Converting Coast Redwood/Douglas-Fir Forests To Multiaged Management: Residual Stand Damage, Tree Growth, And Regeneration, Robert Thomas Muma

Cal Poly Humboldt theses and projects

There is increased interest in multiaged management as a silvicultural and restoration tool in redwood forests of California. The effect of varying residual densities and spatial arrangements on residual stand damage, tree growth and regeneration was studied in a multicohort silviculture experiment on Jackson Demonstration State Forest. Four treatments varying in residual stand density or spatial arrangement were replicated at four sites. The experiment provided 4-year periodic growth measurements of residual trees and annual measurements of redwood and tanoak sprout height increments. Residual trees were more likely to sustain bole scarring when retained at higher densities. Crown damage was more …

Competition, Climate, And Drought Effects On Tree Growth In An Encroached Oak Woodland In Northern California, Jill J. Beckmann

Cal Poly Humboldt theses and projects

Oregon white oak (Quercus garryana Douglas ex Hook.) is experiencing increasing competition from Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) across its range at the same time as climate models are predicting increasing climate variability, including drought. Management recommendations that consider competition dynamics between these species under a changing climate are therefore needed for oak woodlands, but we do not currently understand the combined effects of competition, climate, and drought in this ecosystem. This research examines radial tree growth and drought response in Oregon white oak and Douglas fir in an encroached oak woodland near Kneeland, California. Stem maps …

Tree Squirrels And Fishers In Northern California: The Effects Of Masting Hardwoods On Stand Use, Andria M. Townsend

Cal Poly Humboldt theses and projects

In western North America, tree squirrels such as western gray (Sciurus griseus) and Douglas squirrels (Tamiasciurus douglasii) are potentially important prey for fishers (Pekania pennanti). Western gray squirrels in particular may be highly ranked due to their large body size. Masting trees including black oak (Quercus kelloggii) and tanoak (Notholithocarpus densiflorus) produce an important food source for tree squirrels; therefore, forest stands containing these trees may be useful to foraging fishers. I hypothesized that; 1) the abundance of western gray and Douglas squirrels in a stand is influenced by the …

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 …

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 …

Implications Of Unmanned Aircraft Systems And Sense Of Place: A Case Study In The Mono Basin, Sara Elizabeth Matthews

Cal Poly Humboldt theses and projects

This paper contributes to an understanding of the social implications of using UAS in natural resource areas; specifically, the ways in which these tools impact human constructed sense of place. This paper draws on in-depth interviews and document analysis to (a) develop an understanding of place meanings held among Mono Basin stakeholders and (b) define the ways in which increased UAS presence may interact with these visions of place.

In short, this research shows that sense of place in this rural area is influential in the way that UAS are received by local stakeholders. The changing nature of place meanings …

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 …

Restoration And Tree Drought Resistance In Coast Redwood-Douglas-Fir Forests At Redwood National Park, California, Laura Lalemand

Cal Poly Humboldt theses and projects

With the growing impacts of climate change worldwide and great uncertainty about forests’ vulnerability to a changing climate in the Pacific Northwest, knowledge of coast redwood forest response is crucial. Many of the studies investigating forest response to drought focus on inland forest types rather than coastal forests. This study examined tree growth and drought response in coastal forests at restoration thinning sites, evaluating responses to local climate, tree-level competition, and site-level factors. Tree cores were extracted from previously harvested stands at three restoration sites in Redwood National Park, California, from both thinned and unthinned stands. Douglas-fir (Pseudotsuga menziesii …

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 …

Modeling The Spread Of Sudden Oak Death Across A Heterogeneous Landscape In Redwood National Park Using A Spatially-Explicit Epidemiological Model, Laura A. Morgan

Cal Poly Humboldt theses and projects

The pathogen Phytophthora ramorum, the causal agent of Sudden Oak Death (SOD), is responsible for the deaths of millions of oak (Quercus spp.) and tanoak (Notholithocarpus densiflorus) trees in California and Oregon (USA). A recent infection in Redwood National Park (RNP) in California (USA) provided an opportunity to adapt an existing SOD model to assess the efficacy of current and proposed management strategies. A common method of SOD treatment includes killing both infected and uninfected hosts in the area of infection, as well as the area surrounding the infection to create buffers to account for undetected …

Comparison Of Tree Growth And Restoration Treatment Persistence In Riparian And Upland California Montane Forests, Scott D. Burdette

Cal Poly Humboldt theses and projects

This thesis analyzes the growth of red fir (Abies magnifica) and California white fir (Abies concolor var. lowiana) in three different sites in California and creates an individual-tree, distance-independent growth simulator. The first chapter of this thesis is a literature review discussing the issues facing the forests composed of these montane true fir in California and the forest growth simulators in common use. The second chapter uses AICc model comparison to determine which models for each species best predicts growth of individual trees in terms of basal area increment (BAI). The third chapter of this thesis uses these individual-tree growth …

In The Face Of Drought: Do Fuel Treatments Promote Resistance To Multi-Year Drought In A Mixed-Conifer Forest Of Northern California?, Michael Vernon

Cal Poly Humboldt theses and projects

Climate change is predicted to increase the frequency, duration, and severity of drought events across many bioregions. Forest managers have two active management techniques to promote resistance and resilience to drought: prescribed fire and mechanical thinning. Generally applied to reduce fuels and fire hazard, treated areas may also reduce competition for resources that may improve tree-growth during drought and reduce mortality. The recent severe and prolonged drought in California allowed me to investigate the effects of climate stress and fuel treatments on tree growth responses in a dry mixed-conifer forest ecosystem.

To assess tree-growth responses to fuel treatments during severe …

Performance And Morphology In Sequoiadendron Genotypes Outside Of Their Range, Christopher M. Valness

Cal Poly Humboldt theses and projects

In its current fragmented distribution in 75 groves along the western slope of the Sierra Nevada, Sequoiadendron giganteum (SEGI) may be vulnerable to extreme shifts in environmental conditions such as warming temperatures and drought stress, which may reduce the already limited habitat for SEGI in native groves. Interest in outplanting of this iconic species for the objectives of genetic conservation and timber utilization due to decay resistance of heartwood would be supported by information on population variation to inform seed collection for these plantings. To that end, I assessed three SEGI common-garden trials which had been planted in spring 1981 …

Ninety-Two Years Of Tree Growth And Death In A Second-Growth Coast Redwood Forest, Benjamin Iberle

Cal Poly Humboldt theses and projects

Mature second-growth coast redwood (Sequoia sempervirens) forests are an important and uncommon resource in the redwood region. Development of second-growth redwood forests beyond rotation age (~50 years) is not well understood. Continuous long-term data are especially lacking, considering that the maximum possible age of second-growth stands is now over 150 years. Two permanent observation plots in Arcata, CA, established in 1923 by Woodbridge Metcalf and last measured in 1990, provide a unique opportunity to examine the development of coast redwood forest regenerating after logging in ~1880. We surveyed the Metcalf plots using modern methods and assembled a complete …

Early Seral Mixed-Conifer Forest Structure And Composition Following A Wildfire Reburn In The Sierra Nevada, Erin Alvey

Cal Poly Humboldt theses and projects

Before the era of modern fire suppression, California’s northern Sierra Nevada mixed-conifer and yellow pine forests were self-regulating; recurring short-interval, low-mixed severity wildfires maintained forest structure and composition, which in turn exerted bottom-up controls on subsequent wildfires. As a result of fire suppression, and coupled with the effects of climate warming and other anthropogenic disturbances, the fundamental structure of mixed-conifer and yellow pine forests has shifted. Wildfires may now be increasing in size, severity, and frequency across western North America. However, little is known about the post-fire impacts of repeat wildfire on a forest after a long era of suppression. …

Soil Organic Matter Distribution In A Douglas-Fir-Tanoak Forest, Humboldt County, California, Hollie A. Ernest

Cal Poly Humboldt theses and projects

Soil carbon (C) affects the active gases in the atmosphere, nutrient cycling, and diversity of flora and fauna. Soil organic matter (SOM) is partially comprised of C, and a widely-accepted ratio of 0.58 organic carbon (OC) to organic matter (OM) is used to measure soil C on a landscape scale. However, this ratio varies according to vegetation, depth, hydrology, and may lead to miscalculations of soil C and SOM estimates. Soil C and SOM are inherently complex and it is not completely understood which environmental factors have the most influence in their formation, which occurs on a time scale of …