Climate change, specifically the increasing frequency and intensity of summer heat and drought, has severe influences on the performance of beech forests, including decline in growth, reduced ...nutrient turnover, enhanced mortality, and a shift in spatial distribution northwards and towards higher elevations. The present study aimed to characterize the physiological responses of Croatian beech saplings originating from 10 natural forest stands to experimentally applied water deprivation in a common-garden experiment. The aim was to evaluate the extent to which external factors such as climate, as well as nitrogen (N) and phosphorus (P) availability in the soil of the natural habitats, control the response of beech saplings to water deprivation. For this purpose, beech saplings from 10 forest stands that differed in terms of soil type, chemical soil properties, as well as climate were collected in winter, cultivated in an artificial soil substrate under controlled conditions for one year, and then subjected to 29 days of water deprivation. Responses to water deprivation were observed in the antioxidative system (total ascorbate, reduced ascorbate, oxidized ascorbate, and redox state) in leaves and fine roots. The latter allowed us to categorize saplings as adapted or sensitive to water deprivation. P over N availability in the soil rather than climatic conditions in the natural habitats controlled the response of beech saplings to the water-deprivation event. The categorization of saplings as adapted or sensitive to water deprivation was related to genetic parameters. The results of this multidisciplinary study (tree physiology, climate, and genetic data) are considered to be highly significant and beneficial for the adaptation of European beech forests to changing climatic conditions.
Increased frequency of extreme weather events has seriously affected forestry operations in south-eastern Europe. A precondition for effective artificial restoration of disturbed forest stands is ...site-adapted forest reproductive material (FRM). Common garden experiments (provenance trials) may assist in selecting such FRM. The main objective of this study was to establish among-provenance variation pattern using data from a beech provenance trial. Usefulness of the results in selecting seed sources for restoration of European beech stands is discussed. The trial was set up in 2007, at a slope of Medvednica mount facing north-west at 730-750 m above sea level. Plant heights were measured and survival scored in 2008 and 2015. Height increments were calculated and processed to determine variance components due to various effects. Highly significant provenance-by-block interaction was revealed, indicating strong microsite effects on provenance performances. Therefore, corrections were made and provenance mean height increments recalculated. Provenance mean height increment multiplied with survival was used as a measure of a provenance’s adaptedness. Regression tree (RT) analysis was used to determine the pattern of among-provenance variations. A set of provenance clusters was grown using climatic variables related to the provenance stands of origin as criteria. All analyzed effects were significant (provenance: F=2.07, p<0.05; block: F=5.07, p<0.05; provenance by block interaction: F=7.32, p<0.001). Data corrections reduced the interaction effect, thereby increasing reliability of calculated provenance adaptedness indices (AI). Provenances were grouped into 4 clusters due to elevation, mean July temperature and summer heat-to-moisture index (SHM). Cluster 4, containing provenances from the highest altitudes (>750m), had the highest mean AI (143.9±8.4 cm). The lowest mean AI (106.7±14.8 cm) had cluster 1, containing provenances from lower altitudes with lower mean July temperatures (≤18.4°C). Provenances originating from lower elevations with higher mean July temperatures (>18.4°C) were further divided into two clusters due to the SHM variable. Cluster 2 had the second highest mean AI (141.2±1.5 cm) and contained provenances from relatively wetter habitats (SHM≤48.2). Cluster 3, containing provenances from relatively arid habitats (SHM>48.2), had significantly lower mean AI (116.8±8.6 cm). Established among-provenance variation pattern might be used as a tool in selecting seed sources for artificial restoration of beech stands at mount Medvednica. It is advisable to use FRM from higher altitudes and/or from slightly lower altitudes (up to 150 m lower than a restoring site) but featured with warmer and drier conditions compared to the trial. Generally, provenance trials should be utilized as a valuable decision tool in restoring disturbed forest stands but may also be misleading if not well designed and analyzed.
European black poplar (Populus nigra L.) is a pioneer species that belongs to the Salicaceae family and occurs in riparian ecosystems. It is one of the most endangered forest species in its entire ...distribution area. In Croatia, black poplars are considered an economically important forest species, but mostly clones originate from crossing combinations with American and European black poplar (Populus × canadensis Moench), while a small number of clones are native black poplar. Studies on native black poplar are quite rare and the generative propagation has not been used. The aim of this study was to gain knowledge on the production of high-quality black poplar seedlings and to carry out the selection of genotypes with the aim of establishing a base for future breeding. The female black poplar tree was selected on phenotypic characteristics in the area of Forest Administration Osijek, Forest Office Valpovo. The tree was cut down in April 2019, and branches with half-open seed capsules on catkins were collected. The branches were transferred to the Croatian Forest Research Institute’s greenhouse, where the catkins opened under the influence of the high temperature. Sowing was done in different substrates to test their effectiveness. Black poplar seedlings were selected and transplanted with regard to development and height growth. The results showed differences in height growth between plants sown in two different substrates and the occurrence of fungal diseases only on plants sown in pure sand. With subsequent multiple propagation using cuttings and selection by genotype, it is expected that it will be possible to identify several clones of native black poplar that will be introduced for use in forestry in Croatia. The use of quality plants grown from seeds will increase the genetic diversity and preserve the native black poplar gene pool.
Quercus robur L. exhibits not only a large inter-annual variability in seed production but also considerable variability among locations and individuals within the same year. The differences in how ...individual trees and populations of oaks invest in acorn production, both in terms of the yield size and the acorns quality, is of interest both ecologically and economically. For this research we used data collected from harvesting which has been organised and executed by the largest forestry company in Croatia - public enterprise Croatian Forests Ltd. According to the Act on Forest Reproductive Material, Croatian Forest Research Institute is designated as the Official Body that supervises production and provides analysis of quality of forest reproductive material. Regarding that, we summarized data of 10-year long records (from 2009 to 2018) of submitted seed samples and seed quality testing from 119 Q. robur forest seed objects across Croatia. Our aim was to investigate seed yield and effects of seed size and seed moisture content on seed viability. In the study period there were four years with higher quantity of collected seeds than other years (2010, 2011, 2015 and 2017). There was no significant difference in seed viability among forest seed objects. However, variations among years within forest seed objects were highly significant. It was also found that seed size (indicated by the number of acorns per kg) and seed moisture content were significantly related to seed viability. Bigger seed dimensions, i.e. lower mean number of acorns per kg, correlated with higher viability. Lower moisture content affected decrease in acorn viability. On average, viability dropped below 70% when acorn mean moisture decreased below 36%. Thus, it can be concluded that bigger seeds and seeds with moisture content of 40-44% have better viability.
To preserve the sustainability of Quercus robur forests, which is at risk due to the disturbed natural regeneration, human assisted sowing of acorns or planting of oak seedlings is often performed. ...However, the success of these methods depends greatly on the use of high-quality sowing and planting material. Thermotherapy is thus often employed to decrease the acorn mycobiota and maintain their quality during the storage. The aim of this study was to test the impact of acorn thermotherapy, followed by a short-term storage at −1 °C or 3 °C, on the quality of related oak seedlings, which was assessed based on the easily observable morphological characteristics. Height, root collar diameter and seedling form were measured or noted for the 1284 and 1190 seedlings at the age of four months and three years, respectively. It was found that acorn thermotherapy affirmatively affected seedling height, especially at the early growth stage. Positive impact on other seedling attributes could not be decisively confirmed because of the lack of the continuity of the effect (not visible in both younger and older seedlings) and the prevailing impact of other factors. Different acorn thermotherapy conditions (temperature and duration) and short-term storage temperatures appeared to be associated only with the occurrence of stem forking at the earlier stage of seedling growth.
Cilj rada je predstaviti dva istraživačka projekta Hrvatske zaklade za znanost pod naslovima „Očuvanje genetskih resursa šumskog drveća u svjetlu klimatskih promjena“ – ConForClim IP-2013-11-8131 i ...„Dinamika plodonošenja i očuvanja genofonda hrasta lužnjaka (Quercus robur L.) i obične bukve (Fagus sylvatica L.) u svjetlu klimatskih promjena“ – CropForClim IP-2018-01-8189. Oba projekta imaju za cilj na projektnim vrstama, hrastu lužnjaku i običnoj bukvi, istražiti genetsku varijabilnost i prilagodljivost sa svrhom davanja smjernica za poboljšanje i unapređenje očuvanja genetskih resursa. Projekti se provode na lokalitetima Hrvatskih šuma d.o.o. pod vodstvom dr.sc. Mladena Ivankovića, predstojnika Zavoda za genetiku, oplemenjivanje šumskog drveća i sjemenarstvo na Hrvatskom šumarskom institutu. Istraživački tim oba projekata čine znanstvenici sa Hrvatskog šumarskog instituta i Fakulteta šumarstva i drvne tehnologije Sveučilišta u Zagrebu, dok su na projektu ConForClim bili uključeni i znanstvenici sa Šumarskog instituta Baden-Württenberg i Katedre za fiziologiju drveća Instituta za šumarstvo koji je u sklopu Albert–Ludwigs Sveučilišta Freiburg.
Hrvatski šumarski institut od 2018. godine kroz Laboratorij za kulturu tkiva radi na razvitku protokola za mikropropagaciju najvažnijih i najugroženijih vrsta šumskog drveća u Republici Hrvatskoj. ...Sve intenzivnije klimatske promjene negativno utječu na stabilnost šumskih sustava, dok u isto vrijeme pogoduju pojavi novih, ali i pojačanom širenju već postojećih šumskih štetnika i patogena. Pronalazak i očuvanje superiornih genotipova koji bi mogli opstati u novonastalim okolnostima postaje sve važnije za očuvanje šuma, dok se uz pomoć mikropropagacije ovaj proces može višestruko ubrzati.
Hrvatski šumarski institut (HŠI) već više od 10 godina se bavi projektima očuvanja genofonda
zaštićenih i znamenitih stabala na području Republike Hrvatske (RH). Značaj ovakvih projekata prepoznat je ...od strane brojnih javnih ustanova, lokalne samouprave i udruga za zaštitu prirode koje žele sačuvati genetski materijal takvih stabala za sva vremena. Diljem RH nalaze se brojna znamenita stabla koja nose povijesnu, kulturnu i estetsku simboliku pojedinog kraja, a neka se nalaze i na popisu zaštićenih stabala. Djelatnici HŠI-a obavljaju stručne poslove vezane uz proizvodnju klonskog materijala koji obuhvaćaju: proizvodnju podloga (biljke na koje se cijepe plemke), sakupljanje plemki (grančice od matičnog stabla koje se klonira), vegetativno razmnožavanje (cijepljenje vegetativnog materijala na pripremljene podloge) u plasteniku te uzgoj, školovanje, njegu i zaštitu biljaka u rasadniku instituta. Navedeni postupci dovode do stvaranja genetski identičnih „novih stabala“ čime se omogućuje trajno zadržavanje starih, izvornih stabala na lokalitetima pojedinog kulturnog dobra.
Background and Purpose: Soil microorganisms participate in major processes associated with sustainable soil management and ensure cycling of nutrients required for plant production. Their role is of ...special importance for the dynamics of generation and decomposition of soil organic matter, and they also take part in other processes that provide soil fertility and health. Different anthropogenic influences as well as mechanical and chemical properties of soil have a significant influence on the presence of functional groups of microorganisms and on enzymatic activities in the plough-layer. The main research aim was to study the microbial characteristics and enzymatic activity in pseudogley and luvic soil types of western Slavonia. Materials and Methods: Soil samples collected from soil profiles differently affected by anthropogenic action, from four localities in western Slavonia were analyzed. Results: Average total number of micoorganisms was 13.90 ´ 106 CFU/g soil in pseudogley and 21.33 ´ 106 CFU/g soil in luvic soil. In pseudogley the proportion of functional groups was poor to medium and proteolytic activity was 6.21 (gelatine units/g soil). In luvic soil very good proportion of aerobic asymbiotic nitrogen fixators and cellulolytic fungi was determined. The average proteolytic activity was 5.08 gelatine units/g soil. Research results for cellulolytic activities in luvic soils and pseudogley show that higher values were determined for endogluconase than for cellobiohydrolase.
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