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  • Author or Editor: John Frampton x
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Twenty open-pollinated families from a virginia pine (Pinus virginiana) seed orchard in South Carolina were planted and managed as Christmas trees at three sites. Retail value and related traits were assessed once the tests reached marketable size (4 years in the field). All traits assessed (except survival) proved to 1) be under a moderate degree of genetic control (family mean heritability = 0.68 for retail value) and 2) have a large range among open-pollinated family means ($11.42/tree to $22.00/tree, retail value) suggesting that they will response well to the traditional tree improvement approach of selection, breeding and testing. The retail value of the best five families tested averaged an increase of $3.47/tree or 20.7% more than the average. At a 6 × 6 ft (1.8 m) spacing [1,210 trees/acre (2,990 trees/ha)], these families would produce an increase in revenue of almost $4,200/acre ($10,387/ha). Much of this increase in value is a result of reducing the cull rate from 14.5% to 8.1%. Survival, height, crown density and straightness of these five families also exceeded the average of the 20 families tested.

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The Top-Stop Nipper (TSN), a four-bladed, hand-held tool used to reduce leader growth in Christmas trees, was evaluated on fraser fir (Abies fraseri). The TSN placed incisions (nips) on the previous year's leader to reduce the amount of photosynthate transported to the developing leader. Treatments consisted of a control (zero nips), and one, two, three, or four nips at each of three stages of leader elongation (pre-budbreak, 2–3 cm, and 6–9 cm). The TSN significantly reduced leader elongation. The percentage of leaders that were within the target range of 8 to 14 inches (20.3–35.6 cm) increased from 18% for the control (no nips) to 46% with four nips. The TSN, when combined with traditional knife shearing or growth regulator treatments, might offer a method to produce dense trees with minimal shearing or to leave longer leaders to produce a more open “European-style” tree during a shorter rotation time.

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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.

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