Estimating volume gains in genetically improved stands at rotation age is challenging because first-generation progeny tests in Douglas-fir were typically established to measure the relative growth performance of individual trees from open-pollinated parent trees. The overall goal of this dissertation research was to improve growth simulation of genetically improved Douglas-fir...
In this study an improved model of biomass and nutrient estimation of coastal Douglas-fir (Psuedotsuga menziesii) in the Pacific Northwest has been developed across a wide range of stand management regimes. This study quantifies and defines the type and intensity of biomass harvest and associated removal for actively managed stands...
Knowledge of stand structure, stand dynamics, and production ecology of species mixtures lags well behind that of single-species, even-aged stands. Two mixed-species spacing trials in central Oregon allowed investigation of mixed-species dynamics in a controlled experimental setting. The first site, Pringle Butte, is a mixture of ponderosa pine (Pinus ponderosa...
Two key challenges emerge when initiating individual-tree growth models for bare ground or very young plantations. Both involve the need for a list of individual trees with known or predicted size and known expansion factor (number of trees per unit of area represented by each tree). In the case of...
The silviculture of mixed dipterocarp forests of Peninsular Malaysia can potentially be improved by developing quantitative tools and guidelines for this forest type. This thesis addresses three key objectives; 1) to test the hypothesis that a maximum size-density relationship can be identified in hill dipterocarp forests of Peninsular Malaysia, 2)...
This dataset includes species richness of native plants, pollinators and birds as well as 13 proxies for ecosystem services representing timber production, culturally-valued plants and animals, and regulating services tied to forest productivity. The data were collected from an experiment conducted in the Oregon Coast Range USA that sought to...
Forest soils and topography have long been known to influence forest productivity in complex terrain such as Oregon’s Coast Ranges. Incorporating physical site characteristics into predictions of forest growth and yield, however, has been problematic because of the high spatial variability of soil properties and the challenges associated with representing...
Northeastern Oregon geology and climate provides moderately productive conditions for forest management and timber production. Although site preparation and planting are commonly used silvicultural practices, little research exists on the efficacy of specific forest herbicides and responses of seedling survival and growth in this region. This research seeks to improve...
As the global demand for natural resources increases, more land will be intensively managed for the production of commodities such as timber, with potential consequences to biodiversity, ecological functioning and ecosystem services provided to society. Although there is strong consensus that intensive land management practices can negatively affect biodiversity, less...
Three studies were conducted to characterize and present early-seral
competition between Douglas-fir seedlings and the surrounding vegetation
communities during Pacific Northwest forest establishment. The first experiment
served as the foundation for this dissertation and was designed to quantify tradeoffs
associated with delaying forest establishment activities by introducing a fallow year...
Foresters care about site productivity and stem quality in Douglas-fir plantations for many reasons. The profitability of forest land and the economic returns on silvicultural investments are directly related to site productivity. Thus, understanding the relationships among Douglas-fir productivity, stem form and site characteristics is important economically. My objective was...
Headwater streams are generally small, first-order streams that can comprise up to 80% (by stream length) of the drainage network in mountainous areas of the Pacific Northwest. These streams are intimately connected with downstream reaches, serving as a source of sediment, woody debris, organic matter and nutrients. The surrounding forests...
In terms of production forestry, more often than not any species that is not the crop
species is considered a competitor as they are using finite growing resources that would
otherwise be available to the crop species. With specific regard to Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco) production in the Pacific...
Advances in mobile autonomous vehicles for oceanographic sensing provide new opportunities for passive acoustic monitoring of marine mammals. Acoustically equipped mobile autonomous platforms, including gliders, deep-water profiling floats, and drifting surface buoys can survey for a variety of marine mammal species over intermediate spatiotemporal scales. Additionally, such mobile platforms may...
Recent catastrophic wildfires have forced the forest management community to develop new strategies for reducing forest fuels. Tightly spaced understory trees often create a fire ladder allowing surface fires to encroach into the crowns of overstory trees. This situation can lead to intensive, catastrophic, stand-replacement forest fires. Mechanical removal or...
Field studies were conducted from 1996 to 1998 in three villages in a Highland watershed in Mae Hong Son Province, northern Thailand. The objectives of the study were to classify and define the fruit-based agroforestry cropping system and investigate
management activities used by villagers. In the first part of the...
Weed control in Pacific Northwest forests has been criticized for its potential impact on biodiversity. Changes were evaluated in conifer growth, diversity of vegetation in situ and of recruiting plants through different regeneration mechanisms after applying temporally-varied weed control by herbicide treatments based on the critical period concept. Conifer size...
Measurement error (ME) is a component of any study involving the use of actual measurements, but is often not recognized or is ignored. The consequences of MEs on estimates of tree and stand attributes and the parameters and predictions of forest models can be varied and severe, including the presence...
Without the natural occurrence of fire in ponderosa pine forests of the western US, lodgepole pine has started to dominate regeneration in many forest stands and may be gradually replacing ponderosa pine over time. This development, however, conflicts with recent efforts in this region to restore old-aged, open ponderosa pine...
Riparian areas in the Pacific Northwest provide important biotic and abiotic
features, such as down wood, moist microsites, and abundant invertebrate prey that
benefit aquatic and terrestrial amphibians. Reported high densities of amphibians from
streams and riparian areas in the Pacific Northwest highlight their importance in riparian
food webs. Amphibians...