Search results for "picea"

Multiscale variation in drought controlled historical forest fire activity in the boreal forests of eastern Fennoscandia

2017

Forest fires are a key disturbance in boreal forests, and characteristics of fire regimes are among the most important factors explaining the variation in forest structure and species composition. The occurrence of fire is connected with climate, but earlier, mostly local-scale studies in the northern European boreal forests have provided little insight into fire-climate relationship before the modern fire suppression period. Here, we compiled annually resolved fire history, temperature, and precipitation reconstructions from eastern Fennoscandia from the mid-16th century to the end of the 19th century, a period of strong human influence on fires. We used synchrony of fires over the network…

Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs

2014

Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce ( (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest o…

Picea jezoensis (Sieb. et Zucc.) čiekuri

2019

Latvijas Universitātes Muzeja Botānikas un mikoloģijas kolekciju ekspozīcijā “Čiekuri” apskatāmi 12 dažādu egļu sugu čiekuri, starp tiem arī hokaido jeb ajānu egles čiekuri. Tas ir Tālajos, Austrumos augošs koks, kur tam ir plašs pielietojums. Latvijā to sāka audzēt 19. gadsimta beigās, bet arī šobrīd tas ir dendroloģisko stādījumu retums.

Mežsaimniecības atkritumprodukta – skuju ekstraktvielas un to izmantošanas potenciāls bioekonomika

2021

Bakalaura darbā ”Mežsaimniecības atkritumprodukta- skuju ekstraktvielas un to izmantošanas potenciāls bioekonomikā” ietvaros tika apstrādāti 30 paraugi no parasto priežu (Pinus sylvestris L.) un parasto egļu ((Picea abies) skujām, ekstrahējot tos Soksletā dažādos šķīdinātājos, lai iegūtu ekstraktus, kurus turpmāk izmantoja bakalaura darba izstrādē. Darba teorētiskajā daļā tika apkopota zinātniska literatūra par priežu un egļu skujām un ķīmisko sastāvu, tā izmantošanas iespējām Latvijas tirgū un izmantošanu potenciālu bioekonomikas attīstībai. Pētījumā tika izmantota Folina-Šikoltē (Folin- Ciocalteu) un DPPH metode, lai noteiktu polifenolus un antiradikālo aktivitāti. Ekstraktu ķīmiskā sastā…

Klimata ietekmes uz gadskārtu blīvumu un platumu salīdzinājums parastajai eglei Picea abies (L.) Karst. un āra bērzam Betula pendula Roth

2017

Maģistra darbs „Klimata ietekmes uz gadskārtu blīvumu un platumu salīdzinājums parastajai eglei (Picea abies (L.) Karst.) un āra bērzam (Betula pendula Roth )” izstrādāts Latvijas Universitātes Ekoloģijas un Botānikas katedrā laika posmā no 2016. – 2017. gadam. Darba mērķis ir noskaidrot, vai gadskārtas blīvums precīzāk raksturos klimata saistību ar koka augšanu nekā gadskārtas platums. Pētījumā apskatīts parastās egles un āra bērza gadskārtas platuma un blīvuma saistība ar klimatiskajiem faktoriem. Gadskārtu paraugi ņemti no septiņiem parauglaukumiem, kas izkārtoti transektē pāri Latvijas teritorijai. Klimata dati iegūti no CRU TS 3.23 klimatisko datu kopu sistēmas. Gadskārtas platuma un b…

Macro Element Content in Fertilized Forest Soils in Spruce (Picea Abies (L.) H. Karst.) Stands in Latvia

2012

The present paper provides an overview of analysis conducted with soil samples from depths up to 80 cm, obtained in the Klive area from a spruce stand owned by JSC “Latvijas Valsts meži”. Also test fertilization attempts were made with the use of ash- and potassium-based artificial fertilizers (K2SO4). The content of macro elements (K, Ca, N, and C) was determined in the soil samples in the course of the analysis. The obtained results indicate that the content of K and Ca decreases at greater horizontal depths of the soil. Nutrients are subsequently being leached away from the soil. A higher C/N ratio at the horizontal depth of up to 10 cm in the soil means a higher content of organic subst…

A lake fortress, a floating chronology, and an atmospheric anomaly: the surprising results of a radiocarbon wiggle-match from Āraiši, Latvia

2014

Abstract An Iron Age timber settlement which, in view of the defensive structures uncovered, is described as a lake fortress, on an island in Lake Āraiši, north-eastern Latvia, was excavated in 1965–69 and 1975–79 by teams led by Jānis Apals, who distinguished five construction phases. Dendrochronological analysis produced a c. 100-year floating chronology for Norway spruce (Picea abies (L.) Karst.) timbers from the earliest phase. A 14C wiggle-match was undertaken to obtain an absolute date range for the final year of the floating chronology, and thus for the construction of the settlement. Ten blocks of wood from one timber, each comprising 6-11 years and collectively spanning the whole 9…

Männyn (Pinus sylvestris) ja kuusen (Picea abies) kaupallisesti hyödynnettävissä olevat pienimolekyyliset yhdisteet

2005

Fast pyrolysis of hot-water-extracted and delignified Norway spruce (Picea abies) sawdust by Py-GC/MS

2019

The thermochemical behavior of Norway spruce (Picea abies) sawdust as such and after various chemical treatments (hot-water extraction, delignification, and hot-water extraction followed by delignification) was investigated by analytical pyrolysis–gas chromatography–mass spectrometry. In each case, the yields of major GC-amenable condensable products were semi-quantitatively measured, and the individual compounds were classified into several compound groups. The formation of these groups from feedstock samples with varying mass portions of their structural constituents (carbohydrates and lignin) was determined at 500 °C and 700 °C with a residence time of 5 s and 20 s. The formation of pyro…

Effects of forest-fuel harvesting on the diversity of dead wood and epixylic macrolichens in clear-cuts

2016

Energiapuuta käytetään yhä enemmän uusiutuvan energian lähteenä. Energiapuun korjuussa hakkuutähteitä eli kantoja, oksia ja latvuksia kerätään päätehakkuun ja harvennuksen yhteydessä hakkuualoilta. Tämä vähentää erityisesti pienikokoisen lahopuun ja kantojen määrää. Lahopuu on tärkeä resurssi boreaalisissa metsissä, mutta sen määrä talousmetsissä on alhainen luonnonmetsiin verrattuna. Määrän väheneminen edelleen energiapuun korjuun seurauksena voi johtaa lahopuusta riippuvaisen monimuotoisuuden vähenemiseen, minkä vuoksi on tärkeää tutkia energiapuun korjuun monimuotoisuusvaikutuksia. Teoriat pinta-alan ja habitaatin heterogeenisyyden vaikutuksesta lajimäärään ovat yksiä tärkeimmistä lajimä…