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Pascal Nzokou, Nicholas J. Gooch, and Bert M. Cregg

Irrigation of fraser fir (Abies fraseri) in Christmas tree production is gaining importance in the upper midwestern United States because of the intensive planting of this species out of its natural range. However, current scheduling practices rely on empirical observations with no monitoring of soil moisture and no use of automated irrigation system. The goal of this project was to design, construct, and implement a tensiometer-based automated irrigation system for fraser fir Christmas tree plantations that would (1) use existing technologies, (2) apply water based on changes in soil moisture content, (3) provide operational flexibility, and (4) interface with a computer for system changes, data collection, and system modifications. Soil tensiometers equipped with 4- to 20-milliampere transducers were installed at two drip-irrigated tree farms. Water on demand was controlled by soil moisture tension levels that triggered the stimulation of a relay wired to solenoids delivering irrigation water to the various treatments. The system functioned according to the design as expected. However, several issues associated with the need for regular maintenance of tensiometers, computer programming, and system wiring created some challenges regarding the reliability and transferability of similar system to commercial facilities.

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Eric Hinesley and John Frampton

Orthotropic shoots (tips of primary axes) from 3-year-old Fraser fir seedlings [Abies fraseri (Pursh) Poir.] were grafted onto rootstocks of Fraser fir, Korean fir (A. koreana Wils.), momi fir (A. firma Sieb. & Zucc.), Nordmann fir (A. nordmanniana (Steven) Spach.), Turkish fir (A. bornmuelleriana Mattf.), and West Virginia balsam fir from Canaan Valley (Canaan fir) [A. balsamea (L.) Mill. var. phanerolepis Fern.]. Firstyear survival in the greenhouse was 92% to 98% except for momi fir (83%). The percentage of grafted plants with orthotropic shoots was 92% to 98%, except for Korean (81%) and momi fir (86%). Plants were subsequently established in replicated field experiments on three sites in the piedmont and mountains of North Carolina. In general, leader elongation of grafted Fraser fir scions was greater than leader growth on nongrafted transplants, including Fraser fir. Differences in survival appear to reflect interspecific variation in resistance to phytophthora root rot and/or tolerance of warm environments. Grafting may offer the potential to grow Abies Christmas trees on previously unsuitable sites, or to reclaim or continue using sites already seriously impacted by root rot.

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M. Elizabeth Rutledge, John Frampton, L. Eric Hinesley, and Gary Blank

The Top-Stop Nipper (TSN), a four-bladed, hand-held tool developed for reducing leader growth of Christmas trees, was used as a wounding technique to reduce leader growth of Fraser fir (Abies fraseri). A regression model, based on an apical bud volume index (average bud diameter squared × length), was used to predict the number of nips to apply to each leader to yield a target length of 25 to 36 cm. Treatments included control trees (0 nips) and one to seven nips per leader. Nips were applied in May at budbreak. In an earlier study, increasing the number of nips decreased leader elongation when randomly applied to trees without regard to the size of the apical bud. In this study, when the number of nips increased with increasing bud volume index, leader growth was similar among all TSN treatments. Bud density (per unit length) on the 2006 leader increased with the number of nips applied to the 2005 leader. Results might be useful for growers who want to produce dense trees with minimal shearing or for growers who choose to leave a longer leader to produce a more open, “European-style” tree during a shorter rotation time.

Open access

Stuart L. Warren, Walter A. Skroch, Katharine B. Perry, and Thomas J. Monaco

Abstract

Seven vegetation management programs ranging from 100% cover of grass-dominated vegetation to bare soil were created on opposing north and south aspects. After 3 years, fraser fir [Abies fraseri (Pursh) Poir.] survival had decreased when grown in bare soil, compared to survival in the other management programs. Norway spruce [Picea abies (L.) Karst.] survival was not affected by the management programs. Maximum stem diameter and root growth of Norway spruce were obtained with a bare row regardless of the interrow vegetation. Root growth in fraser fir was similar to spruce, but bare soil was required for maximum stem diameter growth. Height growth in both species was affected little by treatment. Stem diameter and root growth were negatively correlated with above-ground herbaceous biomass in the row. Forbs interfered less than grasses with fraser fir and Norway spruce diameter growth. Norway spruce growth was not affected by aspect, but fraser fir was larger (height and stem diameter) on the south aspect when grown in bare soil.

Open access

Elizabeth J. Mitcham-Butler, L. Eric Hinesley, and David M. Pharr

Abstract

Seasonal changes in soluble carbohydrates of Fraser fir [Abies fraseri (Pursh) Poir.] needles were monitored in Fall 1984, Spring 1985, and Fall 1985 through Spring 1986. Raffinose concentration increased in the fall and decreased in the spring. There was a 23-fold increase in raffinose concentration from Aug. 1985 to Jan. 1986. Sucrose concentration varied from fall to spring with the lowest concentration occurring in February. Postharvest needle abscission from harvested branches held 6 weeks without water was inversely correlated with raffinose concentration at the time of harvest. Diurnal fluctuations in soluble carbohydrates were monitored on 12 July and 26 Oct. 1985. Raffinose concentration fluctuated slightly on both dates with a decrease during the dark period. On 12 July, sucrose increased during the day and decreased at night, whereas hexoses decreased in the day and increased at night. No significant diurnal changes in sucrose or hexose were evident on 26 Oct. Controlled-environment studies at 24° (day)/18°C (night), 18°/12°, and 12°/6° showed that most of the raffinose accumulation was due to low temperature; the remainder to short days. Postharvest needle loss was lowest in plants with high needle raffinose concentrations resulting from the 12°/6° temperature. Storage without water resulted in significant postharvest needle loss for shoots from plants preconditioned with 24°/18° and 18°/12°, but not for those exposed to 12°/76°. Compared to long days, plants preconditioned with short days lost fewer needles following harvest.

Open access

Farrell C. Wise, Frank A. Blazich, and L. Eric Hinesley

Abstract

Timing of severance, auxin treatment, and staking were evaluated for their effects on reducing abaxial-concave bending of softwood Fraser fir [Abies fraseri (Pursh) Poir.] stem cuttings. Cuttings collected 21 July 1983, were much less plagiotropic after a 135-day rooting period than those collected 3 weeks earlier. This upright habit was related to stronger internal support from increased amounts of xylem and lignified pith at severance. Staking also reduced abaxial-concave bending, but postseverance auxin treatment had no effect. Stakes apparently provided external support until stems became lignified. Nonstaked cuttings collected 30 June 1983 continued to exhibit greatest bending at the end of the 2nd growing season. Basal defoliation and wounding in preparation for rooting increased plagiotropic growth and reduced survival during rooting, but did not affect the percentage of rooting. Evaluation of xylem distribution indicated that abaxial-concave bending in the 2nd season was caused by greater production of compression wood and total xylem on adaxial than on abaxial sides of the original cutting segments.

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Sonali R. Padhye and Judith K. Groninger

varying degrees of height suppression in seedlings of fraser fir [ Abies fraseri ( Bryan and Seiler, 1991 )] and happy tree [ Camptotheca acuminate ( Li and Liu, 2003 )]. Conversely, BA promoted stem elongation in chamomile [ Matricaria chamomilla

Free access

Michael D. Meyer and Mary K. Hausbeck

( Enzenbacher, 2011 ), pepper ( Foster and Hausbeck, 2010a ), tomato ( Solanum lycopersicon L.) ( Quesada-Ocampo and Hausbeck, 2010 ), and fraser fir [ Abies fraseri (Pursh) Poir.] ( Quesada-Ocampo et al., 2009 ). Additional studies are necessary to identify

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Ping Li, Dong Liu, Min Guo, Yuemin Pan, Fangxin Chen, Huajian Zhang, and Zhimou Gao

bean ( Phaseolus lunatus L.), snap bean ( Phaseolus vulgaris L.), fraser fir [ Abies fraseri (Pursh) Poir.], and certain weeds ( Davidson et al., 2002 ; Gevens et al., 2008 ; Quesada-Ocampo et al., 2009 ). As a heterothallic species, P. capsici

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Mason T. MacDonald, Rajasekaran R. Lada, Martine Dorais, and Steeve Pepin

fraser fir [ Abies fraseri (Pursh) Poir.], but our study is the first known instance of using high humidity to delay needle abscission in conifers. In addition, low temperatures and high humidity significantly delayed the evolution of ethylene and