend to be small and rare, but have great ecological importance. There is much interest and concern over how aspen in the Sierra Nevada Mountains of the western USA will respond to a changing climate and future disturbances. Impacts from climate change create stress on aspen trees that further compound threats to aspen communities. This analysis assessed the radial growth response of aspen under previously recorded climate conditions to better understand how measurable climate variables affect aspen growth. Along with aspen’s growth response to climate, this analysis also assessed the growth response of aspen …

Long-Term Effectiveness Of Fuel Treatments In Oak And Chaparral Stands Of Northern California, Caroline Ann Martorano

Cal Poly Humboldt theses and projects

Fuel reduction treatments are broadly implemented to reduce the risk of extreme wildfire. Yet, research on the long-term effectiveness and ecological consequences among these treatments is lacking. In this study, I examined short- and long-term changes in fuels and understory vegetation after treatment in chaparral and oak-dominated stands of Whiskeytown National Recreation Area. Treatments included mastication and spring burning, spring burning only, mastication only, and hand-thinning. Treatments were applied randomly to 1 to 2 units within each of 10 blocks. Two plots were established in each treatment unit and fuel and vegetation data was collected and analyzed at the block …

Multidecadal Change In Aspen Experiencing Long-Unburned, Mixed-Severity Wildfire, And Reburn Disturbance Regimes, Cerena Brewen

Cal Poly Humboldt theses and projects

Quaking aspen (Populus tremuloides) is a valued, minor component on western landscapes. It provides a wide range of ecosystem services, and has been in decline for the last century. This decline may be explained partially by the lack of fire on the landscape as aspen benefit from fire that eliminates conifer competition and stimulates reproduction through root suckering. Managers are interested in aspen restoration but have a lack of knowledge about their spatial dynamics in response to fire. Improving our understanding of aspen stand spatial changes over time may be important for maintaining their presence on landscapes where …

Developing A Coastal Gis Model Of Sri Lanka To Pinpoint Areas At Risk Of Tsunamis, John E. Dellysse, Buddhika D. Madurapperuma

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

No abstract provided.

Survey And Map Distribution Of English Ivy (Hedera Helix L.) At Patrick's Point State Park, California, John W. Cortenbach, Buddhika D. Madurapperuma

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

No abstract provided.

Productivity And Cost Of A Cut-To-Length Commercial Thinning Operation In A Northern California Redwood Forest, Kigwang Baek

Cal Poly Humboldt theses and projects

Cut-to-length (CTL) harvesting systems have recently been introduced to the redwood forests of California’s north coast. These machines are being used to commercially thin dense redwood (Sequoia sempervirens) stands which tend to form clumps of stems that vigorously sprout from stumps after a harvest. One of the challenges is to avoid damaging residual trees which can decrease productivity, increase costs, and lower the market value of trees. The goal of this study was to evaluate the productivity and costs associated with CTL systems used in a redwood forests and use that data to develop equations for predictions. Time …

Persistence Of Stream Restoration With Large Wood, Redwood National And State Parks, California, Diedra L. Rodriguez

Cal Poly Humboldt theses and projects

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. In-stream large wood dictates channel morphology, increases retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of large wood. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and restoration managers, in addition to the initial effectiveness of restoration, is the persistence and fate of large wood installations. In this …

Impacts On Soils And Residual Trees From Cut-To-Length Thinning Operations In California's Redwood Forests, Kyungrok Hwang

Cal Poly Humboldt theses and projects

In northern California, a cut-to-length (CTL) system was used for the first time to harvest young redwood forests (Sequoia sempervirens (Lamb. ex D. Don) Endl.). However, landowners and public agencies are concerned about the potential negative impacts of CTL logging to soils and residual trees since the extent and amount of CTL impacts are unknown in these forests. This study was designed to (1) determine soil physical property using bulk density (BD) and hydraulic conductivity (HC) (2) examine the characteristics of stand damage after CTL harvesting, and (3) compare the scar size differences between tree growing patterns (individuals vs. …

Assessing Spatio-Temporal Patterns Of Forest Decline Across A Diverse Landscape In The Klamath Mountains Using A 28-Year Landsat Time-Series Analysis, Drew S. Bost

Cal Poly Humboldt theses and projects

Rates of tree mortality in California and the Pacific Northwest have greatly increased in recent years, driven largely by pest and pathogen outbreaks as well as the effects of hotter, warmer droughts. While there have been a multitude of regional-scale assessments of mortality and forest decline, landscape-level studies are necessary to better identify forests that are most vulnerable to decline and to anticipate future changes. This need is particularly notable in the remote and little-studied mountains of northwest California, which are renowned for their diverse, heterogeneous vegetation types. A recent observation of elevated levels of Shasta red fir (Abies …

Finding Nondestructive Parameters For Root-To-Shoot Ratios In Douglas-Fir, Grand Fir, And Redwood Saplings In Northwest California For Biomass And Carbon Storage Estimates, Walter A. Kast

Cal Poly Humboldt theses and projects

ABSTRACT

FINDING NONDESTRUCTIVE PARAMETERS FOR ROOT-TO-SHOOT RATIOS IN DOUGLAS-FIR, GRAND FIR, AND REDWOOD SAPLINGS IN NORTHWEST CALIFORNIA FOR BIOMASS AND CARBON STORAGE ESTIMATES

Walter A. Kast

There is a need for better understanding of how woody biomass is allocated above and belowground and how this allocation might differ among tree species. In this field of research, investigators face challenges such as the laborious task of removing trees from the soil with destructive sampling, and the cleaning, drying, and weighing of belowground biomass (BGB). Therefore, researchers and practitioners most often rely on existing models to predict BGB from easily-measurable aboveground variables …