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| ŠUMARSKI LIST 11-12/2023 str. 52 <-- 52 --> PDF |
(Pasta et al., 2016). On the edge of the Panonnian basin Q. pubescens is mainly found on the edge of its native range and in isolated populations (Caudullo et al., 2017). These populations have an important role in examining the adaptive potential and field performance of the seedlings, especially considering that the forest-steppe and sub-mediterranean climate is predicted to be the dominant climate in some regions of Central Europe (Bordács et al., 2019). Projections of the regional climate model for south-east Europe generally predict an increasing of temperature and a decreasing of precipitation (Ivetić, Devetaković, 2016), which indicate possibility to promote Q.pubescens as a potential species for oak forest restoration on the continental areas of Balkan and increasing their participation in forests. As heliophilous and thermophilous species tolerant on low precipitation level (<400 mm in vegetation period), summer drought and poor and eroded soils (Bordács et al., 2019) adaptive potential of pubescent oak, but as well as seedlings quality and management might have an increasing role in present and potential future distributional range. Seedlings attributes do not the only one predictor of future success, but it is important one, since artificial regeneration is interaction complex between species, planting and site conditions (South, 2000). Seedlings stocktype could be marked as one of factors which predict future success, and numerous trials reported advantages of container seedlings (Grossnickle, El-Kassaby, 2016). Beaside that, morphological attributes can be predictor of seedlings performance at the field (Tsakaldimi et al., 2012). There are studies which promote better morphological attributes as predictor for better survival (Villar-Salvador et al., 2004; Tsakaldimi et al., 2005; Villar-Salvador, 2012) and growth (Villar-Salvador et al., 2004; Ivetić et al., 2016) on the field for oak seedlings. Pre-planting operations have great role in survival of seedlings, planting date and soil preparation showed significant influence on survival and growth of Q.ilex seedlings in Mediteranian conditions (Palacios et al., 2009). High intensity soil preparation treatments can help survival of lower quality seedlings (South et al., 2001). Pre- and post-planting weed control is desirable and using different methods improve oak seedlings establishment (Ezell, Hodges, 2002; Löf et al., 2006; Ezell et al., 2007), often better than using tree shelters or natural shade (Mc Creary et al., 2011). Study with two Mediterranean oaks in combination with neighbored species showed high competition sensibility of Q.pubescens seedlings and better results in control where it was competitive to natural weed vegetation (Prévosto et al., 2015). Interactions between plants on the field are complex and complicated and in some cases negative effects of competition are lower than benefits. There are several studies which reported positive effect of shrubs on oak seedlings survival and growth in Mediteranian conditions (Gómez-Aparicio et al., 2004; Padilla, Pugnaire, 2006; Rousset, Lepart, 1999). Natural regeneration of oak forests is induced by seed production, seed viability, seed survival, seed dispersal, seedling establishment and sampling growth and survival (Pulido, Díaz, 2005). Reasons for poor oak regeneration could be caused by many factors such as limiting light conditions when oaks are out-competed by more shade-tolerant species or in the conditions after clearcut (light are not limited) when faster-growing species often out-compete oak (Iverson,2008). Natural regeneration of oaks were promoted as primarily method, but there are increasingly more situations in which high potential for oak regeneration failure dictates the use of artificial regeneration including direct seeding and planting seedlings (Dey et al., 2008). If artificial regeneration observed as planting, many problems can be exceed, but work method need be different and intent on seedlings performance and solving on pre- and post-planting conditions. However, there are very limit knowledge about Q.pubescens forest restoration and regeneration in the continental areas, so this study was provided with aim to obtained recommendation about seedlings stocktype for planting in continental Balkan areas for purpose of pubescent oak forests restoration. Material and method Materijali i metode Seed origin – Porijeklo sjemena Acorns were collected in the Natural Monument “Košutnjak Forest” (44.772730, 20.432714), located in Belgrade (Serbia). It is an isolated forests complex, surrounded by an urban area. In a floristically diverse forest four native oak species are present: Q. cerris, Q. petraea, Q. frainetto and Q. robur, as well as Q.rubra as non-native (Šijačić-Nikolić et al., 2021). Given the high rate of hybridization of this species, selection of morphologically typical individuals was needed. In total 88 trees were selected, but acorns were collected from 20 selected maternal trees. Except morphological traits of trees, spatial area was also taken into consideration with preferring long distance trees or tree groups (Figure 1). Nursery trial – Rasadnički ogled Collected acorns were shortly storage into basement (no more than two weeks) before nursery sowing. Nursery trial was established in the last week of October 2019 in nursery near originate population (44.782498, 20.425315). Sowing was performed in seedbeds and containers. In seedbeds density was 50 seeds m-1 and distance between rows 20 cm. In the same time, containers (Bosnaplast 18) were filled |