Mixing effects on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) productivity along a climatic gradient across Europe

Mixed-species stands have been found to be more productive than would be expected from the performance of their component species in monocultures due to facilitation and complementarity between species, although these interactions depend on the combination of species present. Our study focuses on monospecific and mixed species stands of Scots pine and Norway spruce using 20 triplets established in nine countries along a climatic gradient across Europe. Differences in mean tree and stand characteristics, productivity and stand structure were assessed. Basal area increment in mixed stands was 8% higher than expected while volume increment was only 2% greater. Scots pine trees growing in mixed-species stands showed 11% larger quadratic mean diameter, 7% larger dominant diameter, 17% higher basal area and 25% higher stand volume than trees growing in mono specific stands. Norway spruce showed only a non-significant tendency to lower mean values of diameters, heights, basal area, as well standing volume in mixtures than monocultures. Stand structure indices differed between mixed stands and monocultures of Scots pine showing a greater stratification in mixed-species stands. Furthermore, the studied morphological traits showed little variability for trees growing in monospecific stands, except for diameter at breast height, crown length and crown length ratio. For trees growing in mixed stands, all the morphological traits of the trees were identified as different. Some of these morphological traits were associated with relative productivity. Nevertheless, relative productivity in mixed-species stands was not related to site conditions

Stand growth and structure of mixed-species and monospecific stands of Scots pine (Pinus sylvestris L.) and oak (Q. robur L., Quercus petraea (Matt.) Liebl.) analysed along a productivity gradient through Europe

19 Pág.Past failures of monocultures, caused by wind-throw or insect damages, and ongoing climate change currently strongly stimulate research into mixed-species stands. So far, the focus has mainly been on combinations of species with obvious complementary functional traits. However, for any generalization, a broad overview of the mixing reactions of functionally different tree species in different mixing proportions, patterns and under different site conditions is needed, including assemblages of species with rather similar demands on resources such as light. Here, we studied the growth of Scots pine and oak in mixed versus monospecific stands on 36 triplets located along a productivity gradient across Europe, reaching from Sweden to Spain and from France to Georgia. The set-up represents a wide variation in precipitation (456–1250 mm year−1), mean annual temperature (6.7–11.5 °C) and drought index by de Martonne (21–63 mm °C−1). Stand inventories and increment cores of trees stemming from 40- to 132-year-old, fully stocked stands on 0.04–0.94-ha-sized plots provided insight into how species mixing modifies stand growth and structure compared with neighbouring monospecific stands. On average, the standing stem volume was 436 and 360 m3 ha−1 in the monocultures of Scots pine and oak, respectively, and 418 m3 ha−1 in the mixed stands. The corresponding periodical annual volume increment amounted to 10.5 and 9.1 m3 ha−1 year−1 in the monocultures and 10.5 m3 ha−1 year−1 in the mixed stands. Scots pine showed a 10% larger quadratic mean diameter (p < 0.05), a 7% larger dominant diameter (p < 0.01) and a 9% higher growth of basal area and volume in mixed stands compared with neighbouring monocultures. For Scots pine, the productivity advantages of growing in mixture increased with site index (p < 0.01) and water supply (p < 0.01), while for oak they decreased with site index (p < 0.01). In total, the superior productivity of mixed stands compared to monocultures increased with water supply (p < 0.10). Based on 7843 measured crowns, we found that in mixture both species, but especially oak, had significantly wider crowns (p < 0.001) than in monocultures. On average, we found relatively small effects of species mixing on stand growth and structure. Scots pine benefiting on rich, and oak on poor sites, allows for a mixture that is productive and most likely climate resistant all along a wide ecological gradient. We discuss the potential of this mixture in view of climate change.The authors wish to thank the European Union for funding the project ?Mixed species forest management. Lowering risk, increasing resilience (REFORM)? (#2816ERA02S, PCIN2017-026) under the framework of Sumforest ERA-NET. All contributors thank their national funding institutions to establish, measure and analyse data from the triplets. The first author also thanks the Bayerische Staatsforsten (BaySF) for supporting the establishment of the plots and the Bavarian State Ministry for Nutrition, Agriculture, and Forestry for permanent support of the project W 07 ?Long-term experimental plots for forest growth and yield research? (#7831-22209-2013). The French site (FR-1) belongs to the OPTMix experimental site (https://optmix.irstea.fr), which is supported annually by Ecofor, Allenvi, and the French national research infrastructure ANAEE-F. Research on the Lithuanian triplets was made possible by the national funding institution Research Council of Lithuania (LMTLT), agreement No. S-SUMFOREST-17-1. Thanks are also due to Ulrich Kern for the graphical artwork. Finally, we thank two anonymous reviewers for their constructive criticism.Peer reviewe

The modeling of rot spread in Norway spruce (Picea abies (L.) H. Karst.)

Darbo objektas - įvairaus amžiaus centrinio puvinio pažeisti eglės medžiai, kurie auga skirtinguose našumo rajonuose. Darbo tikslas – centrinio puvinio paplitimo tipinėse paprastosios eglės augavietėse (Nc, Nd, Lb, Lc, Ld) vertinimo garsiniu tomografu ARBOTOM 3D galimybių tyrimas. Darbo metodai – duomenys apie puvinio išplitimą rinkti naudojant garsinį tomografą Arbotom 3D. Surinkti duomenys apdoroti naudojant MS Excel, Statistica ir Arbotom programas. Atliekant tyrimą buvo naudoti tokie bendrieji metodai: dokumentų analizės, duomenų grupavimo, modeliavimo, loginis, palyginimo, apibendrinimo. Rezultatai – Duomenys buvo renkami 4 gamtiniuose – našumo rajonuose.Tyrimo metu pamatuota 3269 medžiai iš kurių 703 nuskenuota garsiniu tomografu. Darbo metu nustatyta, kad vaizdus, gautus garsinio tomografo Arbotom 3D pagalba, galima apdoroti su 85,44 proc patikimumu. Geriausiai puvinio buvimo stiebe faktą nusako ne absoliutus garso sklidimo greitis medienoje, bet minimalaus ir maksimalaus greičių sklidimo skirtumo santykis su mažiausiu sklidimo greičiu, bei stiebo skersmeniu 1.3 m aukštyje. Modeliuojant puvinio buvimo tikimybę Lietuvos mastu, modelyje tikslinga papildomai naudoti medžių amžių bei našumo rajoną. Didžiausias puvinio pažeistų medžių procentas buvo nustatytas IV (38,7 proc.) ir I ( 37,8 proc) Krafto klasės medžiams, II ir III klasėje pažeistų medžių buvo atitinkamai 28 proc. ir 34 proc. Tyrimų metu nustatyta, kad Lc ir Nc augavietėse puvinio pažeistų medžių dalis yra didžiausia. Nd augavietėje puvinio pažeistų medžių yra 4,5 proc daugiau nei Ld. Nustatyta, kad vidutinis puvinio pakilimo aukštis - 5,9 m, o sklypuose kuriuose buvo vykdyti ir retinimo ir einamieji kirtimai, puvinys pakyla net iki 11-15 metrų.Subject of work –Norway spruce trees of various age class, that were damage by core rot in respect to regions of natural forest productivity. Aim of work – to investigate the possibilities of ARBOTOM 3D to identify the spread of core rot in Norway spruce regarding to forest type sites (Nc, Nd, Lb, Lc, Ld). Methods of work – material respecting rot spread were collected using tomography ARBOTOM 3D. Collected data was analyzed using Statistica, Excell and Arbotom software applications The following common scientific methods were used in this research: data analyzes, data grouping, modelling logic, comparison, syntheses. Results of work – The data of the research was collected in 4 State forests enterprises in respect to regions of natural forest productivity. In this study, 27 spruce stands of different age were choosen using random selection. The trees parameters were estimated for 3269 spruces, 703 out of estimated trees were scanned using acoustic tomography to determine the spread of rot inside stems. The reliability of 85.55 percentages was reached using ARBOTOM. The results of research revealed, that the most success approach to identify the rot in a stem was the ratio difference between maximal and minimas velocity to minimum velocity also stem diameter in 1.3 meter. Regarding to rot spread modelling in Lithuania it is advisable to use the ages of trees and regions of natural forest productivity additionally. The data of the research revealed that the most rotted stems were in IVth (38.7%) also in Ist (37.8%) classes of Craft. Is was determined that the amount of rotted stems were similar in Lc and Nc forest sites, however, 4.5% amount of rotted stems were the more in Nd than in Ld forest sites. The results of the investigation showed that average height of rotten wood reaches 5,9 m above ground, while in stands treated by thinning cuttings in former time - even 11-15m rot spread.Žemės ūkio akademijaVytauto Didžiojo universiteta

Impact of environmental factors on sustainability and productivity of larch stands

Tyrimai atskleidė, kad Lietuvos miškuose našiausius medynus sudaro europinio, japoninio, hibridinio ir pusantrahidridžio maumedžio medynai. Atlikus maumedynų fitocenotinę analizę nustatyta, kad maumedynuose aptiktos 55 žolinių augalų rūšys, iš kurių 3 yra invazinės. Mišriuose maumedynuose aptikta 9 % mažiau rūšių. Dirvožemio derlingumas ir trako tankumas turėjo didesnę įtaką žolinių augalų padengimui ir rūšių kiekiui nei medyno tankumas. Europinio maumedžio bei jo hibridų atsikūrimas tirtuose medynuose nevyko. Tik 17,5 % tyrimo aikštelių aptiktas tikslinių medžių rūšių pomiškis, iš jų 6,8 % aikštelių jis buvo perspektyvus. Paprastosios eglės pomiškis sudarė apie pusę viso jo kiekio. Didesnę įtaką pomiškio atsiradimui turi medyno tankumas ir augavietė (derlingumas) nei medyno amžius. Vertinant maumedynų sanitarinę būklę nustatyta, kad geros ir vidutinės būklės europiniai maumedžiai sudaro daugiau nei 85 %. Europinių ir hibridinių maumedžių būklė buvo panaši. Europinių maumedžių su kreivais liemenimis dalis yra 27,8 %, o tokių hibridinių buvo 40 % daugiau. Vertinant maumedynų produktyvumą nustatyta, kad tinkamiausiose augavietėse (Nc) trečios-šeštos amžiaus klasės gryni maumedžio medynai buvo vidutiniškai 15,2–23,9 % produktyvesni nei mišrūs, o hibridinio maumedžio gryni medynai vidutiniškai yra 10,8 % produktyvesni už europinio maumedžio medynus. Mišrūs europinio maumedžio su beržu medynai yra mažiau skalsūs lyginant su kitų rūšių mišriais medynais. Didesnė nei 20 % beržų dalis formuoja mažesnį maumedžio stiebo tūrį. Mišriuose maumedynuose su liepa medyno tūris vidutiniškai yra 7,9 %, o maumedžių stiebo tūris yra iki 25 % didesnis nei grynuose. Eglės priemaiša mišriuose želdiniuose mažina vidutinį maumedžio stiebo tūrį iki 6,1 %. Tyrimo metu nustatyta, kad europinių maumedžių radialiniam prieaugiui didesnę įtaką turi krituliai nei temperatūra.Studies have revealed that stands of European, Japanese and Hybrid larch trees are the most productive stands in the Lithuanian forests. A phytocenotic analysis of larch stands has shown the existence of fifty-five herbaceous plant species in larch stands. Three of them were invasive. Nine percent less species were found in mixed larch stands. Habitat fertility and track density had a greater impact on the grass cover and species abundance than the density of the stand. Natural regeneration of European larch and its hybrids was not found in the researched stands. The undergrowth of targeted tree species was found in 17.5% sample plots and only 6.8% of these plots had a perspective undergrowth. The undergrowth of Norway spruce accounted for half of its total amount. Stand density and habitat have a greater impact on the emergence of the undergrowth than the age of the stand. The evaluation of sanitary condition of larch stands has shown that European larch trees of good and average sanitary condition account for more than 85%. The condition of European and Hybrid larch trees was similar. The share of European larch trees with crooked stems was 27.8%, and the number of Hybrid larch trees with crooked stems was 40% higher. Productivity analysis of larch trees has revealed that pure larch stands of age class III–VI in the most suitable sites (Nc) are on average 15.2–23.9% more productive than mixed larch stands, while pure stands of Hybrid larch trees are on average 10.8% more productive than European larch stands. Mixed European larch-birch stands have a lower stocking level if compared to stands mixed with other species. When the admixture of birches is higher than 20%, it decreases the volume of larch stem. The stand volume of mixed larch-linden stands is on average 7.9%, while the volume of larch stem is up to 25% larger than that in pure stands. The admixture of spruce in mixed plantations decreases the average larch stem volume up to 6.1%. The study has shown that precipitation has a greater impact on the radial increment of European larch trees than the temperature.Miškų ir ekologijos fakultetasMiško biologijos ir miškininkystės instituta

Birth and development of the legend of D. Poška’s Baublys – the thickest oak in Lithuania

Straipsnyje, analizuojant mokslinius, mokslo populiarinimo ir beletristinius kūrinius, išsamiai apžvelgiama D. Poškos Baublio – ,,storiausio Lietuvos ąžuolo“ legendos atsiradimas ir raida nuo 1812 metų iki šių dienų. Bandant atstatyti istorinį teisingumą, buvo aiškinamasi kokie tikrieji (ar bent jau labiausiai tikėtini) šio ąžuolo dendrometriniai matmenys (amžius, aukštis, skersmuo) ir kokia buvo Baublio ,,brolio“ kilmėMiškų ir ekologijos fakultetasVytauto Didžiojo universiteta

Ar Dionizo Poškos Baublys buvo storiausias Lietuvos ąžuolas?

Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta

Stelmužės ąžuolas - legenda ir tikrovė

Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta

Aplinkos veiksnių įtaka maumedynų tvarumui ir produktyvumui

Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta

The comparison of productivity of the pure and mixed larch stands in Lithuania

Vytauto Didžiojo universitetasŽemės ūkio akademij

Stelmužės ir Lenkaičių (Medingėnų) ąžuolai

Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta