Fraser Fir Research Articles

The importance of seedling competition in the segregation of spruce and fir in the southern Appalachians

Fraser fir (Abies fraseri [Pursh] Poir.) and red spruce (Picea rubens Sarg.) are codominants of southern Appalachian spruce-fir forests. Fraser fir generally dominates above 1740 m, while red spruce usually dominates below this elevation. This study was designed to determine whether the present segregation of the two species along elevational gradients is associated with seedling competition or contrasting physiological responses to environmental factors. Seedlings were grown for two years in a replacement series experiment along two elevational transects extending from 1300 m to 1900 m, and harvested for growth analysis.

Mortality trends in a southern Appalachian red spruce population

Mortality of red spruce ( Picea rubens Sarg.) was assessed in an old-growth spruce-fir forest before and after adelgid-induced mortality of canopy fir at about 1985. Mortality rates of red spruce canopy trees remained low (less than 2% year −1) following the loss of fir from the canopy. However, the proportion of mortality attributable to wind increased from less than 60 to 90%. Transects placed in areas of concentrated wind damage revealed that uprooting or snapping accounted for 94% of the mortality of spruce canopy trees in the winter of 1987–1988. The transect data were biased toward wind-damaged areas and revealed the potential impact of wind-related mortality on spruce. There was no evidence of atypically high wind velocities in the general area, or of a decline in the radial growth of spruce trees prior to death. It was concluded that the loss of Fraser fir ( Abies fraseri (Pursh) Poir.) from adelgid infestation has increased wind exposure to the remaining canopy trees. The increased exposure of southern Appalachian red spruce to wind must be considered in studies of its health.

Effects of long-term ozone fumigations on growth and gas exchange of fraser fir seedlings

Fraser fir seedlings from two seed sources in the Southern Appalachians (Mt Mitchell, North Carolina, a declining population; and Mt Rogers, Virginia, a relatively healthy population) were subjected to long-term (2·5 years) intermittent ozone fumigations (0·025, 0·070, and 0·150 ppm) while being grown through five growth cycles in an accelerated-growing regime. Fumigations took place during bud break, stem elongation and bud set. Following each growing cycle, gas exchange parameters and dry weights were determined. The ozone fumigations did not produce any effect on seedling growth. The ozone fumigation effects on gas exchange parameters were inconsistent, and generally not statistically different, with no differences occurring between seed sources. There was no correlation between photosynthetic rates and seedling growth. These results provide no evidence that ozone may be contributing to the differences in decline noted between the Mt Rogers and Mt Mitchell populations of Fraser fir.

Gamma Radiation Unpromising as an Insect Quarantine Treatment for Fraser Fir Branches

Dormant branches of Fraser fir [Abies fraseri (Pursh) Poir.] Christmas trees were subjected to single doses of gamma radiation at levels ranging from 0 to 5.0 kGy (0 to 500 kRad). Significant needle loss resulted at doses ≥0.10 kGy and increased with radiation intensity. Irradiation discolored foliage and accelerated drying. Irradiation does not appear to be a viable way to meet insect quarantine requirements on cut Fraser fir Christmas trees.

“Crop-Life” Does Not Slow Postharvest Drying of Fraser Fir and Eastern Red Cedar Christmas Trees

“Crop-Life” Does Not Slow Postharvest Drying of Fraser Fir and Eastern Red Cedar Christmas Trees

Gradient analysis of old spruce – fir forests of the Great Smoky Mountains circa 1935

The response of old-growth spruce – fir vegetation to environmental gradients was investigated using 1930s plot data from the Great Smoky Mountains. Gradients related to forest composition and position of the ecotone with the deciduous forest were identified using canonical correspondence analysis (CCA) and their role in vegetation response to climate change was considered. The data were subsequently stratified into three elevation classes and ordinated separately using CCA to identify gradients at various elevations. The effect of elevation on tree stratum composition and structure was profound. Secondary gradients influencing the tree stratum included slope aspect, potential solar radiation, and topographic position. Abies fraseri basal area and density were high above 1800 m elevation. Comparable basal area levels of Picea rubens were attained at elevations ranging from 1400 to 1900 m. Total stand basal area and density increased with elevation. The importance of topographic position increased with elevation, while that of slope aspect and potential solar radiation decreased. Presumably, the increasing incidence of cloud cover with elevation diminished the effect of slope aspect and potential solar radiation at higher elevations. The transition from deciduous forest occurred in the 1300 – 1600 m elevation range. A substantial proportion (24%) of plots had mixed composition (30 – 70% spruce – fir by basal area), suggesting that the ecotone is not abrupt in old-growth forest. Environmental variables other than elevation did not have a strong effect on ecotone position. Attempts to infer long-term ecotone dynamics along the elevation gradient based on species size-class data were inconclusive. Key words: Abies fraseri, gradient analysis, Great Smoky Mountains, old-growth forest, Picea rubens, spruce – fir forest.

Seed Source Variation for Height and Crown Traits of Fraser Fir Christmas Trees

Abstract Four-year-old open-pollinated progeny of Fraser fir (Abies fraseri [Pursh] Poir.) from several elevations on each of five mountains were planted at three locations in western North Carolina. Total height, crown diameter, branch diameter, number of branch buds, number of buds in theterminal cluster, and tree crown density factor all varied significantly by seed source. Low elevation sources (5000-5500 ft) grew taller and had larger crowns than the high elevation seed sources (6000 and 6500 ft). The seed sources collected from Roan Mountain, the area most often used forcommercial seed collection, were significantly poorer than the best seed sources for total height, crown diameter, and density factor. Seed source x location interactions were significant for total height, crown diameter, number of buds in the terminal cluster, and branch diameter, but thebest seed sources were generally the same in all tests. South. J. Appl. For. 17(1):5-9.

Histology of In Vitro Adventitious Bud Development on Cotyledons and Hypocotyls of Fraser Fir

Cotyledons and hypocotyls of Fraser fir [Abies fraseri (Pursh) Poir.] were excised from seeds treated with H2 O2 for 9 days and placed on bud induction medium containing 10 mg BA/liter and 0.01 mg NAA/liter or medium without growth regulators. Although adventitious buds did not develop, cotyledons exposed to growth regulators responded differently than cotyledons placed on medium lacking growth regulators. Cotyledons and hypocotyls responded similarly to growth regulators during the initial phase in culture, but cell divisions ceased in cotyledons, thus preventing meristemoid and subsequent bud development. After 3 days on medium containing growth regulators cell divisions were localized in epidermal and subjacent layers of hypocotyls, whereas similar cell divisions were' not observed in hypocotyls placed on medium without growth regulators. Cell clusters consisting of two to five cells (promeristemoids) were present after 7 days on hypocotyls placed on bud induction medium. In hypocotyls placed on medium without growth regulators, stomata continued to develop and cells within the cortex became vacuolated during the first 2 weeks in culture. All explants were transferred to secondary medium after 3 weeks. Cell clusters continued to enlarge into meristemoids on hypocotyls initially placed on bud induction medium. Gradually, meristemoids developed into buds and cataphylls were observed covering bud meristems. Chemical names used: N -(phenylmethyl)-1 H -purine-6-amine (BA), 1-naphthaleneacetic acid (NAA).

New Host and Distribution Records from Pennsylvania Conifers

Yellow broom rust of fir caused by Melampsorella caryophyllacearum: first record on Abies fraseri and southernmost record on Abies in eastern North America. Autoecious spruce needle rust caused by Chrysomyxa weirii: first report from Pennsylvania, first record of severe damage to Christmas trees in the eastern United States, and second record on Picea pungens. Seedling blight caused by Discosia pini: first record in eastern United States and first record on Pseudotsuga menziesii. Branch and stem cankers of P. menziesii caused by Dermea pseudotsugae: first report from eastern North America and first report of extensive mortality of Christmas trees. Diaporthe lokoyae associated with chlorosis and dieback of branches of stressed Picea pungens: first record on P. pungens and first record in eastern North America

Intermittent Short Days and Chilling, and Benzylaminopurine Affect the Growth and Morphology of Fraser fir Seedlings

Abstract Fraser fir (Abies fraseri (Pursh.) Poir.) seedlings were either grown continuously under long days (16 hr) or intermittently exposed to short days (8 hr) to induce bud set followed by a chilling period. Additionally, half the seedlings in each treatment received a foliar application of 444 uM benzylaminopurine (BAP). Seedlings that were allowed to set buds, followed by chilling, obtained the greatest height, but this treatment in combination with BAP reduced seedling height. BAP applied to seedlings grown continuously under long days stimulated height growth and prevented long dormant periods typical for non-chilled seedlings. Continuously grown, BAP-treated seedlings had 1.3 times larger root collar diameter, and 1.7 times more biomass, compared to other treatments. Root/shoot ratios for continuously grown, BAP-treated seedlings were comparable to intermittently chilled, non-BAP treated seedlings. These results suggest that either intermittent short days followed by chilling, or foliar BAP applications can be used to accelerate growth of containerized Fraser fir seedlings. However, the combination of chilling and BAP resulted in poorer development than either treatment alone.

Balsam Woolly Adelgid (Homoptera: Adelgidae) Effects on Wood and Bark Structure of Fraser Fir and Silver Fir

Response of Fraser fir, Abies fraseri (Pursh) Poiret, to the balsam woolly adelgid, Adelges piceae (Ratzeburg), was evaluated by studying wood cores and bark samples taken from six sites near Mount Rogers, VA, and five sites in the Black Mountains of North Carolina surrounding Mount Mitchell. For comparison, samples were also collected from silver fir, Abies alba Miller, at four sites in the Black Forest of Germany. Average A. piceae densities were higher on trees at Mount Rogers than on Mount Mitchell trees. Proportions of trees producing abnormal wood in response to low or moderate A. piceae densities was greater for Mount Mitchell trees than for trees at Mount Rogers. Results from Mount Rogers support observations made for other fir species that A. piceae infestation induces outer bark formation, leading to tree recovery. Outer bark formation in trees from the Black Mountains and the Black Forest of Germany was not correlated with A. piceae density. There was indirect evidence that the outer bark measured in Mount Mitchell trees was incompletely formed, with an indistinct boundary layer between living and nonliving bark layers.

Fraser fir seedling gas exchange and growth in response to elevated CO 2

Growth and gas exchange characteristics were examined in Fraser fir ( Abies fraseri (Pursh.) Poir.) seedlings grown from seed in elevated (713 ppm) or ambient (374 ppm) CO 2 for 1 year (two artificial growing seasons) to determine the potential influence of a twice-ambient CO 2 concentration on this species. A subset of seedlings was transplanted from 172 cm 3 pots into 1000 cm 3 pots at 7 months to determine if CO 2 effects were dependent on rooting volume. At 5 and 12 months, net photosynthesis ( P net) and leaf conductance ( g l) were lower in elevated CO 2-grown seedlings grown in 172 cm 3 pots than in ambient CO 2-grown seedlings when measured at either 346 or 796 ppm CO 2. For 12-month-old seedlings grown in 1000 cm 3 pots, P net was reduced by an elevated CO 2 growth environment only when measured at 346 ppm CO 2, although g l was lower in these seedlings when measured at either CO 2 measurement level. Seedlings grown in both pot sizes and in elevated CO 2 for 1 year had greater height, diameter, and leaf, stem, root and total dry weights than seedlings grown in ambient CO 2. Specific leaf weight ( SLW) was greater in elevated than in ambient CO 2-grown needles only in the large pot size treatment. These results suggest that Fraser fir seedling growth will increase in a future elevated CO 2 environment despite changes in gas exchange characteristics.

Foliage Attributes for Current-year Shoots of Fraser Fir

Current-year shoots of Fraser fir [Abies fraseri (Pursh) Poir.] were sampled in Christmas tree plantations in western North Carolina. Needles were sampled at five positions on each shoot: 0% (proximal end), 25%, 50%, 75%, and 100% (distal end). At each position, needles were collected in a tight left-hand spiral beginning on the abaxial side (bottom) and ending on the adaxial side (top). Length, width, thickness, dry weight, and projected surface area were determined for each needle. Specific area (one-sided) averaged 45 cm2·g-1 and increased from the shoot base to the tip. On individual shoots, needle dimensions were maximal at the middle (50% position). Within sample positions, needle dimensions increased from the adaxial to the abaxial side. Needle length, weight, and area differed more than width or thickness by position. Needle surface area per centimeter of shoot was relatively stable. Regression models using shoot length, diameter, needle density, and average needle length or weight yielded good estimates of total foliage area and weight.

Rehydration of Fraser Fir Christmas Trees: Effect of Time since Cutting

Rehydration of Fraser Fir Christmas Trees: Effect of Time since Cutting

A Comparison of Overstory Community Structure in Three Southern Appalachian Spruce-Fir Forests

NICHOLAS, N. S., S. M. ZEDAKER (Department of Forestry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061), AND C. EAGAR (Northeastern Forest Experiment Station, USDA Forest Service, Durham, New Hampshire 03824). A comparison of overstory community structure in three southern Appalachian spruce-fir forests. Bull. Torrey Bot. Club 1 19: 316-332. 1992.-The southern Appalachian spruce-fir ecosystem is described in terms of stand structure and comparisons of current status to descriptions of earlier studies at three sites: Mount Rogers National Recreation Area (NRA) of Virginia, the Black Mountains of North Carolina, and the Great Smoky Mountains of Tennessee and North Carolina Community classification using two-way indicator species analysis delineated four forest types: SPRUCE, SPRUCE-BIRCH, SPRUCE-FIR, and FIR. Both the Mt. Rogers NRA and Black Mountains sites were patchworks of disturbance histories while most of the Smokies site was old-growth. At second-growth plots average dominant and codominant red spruce (Picea rubens Sargent) age ranged from 59-100 years while at the Smokies spruce mean age varied from 168-210. Distribution of basal area at the Smokies was skewed towards diameter distributions of greater than 45 cm DBH while basal area at Mt. Rogers NRA and the Black Mountains was concentrated in trees with diameters of less than 45 cm. Past studies indicated that undisturbed spruce-fir species distribution tended to follow an elevation gradient: spruce dominance changing to Fraser fir (Abiesfraseri (Pursh) Poiret) dominance as elevation increased. Current stand composition at the Black Mountains and the Great Smokies also shows a shift from spruce to fir; however, Mt. Rogers is an exception to that trend. As fir abundance increases with elevation there are increasing levels of balsam woolly adelgid-caused (Adelges piceae Ratzeburg) mortality at the Black and Smoky Mountains where there is a greater proportion of standing dead fir than live fir. Unlike the other two sites, Fraser fir on Mount Rogers still have escaped major damage from the adelgid. But advanced age structure of fir stands on top of Mount Rogers and elsewhere may result in high mortality rates in the near future.

Crooked leaders and nutrition in Fraser fir Christmas trees

Current-year foliage from the upper crown of Fraser fir (Abiesfraseri (Pursh) Poir.) Christmas trees with normal and abnormally spiraled or crooked leaders was sampled monthly between July and November over a 3-year period. Bark, wood, and small roots were also collected in November 1988, and foliage was collected from the upper whorl and leader on two dates in 1989. Concentrations of several nutrients varied significantly between crooked and straight trees in some years, but not across all years. With several elements, changes in concentration during the growing season were inconsistent across years. Some differences were too small to be of practical significance; others favored trees with crooked leaders when compared with nutritional guidelines. Concentrations of all elements varied considerably among trees, and nearly all nutrients exhibited significant temporal changes in concentration during the growing season. Concentrations also varied by sampling position. Nitrogen concentration tended to be higher in the foliage of crooked trees. Because there was no consistent pattern of deficiency, excess, or imbalance for any particular nutrient, the crooked leader problem in Fraser fir appears to have no distinct nutritional basis.

Identification of Nutritional Influences on Cone Production in Fraser Fir

AbstractFraser fir [Abies fraseri (Pursh) Poir.] is highly valued as a freshcut Christmas tree. Commercial cultivation is limited partly by seed scarcity. The purpose of this study was to develop foliar tissue nutrient norms for female cone yield to use in the Diagnosis and Recommendation Integrated System (DRIS), for ultimately improving cone yields. Two sets of these norms were developed, one set based on February and the other on July foliar nutrient levels. Neither single mineralnutrient concentrations nor other assessed tree parameters correlated with cone yield. However, nutritional discrimination between high‐and low‐yielding trees was obtained with July tissue. Discrimination with February needle samples was poor. Reasonable agreement was obtained for orders of nutrient limitations diagnosed from the two seasonally specific sets of norms. Results indicated the potential to use DRIS to aid in selection of clones and prescribing treatments to enhance cone yields.

Yield of Decoration Greenery Fraser Fir Christmas Trees

Fraser fir [Abies fraseri (Pursh) Poir.] Christmas trees up to 3.2 m in height were sampled from 18 well-managed plantations in western North Carolina to determine the yield of decoration greenery (wreaths, roping). Trees were not sidesheared in the year of harvest. The proportion of branch material suitable for decoration greenery decreased with increasing height and crown taper, but crown density had no effect. Mean annual yield of decoration greenery (establishment in the field, until reaching an average height of 3.2 m 10 years later) was 1.9 to 2.3 kg/tree per year, respectively, for trees with medium or heavy crown density.

Expected stand behavior: site quality estimation for southern Appalachian red spruce

An indicator of site productivity and quality was provided for mixed, uneven-aged natural stands of southern Appalachian red spruce ( Picea rubens Sarg.). A set of anamorphic site index curves was developed and validated using the Meyer (1940) nonlinear function using diameter at breast height as a predicting variable. The coefficient of determination for the base curve was good ( R 2 = 0.626) and no consistent bias was detected. Average site quality index decreased with increasing elevation. Site index was highest in pure spruce stands but decreased with increasing elevation and/or increasing Fraser fir ( Abies fraseri (Pursh) Poir.) or yellow birch ( Betula lutea Michaux f.) component.

High‐Elevation Forest Soils of the Southern Appalachians: I. Distribution of Parent Materials and Soil‐Landscape Relationships

AbstractBecause of geomorphic instability imparted both by present‐day slope processes and past periglacial activity, soils in the high‐elevation spruce‐fir (Picea rubens Sarg.‐Abies fraseri [Pursh.] Poir) zone of the southern Appalachians have similar morphological features that make it difficult to assess their variability on the landscape, despite widespread differences in parent material and local geology. We used multiple discriminant analysis to (i) determine whether soils from three extensive areas of southern Appalachian spruce‐fir forests could be separated by physical, morphological, chemical, and mineralogical properties, (ii) determine the relative effectiveness of these properties as differentiae, and (iii) assess the contribution of mineral weathering in offsetting potential base‐cation depletion induced by strong‐acid anion loading associated with atmospheric deposition. A total of 35 pedons at elevations >1450 m were characterized on the high mountain peaks of eastern Tennessee, western North Carolina, and southwestern Virginia. Physical and morphological properties used to separate and field classify these soils were not significantly different between study areas. Soil chemical and mineralogical properties inherited from different parent materials, however, were sufficiently different between study areas to result in the clear separation of soils into distinct groups with >95% classification accuracy. Soils formed from siliceous metavolcanic parent materials were dominated by K‐feldspar and quartz in both the sand and silt fractions. Soils with parent materials derived from more high‐grade metamorphic rocks were less quartzitic, had plagioclase as the dominant feldspar, and had high contents of expansible 2:1 phyllosilicates. Slope processes involved in the transport of solutes and sediments resulted in sorting of surficial materials, higher pH, and greater amounts of silt‐size mica and kaolinite in depositional areas.