Technical resource bulletin. TRB-005, Effect of planting density on the growth and yield of Atlantic white-cedar, eight year results

Technical Resource Bulletin TRB-005 February 2006 THE EFFECT OF PLANTING DENSITY ON THE GROWTH AND YIELD OF ATLANTIC WHITE- CEDAR— EIGHT YEAR RESULTS Bill Pickens. NC Forest Service, Raleigh NC Abstract— This study examines the influence of planting density on the growth and yield of Atlantic white-cedar (Cham aecy pans thyoides (L.) B.S.P.) plantations. Following a clearcut harvest, the study site was root-raked, burned, and planted with bare root Atlantic white-cedar seedlings at three planting densities; 6 ft. x 12 ft. (605 trees/acre), 6 ft. x 6 ft. (1210 trees/acre), and 4 ft. x 6 ft. (1815 trees/acre). After three growing seasons, the tree height was sim¬ ilar across all treatments, averaging 6.4 feet. Survival was 91% (605 trees per acre) 86% (1210 trees per acre), and 83% (1815 trees per acre). Early growth was not affected by planting density in this study. INTRODUCTION Atlantic white-cedar (Chamaecyparis thyoides (L.) B.S.P.) is a wetland species that has been in decline across its range since the late 1800's when it was exten¬ sively logged as a valuable timber product ‘.Today it is valued both ecologically and economically. Regenera¬ tion efforts are needed to restore Atlantic white-cedar to its original range. Artificial regeneration by private land- owners is an important component of the restoration ef¬ fort. The conical shape and small bole of Atlantic white- cedar (2-16 inch diameter at breast height) allow it to naturally regenerate and maintain dense stands (250 to 300 ft2 basal area per acre) 2 \ Because of high seedling and site preparation costs, artificial regeneration of At¬ lantic white-cedar is expensive. Planting fewer trees per acre reduces establishment costs, but may not optimize economic returns. Currently, many resource managers recommend planting densities common to loblolly pine (600-800 seedlings per acre), but that may not be appro¬ priate for Atlantic white-cedar. Little data is available on how planting density affects the growth and yield of At¬ lantic white-cedar stands4 .This study examines the influ¬ ence of planting density on the growth and yield of At¬ lantic white-cedar plantations to determine if higher planting densities will increase volume yield and result in a better rate of return that will offset high establish¬ ment costs. METHODS The study is located at the NCSU Hofman Forest, Onslow County, NC on a former pond pine forest. The soil is very poorly drained, but the tract is extensively ditched. The soil type is a Pantego black fine sandy loam that has a site quality index (base age 50) of 95 for lob¬ lolly pine. The site was clearcut, raked, and burned in preparation for the planting. Planting density treatments were: 1) 605 trees/acre, 2) 1210 trees/acre, and 3) 1815 trees/acre. The treatments were established in a randomized com¬ plete block design with four replications per treatment. Each treatment plot was approximately 0.25 acre in size. North Carolina Division of Forest Resources personnel hand planted a total of 4061 seedlings with dibble bars in February of 2001 . The 1 -0 bare root seedlings were propagated from seed at the North Carolina Division of Forest Resources Claridge Nursery in Goldsboro, NC. Overall seedling quality was poor, as a great many of the seedlings planted were less than 4 inches tall and had sparse root systems. The largest seedlings were about 4- 5 inches tall. The first data collection was made after three growing seasons in March of 2004. Surviving trees were meas¬ ured for height to the nearest 0. 1 feet and stocking densi¬ ty and survival was determined. DBH was not measured since many trees were less than 4.5 feet tall. Height and DBH were measured a second time in Febru¬ ary of 2009 after eight growing seasons since planting. RESULTS After three years in the field survival was 91%, 86%, and 83% for treatment 1, treatment 2, and treatment 3 respec¬ tively. Height was 6.2 feet, 6.6 feet, and 6.5 feet for treatment 1, treatment 2, and treatment 3 respectively, with no significant differences among treatments at P = 0.05. See Table 1.