6 resultados para Multiobjective spanning tree
em DigitalCommons@University of Nebraska - Lincoln
Resumo:
The production of sound, clean fruit is unquestionably one of the major problems facing the modern fruit grower. Culture may be neglected and pruning delayed for a time but the omission of sprays for even a single season demonstrates their absolute necessity. This applies equally to the commercial grower and to the farmer or gardener who has only a few trees. Spray materials, equipment, management, schedules, insect pests and orchard diseases are discussed in this 1928 extension circular.
Resumo:
Establishing a conservation tree planting can be a challenge in semiarid regions like western Nebraska, where annual precipitation of 20 inches or less is the norm. Tree planting failure commonly occurs as a result of poor site preparation coupled with inadequate weed and grass control the first three to five years after planting. Effective site preparation begins the year before planting. The results help young trees survive and grow in several ways. This NebGuide explains when and how to do site preparation for conservation tree planting in Western Nebraska.
Resumo:
Proper nut cultivar (variety) selection is important for successful and satisfying results from the home gardener's efforts. Selection should be determined by personal preferences, available space, and intended use of the nuts. Harvest can be spread over several weeks if cultivars with different periods of maturity are planted. It is important that homeowners select the nut plants or cultivars best adapted for cultivation in their area of the state. This extension circular covers how to select a nut cultivar, the plant hardiness zones, horticultural regions, and length of growing season. It contains a list of all nut cultivars suited for growing in the state of Nebraska.
Resumo:
The Brown Tree Snake (Boiga irregularis) has caused ecological and economic damage to Guam, and the snake has the potential to colonize other islands in the Pacific Ocean. This study quantifies the potential economic damage if the snake were translocated, established in the state of Hawaii, and causing damage at levels similar to those on Guam. Damages modeled included costs of medical treatments due to snakebites, snake-caused power outages, and decreased tourism resulting from effects of the snake. Damage caused by presence of the Brown Tree Snake on Guam was used as a guide to estimate potential economic damage to Hawaii from both medical- and power outage–related damage. To predict tourism impact, a survey was administered to Hawaiian tourists that identified tourist responses to potential effects of the Brown Tree Snake. These results were then used in an input-output model to predict damage to the state economy. Summing these damages resulted in an estimated total potential annual damage to Hawaii of between $593 million and $2.14 billion. This economic analysis provides a range of potential damages that policy makers can use in evaluation of future prevention and control programs.
Resumo:
"Each generation takes the earth as trustees," J. Sterling Morton, founder of Arbor Day, once said, adding, "We ought to bequeath to posterity as many forests and orchards as we have exhausted and consumed."
Resumo:
Every fall millions of blackbirds come down the Mississippi Flyway to return to their winter roosts in Arkansas, Louisiana, and East Texas. When these roosts are located in urban areas, public pressure makes the more common chemical means of control impractical. A less destructive and more permanent method of control was sought. At Rice University, in Houston, Texas, there has been a blackbird roost of various sizes and durations since 1956. For the past two years we have had the opportunity both to study roosting blackbird biology and experiment with habitat alteration as a control method. This particular report concentrates on the results and interpretation of the tree- trimming program initiated in August 1974. The birds involved are primarily Brown-headed Cowbirds (Molothrus ater), along with Starlings (sturnus vulgaris), Common and Great-tailed Grackles (Quiscalus quiscula and Cassidix mexicanus), Red-winged Blackbirds (Agelaius phoenicus) and Robins (Turdus migratorius). The campus comprises 121 ha and was planted with live oaks (Quercus virginiana) in 1912. These trees retain their foliage throughout the winter and now form a closed canopy over some 5-6 ha. In the 60s and early 70s most of the birds that came to Houston for the winter roosted in a 64-ha woodlot 10 km north of campus. In January 1970, the U.S. Fish and Wildlife Roosting Survey reported one million birds at this site we call the North Loop. Fifteen- thousand birds were estimated at Rice.