Search results for "Quercus robur"
showing 10 items of 26 documents
Early response ofQuercus roburseedlings to soil compaction following germination
2018
Logging operations using heavy machinery effect changes in soil characteristics due to compaction; such conditions can negatively influence seedling development. In stands managed on the basis of close-to-nature silviculture or continuous cover forestry, successful establishment of natural regeneration after logging is important to ensure the proper functioning of a forest ecosystem, to promote soil recovery, and to prevent and mitigate land degradation processes (such as soil erosion, mudflow, waterlogging, and landslides) related to soil compaction and rutting. This work aimed to assess the early response of Quercus robur seedlings to soil compaction during the first 1.5 months after germ…
Augsnes faktora nozīme paaugas attīstībai priežu mežos Pierīgā
2015
Latvijas meži atrodas pārejas zonā jeb ekotonā starp nemorālo un boreālo zonu - boreonemorālajā starpzonā (Sjörs, 1963; Ozenda, 1994, Krauklis un Zariņa, 2002), un pēdējās desmitgadēs Latvijā arvien biežāk tiek novērots, ka mežos pazeminās boreālo mežu koku sugu un pieaug nemorālo mežu koku sugu īpatsvars (Laiviņš, 1998). Un būtiski būtu noskaidrot, kā edafiskie faktori ietekmē ozolu paaugas attīstībā priežu mežos. Maģistra darba mērķis ir noskaidrot augsnes faktora lomu ozolu paaugas attīstībā priežu mežos Pierīgā. Darbā ir apkopota informācija par Latvijas un Eiropas ozolu mežiem, abiotisko faktoru, tajā skaitā augsnes, ietekmi uz to izplatību, kā arī ozolu paaugas veidošanos priežu mežos…
Changes in climatic signals of English oak tree-ring width and cross-section area of earlywood vessels in Latvia during the period 1900–2009
2012
Abstract We investigated changes in response of wood formation in English oak (Quercus robur L.) to climatic factors since 1900. It was hypothesised that the effect of winter and spring temperatures has weakened, while summer precipitation has become limiting. Increment cores were taken from 40 sites across Latvia. Tree-ring width and cross-section area of earlywood vessels were measured and cross-dated. Regional chronologies were built by pooling time series of trees within two regions of Latvia (western and eastern region), which differed in continentality. Climatic signals differed between the proxies (tree-ring width and earlywood vessel cross-section area) and between regions. Mean cro…
Fragmentation-related patterns of genetic differentiation in pedunculate oak (<i>Quercus robur</i>) at two hierarchical scales
2016
Populations at speciesâ range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak ( L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing on an islan…
Biotopu apsaimniekošanas ietekme uz veģetāciju un ozolu atjaunošanos dabas liegumā "Paņemūnes meži"
2015
DL „Paņemūnes meži” tika veikta apsaimniekošana – izcērtot 2.stāvā un paaugā esošās egles. Eksperimentālie meža biotopu apsaimniekošanas darbi tika veikti LIFE+ projekta „Natura 2000 teritoriju nacionālā aizsardzības un apsaimniekošanas programma” ietvaros. Izvirzītas hipotēzes:1) pēc apsaimniekošanas darbiem zemsedzē palielināsies ozolu sējeņu skaitas un nemorālo augu sugu segumas;2) ilgtermiņā uzlabosies jau esošo ozolu augšana un attīstība. Pirmajā gadā pēc apsaimniekošanas ozolu sējeņu skaits nepalielinājās. Biotopā parādījās viena nemorālā suga, kā arī 26 jaunas augu sugas, kas varētu nomākt ozolu sējeņus un nemorālo floru, jo tām lielākoties raksturīga strauja izplatīšanās.
Sēņu sugu sastopamība ar akūtās ozolu kalšanas slimību (AOK) inficētā parastā ozola Quercus robur L. koksnē
2019
Ozolu akūtā kalšana (AOK) ir pirms 20-30 gadiem Lielbritānijā atklāta jauna un uztraukumu radoša ozolu slimība, kura pamazām turpina savu izplatību Eiropā. Latvijā šī slimība pirmo reizi konstatēta 2017.gadā Kurzemē, un ir uzsākti pētījumi, lai apzinātu slimības izplatību un varētu rast risinājumus tās ierobežošanai. Šobrīd AOK ir ļoti maz izpētīta un apzināta slimība. Joprojām nav skaidrs, kādā veidā ozoli inficējas ar AOK un kas ir šīs slimības vektori. Tiek uzskatīts, ka slimību izraisa baktērijas, bet ietekmē biotisko un abiotisko faktoru kopums. Iespējams, ka viens no slimības veicinātājiem ir patogēniskas sēnes, kuras var novājināt koku, vai pat novest to līdz bojāejai, tādēļ ir svarī…
Distribution ofLeprariain Latvia in Relation to Tree Substratum and Deciduous Forest Type
2012
The aim of the study was to evaluate the distribution of Lepraria lichen species in dry deciduous forests, in relation to tree substratum and forest characteristics. In total, 34 localities with 1020 trees (13 tree species) were studied in different parts of Latvia. Lepraria spp. were found on 642 trees: L. eburnea on 8 trees, L. incana on 80 trees, and L. lobificans on 568 trees. Lepraria eburnea was recorded for the first time in Latvia. Tree species, tree bark crevice depth, inclination, pH and forest type were the most important variables explaining the presence of Lepraria species. Lepraria incana was associated with Quercus robur and Tilia cordata, while L. lobificans was associated w…
Izmaiņas Quercus robur pieauguma dinamikā pēc atēnošanas mistraudzēs
2021
Maģistra darbs „Izmaiņas Quercus robur pieauguma dinamikā pēc atēnošanas mistraudzēs” izstrādāts Latvijas Universitātes Botānikas un ekoloģijas katedrā, laika posmā no 2019. gada novembra līdz 2021. gada maijam. Boreālo-nemorālo mežu pārejas zonā tiek praktizēta ozolu atēnošana, kas izpaužas kā selektīva citu koku sugu vai krūmu izciršana, kuras mērķis ir uzlabot gaismas apstākļus mistraudzēs, lai veicinātu ozolu ilgtspējīgu augšanu un atjaunošanos. Intensīva atēnošana var izmainīt audzē pastāvošo mikroklimatu, kas var ietekmēt koku jutību pret apkārtējiem vides un klimatiskajiem apstākļiem, dažādi ietekmējot koku tālāko augšanu. Darba mērķis ir noskaidrot, kā egļu izciršana mistraudzēs atē…
Microscopical and Mycological Investigations on Wood of Pendunculate Oak (Quercus robur L) Relative to the Occurrence of Oak Decline
1996
Summary Microscopical studies exhibited great differences between healthy and damaged pendunculate oak trees (Quercus robur L.) relative to the state of sapwood vessels and the degree of fungal infection. In the sapwood of damaged trees deposits, discolorations and early tylosis formations were found which frequently occurred in combination with fungal infections. These results lead to the assumption that the defence reaction of the trees probably induced by fungal infection changes the structure of the tree vessels to such an extent that their water transfer function is disturbed. Some fungal genera playing an important role in the discussion of the causes of oak decline could be isolated.…
Dynamics of natural hemiboreal woodland in the Moricsala Reserve, Latvia: the studies of K. R. Kupffer revisited
2010
Abstract Karl Reinhold Kupffer (1872–1935), an outstanding botanist and plant ecologist, took the initiative that led to the establishment of the first nature reserve in Latvia, on Moricsala Island in 1912. The reserve provided an excellent reference area for natural hemiboreal woodland for future generations. There have been very few studies on the dynamics of natural broadleaved forest in Europe, probably owing to lack of primeval forests of this type. However, Kupffer produced a map of forest types in the reserve with accurate descriptions of the vegetation by layers, and his descriptions include interpretations of forest dynamics processes. This information, together with the present ag…