A Bark Thickness Model for White Spruce in Alaska Northern Forests

Here we developed a simple linear model to estimate white spruce bark thickness in the northern forests of Alaska. Data were collected from six areas throughout interior and southcentral Alaska. Geographic variation of bark thickness was tested between the Alaska statewide model and for each geographic area. The results show that the Alaska statewide model is accurate, simple, and robust, and has no practical geographic variation over the six areas. The model provides accurate estimates of the bark thickness for white spruce trees in Alaska for a wide array of future studies, and it is in demand by landowners and forest managers to support their management decisions.We are obligated to Carol E. Lewis and Edmond C. Packee for supporting this bark thickness research. This research was also supported in part by the United States Department of Agriculture, McIntire-Stennis Act Fund ALK-03-12, and by the School of Natural Resources and Agricultural Sciences, University of Alaska Fairbanks.We thank the associate editor, Han Chen, and an anonymous reviewer for their helpful comments

Measuring changes in preferences and perception due to the entry of a new brand with choice data

Context effects can have a major influence on brand choice behavior after the introduction of a new product. Based on behavioral literature, several hypotheses about the effects of a new brand on perception, preferences and choice behavior can be derived, but studies with real choice data are still lacking. We employ an internal market structure analysis to measure context effects caused by a new product in scanner panel data, and to discriminate between alternative theoretical explanations. An empirical investigation reveals strong support for categorization effects and changes in perception, which affect customers in two out of five segments

Levantamento das espécies arbóreas da Universidade Federal da Bahia, Salvador, Bahia

The urban green areas are important for the maintenance of the microclimate, reduction of the sonorous pollution, for the improvement of human life quality and as shelter to several animals. The Federal University of the Bahia, inserted in a major urban center, is composed by green areas and small forest fragments. The main objectives of this study are to register the arboreal species found on the UFBA and to collaborate with the knowledge of the flora of green areas located in urban centers. We collected arboreal specimens with DBH e” 10 cm, between August 2005 and June 2006, present in squares, buildings and street gardens. Species were identified and included at ALCB Herbarium. A total of 131 species distributed within 100 genera and 31 families of angiosperms and two families of gymnosperm were collected. The most diverse families were Leguminosae (30%), Arecaceae (14%), Moraceae (7%), Bignoniaceae (5%) and Malvaceae (5%). Amongst the species sampled, 65 species (49,6%) were exotic indicating that the landscape managements of the UFBA followed the standards observed in the majority of the public green areas of the Brazilian cities. Landscape interventions should prioritize the use of the native flora and take into account the natural density and distribution of the species, therefore avoiding to compromise landscape attributes and the ecological dynamics of the vegetation and related communities.As áreas verdes urbanas são fundamentais para a manutenção do microclima, redução da poluição sonora, melhoria da qualidade de vida da população e como refúgio aos animais. O conhecimento das espécies que compõem esse sistema mostra-se de grande importância para o manejo e conservação dessa vegetação. A Universidade Federal da Bahia, inserida num grande centro urbano, é composta por áreas arborizadas, incluindo fragmentos de mata nativa. Os principais objetivos deste estudo são realizar o levantamento das espécies arbóreas dos espaços livres da UFBA e contribuir para o conhecimento da flora das áreas verdes localizadas em centros urbanos. Foram coletados espécimes arbóreos com DAP e” 10 cm, durante o período de agosto de 2005 a junho de 2006, presentes nas praças, jardins de edifícios e vias (ruas e avenidas). Os espécimes foram identificados e inseridos no Herbário ALCB. Foram encontradas 131 espécies, pertencentes a 100 gêneros, distribuídas em 31 famílias de angiospermas e duas famílias de gimnospermas. As famílias mais representativas em número de espécies foram as Leguminosae (30%), Arecaceae (14%), Moraceae (7%), Bignoniaceae (5%) e Malvaceae (5%). Entre as espécies, 65 (49,6%) são exóticas, indicando que a arborização da UFBA seguiu o padrão observado na maioria das áreas verdes públicas das cidades brasileiras. Intervenções na arborização devem priorizar o uso da flora nativa e atentar para a densidade e distribuição das espécies, evitando assim possíveis comprometimentos dos atributos paisagísticos e da dinâmica ecológica da vegetação e das comunidades associadas

Long-Term Impacts of Fuel Treatments on Tree Growth and Aboveground Biomass Accumulation in Ponderosa Pine Forests of the Northern Rocky Mountains

In western North America, many low-elevation, dry forest types historically experienced frequent, low-severity fires. However, European settlement and fire suppression policies have contributed to over a century of fire exclusion, substantially altering forest structure and composition. There is considerable interest in restoring fire resilient characteristics to these forests through fuel reduction treatments. One limitation of current research on the impacts of fuel treatments is treatment longevity, as few studies have been able to quantify long-term responses to commonly applied treatments. This research evaluated tree growth and aboveground biomass responses 23 years after treatment in two silvicultural installations with different underburning prescriptions. Thinning and shelterwood treatments were implemented in 1991 in the Lick Creek drainage of southwestern Montana. Aside from a no-cut control, three post-harvest burning prescriptions were applied in each installation: a no burn, a spring/wet burn, and a fall/dry burn. In 2015 stand density was lower in all treated stands relative to the control, and peak growth of volume accumulation had passed. Stand-level basal area increment was the same across treatments, while tree-level basal area increment was greater in the fuel treatments. In the thinning live tree biomass recovered to pre-harvest levels by 2005 in all three fuel treatments, but was still less than the control. Forest floor biomass was lower in the two burned treatments relative to the two unburned treatments. In the shelterwood, tree biomass had recovered to pre-harvest levels in all fuel treatments by 2015, and was lower in the two burned treatments relative to the two unburned treatments. Forest floor biomass also tended to be lower in the burned treatments. This research suggests that tree biomass in fuel treatments can recover to pre-harvest levels within as little as 10 years while still maintaining reduced stand densities that advance several restoration objectives. Additionally, burning treatments maintain reduced forest floor biomass, even 23 years after treatment, indicating a persistent legacy of burning on this component. However, high regeneration densities indicate that a treatment regime strategies that includes understory treatments are required across treatments to maintain structures conducive to low-severity fire

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A PATH TOWARD IMPROVED MANAGEMENT OF THE NORTHERN FORESTS OF ALASKA: FOREST INVENTORY, BARK THICKNESS, AND STEM VOLUME

Thesis contributed as part of Tom Malone collection.This thesis provides three essential forest management tools that resource managers and researchers can use to improve management the northern forests of Alaska. The Cooperative Alaska Forest Inventory (CAFI) is a comprehensive database of northern forest conditions and dynamics. The basis for the CAFI database is a system of permanent sample plots located throughout interior and south-central Alaska. This information can be used to develop forest growth models and track long-term forest changes. The bark thickness model was developed because there was no published white spruce bark thickness model for Alaska. The data used to develop this and volume models were taken from stands located throughout interior and south-central Alaska. Analysis shows that this Alaska statewide bark thickness model accuracy estimates white spruce bark thickness when compared to other bark thickness models. Cubic-foot volume models were developed to estimate total stem and merchantable volume of white spruce in Alaska. These multiple-entry (diameter and height) models estimate volume both outside and inside bark. Analysis shows that these volume models were more accurate for Alaska when compared to published and unpublished white spruce models. These models can be used to estimate individual stem volume, volume per unit area, and to develop biomass models

Short reviews on the genetics and breeding of introduced to Europe forest tree species

Monograph represents short reviews on the genetics and breeding of introduced to Europe forest tree species. The management of tree species non-native to European geographical regions has a long tradition within forestry management practice. Their introduction to Europe (initially focused on growing tree species) dates back to the 18th century when enormous demands were being made on natural resources to sustain the on-going industrialization of Europe. Today issues of biomass production and C sequestration as well as the question of whether these species could increase the adaptive capacity of forests to long-term climate change patterns have fueled a growing interest in non-native tree species in Europe

Vegetation ecology of Ezemvelo Nature Reserve, Bronkhorstspruit, South Africa

A vegetation survey, based on plant communities, was conducted on the Ezemvelo Nature Reserve. The aim of the study was to identify, describe and classify plant communities of Ezemvelo Nature Reserve, and interpret them ecologically. The information derived from this study can then be used in the management of the Reserve. The floristic composition and habitat information were recorded in 210 sample plots. The data was captured in the TURBOVEG database and classified using the TWINSPAN numerical classification algorithm. The resulting phytosociological tables were compiled and organised using the MEGATAB computerised table management programme according to Braun-Blaunquet procedures. The data was also subjected to a Detrended Correspondence Analysis (DECORANA), processed by the PCOrd numerical ordination programme, to confirm the results of the classification. The ordination also illustrates any environmental gradients controlling the existence and distribution patterns of the different plant communities. Twenty-two major plant communities and 4 sub-communities were identified, described, and ecologically interpreted. The localities of the plant communities are indicated on map, compiled by using GIS. The plant communities on the Reserve are distributed in a mosaic of woodlands, grasslands and wetlands, based on the heterogeneous habitats created by the variations in topography, which is typical of Bankenveld vegetation.Dissertation (MSc (Botany))--University of Pretoria, 2007.Plant ScienceMScunrestricte

Feeding preference of pine sawyer beetle (Monochamus carolinensis) on Pinaceae and use of virtual plant walk maps as a tool for teaching plant identification courses

Doctor of PhilosophyDepartment of Horticulture, Forestry, and Recreation ResourcesJason GriffinFeeding preference experiments with the pine sawyer beetle (Monochamus carolinensis Olivier) were conducted using eleven taxa of Pinaceae. One newly emerged adult beetle (≤ 24 hours) was placed into each feeding arena (n = 124) containing three or four shoots of current season's growth from different tree species (one shoot per species) for choice experiments. Beetles were allowed to feed for 48 (2011) or 72 (2012-2014) hours, at which point shoots were removed and data collected on feeding occurrence and percent feeding area. Augmented design analyses of feeding occurrence and percent feeding area of the eleven taxa did not indicate significant evidence for feeding preferences of the pine sawyer beetle on most taxa except for a higher preference for both scots (Pinus sylvestris L.) and eastern white (P. strobus L.) pines compared to deodar cedar [Cedrus deodara (Roxb. ex D. Don) G. Don]. The feeding preference experiments suggest that pine sawyer beetle may feed on a wide-range of Pinaceae taxa. Virtual plant walk maps were developed using a web-application for two semesters of an ornamental plant identification course (n = 87). The maps allowed students to revisit plants and information covered in lecture and laboratory sections at their own convenience, using either a computer or mobile device. Survey results indicated 63% of the students used the virtual plant walk maps as a study resource. Students mainly used the maps to study the most current plant list. Most students who used the virtual maps did so to review the plants online. When asked to rate usefulness of the maps on a scale from slightly useful (1) to very useful (3), 43% of students indicated that the virtual maps study tool was very useful, 25% indicated the maps were useful, and 8% indicated that the maps were slightly useful. A significant dependence between student use frequency and student usefulness ratings of virtual plant walk maps was observed. As students’ use of the virtual maps increased, they perceived the maps to be more useful to their studies in preparing for identification quizzes. No differences between plant identification quiz scores were observed between students who used and did not use the virtual plant walk maps or between learning styles. Our survey indicated students used the virtual plant walk maps as a resource and perceived the maps as a useful tool in preparation for identification quizzes