Arboriculture & Urban Forestry 35(2): March 2009 Arboriculture & Urban Forestry 2009. 35(2): 107–110 107 Eastern Redcedar Seed Source Test in Western Kansas Wayne A. Geyer, Keith D. Lynch, and Charles J. Barden Abstract. Sources of eastern redcedar (Juniperus virginiana L.) were established as a provenance test near Colby, Kansas, U.S. in 1980. Height, diameter, number of stems, crown density, branch angle, and general vigor were evaluated with ANOVA, cluster anal- ysis, simple correlation, and regression analysis techniques. Clear source and cluster differences were found. Total height at 23 years ranged from 3.6 to 5.4 m (11.8 to 17.7 ft), dbh (diameter at breast height) ranged from 2.5 to 14.4 cm (1 to 5.7 in), and mean survival rate was 78%. Sources from the central plains grew best. Selection of fast-growing sources may begin at five years after field planting. Key Words. Growth Characteristics; Juniperus virginiana L.; Juniperus scopulorum; Seed Sources. Eastern redcedar (Juniperus virginiana L.) is the most widely distributed conifer tree in the eastern United States (Burns and Honkaka 1990).The species range extends into southern Can- ada, and has been naturalized into the western Great Plains by natural regeneration from planted trees. Eastern redcedar is a small- to medium-sized, slow-growing intolerant tree (Har- low et al. 1979). There have been numerous taxonomical stud- ies on this tree (Fassett 1944; Comer et al 1982; Adams 1983; Schaefer 1995). Cunningham and King (2000) identified ge- netic variation of various major traits for 10-year-old plant- ings, and seed source selection zones, for the Great Plains area. This test is a part of a larger regional study initiated in 1973 by the now disbanded Technical Committee of the Great Plains Ag- ricultural Council. The objectives were to determine the genetic variation of major traits and to identify the best sources of seed for windbreak applications. This paper presents the portion of the study established in Colby, Kansas after 23 years of growth in the field. MATERIALS AND METHODS A complete description of the methodology used for this greater study can be found in Van Haverbeke and King (1990). Seed cones were collected from 140 trees in natural stands and windbreaks across the Great Plains. Seed trees that had desir- able windbreak characteristics (e.g., abundant branches, dense foliage) were selected. Seed lots were sown in the USDA For- est Service Bessey Nursery near Halsey, Nebraska in 1977 and were out-planted at 12 test sites in 1980. This study reports on the Colby site (39.38°N and 101.07°W), located in the central geographic region of zones established by Van Haverbeke (1968). Soil is from the Keith series loam (e.g., fine-silty, mixed, mesic Aridic Haplustolls) and Richfield silty clay loam (e.g., fine, mont- morillonitic, mesic Aridic Haplustolls). A randomized complete- block with five replications of 4-tree, linear plots was established having 20 trees maximum for each source. A total of 2320 trees were planted, along with 520 Rocky Mountain juniper (Juniperus scopulorum L.). Spacings in the plantation were 2.4 m (8 ft) with- in rows and 3.6 m (12 ft) between rows. A single border row was planted on all sides. Clean cultivation was maintained for five years. Growth evaluations were made at age 5, 10, and 23 years. Statistical analyses were performed with SAS software (Statistical Analysis System, SAS Institute Inc., Cary, NC). Data were analyzed via the analysis of variance procedure, and the Duncan’s means test was used for mean separation. Clus- ter analysis (Ward’s minimum variance) were used to iden- tify seed sources with similar performance characteristics. Variables usse in said analyses were survival rate, total height, dbh (diameter at breast height), number of stems, crown den- sity, branch angle, vigor, latitude, longitude, and elevation. If trees had multiple stems, then only the largest was evalu- ated for height and diameter. Simple Pearson correlations were computed among seed sources of individual trees for each trait. The correlation of each trait with latitude and longitude was also examined. Least squares regression models of differences in lati- tude, longitude, and elevation between source locations and the Colby plantation were run to find the extent of the geographic area from which seed may be collected to give good tree growth performance in western Kansas. To determine the reliability of early seed source selection, age/age correlations were computed for survival and height of source means at age 10 and age 23. RESULTS Significant differences among seed sources existed for survival, height, dbh, number of stems, crown density, branch angle, and vigor. Each is discussed separately, but we also chose to iden- tify more general patterns of variation by using cluster analysis. Survival Seed sources were significantly different at P < 0.01 (analy- sis of variance) in survival rates through age 23, with a range of 10 to 100%. The mean survival was 78%. The best sources were from the central part of the range, while the poorest sur- viving sources were from southern Texas which was 30%. Height Seed sources were significantly different in height at the P < 0.01 (analysis of variance) through age 23 (Table 1). The mean height for all of the trees was 5.3 m (17.5 ft), ranging from 3.1 to 6.2 m ©2009 International Society of Arboriculture
March 2009
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