Growing of the Containerized Seedlings of English Oak (Quercus robur L.) to Establish Sustainable Plantations in Forest-Steppe Ukraine

The topical issues for elaboration of new approaches to grow English oak (Quercus robur L.) seedlings with the purpose to establish sustainable plantations in forest-steppe Ukraine. The goal of the research is to elaborate a technology for growing the containerized seedlings of English oak. Oaks are among the most common tree species found throughout the world. Throughout history, oaks have provided humans and wildlife with shelter, and food. However Ukrainian forests face multiple natural and anthropogenic pressures. Climate change generates a particular threat for Ukrainian forests and stability of agroforestry landscapes. This paper considers the impacts of expected climate change on vulnerability of Ukrainian forests, especially for oaks. In response to forest depletion, stricter forest management practices emerged to replant, protect and maintain forest cover and the multi-functionality of forests in terms of wood production. Even though oaks have wide ecological amplitudes of suitable growing conditions, Ukrainian forests dominated by oaks often fail to regenerate naturally. In this regard, it is necessary to increase the cultivation of crops in containers. Field germination of oak seedlings in containers with different substrate composition was identified in the case study in the conditions of Ukrainian Left-bank Forest-Steppe. The height and diameter values of the seedlings were investigated and summarized including the influence of the root ball substrate composition. We tested different compositions of the substrate containing low-land peat, which is rich in nutrients and mixtures with different ratios of soil, humus and sawdust. The advantage over the control in germination ability, survival and condition has been experimentally proved for variants with the use of peat in the substrate and, to a large extent, for the variant with the use of soil, humus and sawdust. Among tested substrates, the peat-containing variant with equal portions of dark gray wooded middle loamy soil and peat (peat:soil = 1:1) and the variant of the three-component mixture soil:humus:sawdust = 4:2:1 are the most balanced in the basic soil parameters (acidity and nutrient content). In the same time they are the best among the studied ones for the productive growing of English oak seedlings. The use of containerized planting stock allowed foresters not only to significantly extend the terms of forest planting, which is particularly topical for Ukraine, but also to increase the root-taking of planting stock up to nearly 100% in forest-cultivated areas.