Morphological and physiological attributes of root systems and seedling growth in three differentPicea glaucareforestation stock

Abstract

The relationship between certain morphological characteristics of white spruce (Picea glauca (Moench) Voss) planting stock (STK) and post-planting seedling performance was evaluated. Root system size at planting, its expansion, and its capacity to conduct water during the first post-planting weeks were determined. These characteristics were related to the performance of STK planted on two forest sites and measured for three growing seasons and to the performance of seedlings grown in large wooden boxes buried in the soil outdoors for one growing season (grown without competition from other vegetation). The compared STK were (i) polystyroblock grown, (ii) polystyroblock grown with chemical root pruning, and (iii) peat-board grown with mechanical root pruning. After three growing seasons on forest sites, seedlings with mechanically pruned roots grew more above ground than did seedlings from polystyroblock containers. This difference in seedling growth performance was even more significant for seedlings grown in wooden boxes. Of these, the mechanically pruned seedlings grew more not only above the ground but they also produced larger root systems by the end of the first growing season. This was despite the initially significantly smaller root systems of mechanically pruned seedlings, compared with the other two STK. Early (5-7 weeks after planting) post-planting root expansion patterns in the three STK were significantly different, with the roots of mechanically pruned seedlings growing less than the roots in the other two STK. In spite of this, pressure-probe measured hydraulic conductivity and water flux through root systems increased during the first post-planting weeks in mechanically pruned seedlings while declining or changing little in the other two STK. It was concluded that root system size at planting and its early post-planting expansion did not relate well to the root system hydraulic properties or to the post-planting seedling growth performance.

Root system modifications by nursery culture reflect on post-planting growth and development of coniferous seedlings

“…The stock types did not differ in height and ground-level diameter immediately after planting but three seasons later Vapo seedlings grew significantly more in height and stem diameter on both sites as detected by the repeated-measures ANOVA showing significant effects of stock type over time for height (p 0.03) and stem diameter (p 0.02) (Krasowski and Owens 2000). Detailed physiological and morphological measurements were made on seedlings from the same stock types planted into 4L plastic pots filled with nursery soil.…”

“…This experiment used three already introduced stock types of 1+0 spruce: 1) PSB 415B, 2) PCT 415B, and 3) Vapo. The study was reported by Krasowski and Owens (2000) and had the following objectives: a) to evaluate how hydraulic properties differ in root systems of different sizes and in different types of nursery stock and how these properties change during the first weeks after planting, and b) to determine if vigorous root growth shortly after planting results in better performance of seedlings or even in greater expansion of the root systems during the first post-planting season. The study had two components.…”

“…Another question asked in this study (Krasowski and Owens 2000) was whether the small root systems and their slow initial expansion in the Vapo would compromise the seedling growth and root system development during the first growing season after planting. To this end, 16 seedlings of similar sizes (four per container) of each stock type were planted into large, 64L wooden boxes filled with nursery soil and topped (4 cm) with an organic mix (compost, decomposed bark, and peat).…”

“…Shown are means and their standard errors (capped bars). Data from Krasowski and Owens 2000. The Forestry Chronicle Downloaded from pubs.cif-ifc.org by 18.236.120.13 on 05/11/18…”

The growth of styroblock, chemical and mechanical root pruned lodgepole pine seedlings in Interior British Columbia.

“…Once planted, rooting patterns have shown to be inferior from naturally germinated seedlings (Halter et al, 1993). In an attempt to improve container deficiencies, root-pruning methods have been recommended (Wenny et al, 1988;Winter and Low, 1990;Krasowski and Owens, 2000;Jones et al, 2002;Rune, 2003). Since the long-term success of a planted tree is strongly determined by its ability to establish a well-developed root system (Eis, 1978), this research has focused on evaluating the early rooting establishment in planted lodgepole pine (Pinus contorta Dougl.…”