Alustaimestik ja seda mõjutavad tegurid endistel põllumajandusmaadel kasvavates noortes lehtpuuistandikes

The establishment of forest plantations (including short-rotation forest plantations) is seen as one way to reemploy abandoned agricultural sites. The main goal of commercial forest plantations is the production of timber and woody biomass, however, the implications for biodiversity (including floristic diversity) can not be neglected. Due to the agricultural legacy the understorey of forests established on former agricultural land differs from the understorey of forests that were never cleared and these differences may persist for long periods. Since 1999 more than 700 ha of plantations with semi-exotic hybrid aspen (Populus × wettsteinii Hämet-Ahti) have been established on former agricultural land in Estonia that can be managed with 20- to 30-year rotations. Experience from other countries has indicated that environmental problems may occur in the plantations of exotic tree species. Among the native deciduous tree species silver birch (Betula pendula Roth) is considered to be a suitable tree species for the establishment of plantations in Estonia. However, abandoned agricultural sites become afforested also in the process of secondary succession with Betula spp among first arrivers. Studies conducted in former mining areas that have compared unassisted natural succession and the establishment of plantations have pointed out that naturally regenerated stands may support higher understorey species richness and diversity than plantations. Given the above mentioned, the following aims were set to the thesis: 1) to determine which site- and stand-related factors have affected understorey vegetation characteristics in young commercial forest plantations on abandoned agricultural land; 2) to study if plantations of semi-exotic hybrid aspen offer similar habitat for the understorey as plantations of native tree species silver birch; 3) to characterize the formation of the bryophyte layer; 4) to characterize the formation of forest understorey; 5) to compare understorey vegetation characteristics between naturally regenerated birch stands and silver birch plantations. Data on understorey, overstorey and site factors were collected from 73 experimental plots established in 24 hybrid aspen and 11 silver birch plantations and in 11 naturally regenerated birch stands. Two monitorings were carried out in plantations: the first monitoring in 7 to 9-year-old plantations and the second monitoring in 13 to 14-year-old plantations. Based on the results of the thesis, the observable trends in the understorey vegetation of young plantations were mostly driven by the former agricultural land use, site preparation method, and soil properties. With increasing stand age the influence of pre-establishment disturbances becomes less pronounced and the impact of overstorey-related factors increases. The majority of the vascular plant and bryophyte understorey vegetation characteristics were similar in young hybrid aspen and silver birch plantations and it may be concluded that semi-exotic hybrid aspen provides similar habitat for understorey as native silver birch. The proportion of forest species was low in the vascular plant understorey of plantations at the time of both monitorings. Although the number and cover of forest species slowly increased between the two monitorings, clear domininance of grassland species continued. The cover of the bryophyte layer was low in young plantations. Typical bryophytes were light-demanding perennials. The silvicultural management of plantations in the future should include measures that provide habitats for epixylic and epiphytic bryophyte species. The comparison of naturally regenerated stands and plantations showed that the species richness and diversity of bryophytes were higher in naturally regenerated birch stands, but the species richness and diversity of vascular plants did not differ between the two stand types. However, significantly higher numbers of forest species (both vascular plant and bryophyte) indicated that the formation of forest understorey had progressed further in naturally regenerated stands. This can be explained by the longer undisturbed succession and colonization period of naturally regenerated stands. Both natural and artificial regeneration can be recommended as possible alternatives for the establishment of new forests on former agricultural land.Intensiivmeetodil, sh lühikese raieringiga majandatavate puuistandike rajamine on alternatiivseks kasutusvõimaluseks endistele põllumajandusmaadele. Tootmisele suunatud istandikes ehk puupõldudel ei ole peamiseks eesmärgiks metsökosüsteemi kujundamine, vaid soovitakse saavutada maksimaalne puidu või mõne teise puudega seotud toorme produktsioon. Puupõldude pindala pidev kasv maailmas tõstatab aga küsimuse, milline on nende mõju looduslikule, sh floristilisele mitmekesisusele. Kirjanduse andmetel võib endistele põllumajandusmaadele rajatud metsade, sh istandike alustaimestik jääda pikaks ajaks erinevaks põliste metsade alustaimestikust, mis seostub põllumajandusliku maakasutuse mõjudega. Alates 1999. aastast on Eestis endistele põllumajandusmaadele rajatud u 700 ha puuistandikke poolvõõrliigi hübriidhaavaga (Populus × wettsteinii Hämet-Ahti), mida plaanitakse majandada lühikese 20–30-aastase raieringiga. Mujal maailmas on võõrpuuliikidega rajatud istandikes täheldatud mõnikord keskkonnakaitselisi probleeme. Kohalikest lehtpuudest soovitatakse Eestis endiste põllumajandusmaade metsastamiseks eelkõige arukaske (Betula pendula Roth), ent kaasikud võivad endistele põllumajanduskõlvikutele tekkida ka looduslikult. Endiste karjäärialade metsastamisel on istandike ja looduslikult tekkinud puistute võrdlusel täheldatud, et looduslikult tekkinud puistute alustaimestik võib olla liigirikkam ja mitmekesisem kui istandikes. Lähtuvalt eespool toodust seati doktoritööle järgnevad eesmärgid: 1) analüüsida, millised kasvukoha ja puistu tunnused mõjutavad alustaimestiku karakteristikuid endistel põllumajandusmaadel kasvavates noortes istandikes; 2) hinnata, kas poolvõõrliigi hübriidhaava istandikud pakuvad alustaimestiku liikidele sarnaseid kasvutingimusi kodumaise puuliigi arukase istandikega; 3) iseloomustada samblarinde kujunemist ja sammalde liigilist koosseisu; 4) iseloomustada metsa alustaimestiku kujunemist; 5) võrrelda alustaimestiku karakteristikuid arukaseistandikes ja looduslikult tekkinud kaasikutes. Alustaimestikku, puurinnet ja kasvukohta iseloomustav andmestik koguti seitsmekümne kolmelt püsiproovitükilt, mis paiknesid 11 arukase- ja 24 hübriidhaavaistandikus ning 11 looduslikult tekkinud kaasikus. Istandike kohta on doktoritöös esitatud alustaimestiku esimese kirjelduse (vanuses 7 kuni 9 aastat) ja korduskirjelduse (vanuses 13 kuni 14 aastat) andmed. Doktoritöös leiti, et noore istandiku alustaimestiku karakteristikuid mõjutasid esialgu eelnev põllumajanduslik maakasutus, istandiku rajamisel rakendatud maapinna ettevalmistusviis ja mullastiku tingimused. Istandike vanuse kasvades muutub istandiku rajamisele eelnenud häiringute mõjust olulisemaks puurindega seotud tegurite mõju rohu- ja samblarindele. Hübriidhaava- ja arukaseistandike alustaimestiku (soontaimede ja sammalde) karakteristikud olid suures osas sarnased, mis lubab väita, et hübriidhaavikute rajamisega Eestis ei kaasne alustaimestikus ebasobivaid arenguid, nt võõrliikide levikut. Metsaliikide osakaal istandike alustaimestikus oli väike nii esimese kirjelduse kui ka korduskirjelduse ajal. Hoolimata sellest, et metsaliikide arv ja katvus kasvasid vähehaaval, domineerisid ka 13–14-aastaste istandike alustaimestikus jätkuvalt rohumaaliigid. Ka samblarinde katvus noortes istandikes oli väike. Tüüpilised noortes istandikes kasvavad liigid olid valgusnõudlikud mitmeaastased samblad. Istandike edasisel majandamisel oleks soovitatav rakendada abinõusid, mis pakuvad lisakasvukohti epiksüülsetele ja epifüütsetele samblaliikidele. Hüpotees, et endistele põllumajandusmaadele looduslikult tekkinud puistud toetavad suuremat alustaimestiku liigirikkust, leidis kinnitust üksnes maapinnal kasvanud sammalde arvu ja mitmekesisusindeksi osas. Lisaks kasvas looduslike kaasikute alustaimestikus rohkem metsaliike (nii soon- kui sammaltaimi), mida võib seletada pikema rahuliku suktsessiooni ja kolonisatsiooni ajaga.Publication of this dissertation is supported by the Estonian University of Life Sciences and by the Doctoral School of Earth Sciences and Ecology created under the auspices of European Social Fund

Effect of environmental factors on the composition of terrestrial bryophyte and lichen species in Scots pine forests on fixed sand dunes

Aim of the study: To investigate terrestrial bryophyte and lichen species richness and environmental factors affecting the composition of species.Area of the study: Four Boreal zone fixed dunes were selected in the coastal area of the Baltic Sea in southwest Estonia.Material and methods: Non-metric multidimensional scaling was performed to analyse distribution patterns and environmental factors like canopy cover, photosynthetically active radiation, soil organic horizon thickness and decomposition rates, soil volumetric water content, soil pH and electrical conductivity and soil nutrients correlated with bryophyte and lichen species composition.Main results: Thirty bryophytes and 22 lichens were found on 232 sample plots, the most frequent species were Pleurozium schreberi (Willd. ex Brid.) Mitt., Hylocomium splendens (Hedw.) Schimp., Dicranum polysetum Sw. ex anon., Cladonia arbuscula (Wallr.) Flot. and Cladonia furcata (Huds.) Schrad. The lichen species richness was highest on the slopes of the dunes and decreased towards the bottoms and tops; bryophyte species richness was higher on the bottoms and decreased towards the tops of the dunes.Research highlights: The composition of bryophytes and lichens is significantly influenced by the aspect and the location on the dune, light conditions, soil pH, soil salinity (measured as electrical conductivity) and volumetric water content, thickness of moderately decomposed organic horizon and vascular plant species cover.KeywordsInland dunes; terrestrial bryophyte and lichen communities; environmental factors; topography

Forests for university education: The example of Estonia

Teaching methods change during times. The authors consider it essential to anchor the theoretical part of studies with practice in the natural environment. Therefore, to ensure the achievement of leaming outcomes, practical training is included in a number of courses in Estonian academic forestry education. The history of academic forestry education in Estonia starts in 1920. The Experimental Forest District at Järvselja was established in 1921. Since 1997 its name is the Foundation Järvselja Experimental and Training Centre and it belongs to the Estonian University of Life Sciences. The Järvselja Center's total area is 10 553 ha. Forest land comprises 6 626 ha, of which 2 723 ha are protected. Bogs form 3 147 ha of the Järvselja Centre's land. Järvselja Experimental and Training Centre is the only one in Estonia which has complete infrastructure for accommodation and catering. Every year Estonian forestry students have various practical training courses in Järvselja. In most cases, practical training is held in summer, but some courses are offered in winter (e.g. forest and timber measurement) as well. Also every year some graduation theses are defended on themes done in Järvselja forests. Forests in Järvselja are used to carry out several research projects, too

Võro- ja setokeelsed trükised 1987–2017: bibliograafia

http://www.ester.ee/record=b5049588*es

Biopsy-proven Henoch-Schönlein purpura nephritis: a single center experience

Background: Knowledge on normal progress and treatment of Henoch-Schönlein purpura nephritis (HSPN) is limited. This study reviews outcome, clinical, pathological, and therapeutic factors affecting the prognosis of HSPN patients. Methods: Forty-nine children with biopsy-confirmed HSPN diagnosed between September 2008 and 2018 were included. Demographics, clinical and laboratory data, treatment, and outcome were recorded at the time of biopsy, 3, 6, 12, and 24 months and at last visit. Clinical outcome was graded according to Meadow’s criteria. Results: The median age at time of biopsy was 10.1 years (IQR:5.7) and female/male ratio 24/25. At presentation, 40.8% of patients had nonnephrotic proteinuria, 18.4% nephrotic syndrome (NS), 4.1% nephritic syndrome (NephrS), and 36.7% NephrS+NS. There were 11 patients with an estimated glomerular filtration rate below 90 ml/min/1.73 m2. Biopsy specimens were classified according to International Study of Kidney Diseases in Children (ISKDC) and Oxford Classification MEST-C scoring systems. Forty-one patients received angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, 37 patients steroids, and 35 patients other immunosuppressive medications. At last visit, 24 patients had stage 1 chronic kidney disease (CKD), three stage 2 CKD, and two had stage 5 CKD. Neither clinical parameters nor ISKDC biopsy grade or treatment modalities effected the final outcome. The Oxford classification showed significantly increased segmental glomerulosclerosis in patients with unfavorable outcome. Favorable outcome was associated with shorter time from kidney involvement to biopsy and start of treatment. Conclusion: A large proportion of patients continued to show signs of CKD at last follow-up while only a small proportion developed stage 5 CKD

Soil mycobiomes in native European aspen forests and hybrid aspen plantations have a similar fungal richness but different compositions, mainly driven by edaphic and floristic factors

BackgroundThe cultivation of short-rotation tree species on non-forest land is increasing due to the growing demand for woody biomass for the future bioeconomy and to mitigate climate change impacts. However, forest plantations are often seen as a trade-off between climate benefits and low biodiversity. The diversity and composition of soil fungal biota in plantations of hybrid aspen, one of the most planted tree species for short-rotation forestry in Northern Europe, are poorly studied.MethodsThe goal of this study was to obtain baseline knowledge about the soil fungal biota and the edaphic, floristic and management factors that drive fungal richness and communities in 18-year-old hybrid aspen plantations on former agricultural soils and compare the fungal biota with those of European aspen stands on native forest land in a 130-year chronosequence. Sites were categorized as hybrid aspen (17–18-year-old plantations) and native aspen stands of three age classes (8–29, 30–55, and 65-131-year-old stands). High-throughput sequencing was applied to soil samples to investigate fungal diversity and assemblages.ResultsNative aspen forests showed a higher ectomycorrhizal (EcM) fungal OTU richness than plantations, regardless of forest age. Short-distance type EcM genera dominated in both plantations and forests. The richness of saprotrophic fungi was similar between native forest and plantation sites and was highest in the middle-aged class (30–55-year-old stands) in the native aspen stands. The fungal communities of native forests and plantations were significantly different. Community composition varied more, and the natural forest sites were more diverse than the relatively homogeneous plantations. Soil pH was the best explanatory variable to describe soil fungal communities in hybrid aspen stands. Soil fungal community composition did not show any clear patterns between the age classes of native aspen stands.ConclusionWe conclude that edaphic factors are more important in describing fungal communities in both native aspen forest sites and hybrid aspen plantation sites than forest thinning, age, or former land use for plantations. Although first-generation hybrid aspen plantations and native forests are similar in overall fungal diversity, their taxonomic and functional composition is strikingly different. Therefore, hybrid aspen plantations can be used to reduce felling pressure on native forests; however, our knowledge is still insufficient to conclude that plantations could replace native aspen forests from the soil biodiversity perspective

Stores, impacts and dispersal of sediments contaminated by mining legacy in rivers and estuaries induced by climate change effects.

PhD Theses.The history of mining exploration has left a significant stock of legacy contamination in the UK’s river sediments. Flood events have contributed to the erosion of upstream sediment deposits and widespread the contamination throughout river basins, carrying mining legacy sediments to lowland rivers and estuaries. This thesis investigates how the increase of climate change effects could disturb the mining legacy deposits and the consequences for the river health. The physical characteristics and the proximity to the Tamar Estuary makes the mining legacy sediments in the Cotehele a good site to understand the dispersal and impacts of such sediment to rivers and estuaries. The metals Cu and Pb were the most explored metals in upstream mines. In terms of magnitude, the sediment deposits presented concentrations ranging between 38 to 140 times higher than background values for Cu and 2 to 16 times above background values for Pb. A bioaccumulation experiment exposing snails to re-suspended sediments in waters with different salinities was performed. The aim was to understand how different salinities can influence the uptake of metals. The bioaccumulation experiment demonstrated that the disturbance of sediments released metals at a concentration that may cause deleterious ecotoxicological effects. Modelling simulations demonstrated that the worst-case scenario would spread Cu concentrations above EQS (Environmental Quality Standards) in areas with high potential for bioaccumulation for a prolonged time. After agriculture, pollution from abandoned mines is the second main reason for the deterioration of the Lower Tamar. The results demonstrated that the impacts of climate change could bring further challenges to the improvement of the Lower Tamar water quality

Lehtmetsade kasvatamine

TäistekstTeie ees olevasse raamatusse on haaratud paljude Eesti metsateadlaste tähelepanekud ja soovitused lehtpuupuistute kasvatamisel. Kuna alati ei ole kerge leida iga tarkuse esimest väljaütlejat ja kirjasõnas fikseerijat, siis on siin loobutud kasutatud kirjanduse detailsest loetelust. Vaieldamatult kehtivad ka tänapäeval need metsakasvatuslikud põhitõed, mida oma teadusartiklites on hooldusraiete kohta üldistanud Lembit Muiste, või millest kirjutab esimeses eestikeelses metsakasvatuse õpikus Oskar Daniel. Korduvalt on hooldusraiete juhendites ja eeskirjades lehtpuupuistute kasvatamise tarkusi üldistanud Ivar Etverk. Meie teadmised kase kasvatamisest oleksid tagasihoidlikumad, kui poleks Olev Henno uurimusi. Viimastel aastakümnetel on lisandunud uusi teadmisi hall-lepikute ökoloogiast ja majandamisest Veiko Uri uurimustest. Hübriidhaava esimesed istandikud on Eestis jõudnud raieringi teise poolde ja soovitusi metsaomanikele on esitanud käesoleva raamatu autor. Samas tuleb tunnistada, et meie metsakasvatusliku teaduse ja praktika kogemused on erinevate lehtpuuliikide osas oma põhjalikkuses küllaltki erinevad. Näiteks kaasikute kasvatamiseks oskame anda küllaltki detailseid soovitusi, kuid saare või sanglepa metsade teadliku majandamise kogemusi on väga vähe. Ja näiteks uusi tammekultuure võiks Eestis olla tunduvalt rohkem, kogemusi ja teadmisi meil selle puuliigi suhtes jätkub. Trükises kirjapandud metsakasvatuslikud tarkused moodustavad ühtse terviku juba varem kirjastamist leidnud metsanduslike käsiraamatute ja juhendmaterjalidega. Seetõttu soovitan lugejal tutvuda järgmiste kirjandusallikatega, mis on olnud ka selle raamatu koostamisel autorile toeks ja mida ta on püüdnud edasi arendada ning kaasajastada. Laiahaardelise ülevaate metsade kasvatamisest ja majandamisest leiate Eino Laasi toimetatud kõrgkooli õpikust „Metsamajandamise alused” (Tartu, 2011). Peamised metsanduslikud aabitsatõed on kirjas Viio Aitsami koostatud „Metsaomaniku käsiraamatus” (2012). Väga hea ülevaate metsakasvukohatüüpidest ja nende eristamise alustest, kultiveeritava puuliigi valiku alustest ja mulla ning metsa seostest võib leida: Erich Lõhmus, „Eesti metsakasvukohatüübid” (Tartu, 2004). Metsade uuendamise põhitõed ja praktilised soovitused, mõistetavana nii kõrgharidusega metsamehele kui ka algajale erametsaomanikule, on kirjas: Eino Laas, „Metsauuendamine ja metsastamine” ( Tartu, 2001). Soovitused, mida arvestada põllumaade metsastamisel, on koondatud trükisesse: Endla Asi, Raimo Kõlli, Eino Laas, „Põllumaade metsastamine” (SA Erametsakeskus, Tartu, 2004). Detailne ülevaade Eesti metsaressursist on kirjas metsastatistika aastaraamatutes. Käesolevas raamatus kasutatud arvulised andmed meie metsade kohta pärinevad: Aastaraamat „Mets 2014” (Tallinn, 2016). Kirjutisi lehtpuumetsadest, muuhulgas ka lehtpuudest XX sajandil ilmunud kirjanduse põhjalik loetelu, mis võib Eesti lugejale huvi pakkuda, on esitatud kogumikus: „Lehtpuupuistute kasvatamine Eestis”, koostajad H. Tullus, A. Vares (Akadeemilise Metsaseltsi Toimetised XIV, Tartu, 2001). Konspektiivses vormis on tarkused lehtpuude kasvatamisest kirjas pisiraamatus: Aivo Vares, Arvo Tullus, Ivar Sibul, „Lehtpuupuistute majandamine” (Tartu, 2004)