Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2021
Abstract
No abstract has been registered
Authors
Hui Tang Kjetil Schanke Aas Eirik Aasmo Finne Inge Althuizen Rosie A. Fisher Hans Tømmervik Ane Vollsnes Anders Bryn Sonya Rita Geange Sunniva Indrehus Vigdis Vandvik Jarle Werner Bjerke Terje Koren Berntsen Frode StordalAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Increasing atmospheric nitrogen deposition and climate change are considered the main factors accelerating the long-term growth of forests. Quantification of changes in growth rate can be extremely useful in monitoring and assessing the impact of climate change on site productivity. In this study, we carried out a country-wide analysis of long-term (100 years) dynamics and changes in the height growth rate and site index (SI) of Scots pine in Poland. To ensure representativeness we used a large sample of stem analysis trees collected on 312 plots selected using stratified sampling. To control the effect of site fertility and thus avoid the over-representation of older stands on infertile sites, we measured a range of soil properties that, together with environmental indicators characterising climatic conditions and topography, were used in growth trend modelling as explanatory variables. We found that trees planted in successive years have grown faster. The SI calculated for individual trees is linearly dependent on the year of germination and with increasing age of germination, the SI at the base age of 100 years has increased by 8.4 cm per year. Despite the differences in the growth dynamics of pines planted in different germination years, tree growth follows the same growth pattern. The observed continuous changes in site productivity correspond to an increase in the SI by over 29% between 1900 and 2000. A consequence of continuous changes in site conditions and height growth rate is ambiguity in derived SI values. Under changing site conditions, SI values calculated based on stand height and age depend not only on site productivity but also the year of germination. As a consequence, stands growing under identical site conditions show different SIs, which should be acknowledged if the SI is to be used in forest management. Therefore, determining the SI of newly established stands based on the SI of older generations requires the application of an amendment to account for stand age. Continuously improving our understanding of potential climate change impacts on forest ecosystems is essential and provide information to support forest managers seeking to develop effective adaptation measures and determine sustainable forestry production. As such, our results provide valuable support when making long-term decisions and developing effective adaptation strategies in forest management.
Abstract
No abstract has been registered
Authors
Harri Mäkinen Helena M. Henttonen Ulrich Kohnle Christian Kuehne Pekka Nöjd Chaofang Yue Joachim Klädtke Jouni SiipilehtoAbstract
No abstract has been registered
Authors
Christel C. Kern Laura S. Kenefic Christian Kuehne Aaron R. Weiskittel Sarah J. Kaschmitter Anthony W. D'Amato Daniel C. Dey John M. Kabrick Brian J. Palik Thomas M. SchulerAbstract
We compiled data from several independent, long-term silvicultural studies on USDA Forest Service experimental forests across a latitudinal gradient in the northeastern and north-central U.S.A. to evaluate factors influencing aboveground live-tree carbon sequestration and mortality. Data represent five sites with more than 70,000 repeated tree records spanning eight decades, five ecoregions, and a range of stand conditions. We used these data to test the relative influence of factors such as climate, treatment history (uneven-aged or no management), species composition, and stand structural conditions on aboveground live-tree carbon sequestration and mortality in repeatedly measured trees. Relative to no management, we found that uneven-aged management tended to have a positive effect on carbon sequestration at low stocking levels and in areas of favorable climate (expressed as a combination of growing season precipitation and annual growing degree days > 5 ◦C). In addition, losses of carbon from the aboveground live-tree pool due to tree mortality were lower in managed than unmanaged stands. These findings suggest that there may be conditions at which rate of sequestration in living trees is higher in stands managed with uneven-aged silviculture than in unmanaged stands, and that this benefit is greatest where climate is favorable.
Abstract
Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger; however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.
Authors
Anne Sophie Daloz Johanne Hope Rydsaa Øivind Hodnebrog Jana Sillmann Bob van Oort Christian Wilhelm Mohr Madhoolika Agrawal Lisa Emberson Frode Stordal Tianyi ZhangAbstract
The Indo-Gangetic Plain (IGP) is one of the main wheat-production regions in India and the world. With climate change, wheat yields in this region will be affected through changes in temperature and precipitation and decreased water availability for irrigation, raising major concerns for national and international food security. Here we use a regional climate model and a crop model to better understand the direct (via changes in temperature and precipitation) and indirect (via a decrease in irrigation availability) impacts of climate change on wheat yields at four sites spread across different states of the IGP: Punjab, Haryana, Uttar Pradesh and Bihar. The results show an increase in mean temperature and precipitation as well as maximum temperature during the growing season or Rabi season (November–April). The direct impact of climate change, via changes in temperature and precipitation, leads to wheat yield losses between −1% and −8% depending on the site examined. Then, the indirect impact of climate change is examined, considering the impact of climate change on water availability leading to a decrease in irrigation. In this case, the yield losses become significant and much higher, reaching −4% to −36% depending on the site examined and the irrigation regime chosen (6, 5, 3 or 1 irrigations). This work shows that the indirect impacts of climate change may be more detrimental than the direct climatic effects for the future wheat yields in the IGP. It also emphasizes the complexity of climatic risk and the necessity of integrating indirect impacts of climate change to fully assess how it affects agriculture and choose the adequate adaptation response.
Abstract
No abstract has been registered