Forest management practices emphasizing stand structural complexity are of interest across the northern forest region of the United States because of their potential to enhance carbon storage. Our research is nested within a long-term study evaluating how silvicultural treatments promoting late-successional forest characteristics affect aboveground biomass development in northern hardwood forests. We are testing the hypothesis that biomass development (carbon storage) will be greater in structural complexity enhancement (SCE) treatments when compared to conventional uneven-aged treatments. SCE treatments were compared against selection systems (single-tree and group) modified to retain elevated structure. Manipulations and controls were replicated across 2-hectare treatment units at two study areas in Vermont, USA. Data on aboveground biomass pools (live trees and coarse woody material, standing dead and downed wood) were collected pre- and post-harvest then again a decade later in 2013. Species group-specific allometric equations were used to estimate live and standing dead biomass and downed log biomass was estimated volumetrically. We used Forest Vegetation Simulator to project "no-treatment" baselines specific to treatment units, allowing measured carbon responses to be normalized relative to differences in site-specific characteristics and pre-treatment conditions. Results indicate that 10 years post-harvest biomass development and carbon storage were greatest in SCE treatments compared to conventional treatments, with the greatest increases in coarse woody material (CWM) pools. Structural complexity enhancement treatments contained 12.67 Mg ha-1 carbon in CWM compared to 6.62 Mg ha-1 in conventional treatments and 8.84 Mg ha-1 in areas with no treatment. Percentage differences between post-harvest carbon and baseline values indicate that carbon pool values in SCE treatments returned closest to pre-harvest or untreated levels over conventional treatments. Total carbon storage in SCE aboveground pools was 15.90% below baseline conditions compared to 44.94% less in conventionally treated areas (P = 0.006). Results from CART models indicated treatment as the strongest predictor of aboveground C storage followed by site-specific variables, suggesting a strong influence of both on carbon pools. Structural enhancement treatments have potential to increase carbon storage in managed northern hardwoods based on these results. They offer an alternative for sustainable management integrating carbon, associated climate change mitigation benefits, and late-successional forest structure.

No description available.

Although the American marten (Martes americana) generally is recognized as an obligate late-seral species, the factors dictating this association are poorly understood. Martens were studied in Newfoundland, Yellowstone National Park, and in a captive setting. As expected, use of habitat types was not proportional to availability P < 0.001). Defoliated and late-seral conifer stands were used more than expected, while all other types indicated expected or less than expected use. Habitat selection by martens was detectable at spatial scales greater than 80 m (P < 0.001). Newfoundland martens were radio-collared and monitored for diet activity during the winters of 1990 and 1991. A regression of the percent active fixes on temperature had a negative slope (P = -4.45, P= 0.084, n = 12), indicating that martens did not minimize their exposure to low temperatures. A log-linear model suggested that the presence or absence of light was the only factor associated with marten activity patterns (P < 0.001). Martens in Western Newfoundland and a population in Yellowstone National Park were tested for their response to predation risk using bait stations in various habitat types. Visitation rates of martens at bait-boxes were not different between study sites (P = 0 .190). However, martens visitation by habitat was different (P = 0.001). Martens use of bait-boxes was similar in old-growth and defoliated habitats, suggesting that foliar cover may not have a strong influence on the risk of predation for martens during winter. Martens did use bait-boxes in defoliated stands to a greater extent than those in open habitats (P < 0.001), suggesting that they perceived stem structure as decreasing predation risk. In captive experiments, martens selected areas with both overhead cover and woody stem structure (P = 0.012). I detected no difference between the use of areas with only overhead cover and those having only stem structure (P = 0.671). However, martens decreased foraging activity in response to a predatory cue (P = 0.004). The inability of martens to use food resources in areas lacking cover during the summer suggests a perception of increased threat associated with these areas.

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia.

Ginn Woods, a 161 acre tract of woodlands located in northern Delaware County, contains one of the largest remaining sections of old growth forest in East Central Indiana. Located approximately 15 miles north of Muncie, it has been regularly used by Ball State students and faculty for education and research for over 60 years. Despite this frequent use, little formal botanical exploration has been published. This study presents a comprehensive inventory of the vascular flora found in the woods and documents the composition and sizeclass distribution of the canopy tree species. The 370 species represent 237 genera and 94 families based on family classification by Gleason and Cronquist (1991). A total of 123 species were recorded for the first time in Delaware County. Of the 370 species listed, 56 or 15.1 % are non-native or naturalized species, thus indicating that the native species are dominant. The overstory canopy species are typical of a beech-maple woods with Acer saccharum and Fagus grandifolia as overallco-dominant species. However the importance of Fagus grandifolia varies in the sections known as North, South and Nixon Woods. With the fragmentation of regional ecosystems into isolated forest systems by urbanization and agricultural development, the maintenance and preservation of original communities becomes more difficult. Ginn Woods is one of the few remaining remanents of old growth forests in East Central Indiana and serves as an important reserve of the native flora of this area. The inventory and overstory tree species analysis provided by this study establishes important baseline data to which future studies can be compared.Ball State UniversityMuncie, IN 47306 / Department of Biology

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia.

Thesis (M.A.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 37-42). Also available via Humboldt Digital Scholar.

Thesis (M.R.M.)--Simon Fraser University, 1995. / "This is an authorized facsimile, made from the microfilm master copy of the original dissertation or master thesis published by UMI." Includes bibliographical references (p. 83-91).

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia. / Arts, Faculty of / Geography, Department of / Graduate

På grund av hårt skogsbruk har den generella skogsstrukturen i Sverige förändrats, vilket har påverkat ljusklimatet i skogsvattendrag. Övergången från gammal skog till yngre produktiv skog i kantzonen längs vattendrag har lett till ett strukturellt skifte mot mer enskiktade krontak som förmodligen lämnar lite utrymmer för ljus att tränga igenom. Ljus är en fundamental faktor som möjliggör många ekologiska processer i skogsvattendrag, vilket gör det till en viktig aspekt att undersöka för att kunna upprätthålla ett hållbart skogsbruk. Denna studie avsåg att undersöka ljusklimatet i skogsvattendrag, med syftet att utreda om det fanns skillnader i förhållande till skogens ålder. Studien utfördes i augusti 2020 i Stockholms län, och innefattade fem vattendrag i medelåldrig skog (40 – 80 år) samt fem i gammal skog (&gt;140 år). Krontakstäckning uppskattades genom hemisfäriska foton tagna med en fish-eye lins vid åtta punkter i varje provlokal, och analyserades med hjälp av en mobilapplikation (GLAMA). En inventering av träd i kantzonerna utfördes enligt point-centered quarter method, och datan användes för att beräkna träddensitet, artrikedom samt absolut densitet för varje påträffad art. Resultaten visade en liten men icke-signifikant skillnad i krontakstäckning mellan ålderskategorierna, med en något högre medelprocent i gammal skog. Både medelåldrig och gammal skog dominerades av gran, och artsammansättningen var lika oavsett ålderskategori. Träddensiteten skilde sig något mellan kategorierna, med indikationer på en högre medeldensitet i gammal skog. Ytterligare studier krävs för att minska osäkerheter samt vidare öka kunskaperna om skogsbrukets effekter för att kunna bevara de akvatiska och terrestra miljöerna i skogsekosystem. / Due to intensive forestry, the general stand structure in Swedish forests has changed, which in turn has affected light availability in forest streams. The transformation from old growth to younger productive forests in the riparian zone has led to a structural shift towards a higher density and single-leveled canopies that limits light penetration. Light is a fundamental factor promoting many ecological processes in forest streams, which makes it an important feature to examine in a sustainable forestry context. This study investigated the light climate in forest streams, with the purpose to look for differences in relation to forest age. The study was conducted in August 2020 in Stockholm County, and consisted of five streams in middle stage forests (40 – 80 years) and five in old growth forests (&gt;140 years). Canopy closure was estimated using hemispherical photos taken with a fish-eye lens at eight sample points within each site and analyzed with a mobile app (GLAMA). An inventory of trees in the riparian zone was carried out according to the point-centered quarter method, and the data were used to measure tree density, species richness and absolute density of each observed species. The results showed small non-significant differences in canopy closure between age categories, with a higher mean percentage in old growth forests. Both middle stage and old growth forests were dominated by spruce, and the species richness was the same regardless of age category. The tree density differed slightly between categories, with a tendency for a higher mean density in old growth forests. Further research is needed to reduce uncertainty and expand on the effects of forestry if we are to sustain the aquatic and terrestrial environments in forest ecosystems.