Thesis (M.S.) in Forestry--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 83-88).

Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on June 12, 2006). Thesis advisor: Jennifer A. Franklin. Vita. Includes bibliographical references.

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Den produktiva skogsarealen i Sverige som är grandominerad utgörs av 9,5 miljoner ha(Skogsstyrelsen 2011). Varav knappt 0,2 miljoner ha står på torr mark (personlig kommunikation Göran Kämpe, 2015). Problematiken i södra Sverige är att gran planteras på allt för torra marker, eftersom att tall anses för osäkert pga av betestrycket av vilt.  I undersökningen utreds om och när tillväxten avtar för granen på torrare marker i sydöstra Sverige med hjälp av bestämning av ståndortsindex (SI).  Höjdtillväxten har, med hjälp av borrning/kapning på olika trädhöjder, rekonstruerats i granbestånd för en hel omloppstid. Detta har utförts på två olika lokaler där tall hade varit det naturliga valet och där granen bedöms lida av vattenbrist. Fokusområdet är ifall höjdtillväxten och SI avtar för granen på tall/torra marker under omloppstiden, som kan ses som en indikation på granknytning. Resultatet visar att granbestånden har ett betydligt högre ståndortindex i ungskogsfasen jämfört med när beståndet är äldre.  Under omloppstiden visar det sig att ståndortindexen ändrar sig vid två tillfällen under granbeståndets livslängd, eventuell vattenbrist uppstår. Bestämning av SI visade att bestånden motsvarade en G30 i ungskogsfasen men vid slutavverkning hade det sjunkit till en G24. / Today we know that 9,5 million hectares of productive forest land in Sweden consists of Norway spruce (Skogsstyrelsen 2011), of which almost 0.2 million hectares are standing on dry land with low moisture content (personal, communication Göran Kämpe, 2015). The problem today in southern Sweden is that Norway spruce is planted on arid lands, because that pine is considered unsafe due to damage on young plants done by wild animals. The study investigates if and when growth slows down for spruce on arid lands in south-eastern of Sweden, based on determination of a site index (SI) for a whole rotation. In order to determine SI, increment cores/cutting at different tree height has been conducted. It compares the height growth of spruce stands during the rotation period, on land where the pine had been the natural choice and where the spruce likely suffers from a water deficit. The focus area of this study is if height growth and SI declines with age as an indication of water deficit in older stands. The boundaries are the economic part. The result shows that the spruce stands had a considerably higher site index at an early age, compared when it reaches older ages. During the rotation period, it turns out that site index drops twice during the rotation period, when a possible water deficit occurs. Calculations of the site index show that SI of G30 in the young stand but at time for clear-felling, it drops to a G24.

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.