The occurrence of winter injury in red spruce (<u>Picea rubens</u>) L. sarg. and Fraser fir (<u>Abies fraseri</u>) pursh. poir. in relation to the level of atmospheric nitrates and climatic parameters of precipitation and temperatures was investigated. Data and foliage samples were collected from established field plots at 5500, 6000, and 6500 feet in the Black Mountains of North Carolina and from seedlings under 4 treatments of artificial rainfall. varying by N03 concentration. Samples were collected 4 times over the 1987 growing season. Responses were similar in shadehouse and field samples. Wax content differed between collections but not between treatment levels. except for shadehouse spruce. and wax content decreased after collection 2. Between treatment levels. differences were found in the amount of water lost over 14 hours, but not in the average initial fresh weight dry weight ratio (RWT). Differences were found in both RWT and transpiration rate over the growing season with field trees decreasing or remaining stable with each collection. and shadehouse seedlings increasing. No relationship between climatic parameters and annual leader growth was modeled because understory field trees were immature and exhibiting height growth. masking the effects of climate to understory trees. Winter injury ratings decreased from summer of 1987 to spring of 1988 and no significant differences in ratings were found between elevations. Classic winter injury symptoms were observed on one plot at 6500 feet, but most ratings greater than 0 were given because of the effects of shading from the overstory. / Master of Science

During the late 19th and early 20th centuries, extensive logging reduced the forests of red spruce (Picea rubens) by nearly 99% through portions of West Virginia. In the wake of this disturbance, red spruce has begun regenerating on the ridge and mountaintop areas of Canaan Valley, West Virginia, where heath and grassland communities have both persisted in natural barrens and expanded into formerly forested areas. To understand abiotic and biotic conditions guiding the advance of the red spruce stand, I conducted a broad-scale assessment of thirty-one demographics plots spread across two sites (north Cabin Mountain and Bear Rocks/Dolly Sods), and a more focused assessment of red spruce species associations within thirty-two paired plots at Cabin Mountain. At the 15m x 15m demographics plots, I conducted a count of all P. rubens present, measured specimen height, DBH or diameter at ground level (DGL) for specimens < 1.37m tall, and assessed the relative percent cover of rock, shrub, herbaceous, and tree cover. These data, along with additional abiotic components derived from a DEM, formed the basis of my assessment using a generalized linear mixed model (GLMM) to identify the most significant biophysical variables related to P. rubens count. In the paired plots, I used the relative interactions index (RII) to compare the total cover of each present non-graminoid vascular species and the grouped cover types Rock, Graminoid, Lichen, Litter, and Moss in one 45cm-radius plot with a < 1.37m P. rubens specimen, and one paired 45cm-radius plot in open heath. The significance of differences in total cover were assessed with the Wilcoxon test and Tukey HSD. The GLMM identified percent rock cover and distance from the nearest P. rubens stand to be important correlates of P. rubens count at the demographic plots. Graminoid cover was found to be higher in P. rubens 45cm-radius plots than in paired heath plots, and Vaccinium angustifolium cover was found to be concentrated in 45cm radius plots beyond the first 15cm from the P. rubens stem. These findings reinforce a complex interplay between both the biotic and abiotic characteristics of a microsite and the successful germination and regeneration of a red spruce seedling in the heathland. / Master of Science / During the late 19th and early 20th centuries, extensive logging reduced the forests of red spruce (Picea rubens) by nearly 99% through portions of West Virginia. In the wake of this disturbance, red spruce has begun regenerating on the ridge and mountaintop areas of Canaan Valley, West Virginia, where heath and grassland communities have both persisted in natural barrens and expanded into formerly forested areas. To understand the necessary abiotic and biotic conditions guiding the advance of the red spruce stand, I conducted a broad-scale assessment of thirty-one demographics plots spread across two sites (north Cabin Mountain and Bear Rocks/Dolly Sods), and a more focused assessment of red spruce species associations within thirty-two paired plots at Cabin Mountain. At the 15m x 15m demographics plots, I measured and counted all red spruce present. I collected landscape and community data on each plot using field surveys and a digital elevation model (DEM) to the variables most associated with a higher count of red spruce in each plot. In the 45cm-radius paired plots, I used simple mathematical comparisons to identify positive and negative interactions between red spruce shorter than breast height (1.37m) and different types of cover, including heathland species such as Vaccinium angustifolium (lowbush blueberry), rock, graminoid, and moss. Modeling indicated that rock cover, and distance between the plot and the nearest stand of red spruce, were found to be the most significant variable affecting the count of red spruce at each plot, with increased rock cover and shorter stand distance both associated with higher numbers of spruce. In the paired plots, there was slightly higher graminoid cover associated with the tree than with the open heath plot, and V. angustifolium was more concentrated beyond 15cm from each red spruce specimen. These findings suggest that rock cover is important for tree regeneration both the biotic and abiotic characteristics of a microsite and the successful germination and regeneration of a tree seedling in heathlands.

Dendrochronology studies in Atlantic Canada are rare partly because old-growth forests are scarce making it difficult to establish multiple-century tree-ring chronologies. One approach to overcome this problem is to use tree-ring records found in the wood of historical structures. For our study, the Sinclair Inn in Annapolis Royal, Nova Scotia, was selected for a dendroarchaeological assessment because of its rich and complex history: it resulted from the merging of two early 18th Century houses (the Soullard and Skene houses). To date the Sinclair Inn, three other historical structures of a younger age were used to establish an annual ring record in lieu of old-growth forest data. Red spruce (Picea rubens), a dominant tree species in the Maritimes, was the most prominent wood found in the structures and allowed for the creation of a regional red spruce reference chronology extending far enough into the past to cover the supposed period of construction of the Sinclair Inn. Crossdating results indicate cutting dates of 1709 and 1710 for the Skene and Soullard houses, respectively, and 1769 for the inn itself. In the process of dating the structure, a ,200-year long regional floating red spruce chronology (1591–1789) was developed that will further help future dendrochronological investigations in the Maritimes.

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<p>Red spruce forests, one of the most critically endangered ecosystems in the United States</p>provides critical habitat for several endemic species or subspecies of the Appalachian Mountains, including the Virginia northern flying squirrel. Once listed as threatened under the Endangered Species Act, the Virginia northern flying squirrel was delisted in 2013. Managers are currently focusing their efforts on projects that increase the extent and connectivity of the squirrel’s habitat through red spruce restoration. At present, there is a paucity of available data to assess the implications of the silvicultural activities associated with red spruce restoration on the movement and occupancy of the Virginia northern flying squirrel. In order to inform management activities, I measured home range, fine-scale habitat use, and estimated detection and occupancy for northern flying squirrels across a gradient of red spruce stands in the Monongahela National Forest. I concluded that home ranges for northern flying squirrels within this region are comprised primarily of red spruce and that northern flying squirrels were selecting larger diameter trees compared to the nearest available neighbor. Additionally, I found that microhabitat characteristics alone did not sufficiently predict northern flying squirrel occupancy and that acoustic methods for surveying northern flying squirrels will require further refinement. Future research efforts should focus on a combination of landscape-level and microhabitat covariates to best predict occupancy of this species across the landscape. Future red spruce management should be approached with caution regarding the potential impact on northern flying squirrel habitat in the short-term. I recommended using spatially-explicit modeling to assess the long-term effects of proposed red spruce restoration projects on northern flying squirrel population demographics, dispersal, and metapopulation connectivity prior to the implementation of silvicultural treatments.

Picea rubens(red spruce) populations experienced a synchronous rangewide decline in growth and vigor starting in the 1960’s, which was likely caused by climate change or environmental disturbances (e.g., acid deposition); However, it is yet unknown if populations continue to decline or have recovered. In the context of global warming, red spruce is a species of concern because it is at its southern continuous range margin in Massachusetts. This study uses tree-ring data coupled with population data from permanent plots to quantify the status of red spruce in Massachusetts. Tree cores were extracted from red spruce and used to examine radial growth rates, determine a growth-climate relationship, and document disturbance events. Red spruce at these plots ranged from 90 to 184 years old, and comprised 15 to 29 m2/ha-1 basal area. Over the past 50 years, red spruce has decreased in density, basal area, and relative importance while red maple, yellow birch, and American beech have increased. Red spruce saplings persisted in some plots, but the sapling layer was comprised mostly of American beech or red maple. However, red spruce seedlings were common at red spruce dominant plots indicating that if favorable conditions occur, it could return to its more dominant position in the canopy. Dendroclimatological analyses show that red spruce is sensitive to both temperature and precipitation. Most sites are correlated with temperature, while only twoforests were correlated to precipitation. The general temperature response of the red spruce studied was positively correlated with winter temperatures while the general precipitation response was negatively correlated with precipitation. Temporal analysis of the climate-growth response indicates that red spruce here have not had a temporally-stable, climate-growth relationship. Prior to 1960, radial growth was positively correlated with temperatures from November of the previous growing season to January of the current year. After 1960, all sites showed a shift in growth responses consistent with increased summer temperature stress; narrowed tree rings were formed during warm temperatures in July and August. Precipitation remained relatively constant over the past century, while temperatures have increased up to 2˚C across the study area. Of the two precipitation-sensitive forests, one forest shifted from being positively correlated with current January precipitation to negatively correlated with previous October precipitation while the second forest showed a strong positive relationship with August precipitation. Because the radial growth of red spruce here are mostly constrained by temperatures, there has been negative growth response to regional warming and precipitation has been stable, I suggest the change in climate response is potentially due to warming and a physiological threshold response to increasing temperatures. Interestingly, disturbance frequency and intensity have increased over the same time period, which could be either a trigger or a response to the shift in the growth-climate relationship.

Understanding tree physiological responses to climate change is critical for quantifying forest carbon, predicting species' range change, and forecasting growth trajectories. Continued increases in temperature could push trees into conditions to which they are ill adapted -- such as decreased depth of winter snow cover, altered water regimes, and a lengthened effective growing season. A complicating factor is that in the northeastern United States, climate change is occurring on a backdrop of acid deposition and land-use change. In this dissertation, I used three studies to investigate the spatiotemporal nuances of resultant tree and sapling physiology to environmental change. First, I compared annual growth of co-occurring tree species (sugar maple, red spruce, red maple, yellow birch, and balsam fir) along an elevational gradient on Vermont's tallest peak: Mt. Mansfield. I found baseline differences in growth among species, and many annual variations were associated with species-specific events. Yet, protracted growth patterns, such as recent increases for red spruce and red maple, were correlated with increased temperature and cooling degree days (a heat index). For most species, temperature was positively associated with current growth, but negatively associated with growth the following year. This work demonstrated species' differences in response to change and the complex relationships between growth and temperature. Next, I analyzed how climate, environmental parameters, and site and tree factors related to recent, regional increases in red spruce growth. While there was variability in response to climate and acid deposition by elevation and location, site and tree factors did not adequately explain growth. Higher temperatures outside the traditional growing season were positively related to growth, while nitrogen deposition was strongly negative. However, if nitrogen inputs decline as projected then the strength of this relationship may decrease over time. These results suggest continued favorable conditions for red spruce in the near term as acid deposition declines and temperatures increase, provided precipitation remains adequate to support growth. Lastly, I used a replicated micro-catchment study to examine how four species of tree saplings (paper birch, quaking aspen, American chestnut and black cherry) responded to experimentally elevated temperature (2-4C above control) and reduced early winter snow (first six weeks of winter), depending on soil type. Soil and species characteristics strongly influenced sapling response. However, natural weather patterns during the treatment period were highly variable and muted or exacerbated results. Heating increased the potential photosynthetic period in the fall, causing an overall increase in leaf area. Many two- and three-way interactions of treatment factors were also detected. These outcomes demonstrate the variability in sapling response to a changing climate, as well as the complex interactions that occur among soil, species, and weather parameters.

The (Plethodon nettingi) Cheat Mountain Salamander is a rare and endangered species that relies heavily on (Picea rubens) Red Spruce for habitat. P. rubens communities on the Cheat Mountain range in West Virginia have been disturbed by fires and logging, and regeneration of P. rubens stands are central to the survival of the P. netting. A supervised and unsupervised landscape classification of three Landsat images over the past 26 years was conducted to analyze change in P. rubens communities on Cheat Mountain Range. Change detection results revealed that from 1986-2012 a 52% growth increase of P. rubens stands, 18% loss, and 29% stayed the same over the last 26 years. P. rubens stands are vital habitat to the rare and endangered P. netting and regrowth of P. rubens is vital in restoring the habitat of the salamander on the Cheat Mountain. The regrowth of P. rubens on the Cheat Mountain range is critical to the survival of the P. nettingi. Identifying critical forest as it relates to salamander habitat is essential for conservation efforts. Since not all P. rubens stands are of equal significance to the P. nettingi, it is important to identify and map those that adhere to their stringent habitat needs as defined by forest fragmentation, aspect, slope, and lithology. I used spatial analysis and remote sensing techniques to define critical forest characteristics by applying a forest fragmentation model utilizing morphological image analysis, northeast and southwest aspects, moderate slopes, and limestone lithology. Patches were ranked based on this quantitative model and key P. rubens stands identified using spatial statistics. The results could aid in prioritizing research areas as well as conservation planning in regards to P. rubens and the P. nettingi. In this study, the MaxEnt modeling framework was used to predict habitat suitability for P. rubens under current conditions and under two future climate change scenarios. P. rubens distribution data was acquired from the U.S Geological Survey. Both the IPCC A1B and A2 emission scenarios of the HadCM3 global circulation model were projected to years 2040-2069 and 2070-2099. Results showed that a substantial decline in the suitability of future P. rubens habitat on the Cheat Mountain is likely under both climate change scenarios, particularly at lower elevations. By the end of the century, P. rubens is likely to be extirpated from the Cheat Mountain Range. By the end of century, the A1B and A2 scenarios predict the average habitat suitability for P. rubens on Cheat Mountain will be 0.0002 and 0.00004 respectively. Conservation as well as species migration efforts for P. rubens should be focused on areas such as Cheat Mountain to preserve this vital habitat.

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