Root Morphology, Stem Growth and Field Performance of Seedlings of Two Mediterranean Evergreen Oak Species Raised in Different Container Types

Abstract

Outplanting container-grown oak seedlings with undesirable shoot and root characteristics result in poor establishment and reduced field growth. The objective of this study was to determine the influence of container type on both above-and below-ground nursery growth and field performance of one-year old taprooted seedlings Quercus ilex L. and Quercus coccifera L. The experiment was conducted in an open-air nursery and the seedlings were grown in three container types. At the end of the nursery, growth period seedlingsÕ shoot height, diameter (5 mm above root collar), shoot and root biomass, root surface area, root volume and total root length were assessed. Then the seedlings were planted in the field and their survival and growth were recorded for two growing seasons after outplanting. The results showed a difference between the Quercus species in the effect of container type. Q. ilex seedlings raised in paper-pot had significantly greater height, diameter, shoot and root biomass and root volume than those raised in the other two container types. Similarly, Q. coccifera seedlings raised in paper-pot, had significantly greater above-and below-ground growth than those raised in the other two container types. Both oak species showed relatively low survival in the field; the mortality was mainly observed the first year after outplanting, especially after the summer dry period. However, 2 years after outplanting, the paper-pot seedlings of the two oak species showed better field performance.

Germination and seedling growth of holm oak (Quercus ilex L.): effects of provenance, temperature, and radicle pruning

“…The slow growth and poor survival of planted oaks may be in part due to the root system (Barden & Bowersox 1989). Finally, Tsakaldimi et al (2005) highlighted that grading criteria for oak seedlings' shoot height and root-collar diameter are important parameters to be considered for successful reafforestation of sites with high environmental stress.…”

The impact of the container size and soil preparation on afforestation success of one year old holm oak (quercus ilex) seedlings in Croatian Mediterranean area

“…Villar -Salvador et al (27) noticed that plants with a higher aboveground part had significantly lower mortality. Seedlings with larger diameter, planted in a field ex- periment, had significantly lower mortality (26). Our results show that plants with such morphological features can be produced only in larger containers.…”

“…Chirino et al (3) also determined much greater root volume by cultivating cork oak (Quercus suber L.) seedlings in containers with a greater depth. Seedlings with greater root volume have a higher water and nutrient intake compared to the seedlings with a smaller root volume, and it is one of the key factors in avoiding stress in the early stages after field transplantation, especially during the summer dry season (26). Consequently, it could be concluded that the root volume, with regard to the morphological aspect, can be an important indicator of the seedlings' quality.…”

“…In this case, also, the effect of the large container (LC) on the survival rate came to expression. The explanation for this could be found in the work of Tsakaldimi et al (26), who obtained higher specific root length (SRL) for seedlings cultivated in containers of larger volume, and Pemán (16), who obtained higher SRL in deeper containers. The higher SRL implies thinner roots (less resistance to radial flow in these roots compared to denser or thicker roots) and thus a better utilization of water and nutrients from the soil, due to the higher hydraulic conductivity (12).…”

Use of alternative containers for promoting deep rooting of native forest species used for dryland restoration: the case of Acacia caven

“…Limitations of small containers result in serious morphological constraints and higher shoot/root ratios. This has a strong and negative impact on seedlings' water economy after they are outplanted, particularly under arid and semiarid climate conditions (Romero et al 1986, Tsakaldimi et al 2005.…”