The Effect of Polypropylene Tree Shelters on Growth and Survival of Pedunculate Oak Seedlings (Quercus robur L.)

Abstract

Background and Purpose: The declining and dieback of lowland oak forests as the result of global climate change, as well as the attack of various pathogenic organisms, industrial pollution, and other negative effects reduce acorn yield and will continue to do so in the future. As a result of this fact, the areas on which artificial regeneration will be applied by planting seedlings will have to be increased. The artificial regeneration process is more expensive than the natural one, so protection measures need to be applied to minimize the loss of young seedlings. Materials and Methods: Experimental plots were set up in the forest area of Spačva Basin. A completely randomized block design experiment in four repetitions was used, in which four variants of planting and protection of oak seedlings were examined. We tested polypropylene tree shelters and hydrophilic superabsorbent based on maize starch. Heights of the plants were measured by measuring tape, and survival was registered by numbering of dead and living plants. For statistical purposes, we have used analysis of variance (repeated measure ANOVA), which allows us to prove statistically significant difference between morphological traits of studied variants. Results: Two years after planting, the lowest level of survival was found in unprotected seedlings (79.5%), while tree shelters provided the best conditions for seedlings survival (88.75%). In the case with the hydrophilic granules Zeba the result is slightly worse. When analyzing average height in a particular case, significantly higher plants are recorded in cases where the polypropylene tree shelters are used. The average height, with tree shelters (128.27 cm), is more than three times higher than the unprotected seedlings (37.97 cm). The addition of hydrophilic granules did not show a statistically significant difference. In cases where the seedlings were not under the tree shelter protection, the effect of hydrophilic granules was also not statistically significant. Conclusions: Sheltering accelerated the height growth of the planted oaks substantially and also provided best conditions for seedlings survival. During the research period the usage of Zeba did not justify the purpose for which it was applied. Although the first results are promising in order to gain a complete insight into the potential of tree shelters it is necessary to record the changes and maintain the experiment for a further 2-3 years with quantification of other harmful factors that may appear (drought, game etc.) after which a more reliable judgment regarding their usefulness could be provided.

Study of the Effects of Polypropylene Tree Shelters and Hydrophilic Polymers on Growth, Survival, Health and Physiological Condition of Pedunculate Oak Seedlings ( L.)

“…The experiment is a continuation of a multi-annual scientific research, whose results of monitoring survival and height growth were published in scientific journal SEEFOR (Liović et al 2019).…”

“…In 1979, English forester Graham Tuley introduced the first shelters for seedling protection (Tuley 1983, Tuley 1985. The advantages of shelters are rapid growth and height growth and better seedling survival, which have been reported by numerous authors (Potter 1988, Bainbridge 1991, Kerr 1992, Lantagne 1995, Liović 1997, Conner et al 2000, Liović et al 2001, Liović et al 2013, Liović et al 2019, Benko 2020. The use of shelters positively affects growth and survival as well as transplant stress that usually occur after seedlings is moved from the nursery to the forest habitat, a condition also known as "transplant shock".…”

“…Oak seedlings are particularly sensitive to competition from weeds, shrubs and other competitive species that reduce available sunlight, moisture and nutrients in the soil (Matić 1996). Pedunculate oak seedlings protected with a shelter achieved a three times higher average height compared to seedlings without shelter protection, and such height growth would enable them to quickly leave the zone of competition with weeds and achieve better survival rate (Liović et al 2019). In addition to protection from weeds, shelters provide shade for the seedlings, i.e.…”

“…The influence of game on the natural regeneration in pedunculate oak stands during shelterwood cutting was research by Krejči et al (1997), Krejči et al (2001), Krejči and Dubravac (2004). The use of shelters also reduces the attack of powdery mildew on oak (Microsphaerae alphitoides Griff et Maubl) because of the specific climate inside the shelter (Liović 1997, Liović et al 2019, Benko 2020.…”

Study on the Ecology, Biology and Ethology of the Invasive Species Corythucha arcuata Say, 1832 (Heteroptera: Tingidae), a Danger to Quercus sp. in the Climatic Conditions of the City of Sibiu, Romania

“…Invasive insect species pose a threat to biological diversity and ecosystems [14]. With free movement of goods (trade in products of plants of origin), global changes in the environment: the degradation of ecosystems, deforestation, climate change, and industrial pollution [15], has led to greater impact of the spread of invasive species occupying new territories [16].…”