Effects of Douglas-fir 2+0 seedling morphology on field performance

Abstract

Application. Survival and height growth of Douglas-fir bareroot 2 + 0 seedlings during plantation establishment can be increased significantly by using seedlings with both large diameters and root systems. Specific criteria for culling seedlings with small diameters and root size will depend on the characteristics of each nursery crop rather than on the same absolute values for all crops.Abstract. The relationships between field performance of Douglas-fir (Pseudotsuga menziesii) 2 + 0 seedlings and their initial diameter and root mass were evaluated on five sites in Oregon in the early 1980s to identify opportunities for improving seedling grading prior to planting. Survival and height 3--5 years after planting were positively related to seedling size at the time of planting. On all sites, survival nearly doubled from the smallest to largest diameter classes. Root mass had a similar relationship to survival on sites with environmental stress. Increasing root size class increased survival more for the small diameter classes than for the larger diameter classes. On the other hand, increasing root size class increased total height more for the large diameter class than the smaller ones. Although height was not as strongly affected as survival on several sites, height differences among initial seedling diameter classes were still significant and increasing after five years. Root class effects on height were less important than diameter class effects.

Interaction of initial seedling diameter, fertilization and weed control on Douglas-fir growth over the first four years After Planting

“…The 2 mm difference in stem diameter at planting resulted in a 35% (775.2 vs. 1043.2) increase in fourth-year stem volume at the Orting site and a 43% (619.7 vs. 891.1) increase at the Belfair site. The benefit derived from planting larger stock was consistent with other published studies for Douglas-fir [11,27,35]. Similar trends have also been reported for other conifer species in dramatically different environments [17,[31][32][33].…”

“…A variety of studies have demonstrated that planting stock with larger initial stem diameter can accelerate early plantation survival and growth [11,22,41]. Similarly, several studies have demonstrated positive survival and growth responses of Douglas-fir to site preparation and first-year and sometimes second-year herbaceous weed control [6,16,20,28,42].…”

Integration of soil moisture, xylem water potential, and fall–spring herbicide treatments to achieve the maximum growth response in newly planted Douglas-fir seedlings

“…To minimize seedling variability and maximize the potential for vigorous growth (Long and Carrier 1993), grading criteria were established based on height and stem diameter measurements taken from a random sample of 300 seedlings prior to lifting and sorting at the nursery. Based on this information, seedlings selected for this study were 35-55 cm in height and 7-9 mm in stem diameter.…”

Influence of initial root length on physiological responses of cherrybark oak and Shumard oak seedlings to field drought conditions

“…Morphological attributes such as stem height, root collar diameter and root:shoot ratio are used to assess seedling quality together with root morphological information such as root growth, length of lateral roots and length of tap root (Kormanik, 1986;Haase and Rose, 1993;Pallardy and Rhoads, 1993;Symeonidou and Buckley, 1999). The amount of functional roots prior to transplanting is important to successful establishment of seedlings in the field (Haase and Rose, 1993;Long and Carrier, 1993;McGrath and Duryea, 1994;Thompson and Schultz, 1995;Krasowski and Owens, 2000). Development of a vigorous root system after planting is crucial for the effective absorption of water and nutrient resources (Pallardy and Rhoads, 1993;Thompson and Schultz, 1995).…”