Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2002
Sammendrag
Overvåkingsprogram for skogskader (OPS) har vært i drift siden 1986. Formålet er å overvåke skogens vitalitet, og vurdere betydningen av langtransporterte luftforurensninger. Overvåkingen omfatter registreringer på to omfattende og landsdekkende sett av overvåkingsflater, 15 intensivt overvåkede flater, samt deler av den nasjonale overvåkingen av langtransporterte luftforurensninger. Skogens vitalitet, vurdert ut fra kronetetthet, kronefarge og mortalitet, har vært relativt stabil gjennom overvåkingsperioden. I de siste årene har det vært en stabilisering og til dels økning av kronetetthet, og dette har brutt en tidligere nedadgående trend. Trøndelag og det indre Østlandet har vært de regionene som har skilt seg ut i negativ retning. For hele landet har det vært noe mer misfarging de siste seks årene sammenliknet med perioden foran. På furu forårsaket de uvanlig sterke angrepene av furuas knopp- og greintørkesopp misfarging og redusert kronetetthet i Sør-Norge. For gran var det i årene 1991-94 i Sørøst-Norge en utbredt misfarging om høsten, men denne typen misfargingen var nå lite utbredt. Mortaliteten har i gjennomsnitt vært omkring 0,2 prosent pr år, og den toppet seg i gammel granskog på Østlandet i årene 1996-97. Strøfallet har variert betydelig mellom felter og år, og har vært høyt i forbindelse med perioder med sterk vind og tørke. Det er ingen trender over tid å spore i nålekjemi, men betydelige variasjoner mellom år. Over tid har konsentrasjonene i jordvannet avtatt for sulfat, vært stabilt eller svakt økende for aluminium, både økende og avtakende for pH og vært stabilt lavt for nitrogenforbindelser. Tilførsler av svovel og sterk syre med nedbør og luft har avtatt sterkt de siste 30 årene, mens nitrogentilførslene har hatt mindre endringer. Konsentrasjonen av ozon har variert mellom år, men uten noen tydelig trend. Ozoneksponeringen, målt som AOT40 var klart høyest i 1992. Tilførslene av langtransporterte luftforurensninger har i alle årene vært høyest i kystområdene i de sørligste delene av landet. De geografiske mønstre i skogtilstand, og deres endringer over tid, samsvarer ikke med de geografiske mønstre for luftforurensninger. Konsentrasjoner av luftforurensninger i luft og av mulig toksisk aluminium i jordvann på de intensive flatene er lavere enn grenseverdier for skadelige effekter på skog. Magnesiumkonsentrasjoner i barnåler ligger stabilt over grenseverdier for mangel. Omfanget av skogskader i Norge synes ikke å være unormalt stort. For tilstand og utvikling av trærnes vitalitet har Trøndelag og Østlandet skilt seg ut i negativ retning. Det er ikke funnet tegn som tyder på at langtransporterte luftforurensninger har ført til skader på skog. Det kan likevel ikke utelukkes at effekter finnes, eller kan komme på lengre sikt.
2001
Sammendrag
This manual contains description of field instrumemntation and the proceedures for field sampling of water and hadling of data at the Cai Jia Tang monitoring site in the Hunan province of China
Forfattere
Dagang Tang Espen Lydersen H.M. Seip Valter Angell Odd Eilertsen Thorbjørn Larssen X Liu G. Kong Jan Mulder Arne Semb Svein Solberg K. Torseth Rolf D. Vogt Jinshong Xiao Dawei ZhaoSammendrag
A 5-year Chinese-Norwegian research project was launched in the autumn of 1999. Forested sites for intensive studies are or will be established in the Chongqing municipality and in Guizhou, Hunan and Guangdong provinces in southern China. Previous studies have shown that harmful effects of acid deposition are likely to be most severe in this region. The research and monitoring sites shall give information about acidification mechanisms and effects on vegetation in order to improve policy oriented acidification models and critical load estimates as well as function as interdisciplinary training centers for acid rain research. Furthermore, the project shall improve the basis for developing an efficient regional acid rain monitoring system. At one site in Guizhou and one in Chongqing, research on soil and soilwater chemistry has been ongoing for several years. The forest at these sites appears to show symptoms of reduced vitality. The sensitivity of Chinese forests to acidification is uncertain and will be focused. Decision-makers should get an improved basis for optimal mitigation measures through the project.
Sammendrag
This manual contains description of field instrumemntation and the proceedures for field sampling of water and hadling of data at the Lei Gong Shan monitoring site in the Guizhou province of China
Sammendrag
This manual contains description of field instrumemntation and the proceedures for field sampling of water and hadling of data at the Liu Shon Guang monitoring site in the Guizhou province of China
Forfattere
Svein SolbergSammendrag
Det er ikke registrert sammendrag
Sammendrag
This manual contains description of field instrumemntation and the proceedures for field sampling of water and hadling of data at the Tie Shan Ping monitoring site in the ChongQing municipality of China
Sammendrag
Foliage nutrient concentrations of overstorey and understorey Norway spruce (Picea abies (L.) Karst.), and height growth and needle weights of understorey saplings, were studied in a seven-year period after harvest. The following treatments were applied on each of three sites five years prior to needle sampling: control with no cutting, partial cutting with 50-60 % removal of basal area, and patch cut (25 x 25 m - 0.063 ha clear-cut). Saplings on control plots had higher concentrations of K and Cu in current-year needles (C) than overstorey trees. Increased harvest intensity led to a reduction of K in C- needles and Mg in (C+1)-needles of saplings, and of B in both saplings (C, C+1) and overstorey trees (C+1). Sapling needle weights generally increased with harvest intensity, whereas no effect of foliage N status on needle weights could be detected. The growth response of saplings was explained by the interaction between foliage N status, quantified as average N concentration in C- and (C+1)-needles, and harvest intensity. The results illustrate that sufficient N supply is a key factor for the ability of advance regeneration to utilize the improved light condition associated with overstorey removal.
Forfattere
Aksel GranhusSammendrag
The risk of logging damage to residual trees (height >3.0 m) and advance regeneration saplings (height 0.5–3.0 m) was evaluated after mechanized (single-grip harvesters + forwarders) and motor-manual (chain saw + skidding) selection harvesting in studies I and II. Harvesting took place during the winter season. Mechanized harvesting caused the highest injury rates, and the difference was highest at high cutting intensity in densely stocked stands. Another important difference between the two operating methods was the spatial distribution of the injury risk relative to striproads. The most important injuries on the larger (>3.0 m) trees were stem- and root wounds, and loss of branches. Wounds tended to be larger, and crown injuries more serious, after mechanized harvesting, but differences were not statistically significant. The most frequent injuries on saplings were crown injuries (loss of branches, stem breakage) and stem lean. In motor-manually harvested stands saplings without pre-harvest deformities in the form of top- or leader defects were more prone to damage than saplings with such defects. A similar difference was not found in stands subjected to mechanized harvesting. This result was attributed to the different work patterns during felling and processing with the two operating methods, in combination with the spatial distribution of saplings of different quality relative to larger trees and stand openings. In study III sapling mortality, and recovery from logging damage in a five-year period after selection harvesting, was investigated. Mortality on the different plots (n=11) was highly variable. For saplings without previous logging damage mortality was related to pre-harvest vigour, and increased with increasing cutting intensity in the immediate surrounding of the sapling. Unspecified site factors also contributed to explain the probability of mortality. Saplings that had been pushed over during harvesting often survived and recovered, while injuries to the crown led to poor survival. Crown injuries were most common on plots subjected to mechanized harvesting, while stem lean was correspondingly important on motor-manually harvested plots. Whether this pattern was attributed to differences in temperature at the time of harvesting (winter), or operating method, is uncertain. In study IV advance regeneration responses in terms of height growth, needle dry weights, and foliar nutrient concentrations were compared after three different release treatments: untouched control, selection harvesting with 50-60 % removal of basal area (BA50-60), and patch cut (25x25 m - 0.063 ha clear-cut). The foliar analyses were carried out five years after treatment, and included dominant and co-dominant (overstorey) trees on control and BA50-60 plots. Height growth and needle dry weights of saplings generally increased with increasing overstorey removal. The growth response was explained by an interaction of foliar nitrogen concentration in current (C) and one-year-old (C+1) needles, and degree of overstorey removal. The foliar analyses did, however, not confirm improved N status after cutting. Increasing overstorey removal led to a reduction of K (C), Mg (C+1) and B (C, C+1) in saplings. A parallel decline of B (C+1) occurred in the overstorey trees (BA50-60). Saplings on control plots had higher concentrations of K and Cu in C-needles, relative to overstorey trees. The influence of neighbour tree basal area on sapling height growth and presence of natural defects (top- and leader damage) was examined in study V. The three stands selected for the study had not been subjected to cutting for several decades, and basal areas ranged from 25–33 m2 ha-1. The relationship between growth and four basal area variables was evaluated: basal area (m2 ha-1) of taller (>3.0 m) neighbour trees within 2.82, 3.99 and 5.64 m radius from the sapling (25, 50 and 100 m2 circular plots), and basal area (m2) of trees within 5.64 m radius weighted according to distance from the sapling. A reduction of growth attributed to increasing basal area of neighbour trees was only observed for the tallest saplings (2.1-3.0 m). Between 33 and 42 % of the saplings had leader- or top defects, and damage frequencies increased with declining distance to the nearest taller neighbour tree.
Sammendrag
Omfattende skader på skog i Ottadalen, karakterisert som tilbakedøing av skuddene i krone og topp, var forårsaket av bormangel (Kohmann 1997). En senere undersøkelse (Kohmann 1999) viste at gjødsling med borax økte konsentrasjonen av bor til nivå langt over det kritiske. For å få oversikt over hvor store arealer bormangel kan gjøre seg gjeldende på, tok Skogavdelingen ved Fylkesmannen i Oppland initiativet til en mer omfattende registrering i den sentrale Gudbrandsdalsregionen. Målsettingen var også å finne parametre knyttet til de geografiske, edafiske og biotiske forhold som kunne gi indikasjoner på forventet bormangel. Hovedtyngden av undersøkte felt ligger i kommunene Skjåk,Lom, Vågå og Sel hvor i alt 148 av de 167 felt felt ligger. Det er 68 felt hvor hovedtreslaget er gran og 99 felt hvor hovedtreslaget er furu. I alt er det funnet at 22 felt (13 %) har sterk bormangel (konsentrasjonen av bor i siste nåleargang mindre enn 4 ppm B), mens 52 felt (31 %) har verdier som er klassifisert som moderat bormangel (4-8 ppm B).