requirements for heating and cooling buildings ( McPherson and Simpson, 1999 ; Nowak et al., 2008 ; Peper et al., 2009 ). However, processes used during tree production at the farm level can negatively affect environmental impact factors. LCA has been used to
Benjamin G. Mullinix and R. E. Worley
Three out of many pecan cultivars (Gloria, Pabst, & Stuart) were examined over long periods of time. The latter two cultivars have been planted since 1921 when the first pecan orchard was established. One tree of each of these cultivars were removed because of overcrowding. Gloria and Pabst were planted in 1954. Best production practices known were used until 1962. Fertilization and insecticide sprays were adopted. In 1970, spraying for disease was adopted. In 1974, drip irrigation and selective limb pruning were adopted. GrowSeason (GS) [(Year-Planted+l)-mean GS] was used in a linear (L), quadratic (Q), or cubic (C) model where the best model was chosen (significant F-test). Yield was expressed as cumulative yield. Older trees tended to produce more after 1962 (C trend), mid-aged trees more after 1970 (Q/C trend), and younger trees more after 1974 (L/Q trend). Younger trees had the greatest average yearly cumulative yield.
Glenn B. Fain and Patricia R. Knight
On 24 Apr. 2003, 3-gallon (11.4-liter) Quercus shumardii were potted into 13.2-gallon (50-liter) containers using a standard nursery mix. Treatment design was a 3 × 2 × 2 factorial with two fertilizer placements, three irrigation methods, and two herbicide rates. Controlled-release fertilizer 17N–2.9P–9.8K was dibbled (placed 10.2 cm below the surface of the container media at potting) or top-dressed at a rate of 280 grams per container. Irrigation was applied using one of three methods: 1) a spray stake attached to a 3-gallon- (11.4-L-) per-hour pressure compensating drip emitter; 2) a surface-applied pressure-compensating drip ring delivering water at a rate of 2.3 gallons (8.9-L) per hour; and 3) the same drip ring placed 4 inches (10.2 cm) below the container substrate surface. A granular preemergent herbicide (oxyfluorfen + oryzalin) was applied at 2.0 + 1.0 lb/acre (2.24 + 1.12 kg·ha-1). At 75 days after treatment (DAT), containers with no herbicide and top-dressed fertilizer had a percent weed coverage of 46% compared to 18% for dibbled containers with no herbicide. At 180 DAT weed top dry weight was greater for top-dressed containers compared to dibbled. None of the treatments in the study had any effect on height increase. At 240 DAT, trees irrigated with drip rings at the surface had a 28% greater caliper increase among the dibbled fertilizer-treated containers. Trees irrigated with the drip ring placed below the surface and fertilizer top-dressed had the smallest caliper increase. Irrigation method had no effect on weed control in this study; however, a repeat fall application showed a significantly greater weed control with the drip ring below surface compared to the spray stake.
James C. Sellmer, Ricky M. Bates, Tracey L. Harpster, David Despot, and Larry J. Kuhns
Jenny Knoth, John Frampton, and Ray Moody
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.
Karla M. Addesso, Anthony L. Witcher, and Donna C. Fare
Adoption of biological control tools in woody ornamental nursery production has lagged behind other agriculture fields. One of the major obstacles to adoption is lack of information on the efficacy of various biological control agents in nursery production systems. The predatory mite Amblyseius swirskii, sold commercially as “swirski mite,” is a generalist predatory mite that has recently been adopted as a generalist control for a wide range of mite and insect pests, including thrips (Thripidae), whiteflies (Aleyrodidae), eriophyid mites (Eriophyidae), broad mite (Polyphagotarsonemus latus), and spider mites (Tetranychidae). A controlled-release sachet formulation of swirski mite was evaluated in three experiments to determine whether size of the tree, timing of first application, or sun intensity would affect treatment efficacy. Pest numbers on plants was evaluated biweekly for 12 weeks. The swirski mite sachets controlled broad mite and spider mite outbreaks on red maple trees (Acer rubrum) grown in nos. 3 and 15 nursery containers, respectively. Application at the time of red maple rooted cutting transplant was not necessary to achieve summer-long control of pests. No outbreaks of target pests on flowering dogwood (Cornus florida) in no. 5 containers grown under both full sun and shade, but with low levels of broad mite persisting in the shade treatment and thrips persisting in sun. These results suggest that swirski mite is a promising candidate for biological control in woody ornamental nursery production.
Edward W. Bush and Pamela B. Blanchard
A small inexpensive (less than $1000) container yard, measuring 10 × 10 ft square, with an automatic irrigation system was designed for schools participating in the Louisiana State University Coastal Roots Program: A School Seedling Nursery Program for Habitat Restoration. Students helped install the container yard on their school site and oversee native plant production through the course of the school year. Teachers and other school staff checked the nursery during summer months to ensure that the irrigation system was working properly and the plants were healthy. Students grew ≈1000 restoration seedlings per year in their container yard. Each year they transplanted their seedlings and grass plugs on trips to habitat restoration sites across Louisiana's coastal zone. Since the inception of the program in 2000, the students using this container yard design have produced nearly 24,500 trees and shrubs and over 8000 grass plugs.
Alex B. Daniels, David M. Barnard, Phillip L. Chapman, and William L. Bauerle
The primary goal of this study was to determine the optimum number of substrate moisture sensors needed to accurately determine substrate water content for 10 tree species in a containerized nursery. We examined variation in volumetric water content (VWC, m3·m−3) within containers, within species, among species, and over time. Across time, differences among species were not significant (P = 0.14). However, differences among time periods and the interaction effect between species and time periods were significant (P < 0.001). Seasonal differences in within-species variation were also evident in nine of the 10 species. In an attempt to understand species-specific mechanistic factors that influence within-species variation in VWC, we accounted for physiological and morphological differences affecting transpiration with a spatially explicit mechanistic model, MAESTRA. Neither estimated transpiration rate per whole crown or m2 of leaf area could explain variation in VWC. Based on our results, we recommend species-specific sensor deployment and report sensor quantities that estimate the mean substrate VWC of each species within a confidence interval of ± 5% VWC. Given the economic value of water and its control on biomass production, we conclude that nursery managers can maintain optimal substrate moisture with minimal sensor deployment.
Jennifer L. Emerson, John Frampton, and Steven E. McKeand
). Information about the genetic variation of Fraser fir in natural stands is necessary to conserve its genetic diversity in the face of this ecological threat and to make improvements for Christmas tree production. One previous provenance–progeny test series of
Benjamin K. Hoover and R.M. Bates
managing PRR in fraser fir Christmas tree production requires an integrated control program. Critical components include avoiding exposure to Phytophthora inoculum through sanitation and reducing the activity of Phytophthora through ensuring proper soil