<div>Prescribed fire is one of the most useful tools available to forest managers attempting to maintain oak-hickory forests in the Central Hardwood Region. Prescribed fire can be useful in promoting regeneration of desirable species groups like oak (Quercus spp.) and hickory (Carya spp.) by preparing the seedbed, managing competition, and creating canopy gaps. The use of prescribed fire has been limited by concerns regarding the effect of the practice on standing timber. A perception of strong negative effects to tree-quality and tree-value from fire originated largely from sometimes deleterious effects of wildfire on timber. Less research exists demonstrating the potential effects of controlled, prescribed burning on timber quality and value. Furthermore, most research that exists focuses on individual tree characteristics, and is often focused on a relatively small geographic areas.</div><div><br></div><div>I conducted a regional study on the effects of prescribed fire on timber quality across a gradient of the Central Hardwood Region, ranging from the Missouri Ozarks to the Appalachian foothills. I studied 139 stands in selected prescribed fire units and control sites in Mark Twain National Forest (MO), Hoosier National Forest (IN), Wayne National Forest (OH) and Daniel Boone National Forest (KY). Selected stands were dominated by hardwoods species and had variable prescribed fire histories, ranging from 0 to 6 prescribed fires. </div><div><br></div><div>Measurements were taken concurrently across this plot network for two studies. First, we assessed the estimated effect of prescribed fire on stumpage value, and secondly, we assessed wounding patterns and effects of prescribed fire on tree-quality. Loss in estimated stumpage value from prescribed fire averaged approximately 4.2% across all measured stands. Estimated loss in stumpage value varied significantly by the number of prescribed fires in the last 30 years, with increasing numbers of prescribed fires leading to higher estimated losses in stumpage value. Further, stands in Mark Twain National Forest exhibited higher estimated loss in stumpage value, exceeding 10% on average. Stands in Hoosier, Wayne, and Daniel Boone National Forest only rarely exceed 5% losses in estimated stumpage value, and averaged less than 3%. </div><div><br></div><div>Approximately 25% of trees had at least one wound associated with prescribed fire across all study sites, while approximately 5% of trees experienced a reduction in tree quality (as measured by United States Forest Service tree grade) from prescribed fire. Both the rate of wounding and rate of tree grade reduction increased with increasing numbers of prescribed fires. Stands in the western portion of the Central Hardwood Region (Hoosier and Mark Twain National Forest) exhibiting higher rates of wounding from fire compared to eastern sites (Wayne and Daniel Boone National Forest.)</div><div><br></div><div>Effects of wounding varied significantly by type of wound. Catfaces accounted for far more volume loss and reduction in tree grade than any other wound type. Alternatively, some wound types, like seams and bark slough, caused minimal tree-quality and tree-volume effects. Effects also varied by species, with higher wounding effects on sugar maple and red oak, and relatively low effects on white oak and yellow-poplar. </div><div><br></div>

The Forest Inventory and Analysis (FIA), the United States’ forest census, measured sixty-six Mexican spotted owl nest stands in order gain insight into the structure and composition of the nest habitat of this threatened species. I used these data, along with the greater FIA database and the Forest Vegetation Simulator to explore questions surrounding the management of Mexican spotted owl habitat, specifically how to balance the objective of sustaining and enhancing nest habitat in face of increasing forest fire size and severity in the Southwest. My research consisted of three studies. The first study quantified the structure and composition of the Mexican spotted owl nest stands and scrutinized current evaluation criteria of nest habitat. The second study estimated how much of the Southwestern landscape is at risk to high-severity crown fire and how much of the landscape is suitable Mexican spotted owl nest habitat. The third study modeled forest dynamics and silvicultural intervention in potential Mexican spotted owl nest stands. The purpose of this research is to assist in management of Southwestern forests in order to decrease fire size and severity while sustaining and enhancing current and future Mexican spotted owl nest habitat.

Thousands of hectares of red pine (Pinus resinosa Ait.) plantations were established during the early 20th century to restore abandoned agricultural lands and increase forest cover. Concern over the ecological integrity [i.e. the degree to which a community is determined to be characteristic of its natural region, including abiotic and biotic components, likely to persist and maintain the rates of change and supporting processes (Canada National Parks Act (S.C. 2000, c. 32) 2011) of these plantations and a desire to increase native forest cover has prompted a more thorough understanding of the understory succession of these plantations. This study addresses the question, how does the understory vegetation composition and diversity in managed red pine plantations compare to the understory of a reference deciduous forest?. I examined the understory diversity in a chronosequence of managed red pine plantations owned by Simcoe County. Biophysical characteristics including diffuse non-interceptance (DIFN), tree regeneration, litter depth, and soil physical and chemical properties were gathered from three replicates of each of four age groups and from a reference deciduous forest group in order to determine how each variable changed and influenced the succession of the understory diversity. Field investigations were completed during the spring, summer, and fall of 2009 in order to examine seasonal differences in diversity. A two-way analysis of variance with a Tukey’s post hoc test was used to determine if the forest groups were significantly different from each other for each variable measured. Species diversity (measured by the Shannon-Wiener Index) generally increased with plantation age and seasonal differences were apparent. A lack of significant difference between the oldest plantation group (est. 1927-1932) and the reference forest group indicates diversity is increasing; this is intriguing because, in contrast, species composition is only 30% similar. This may indicate either not enough time has passed for the understory to regenerate or the understory in the plantations is succeeding in a different trajectory. Furthermore, spring ephemeral species were lacking in the understory of the plantation forests indicating this phenological group is not regenerating in the plantations. Tree density is generally increasing in the plantation groups and the dominant tree species regenerating in the oldest plantation group includes a similar suite of species to that found in the reference forest groups. This indicates that the canopy is succeeding towards a native forest community. Pearson correlation analysis revealed that litter depth is significantly negatively correlated to diversity in the summer and fall (p<0.01). Litter depth was also the primary predictor variable produced by the forward stepwise regression in the summer and fall indicating that litter depth is a major driver of diversity. From comparative studies, a deeper litter layer often inhibits the germination and emergence of herbaceous species; from my study, this may explain the lack of spring ephemerals in the plantation groups observed. DIFN was significantly negatively correlated to diversity in the spring (p<0.01) and was the predictor variable for spring diversity indicating that light characteristics in the spring are a major variable influencing spring diversity. With increasing age of plantation group the DIFN followed a similar pattern to the reference forest group indicating that the thinning regime and regeneration is shifting the light characteristics to that found in a natural forest stand. I conclude that the thinning regime in red pine plantation is promoting the regeneration of trees and increasing the diversity of understory vegetation. However, in order to direct the successional trajectory of the understory vegetation of red pine plantations to a composition similar to the native woodlands of that area, a modified management program should be considered and active restoration should be implemented.

Le bois est un matériau complexe, hétérogène et anisotrope. Ses propriétés mécaniques varient fortement en fonction de l'essence et de l'échelle considérées. Pour mieux comprendre le comportement du bois en fonction de sa structure, nous proposons dans le cadre de cette thèse une étude expérimentale à l'échelle des tissus qui est réalisée sur plusieurs types de bois : bois de peuplier, y compris bois de tension et bois d'épicéa. Compte tenu des faibles dimensions des échantillons testés, les mesures de déformation sont effectuées " sans contact " afin de s'assurer de ne pas perturber l'échantillon en cours de l'essai.Les premières séries de mesures sont réalisées sur les trois zones (tendue, normale, opposée) et selon les 3 directions matérielles (longitudinale, radiale et tangentielle) d'une tige de peuplier inclinée. Les résultats obtenus permettent de comparer des comportements mécaniques du bois de peuplier dans toutes les zones considérées en fonction de ses propriétés microscopiques.Les deuxièmes séries de mesures sont réalisées en compression, grandes déformations, dans la chambre d'un ESEM (Microscope électronique à balayage environnemental) sur du bois feuillu (peuplier) et sur du bois résineux (épicéa). Grâce aux images obtenues en période d'essai, du domaine élastique jusqu'à la densification, la réponse de chaque type du bois à la même sollicitation est illustrée.Enfin, une partie de la modélisation numérique par la MPM (Materiel Point Method) est proposée dans notre projet envisagé comme prolongement de ce travail. Il permettra de simuler le comportement mécanique du bois en grande déformation.

För tallen finns många alternativa slutanvändningsområden, och kraven på virket varierar. Några egenskaper som har stor betydelse är stamrakhet, grengrovlek, grenvinkel och om det finns sprötkvist eller ej. Kvalitetsförsämringen i Sydsveriges tallskogar kan vara ett allvarligt problem och härör bl.a. till ökad produktion och rationaliseringar inom skogsbruket. Lönsamhet har varit målet, men har det skett på bekostnad av kvalitet? För att närmare belysa frågan om förekomsten av tall av god kvalitet syftar denna studie till att bedöma rotstockar i konventionellt skötta och stamkvistade bestånd samt deras potential att växa in i värdefulla klasser eller sortiment. Fältstudien är avgränsad till Bergslagen. I mätningarna har endast rotstock (upp till 3,4 m i längd) av träden bedömts, huruvida de har potential att hålla klass 1-kvalitet, sortiment stamblocks-kvalitet eller sortiment rotstock-kvalitet vid en brösthöjdsdiameter av 320 mm. Andelen rotstockar ≥ klass 1 uppskattades i de stamkvistade bestånden bli 72-94 %, då skötseln också syftat till en värdeökning.  Andelen rotstockar ≥ klass 1 i de konventionellt skötta bestånden uppskattades bli 46-56 %. Med stor sannolikhet kommer ingen av dem dock få växa in i de värdefullaste klasserna. Vanligaste nedklassningssorsakerna är för många kvistar och ibland även i kombination med krök i de konventionellt skötta bestånden samt långkrök i de stamkvistade bestånden. I rapportens teori avhandlas olika sortiment och kvalitetsklasser, och sedan undersöks kvalitetsdanande faktorer bl.a. ekologiska förutsättningar och olika skötselåtgärder. En hög röjningsstyrka kan t.ex. resultera i en grövre diameter på grenar. Likaså har sen röjning inverkan på den grövsta grenens diameter, då den minskar. Det finns alltså en potential att erhålla god virkeskvalitet av tall i våra skogar. Detta är möjligt genom aktiv skötsel, att hålla täta förband, genom att gallra ut lågkvalitativa stammar och stamkvistning. Raka tallar ur vilka kan man utvinna ett högt sågutbyte är och kommer att vara en värdefull resurs i framtiden. / In Sweden the quality of Scots pine (Pinus sylvestris) saw timber has decreased. It is especially due to increased labour cost that has led to rational and effective forest management. This study investigated the quality of Scots pine and the potential to produce high quality stems in 9 stands in Bergslagen, Sweden. Two different stand types were investigated: Pruned stands and conventional managed stands. The outcome was a high percentage of valuable stems in the pruned stands (72-94 %), and 46-56 % in the conventional managed stands. It is possible to produce high quality timber of Scots pine with active management, for example by pruning and careful selection of stems in thinnings.

The establishment of intensively managed woody energy crops on reclaimed surface mine lands provides an opportunity to diversify domestic biomass sources, while increasing the productivity and economic value of underutilized land. Our objective is to test the effect of fertilization and irrigation on the growth, survival, biomass accumulation, biomass allocation, leaf area, and nutrient dynamics of American sycamore (Platanus occidentalis L.) and black locust (Robinia pseudoacacia L.) planted on a reclaimed surface mine. In 2008, replicated plantings of sycamore and black locust were established on the Big Elk mine in eastern Kentucky. Treatments tested include annual granular fertilizer applications of 37 kg N, 30 kg P, and 16 kg K ha-1, irrigation, irrigation + fertilization, and control. Following two growing seasons, American sycamore exhibited significantly (p < 0.05) greater height, diameter, leaf area, and stem biomass in fertilizer treatment compared to all other species and treatment combinations. Treatments had no affect on survival, but American sycamore exhibited significantly higher survival than black locust. Poor locust survival and growth were likely attributed to excessive ungulate browsing. Our findings indicate that fertilizer applications at young plantations on reclaimed mines in Appalachia increases tree height, diameter, and biomass accumulation.

Thousands of hectares of red pine (Pinus resinosa Ait.) plantations were established during the early 20th century to restore abandoned agricultural lands and increase forest cover. Concern over the ecological integrity [i.e. the degree to which a community is determined to be characteristic of its natural region, including abiotic and biotic components, likely to persist and maintain the rates of change and supporting processes (Canada National Parks Act (S.C. 2000, c. 32) 2011) of these plantations and a desire to increase native forest cover has prompted a more thorough understanding of the understory succession of these plantations. This study addresses the question, how does the understory vegetation composition and diversity in managed red pine plantations compare to the understory of a reference deciduous forest?. I examined the understory diversity in a chronosequence of managed red pine plantations owned by Simcoe County. Biophysical characteristics including diffuse non-interceptance (DIFN), tree regeneration, litter depth, and soil physical and chemical properties were gathered from three replicates of each of four age groups and from a reference deciduous forest group in order to determine how each variable changed and influenced the succession of the understory diversity. Field investigations were completed during the spring, summer, and fall of 2009 in order to examine seasonal differences in diversity. A two-way analysis of variance with a Tukey’s post hoc test was used to determine if the forest groups were significantly different from each other for each variable measured. Species diversity (measured by the Shannon-Wiener Index) generally increased with plantation age and seasonal differences were apparent. A lack of significant difference between the oldest plantation group (est. 1927-1932) and the reference forest group indicates diversity is increasing; this is intriguing because, in contrast, species composition is only 30% similar. This may indicate either not enough time has passed for the understory to regenerate or the understory in the plantations is succeeding in a different trajectory. Furthermore, spring ephemeral species were lacking in the understory of the plantation forests indicating this phenological group is not regenerating in the plantations. Tree density is generally increasing in the plantation groups and the dominant tree species regenerating in the oldest plantation group includes a similar suite of species to that found in the reference forest groups. This indicates that the canopy is succeeding towards a native forest community. Pearson correlation analysis revealed that litter depth is significantly negatively correlated to diversity in the summer and fall (p<0.01). Litter depth was also the primary predictor variable produced by the forward stepwise regression in the summer and fall indicating that litter depth is a major driver of diversity. From comparative studies, a deeper litter layer often inhibits the germination and emergence of herbaceous species; from my study, this may explain the lack of spring ephemerals in the plantation groups observed. DIFN was significantly negatively correlated to diversity in the spring (p<0.01) and was the predictor variable for spring diversity indicating that light characteristics in the spring are a major variable influencing spring diversity. With increasing age of plantation group the DIFN followed a similar pattern to the reference forest group indicating that the thinning regime and regeneration is shifting the light characteristics to that found in a natural forest stand. I conclude that the thinning regime in red pine plantation is promoting the regeneration of trees and increasing the diversity of understory vegetation. However, in order to direct the successional trajectory of the understory vegetation of red pine plantations to a composition similar to the native woodlands of that area, a modified management program should be considered and active restoration should be implemented.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Existem na região sudoeste do Rio Grande do Sul campos recobertos de areia conhecidos pelo nome de “areais”, ou campos de areia. O interesse por estudar esses campos de areia surge da constatação que esses campos de areia se apresentam como um problema para a sociedade, principalmente a partir da década de 70, quando os areais passam a ser chamados de “desertos” e a possibilidade de alastramento desses “desertos” passa a representar uma ameaça para as sociedades que vivem em seu entorno. Nesse contexto, novas percepções e concepções surgem acerca desses campos de areia, influenciando o modo como os agricultores agem em relação aos areais. Nesse sentido, os agricultores que habitam seu entorno, passam a adotar uma série de atitudes na tentativa de controle dos areais mediante a instalação de dispositivos que resultam em modificações na paisagem, deixando marcas humanas capazes de revelar as intenções de sua construção. Entre essas atitudes ambientais destaca-se a proposição do plantio de espécies arbóreas, entre as quais se destaca o eucalipto, apresentadas à sociedade como capaz de controlar a dinâmica de arenização e inserir a região de ocorrência dos areais em uma nova matriz econômica, mediante sua inserção no mercado da silvicultura industrial. No presente estudo de caso, os “Campos de Areia da Vila Kraemer” (São Francisco de Assis/Rio Grande do Sul/Brasil), foi identificada uma tendência crescente de plantio de espécies arbóreas como uma proposição de controle humano dos areais, amplamente difundida entre os agricultores e a assistência técnica local e que configura o processo chamado de “verticalização da paisagem”. Para o entendimento das dimensões subjetivas que envolvem a “verticalização da paisagem”, foi adotada a fundamentação teórica e metodológica que investiga a participação dos valores ambientais como mecanismo transformador da paisagem, ou, ainda, a paisagem como manifestação espacial dos valores ambientais. Os resultados dessa pesquisa exploratória contemplam o desenvolvimento, ao longo das últimas três décadas, de uma transformação cultural, motivada por aspectos externos, regionais e globais, que resultou em valores ambientais, de âmbito local, amplamente favoráveis a uma recorrente transformação de paisagens vernaculares, predominantemente campestres, em paisagens exóticas, mediante a introdução da monocultura arbórea. / In southwest Rio Grande do Sul there can be found fields covered with sand. These specific places are called “areais”, or sand fields. The interest in studying these sand fields took place mainly after de 70s, when sand fields begin to be seen as a problem to society, as “areais” they are associated to “deserts” and the possibility of their spreading is understood as a threat to surrounding societies. In this context, new perceptions and conceptions about the sand fields begin influencing the way local farmers act in relation their existence. Since then, neighbor farmers have installed new devices that end up changing the local landscape, in order to control the "areais". These changes reveal their intentions, such as the planting of tree specimens (especially Eucalyptus) that are presented to society as capable of controlling the dynamics of sandization and the insertion of the “areais” region in a new economical matrix: the industry of silviculture. In the present study case, the “Sand Fields of Kraemer Village” (“Campos de Areia da Vila Kraemer”), in the municipality of São Francisco de Assis, was identified as a place with an increasing tendency to the planting of tree specimens with the purpose of controlling the sand fields. The practice, known as “landscape verticalization”, was broadly spread among farmers and local technical assistance as a positive method to contain sandinization. In order to understand the subjective dimensions that involve the “landscape verticalization”, the theoretical and methodological framework adopted in this study investigate environmental values that has supported these landscape transformation or, moreover, landscape as a spatial manifestation of environmental values. The results of this research contemplate the development, along the three last decades, of a cultural changing, motivated by external, regional and global aspects that have resulted in the consolidation of environmental values that favor the modification of vernacular landscapes, predominantly that of fields, into exotic ones where there can be seen monoculture trees plantations.