Growth Patterns of Red Spruce Populations in Two Spruce-Fir Forest Stands in the Great Smoky Mountains National Park (original) (raw)
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Reference Curves for Central Appalachian Red Spruce
Forests
Red spruce (Picea rubens Sarg.) was a prized timber species in West Virginia during the era of resource exploitation in the late 1800s and early 1900s. As a result, central Appalachian red spruce comprise a much smaller component of high-elevation stand composition and a greatly constricted presence across the region. Widespread restoration efforts are underway to re-establish red spruce across this landscape. However, without benchmarks to gauge growth rates and stand developmental patterns, it is unclear whether these efforts are successful. Our goal was to develop reference curves predicting centile height growth for understory red spruce (≤7.6 m) across the region. We reconstructed the height growth patterns of over 250 randomly selected red spruce seedlings and saplings from 22 high-elevation stands in West Virginia. We also harvested 24 mature red spruce from the same stands to develop juvenile growth curves up to 7.6 m to compare understory growth rates of historical to conte...
Red Spruce Stand Dynamics, Simulations, and Restoration Opportunities in the Central Appalachians
Restoration Ecology, 2007
Red spruce (Picea rubens)-dominated forests occupied as much as 600,000 ha in West Virginia prior to exploitive logging era of the late nineteenth and early twentieth centuries. Subsequently, much of this forest type was converted to northern hardwoods. As an important habitat type for a number of rare or sensitive species, only about 12,000 ha of red spruce forests presently remain in the state. In order to assess the prospects for restoration, we examined six northern hardwood stands containing understory red spruce to (1) characterize stand dynamics and regeneration patterns and (2) simulate the effectiveness of restoration silviculture to enhance red spruce overstory recruitment. Stands originated in the late 1800s to early 1900s and are currently in the (late) stem exclusion or understory reinitiation stages. Five of the six stands had even-aged overstories that originated after clear-cutting. Tree-ring chronologies show high initial growth rates consistent with stand initiation. One stand, partially harvested in 1915, was uneven aged with older, legacy residuals in the canopy. Most stands had two cohorts of understory red spruce, with more than 40% of these individuals showing prior release. Our 100-year growth simulation suggested that a 50% basal area thinning from above could double red spruce basal area to support a mixed sprucehardwood stand in approximately 20-40 years. These results indicate that restoration silviculture could be an effective tool for increasing the amount and quality of this reduced forest type in the central Appalachians.
Ecological Modelling, 2011
This study provides a method for assessing a multiplicity of environmental factors in red spruce growth in the Great Smoky Mountains National Park (GSMNP) of Southeastern USA. Direct and indirect factors in the annual growth increment are first organized into a schematic input-output envirogram (ARIRS), and this information is then used to construct a simulation model (ARIM). The envirogram represents a structured conceptualization of most environmental factors involved in growth, as developed from relevant literature. This interdisciplinary synthesis distinguishes direct vs. indirect factors in growth and takes account of the systems ecology concept that indirect factors may be as important as or more important than direct ones in regulating growth. The ARIRS envirogram summarizes hierarchically organized, within-and cross-scale, local-to-global interactions, and its construction makes it obvious that growth is influenced by many cross-scale spatiotemporal interactions. More research on genecology is still needed to clarify the role of phenotypic plasticity and adaptive capacity in nutrient cycling, global change, and human disturbance.
Red spruce−Fraser fir forests are geographically limited to high elevations in the Appalachian Mountains (USA) and are considered to be endangered in the USA. We investigated the successional status and radial growth patterns in the heavily disturbed red spruce Picea rubens Sarg. and Fraser fir Abies fraseri (Pursh) Poir. forest of Roan Mountain, Tennessee and North Carolina. This study elucidates the complexity of second-growth red spruce development after logging and disturbances by balsam woolly adelgid Adelges piceae Ratz. We documented precise temporal information of stand age, disturbance regimes, recruitment patterns, and the successional trajectory of the spruce−fir forest community. We used radial growth patterns of red spruce samples to detect the frequency and magnitude of disturbance. Red spruce was the oldest dominant canopy species, although Fraser fir had high recruitment rates over the past 80 yr. Changes in forest structure and species richness coincided with stand-wide disturbance events such as balsam woolly adelgid infestation and widespread early twentieth-century logging. The competitive advantage of Fraser fir over red spruce has resulted in an even-aged Fraser fir-domi- nant forest that occupies a relatively early stage of successional development. This study provides a 130 yr environmental history to assist land managers in the southern Appalachian Mountains as they develop long-term restoration plans for this unique ecosystem. KEY WORDS: Disturbance · Spruce−fir forest · Dendroecology · Stand dynamics · Logging · Balsam woolly adelgid
Red spruce (Picea rubens) populations experienced a synchronous rangewide decline in growth and vigor starting in the 1960s, likely caused by climate change and a combination of environmental disturbances. However, it is not yet known if populations continue to decline or have recovered. Red spruce growing near its southern range margin in Massachusetts is a species of concern, in light of the vulnerability to climate change. This study uses population data from 17 permanent plots coupled with tree-ring data to examine radial growth rates, determine the growth-climate relationship, and document disturbance events. Red spruce at these plots ranged from 90 to 184 years old, and comprised 15 to 29 m 2 /ha basal area. Red spruce seedlings and saplings were common at plots with previously high overstory spruce abundance, indicating it could return to a more dominant position under favorable growing conditions. However, permanent plot measures over a 50 year time span did not indicate any consistent trends for changes in basal area or density for red spruce or other woody species. Climate data show that mean annual minimum, maximum, and summer temperatures have increased over the last 100 years. Dendroclimatological analyses indicated that red spruce growth was sensitive to both temperature and precipitation. Prior to the 1960s, spruce at these sites showed a positive response to precipitation; however after a multi-year drought in the 1960s showed an increasingly negative correlation with precipitation. There has been a negative growth response to regional warming, as spruce radial growth was mostly constrained by increasing temperatures, potentially coupled with the associated increasing drought-dress. I suggest the change in climate response is potentially due to a physiological threshold response to increasing temperatures, which may cause spruce to continue to decline or be lost from the lower elevation sites, while the high elevation sites has a persistent spruce population. Allen CD, Macalady AK, Chenchouni H. 2010. A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecology and Management 259:660-684 (86)90107-9. Conkey LE. 1988. Decline in old-growth red spruce in western Maine-an analysis of wood density and climate. Lazarus BE, Schaberg PG, Hawley GJ, DeHayes DH. 2006. Landscape-scale spatial patterns of winter injury to red spruce foliage in a year of heavy region-wide injury. Canadian Journal of Forest Research 36:142-152 DOI 10.1139/x05-236. Likens GE, Driscoll CT, Buso DC. 1996. Long-term effects of acid rain: response and recovery of a forest ecosystem. Science 272:244-246 DOI 10.1126/science.272.5259.244. Loarie SR, Duffy PB, Hamilton H, Asner GP, Field CB, Ackerly DD. 2009. The velocity of climate change. Nature 462:1052-1055 DOI 10.1038/nature08649. Lorimer CG, Frelich LE. 1989. A methodology for estimating canopy disturbance freuency and intensity in dense temperate forests. Moore PT, Van Miegroet H, Nicholas NS. 2008. Examination of forest recovery scenarios in a southern Appalachian Picea-Abies forest. Forestry 81:183-194 DOI 10.1093/forestry/cpn013. Morin X, Viner D, Chuine I. 2008. Tree species range shifts at a continental scale: new predictive insights from a process-based model. Journal of Ecology 96:784-794
Development of old-growth structure and timber volume growth trends in maturing Douglas-fir stands
Forest Ecology and Management, 1998
Interest in the contributions to biological diversity of old-growth forests has increased in many regions of the world. In the Pacific Northwest of the United States, concern for the contributions has lead to proposals to extend the rotation between timber harvests from the conventional 40-80 years to 150 years and longer. However, the implications of such a change for Ž both development of old-growth structure and timber production are unknown. We examined long-term records up to 82 . Ž . years from permanent plots established in 20 stands of Pseudotsuga menziesii Mirb. Franco in western Oregon and Washington that are approaching these proposed rotation ages. Similarity to old-growth structure was assessed by comparing the observed values of four structural variables to published mean values for young and old-growth forest. The assessment of similarity to old-growth structure was limited to characteristics of the live forest stand, due to the lack of measurements of snags and downed logs at initiation of the permanent plots. Timber production was assessed by examining trends in mean Ž . annual increment MAI of cubic volume. Development towards old-growth structure was rapid up to about age 80 years, and gradual thereafter. About half of the transition from young to old-growth forest structure occurred by age 100 years. Stands least similar to old-growth in early observations had relatively high tree densities and relatively small trees of uniform size. In later observations, stands most similar to old-growth structure were those with higher densities of large Ž . ) 100 cm DBH P. menziesii. In general, MAI declined gradually, averaging about 0.3% per year. Thus, longer rotations may not result in large declines of timber growth while providing for forest structure similar to old-growth. Early control of tree density may serve to hasten development of old-growth structure. Our approach to understanding the development of old-growth forest structure could be applied to long-term plot data from forests in other regions, as long as there is adequate information on old-growth and other forest stages. q 1998 Elsevier Science B.V.