2022
Sammendrag
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Forfattere
Ishita AhujaSammendrag
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Forfattere
Mari Mette TollefsrudSammendrag
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Sammendrag
I 1921 kjøpte Vestlandets forstlige forsøksstasjon 340 dekar av utmarka på Auestad i Gjesdal kommune i Rogaland, der formålet var å gjera vitskaplege undersøkingar av skogetablering og produksjon i ulike treslag. Arealet var snaumark og i all hovudsak røsslynghei, ein arealtype som ofte gir langvarig veksthemming etter planting av granartar. Feltet ligg på Høg-Jæren 240-310 m o. h. på næringsfattig grunn. Litt under halvparten av arealet vart før anlegg klassifisert som eigna mark for skogreising. Jorda er morene med frisk råme, og med råhumus som dominerande humustype. Frå 1922 til 1933 vart det planta om lag 120 dekar med vanleg gran, sitkagran, engelmannsgran , blågran, vanleg furu, bergfuru, vrifuru, europeisk edelgran, douglasgran, nutkasypress og europeisk lerk. Plantinga vart gjort i ruter på om lag 70 x 70 m, med ei rute for kvar proveniens og treslag, og seinare i mindre ruter med vestamerikansk hemlokk og douglasgran. Det vart òg gjort forsøk med såing av dunbjørk. I åra 1953 til 1984 vart det oppretta 15 skogproduksjonsforsøk i planteruter med vanleg gran, sitkagran, engelmannsgran, europeisk lerk, edelgran, furu og bergfuru. Alle forsøksflatene har vore tynna ein eller fleire gonger, og forsøka har vore jamleg reviderte med nokre års mellomrom. Sju forsøk finst framleis i 2022, resten er nedlagde på grunn av ulike skadar eller hogst. Forsøksfelta i Auestad inngår i mange vitskapelege skogundersøkingar, og nokre resultat etter om lag 100 år med målingar og observasjonar er tekne med her. Alle treslaga i produksjonsforsøka, unnateke europeisk lerk, har hatt ein differanse mellom brysthøgde- og totalalder på 20 år eller meir, som viser at etableringa på lyngmark har teke tid. Produksjonen i vanleg furu etter 100 år har vore rundt 6 m3/ha/år. Lerka fekk mykje lerkekreft og forsøket vart tidleg lagt ned. Bergfurua har vist produksjon på høgde med vanleg furu, men har på grunn av sopp- og vindskadar vorte nedlagt. Tyngda av forsøksrutene i sitkagran har over eit omløp på 100 år hatt ein produksjon på 12-14 m3/ha/år, medan produksjonen for vanleg gran og edelgran ligg mellom 8 og 10 m3/ha/år. Engelmannsgrana har vist ein produksjon noko lågare enn vanleg gran og er det einaste treslaget som til no har kulminert. I furubestanda er det i biomassen bygd opp om lag 125 tonn C per hektar i løpet av 100 år, medan det i vanleg gran- og sitkagranbestanda er bygd opp høvesvis 200 og 320 tonn C. Furu-, vanleg gran- og sitkagranplantefelta inneheld høvesvis 5, 8 og 13 gonger meir karbon enn skoglaus røsslyngmark. I tillegg til eit stort kvantum med tømmer er det på dei skogreiste areala i Auestad gjennom 100 år bunde om lag 9 600 tonn CO2-ekvivalentar i biomassen. Dette utgjer skyggeverdiar estimert til 19,2 mill. kr. På hogstflater og mellom forsøksrutene er det rike oppslag av lauvtre. Areala dekkjer fleire økosystemtenester der til dømes jakt kan verdsettast, medan andre er fellesgode som det er meir vanskeleg å verdsette, mellom anna sopp- og bærplukking og bruk av stiar og vegar til rekreasjon.
Forfattere
Tore SkrøppaSammendrag
Short-term trials on cultivated soil were planted with families of Norway spruce that had shown epigenetic memory effects in early tests up to age two years. Measurements and assessments were made of phenology traits, tree heights and stem defects until age 16 years in these trials. The memory effects of the temperature conditions during embryo development and seed maturation were confirmed for the timing of bud flush and for start and cessation of shoot elongation at age six years. The mean differences in timing of these events caused by temperature treatments were on average less than two days. They were considerably larger for families with strong effects on terminal bud set at the end of the first growing season. The memory effects did not result in a prolonged shoot growth period, nor did they affect height growth. Interaction effects expressed in adaptive traits between factorial treatments of temperature and daylength during seed production were large in the short-term trial and were still present at age nine years. The results presented demonstrate that strong memory effects observed in early tests may also be expressed in phenology traits for at least the next five growing seasons.
Forfattere
Inge Dox Tore Skrøppa Mieke Decoster Peter Prislan Aina Gascó Jožica Gričar Holger Lange Matteo CampioliSammendrag
Historically, the autumn dynamics of deciduous forest trees have not been investigated in detail. However, autumn phenological events, like onset of loss of canopy greenness (OLCG), onset of foliar senescence (OFS) and cessation of wood growth (CWG), have an important impact on tree radial growth and the entire ecosystem's seasonal dynamics. Here, we monitored the leaf and wood phenological events of silver birch (Betula pendula) at four different sites in Ås, southeastern Norway: (a) a natural mature stand, (b) a plantation on former agricultural ground, (c) young natural trees, and (d) young trees in pots under different fertilization levels. The study took place over four consecutive years (from 2017 to 2020), with a particular focus on 2018, a year in which there was a severe summer drought, and the next year, 2019, which featured more normal conditions. First, we provided a description of birch phenology within its mid-north distributional. Second, we showed that drought advanced CWG by about 5 to 6 weeks and it delayed OLCG and OFS up to 30 days. Third, we observed an unexpected advance in OLCG in 2019 compared to 2018 (30 days) and 2020 (14 days). OFS presented similar dynamics as OLCG, whereas CWG was advanced only in 2018. These findings might indicate lag-effects of severe drought on the next year autumn leaf phenology but not on wood growth. On the other hand, the comparison between the natural stand and the plantation showed that, under drought conditions, wood growth is more sensitive to site fertility than autumn leaf phenology. In summary, our study elucidated the autumn dynamics of an important deciduous forest species in the northern temperate zone and showed unexpected impacts of a severely dry and warm summer on the current and next year leaf phenology.
Forfattere
Simo Maduna Adam Vivian-Smith Ólöf Dóra Bartels Jónsdóttir Albert Imsland Cornelya Klutsch Tommi Nyman Hans Geir Eiken Snorre HagenSammendrag
We determined the mitogenome of Cyclopterus lumpus using a hybrid sequencing approach, and another four closely related species in the Liparidae based on available next-generation sequence data. We found that the mitogenome of C. lumpus was 17,266 bp in length, where the length and organisation were comparable to those reported for cottoids. However, we found a GC-homopolymer region in the intergenic space between tRNALeu2 and ND1 in liparids and cyclopterids. Phylogenetic reconstruction confirmed the monophyly of infraorders and firmly supported a sister-group relationship between Cyclopteridae and Liparidae. Purifying selection was the predominant force in the evolution of cottoid mitogenomes. There was significant evidence of relaxed selective pressures along the lineage of deep-sea fish, while selection was intensified in the freshwater lineage. Overall, our analysis provides a necessary expansion in the availability of mitogenomic sequences and sheds light on mitogenomic adaptation in Cottoidei fish inhabiting different aquatic environments.
Sammendrag
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Sammendrag
Reusing soil can reduce environmental impacts associated with obtaining natural fresh soil during road construction and analogous activities. However, the movement and reuse of soils can spread numerous plant diseases and pests, including propagules of weeds and invasive alien plant species. To avoid the spread of barnyardgrass in reused soil, its seeds must be killed before that soil is spread to new areas. We investigated the possibility of thermal control of barnyardgrass seeds using a prototype of a stationary soil steaming device. One Polish and four Norwegian seed populations were examined for thermal sensitivity. To mimic a natural range in seed moisture content, dried seeds were moistened for 0, 12, 24, or 48 h before steaming. To find effective soil temperatures and whether exposure duration is important, we tested target soil temperatures in the range 60 to 99 C at an exposure duration of 90 s (Experiment 1) and exposure durations of 30, 90, or 180 s with a target temperature of 99 C (Experiment 2). In a third experiment, we tested exposure durations of 90, 180, and 540 s at 99 C (Experiment 3). Obtaining target temperatures was challenging. For target temperatures of 60, 70, 80, and 99 C, the actual temperatures obtained were 59 to 69, 74 to 76, 77 to 83, and 94 to 99 C, respectively. After steaming treatments, seed germination was followed for 28 d in a greenhouse. Maximum soil temperature affected seed germination, but exposure duration did not. Seed premoistening was of influence but varied among temperatures and populations. The relationships between maximum soil temperature and seed germination were described by a common dose–response function. Seed germination was reduced by 50% when the maximum soil temperature reached 62 to 68 C and 90% at 76 to 86 C. For total weed control, 94 C was required in four populations, whereas 79 C was sufficient in one Norwegian population.
2021
Sammendrag
Old trees are important for biodiversity, and the process of their identification is a critical process in their conservation. However, determining the tree age by core extraction, ring counts, and eventually, cross-dating by means of dendrochronology is labor-intensive and expensive. Here we examine the alternative method of estimating determining tree age by visual characteristics for old Norway spruce and Scots pine trees. We used forest stands previously identified as “Old tree habitats” by visual criteria in Norwegian boreal forests. The efficiency of this method was tested using pairwise comparison of the age of core samples from trees within these sites, and within neighboring sites. Age regression models were constructed from morphological traits and site variables to investigate how accurately old trees can be detected. Cored trees in the Old-tree habitats were on average 41.9 years older than compared to a similar selection of trees from nearby mature forests. Several characteristics such as bark structure, stem taper and visible growth eccentricities can be used to identify old Norway spruce and Scots pine trees. Old trees were often found on less productive sites. Due to the wide range of environments included in the study, we suggest that these findings can be generalized to other parts of the boreal zone.