Fraser Fir Research Articles

Determination of Monoterpenes in Oleoresin: A Chemosystematic Study of the Interaction between Fraser Fir (Abies fraseri) and Balsam Woolly Adelgid (Adelges piceae)

The Fraser fir (Abies fraseri), a conifer native to high elevation sites in the southern Appalachians, has suffered severe mortality attributed to an exotic insect, the balsam woolly adelgid (BWA) (Adelges piceae). Fraser fir, like many other plants, produce volatile organic compounds called monoterpenes in a variety of tissues, including the cortical oleoresin found in blisters on the bark. The purpose of this study was to perform a chemosystematic study to evaluate whether differences in monoterpene composition of Fraser fir oleoresin were observed as a function of the season sampled, the presence or absence of BWA infestation, the health of a tree, and the susceptibility of trees to BWA, based on geographic location. Oleoresin was collected in September and December, 1994, at two mountains, Mount Rogers, where the fir were relatively healthy, and Roan Mountain, where heavy to moderate mortality has been observed. The oleoresin samples were dissolved in methylene chloride, and the monoterpenes were determined by gas chromatography. This method was shown to have acceptable precision for chemosystematic studies for five monoterpenes and the total of all monoterpenes. The levels of monoterpenes in oleoresin were statistically the same for most compounds in September and December, although the total monoterpenes were higher in September at Mount Rogers and α-pinene was higher in December at Roan Mountain. Infested and uninfested fir had the same levels of oleoresin monoterpenes at both mountains. No differences in monoterpene levels were observed at Mount Rogers with healthy and unhealthy fir, but at Roan Mountain, the total monoterpene concentrations were different in these categories. A comparison of monoterpene concentrations in oleoresin from Mount Rogers and Roan Mountain showed statistically significant differences for 3-carene, β-phellandrene, and total monoterpenes.

Determination of Aluminum, Calcium, and Magnesium in Fraser Fir, Balsam Fir, and Red Spruce Foliage and Soil from the Southern and Middle Appalachians

Spruce–fir forests form unique ecosystems in the eastern United States and Canada. These forests are composed of Fraser fir (Abies fraseri) and red spruce (Picea rubens) in the Southern Appalachians, and balsam fir (Abies balsamea) and red spruce in the middle and northern Appalachians. Decline of spruce–fir forests has been observed since the 1960s that has been attributed, at least in part, to acidic deposition. Acidic deposition has been reported to decrease the availability of calcium and increase the availability of aluminum and induce decline of red spruce at high elevation sites above 1800 m. Aluminum, calcium, and magnesium were determined in Fraser fir, balsam fir, and red spruce foliage and soil from sites in the southern and middle Appalachians in order to evaluate whether acidic deposition may play a role in the decline of the conifers. Our nutrient studies did not provide any evidence that acidic deposition was affecting the conifers.

Thyronectria balsamea on Abies fraseri in Pennsylvania and North Carolina.

In August 1996, several 4- to 6-m-tall Abies fraseri (Pursh) Poir. in Adams County, PA, were found bearing numerous dead branches and/or dead tops. The trees had been severely stressed by being ball-and-burlapped and replanted in 1993. Distinct cankers occurred between the living and dead portions of stems and branches. Associated with these cankers were abundant, reddish-orange, erumpent stroma, each bearing three to 10 similarly colored cupulate ascomata. The latter contained asci bearing two to four large, muriform ascospores that, as they matured, formed large numbers of small ascoconidia, indicating the pathogen was Thyronectria balsamea (Cooke & Peck) Seeler (= Nectria balsamea Cooke & Peck). In September 1996, cankered dead stems and branches from affected A. frasrei Christmas tree plantations in Avery County, NC, were found bearing the same pathogen. This fungus is known on A. bal-samea (L.) Mill. from northern Minnesota east through Canada to northern New York and Newfoundland (2). Funk (1) reported it from A. lasio-carpa (Hook.) Nutt. in (presumably) British Columbia, but gave no details. This is the first report of it in the eastern United States south of northern New York, a considerable extension of its known range, and the first report of it from A. fraseri. Voucher specimens are in PACMA (Pennsylvania State University Mycologica Herbarium, Mont Alto Campus).

Determination of Aluminum, Calcium, and Magnesium in Fraser Fir (Abies fraseri) Foliage from Five Native Sites by Atomic Absorption Spectrometry: The Effect of Elevation upon Nutritional Status

The Fraser fir (Abies fraseri) is a conifer native to high elevation sites in the southern Appalachians that has recently suffered severe mortality because of an exotic insect, the balsam woolly adelgid (BWA). The companion tree of the Fraser fir, the red spruce (Piceae rubens) has suffered relatively mild decline induced by acidic deposition, due to reduction of extractable calcium and magnesium levels in the soil, while causing an increase in extractable aluminum. We hypothesized that acidic deposition may be involved, along with the BWA, in inducing Fraser fir decline. Our hypothesis was tested by collecting Fraser fir foliage and soil from five sites on Clingman's Dome, NC/TN, Roan Mountain, NC/TN, and Mount Rogers, VA, and determining foliar and extractable soil aluminum, calcium, and magnesium. Foliar aluminum was done by graphite furnace atomic absorption (GFAAS) with continuum source background correction, while all other analyses were done by flame AAS. The analysis of composite samples was shown to provide improved precision by a factor of 2–4 for elemental analysis of a class of conifers compared to averaging individual analyses. Although aluminum levels were larger and calcium/aluminum ratios were smaller at the high elevation sites at two mountains, calcium levels were statistically the same at the high and low elevation sites. Consequently, it is difficult to definitively conclude that acidic deposition has contributed to Fraser fir decline.

An Evaluation of Four Glyphosate Formulations on Dormant Conifers

In 1995, Monsanto Chemical Co. announced that they would replace Roundup herbicide with Roundup Pro for use in the ornamentals and turf markets. Both products contain 4 lb a.i./gal glyphosate, but Roundup Pro contains a more-active surfactant. Though Roundup was labeled as a nonselective herbicide, dormant conifers were found to have varying degrees of resistance to it. Directed sprays that hit the lower two-thirds of many dormant conifers became common practice in the industry. Because the surfactant in Roundup Pro increases the activity of the glyphosate, a series of trials were initiated in 1996 in Connecticut, Pennsylvania, and Vermont in which four glyphosate formulations were applied to a variety of dormant conifers. Roundup, Roundup Pro, Glyfos, and Accord (with and without surfactant) were applied either over-the-top or as directed sprays to the lower 18 inches of the plants at rates between 0.5 and 3 lb a.i./acre. Plants treated included globe arborvitae; upright yew; Canadian hemlock; Colorado, Norway and white spruce; Douglas fir; eastern white pine; and balsam, Canaan, and Fraser fir. In a preliminary study, injury to the spruces in the form of dwarfed and chlorotic new growth was primarily associated with fresh pruning wounds. Accord plus surfactant and Roundup Pro injured more spruces than Roundup, but injury was slight. No injury was observed in upright yew with any formulation at rates up to 0.75 lb a.i./acre. Injury to arborvitae was greatest with Accord plus surfactant, intermediate with Roundup Pro, and least with Roundup. Results are inconclusive at this time, but the results of additional studies available early in the next growing season.will be presented.

Extraction Method for the Isolation of Terpenes from Plant Tissue and Subsequent Determination by Gas Chromatography

A method for the isolation and determination of terpenes from plant tissues is reported, involving extraction with methylene chloride for 24 h and quantitative analysis by gas chromatography. Relatively small masses of samples are required, the method is suitable for the analysis of large numbers of samples, and good precision (5–10%) was obtained. The utility of the method for a variety of plant materials was demonstrated by the analysis of Fraser fir (Abies fraseri) leaves and seeds, Balsam fir (Abies balsamea) leaves, red spruce (Picea rubens) leaves, and Queen Anne's lace (Daucus carota) seeds. The use of a composite method of sample preparation was investigated to improve the precision compared to the analysis of a class of individuals by averaging the analysis of individuals. Equal masses of 5–10 g of foliage from 10–20 individuals were mixed well to form the composite sample. The composite method had superior precision by an average factor of 7 over averaging the analysis of individuals.

Basal Pruning Fraser Fir Christmas Trees

Fraser fir [Abies fraseri (Pursh) Poir.] Christmas trees were basal pruned (branches were removed from the lower 15 to 25 cm of the stem, i.e., handle) at heights ranging from 0.6 to 0.9 m up to 1.5 to 1.8 m tall, and were harvested 2 to 4 years later. Basal pruning reduced cutting time ≈25%, and baling time ≈10%. Commercial height and stem diameter were unaffected, but the average harvest weight of pruned trees 2.1 to 2.4 m tall (2 to 4 years after basal pruning) was reduced ≈1.4 kg.

Harvest Time and Nitrogen Source Influence In Vitro Growth of Apical Buds from Fraser Fir Seedlings

Information was obtained concerning appropriate bud harvest time and nitrogen source to be used in the tissue culture of Fraser fir [Abies fraseri (Pursh) Poir] apical buds from 2-year-old seedlings. April was the preferred time to harvest buds for culture, as summer buds had a high contamination frequency, and fall and winter buds did not develop well. Shoot elongation of buds collected in April (1.6 cm) was more than twice that of buds collected in February (0.7 cm) after 100 days in culture; during the same period, shoot fresh mass increased 5-fold (0.21 g in April, 0.04 g in February). Inclusion of a nitrate source reduced the frequency of bud browning, and glutamine was superior to ammonium as a source of reduced nitrogen. Litvay's basal medium containing 10 mm glutamine and 10 mm nitrate was the best nitrogen source combination tested when considering bud browning frequency and shoot fresh mass and length after 100 days in culture.

Induction of embryogenesis in cultured mature zygotic embryos of Abies fraseri (Pursh) Poir

Embryo suspensor masses were induced by culture of isolated mature zygotic embryos of Fraser fir (Abies fraseri [Pursh] Poir.). Maximum induction frequencies were observed after 10 weeks culture on one-half strength Murashige and Skoog medium containing 10 µM thidiazuron and on one-half strength Verhagen and Wann medium containing 10 µM cytokinin [6-(dimethylallylamino)purine, 6-benzyladenine, or thidiazuron). Proliferation of embryo suspensor masses occurred on one-half strength Verhagen and Wann medium supplemented with 10 µM cytokinin. When embryo suspensor masses were transferred to media containing 5-80 µM abscisic acid, cotyledonary-stage embryos were formed. Somatic embryos germinated on medium lacking plant growth regulators, but abnormal cotyledonary-stage somatic embryos with stunted cotyledons and reduced embryo axes were also observed.

Environmental hazards of aluminum to plants, invertebrates, fish, and wildlife.

Aluminum is extremely common throughout the world and is innocuous under circumneutral or alkaline conditions. However, in acidic environments, it can be a major limiting factor to many plants and aquatic organisms. The greatest concern for toxicity in North America occurs in areas that are affected by wet and dry acid deposition, such as eastern Canada and the northeastern U.S. Acid mine drainage, logging, and water treatment plant effluents containing alum can be other major sources of Al. In solution, the metal can combine with several different agents to affect toxicity. In general, Al hydroxides and monomeric Al are the most toxic forms. Dissolved organic carbons, F, PO(3)3- and SO(4)2- ameliorate toxicity by reducing bioavailability. Elevated metal levels in water and soil can cause serious problems for some plants. Algae tend to be both acid- and Al tolerant and, although some species may disappear with reduced pH, overall algae productivity and biomass are seldom affected if pH is above 3.0. Aluminum and acid toxicity tend to be additive to some algae when pH is less than 4.5. Because the metal binds with inorganic P, it may reduce P availability and reduce productivity. Forest die-backs in North America involving red spruce, Fraser fir, balsam fir, loblolly pine, slash pine, and sugar maples have been ascribed to Al toxicity, and extensive areas of European forests have died because of the combination of high soil Al and low pH. Extensive research on crops has produced Al-resistant cultivars and considerable knowledge about mechanisms of and defenses against toxicity. Very low Al levels may benefit some plants, although the metal is not recognized as an essential nutrient. Hyperaccumulator species of plants may concentrate Al to levels that are toxic to herbivores. Toxicity in aquatic invertebrates is also acid dependent. Taxa such as Ephemeroptera, Plecoptera, and Cladocera are sensitive and may perish when Al is less than 1 mg.L-1 whereas dipterans, molluscs, and isopods seem to be tolerant. In Al-sensitive species, elevated levels (approximately 500 micrograms.L-1) affect ion regulation and respiratory efficiency. Toxicity tends to be greatest near a species' threshold of pH sensitivity. At lower pHs, Al may have a slight ameliorative effect by interfering with H+ transport across membranes. Aquatic invertebrates can accumulate very high levels of Al, but most of this appears to be through adsorption rather than assimilation. Aluminum concentrations may be as high as 5000 mg.kg-1 in insects and greater than 17,000 mg.kg-1 in other invertebrates.(ABSTRACT TRUNCATED AT 400 WORDS)

Postharvest Drying of Leyland Cypress, Eastern Red Cedar, and Fraser Fir Christmas Trees

Postharvest drying of Leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. & Dallim.)] branches was intermediate between eastern red cedar (Juniperus virginiana L.) and Fraser fir [Abies fraseri (Pursh) Poir.] in two laboratory experiments. Leyland cypress rehydrated without adverse effect until xylem pressure potential reached –4.0 to –5.0 MPa (shoot moisture content = 60% to 65%). For branches continuously maintained in water, Fraser fir and Leyland cypress kept equally well over 4 weeks of display, but Leyland cypress lasted longer than Fraser fir over 8 weeks. Postharvest keeping quality of Leyland cypress and Fraser fir was better than that of eastern red cedar.

Seed Source Variation for Growth and Quality Traits of Fraser Fir Christmas Trees: Rotation Age Results

Abstract Open-pollinated Fraser fir (Abies fraseri [Pursh] Poir.) progeny from several elevations on each of 5 mountain sources were assessed at 8 yr (rotation age) for growth and quality traits. Seed sources varied significantly in total height, crown diameter, branch diameter, straightness, crown density, USDA Christmas tree grade, and Christmas tree value. Age 8 yr results were very similar to both 1 and 4 yr results; lower elevation, southern sources showed superior performance in most traits including wholesale value. The common commercial seed sources on Roan mountain performed poorly by comparison. Statistically significant seed source X location interaction found for height, crown diameter, branch diameter, and value proved practically unimportant. Top-ranked seed sources overall maintained superiority at all sites. Potential rotation age tree wholesale value gains to Christmas tree growers through changing from the current chief commercial seed source on Roan Mt. to superior seed sources may exceed 7%. South. J. Appl. For. 19(4):157-161.

Determination of Calcium and Magnesium by Flame Atomic Absorption Spectrometry in Fraser Fir (Abies fraseri) and Red Spruce (Picea rubens) Foliage from Richland Balsam Mountain, North Carolina

The red spruce (Picea rubens) and Fraser fir (Abies fraseri) are conifers which grew naturally at high elevation sites in the southern Appalachian mountains. The Fraser fir has suffered a severe decline, due to an exotic insect, the Balsam woolly adelgid (BWA), while the red spruce in the Great Smoky Mountains National Park has undergone a mild decline that has been attributed to reduced foliar calcium and magnesium levels induced by acidic deposition. The first goal of this project was to develop a suitable method for the determination of conifer foliage. A dry combustion procedure followed by flame atomic absorption analysis was shown to be convenient and provide good accuracy and precision. The second goal of the project was to analyze red spruce and Fraser fir foliage from 10 saplings at Richland Balsam Mountain, NC for calcium and magnesium, and compare the results to a study done at this site in 1968-1969. Foliar red spruce concentrations of calcium and magnesium in 1994 were 1932 ± 712 and 330 ± 68 μg/g, respectively, compared to values of 4164 ± 388 and 788 ± 62 μg/g in 1968-1969 that were reported in the literature. For Fraser fir, a similar trend was observed: in 1994, foliar calcium and magnesium levels were 2830 ± 873 and 387 ± 81 μg/g; in 1968-1969 the literature levels were 4095 ± 219 and 853 ± 60 μg/g. Statistical analysis of these data at the 0.01 critical value showed a decrease in foliar calcium and magnesium concentrations in this study compared to the earlier work, indicating that acidic deposition may have a role in the decline of red spruce and Fraser fir.

Relationship of U.S. Department of Agriculture Grades to the Value of Fraser Fir Christmas Trees

Wholesale values, retail values of five eastern United States lots, U.S. Dept. of Agriculture (USDA) Christmas-tree grades, and measurements of various growth and quality traits were obtained on ≥1400 Fraser fir [Abies fraseri (Pursh) Poir.] (8 years old) Christmas trees. Retail lot values were similar, but average retail value correlated poorly with wholesale value within merchandising height classes. For each of the current wholesale categories (defined by the combination of 30.5-cm interval height classes and USDA grades), average values ranged widely. Some cull-grade trees, which would be unmerchantable according to USDA standards, had moderate retail value. Also, the retail mean of any one wholesale category generally was not significantly different from that of adjacent categories. Some tree quality defects that have equal impact on USDA grade, and consequently wholesale value, differed widely in their effect on retail values. This study indicates that current USDA Christmas-tree grade standards do not adequately differentiate Fraser fir trees with respect to their retail value. We propose a new method of Christmas-tree quality certification that involves computed Christmas-tree quality index values that offer greater accuracy in describing quality with respect to retail value.

Correcting Loss of the Terminal Bud in Fraser Fir Christmas Trees

Various pruning treatments were evaluated to determine the best procedure to correct terminal bud loss in Fraser fir [Abies fraseri (Pursh) Poir.]. Removing the top node (expanding terminal and subterminal buds) soon after budbreak combined with light pruning of the major branches in the next two lower whorls best restored a normal leader. This procedure allowed one or more shoots just below the cut to become orthotropic leaders in the first growing season. All but one of these shoots were removed, and only a single leader was retained after growth matured in late August or September.

Balsam woolly adelgid (Homoptera: Adelgidae): effects on growth and abnormal wood production in Fraser fir seedlings as influenced by seedling genetics, insect source, and soil source

Fraser fir, Abiesfraseri (Pursh) Poir., seedlings were grown in the greenhouse and at four field sites in the southern Appalachian Mountains to study the effects of infestation by the balsam woolly adelgid (BWA), Adelgespiceae (Ratz.). Swelling in the main stem was used as an indicator of abnormal wood (i.e., "rotholz") production induced by infestation. At three of the four field sites, the main stems of infested seedlings were significantly more swollen than those of uninfested seedlings. The amount of swelling caused by BWA generally was not affected by seed source (half-sib family), soil source (soil from higher or lower elevations), or interactions of these variables. At two of four field sites, infestation was associated with a significant increase in root:shoot ratio. Variability in root:shoot ratios and total dry weights of seedlings was influenced by interactions of infestation, soil source, and seed source. This result demonstrates that both tree genetics and environment play a significant role in the growth responses of infested Fraser fir seedlings. Results from the greenhouse study indicated that BWA might be represented by two or more biotypes in the southern Appalachians. Shoot weights and diameter increases were relatively large for Mount Mitchell seedlings infested by BWA from Mount Rogers, and relatively small when infested by BWA from Mount Mitchell. For seedlings from Mount Rogers, the converse was true. Overall, these results suggest that environment is probably more important than tree or insect genetics in explaining why so many infested trees have died in the Black Mountains of North Carolina.

Effect of drought stress and infestation by the balsam woolly adelgid (Homoptera: Adelgidae) on abnormal wood production in Fraser fir

Fraser fir (Abiesfraseri (Pursh) Poir.) seedlings were artificially infested with balsam woolly adelgid, Adelgespiceae (Ratz.), then subjected to drought-stress treatments. Infestation caused a distinct swelling in the main stem, caused by the accumulation of abnormal wood (i.e., "rotholz"). As expected, drought stress reduced diameter growth in the main stem. However, the reduction in wood increment caused by drought stress was relatively small for infested seedlings as compared with uninfested seedlings, owing to the production of rotholz. This implies that infested trees expend considerable energy and nutrients for the production of poorly functioning wood even during periods of stress. The implications of this research for interpreting patterns of tree mortality in the southern Appalachian Mountains are discussed.

Natural variation and genetic parameters in Fraser fir for growth and Christmas tree traits

Open-pollinated progeny trials of Fraser fir (Abiesfraseri (Pursh) Poir.) assessed at 8 years provided genetic parameter estimates for growth, Christmas tree quality traits, and wholesale value at harvest age. Significant variation was found between and within nine different seed sources. Estimated individual tree heritabilities of important traits ranged from a low of 0.13 for USDA Christmas tree grade to a moderate value of 0.33 for crown diameter. Heritabilities within the better performing seed sources tended to be higher. Of the two traits that determine wholesale value, USDA grade and height class, the latter proved to have the greater influence, both phenotypically and genetically. Genetic correlations of early age height growth with 8-year total height, height class, USDA Christmas tree grade, and individual tree wholesale value proved favorable and strong (range of 0.57–0.96). In combination with moderate heritabilities for early growth traits, such correlations provide potential for effective early age selections in Fraser fir Christmas trees.

Single- and multiple-trait index selection efficiencies in Fraser fir Christmas trees

Selection methods for Abiesfraseri (Pursh) Poir. for Christmas tree wholesale value were evaluated based on parameters from the species' first genetic field test. For single-trait individual selection, combined individual plus family selection at half rotation age (4 years) on total height (HT4) gave the greatest estimated full rotation (8-year) retail value (VALUE) gain of 24.3%. The best 8-year trait, crown diameter, resulted in a gain of only 22.4%. Incorporation of family mean information together with individual values in the selection process was important in maximizing gains. Only 8-year stem straightness (STR8) had unfavorable genetic and phenotypic correlations with other traits. With multitrait combined optimum index selection, use of Kempthorne restrictions to prevent adverse change in this trait seriously limited gains in other 8-year traits. Severity of this limitation increased for younger age indices, and for those with fewer traits. Unrestricted combined optimum indices offered substantial VALUE gain advantages and only small decreases in STR8. Initial selection among seed sources also increased VALUE gain, despite decreasing the effective additive genetic variation. VALUE gains through initial source selection exceeded gain reductions from the genetic variation decreases. The optimum selection strategy, with 30.5% VALUE gain, involved initial source selection followed by unrestricted combined optimum index selection on HT4, and 4-year density. Though slightly below the maximum, this strategy would provide substantial economic and technical advantage in conducting field tests.

Propagation of Fraser Fir

Abstract Fraser fir [Abies fraseri (Pursh) Poir.], the most important Christmas tree species in North Carolina, is rapidly gaining popularity nationwide. It is propagated by seed, but special needs such as genetic improvement will involve use of grafting, air layering, propagation by stem cuttings, and micropropagation (tissue culture). This paper summarizes research conducted to date on Fraser fir concerning these techniques in addition to information regarding seed production and sexual propagation.