scholarly journals Aboveground biomass increments over 26 years (1993–2019) in an old-growth cool-temperate forest in northern Japan

2022 ◽  
Author(s):  
Mahoko Noguchi ◽  
Kazuhiko Hoshizaki ◽  
Michinari Matsushita ◽  
Daiki Sugiura ◽  
Tsutomu Yagihashi ◽  
...  
Keyword(s):  
Air Temperature ◽  
Aboveground Biomass ◽  
Census Data ◽  
Local Scale ◽  
Ecosystem Functions ◽  
Small Scale ◽  
Old Growth ◽  
Cool Temperate ◽  
Northern Japan

AbstractAssessing long-term changes in the biomass of old-growth forests with consideration of climate effects is essential for understanding forest ecosystem functions under a changing climate. Long-term biomass changes are the result of accumulated short-term changes, which can be affected by endogenous processes such as gap filling in small-scale canopy openings. Here, we used 26 years (1993–2019) of repeated tree census data in an old-growth, cool-temperate, mixed deciduous forest that contains three topographic units (riparian, denuded slope, and terrace) in northern Japan to document decadal changes in aboveground biomass (AGB) and their processes in relation to endogenous processes and climatic factors. AGB increased steadily over the 26 years in all topographic units, but different tree species contributed to the increase among the topographic units. AGB gain within each topographic unit exceeded AGB loss via tree mortality in most of the measurement periods despite substantial temporal variation in AGB loss. At the local scale, variations in AGB gain were partially explained by compensating growth of trees around canopy gaps. Climate affected the local-scale AGB gain: the gain was larger in the measurement periods with higher mean air temperature during the current summer but smaller in those with higher mean air temperature during the previous autumn, synchronously in all topographic units. The influences of decadal summer and autumn warming on AGB growth appeared to be counteracting, suggesting that the observed steady AGB increase in KRRF is not fully explained by the warming. Future studies should consider global and regional environmental factors such as elevated CO2 concentrations and nitrogen deposition, and include cool-temperate forests with a broader temperature range to improve our understanding on biomass accumulation in this type of forests under climate change.

scholarly journals Aboveground biomass increments over 26 years (1993–2019) in an old-growth cool-temperate forest in northern Japan

2021 ◽  
Author(s):  
Mahoko Noguchi ◽  
Kazuhiko Hoshizaki ◽  
Michinari Matsushita ◽  
Daiki Sugiura ◽  
Tsutomu Yagihashi ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Mixed Forest ◽  
Local Scale ◽  
Small Scale ◽  
Old Growth ◽  
Old Growth Forest ◽  
Mean Temperature ◽  
Cool Temperate ◽  
Northern Japan

Assessing long-term changes in biomass of old-growth forests is critical in evaluating forest ecosystem functions under a changing climate. Long-term biomass changes are the result of accumulated short-term changes, which can be affected by endogenous processes such as gap filling in small-scale canopy openings. Here, we used 26 years (1993–2019) of repeated tree census data in an old-growth, cool-temperate, deciduous mixed forest that contains three topographic units (riparian, denuded slope, and terrace) in northern Japan to document decadal changes in aboveground biomass (AGB) and their processes in relation to endogenous processes and climatic factors. AGB increased steadily over the 26 years in all topographic units, but different tree species contributed to the increase among the topographic units. AGB gain within each topographic unit exceeded AGB loss via tree mortality in most of the measurement periods despite substantial temporal variation in AGB loss. At the local scale, variations in AGB gain were partially explained by compensating growth of trees around canopy gaps. Climate affected the local-scale AGB gain: the gain was larger in the measurement periods with higher mean temperature during the current summer but smaller in those with higher mean temperature during the previous autumn, synchronously in all topographic units. The decadal climate trends of warming are likely to have contributed to the steady increase in AGB in this old-growth forest.

Long-term rewetting of fen peatlands alters the response of water tables to rainfall and temperature

2021 ◽  
Author(s):  
Sate Ahmad ◽  
Haojie Liu ◽  
Shajratul Alam ◽  
Anke Günther ◽  
Gerald Jurasinski ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Table ◽  
Air Temperature ◽  
Meteorological Factors ◽  
Water Storage ◽  
Ecosystem Functions ◽  
Effective Measure ◽  
North East ◽  
The Impact

<p>Fens belong to the most threatened ecosystems in Europe. Maintaining a high water table through rewetting is an effective measure to rehabilitate many of their ecosystem functions. However, the impact of meteorological factors such as relative humidity, precipitation and air temperature on water storage and its dynamics is still unclear especially for rewetted fens in the temperate regions. Here, we quantify the impact of meteorological factors on water table dynamics comparing a drained and a rewetted fen in North-East Germany, using multiple linear regression with data from continuous high-resolution (temporal) water level monitoring and weather stations. We found that a 1-degree rise in daily maximum air temperature causes a drop of about 4 mm in the water table in the drained and degraded fen but only a drop of around 2 mm at the rewetted site, mainly through evapotranspiration. Higher minimum relative humidity limits evapotranspiration and is, thus, negatively associated with water table elevation at both sites. Precipitation contributes to recharge, causing the water table to rise almost six times higher at the drained site than at the rewetted site. We attribute the differential impacts of meteorological factors on water table dynamics to (1) differences in vegetation, which acts as surface control and (2) differences in soil properties. We found that for the depths at which the groundwater fluctuates, the peat of the rewetted fen has a higher specific yield compared to the drained fen, causing the water table to rise or recede at smaller rates. A period of 20 years of rewetting was sufficient to form a new layer of organic matter with a substantial fraction of macropores providing water storage capacity and thereby changing water table response. Our study underlines the importance of long-term rewetting and meteorological factors for peatland restoration. Continuous monitoring of water table and vegetation development in rewetted fens is advisable to ensure long-term success, especially under climate change conditions.</p>

A 370-year dendroecological history of an old-growth Abies-Acer-Quercus forest in Hokkaido, northern Japan

1999 ◽  
Vol 29 (12) ◽  
pp. 1891-1899 ◽  
Author(s):  
Marc D Abrams ◽  
Carolyn A Copenheaver ◽  
Kazuhiko Terazawa ◽  
Kiyoshi Umeki ◽  
Mika Takiya ◽  
...  
Keyword(s):  
Tree Species ◽  
Volcanic Eruption ◽  
Large Scale ◽  
Small Scale ◽  
Old Growth ◽  
Old Growth Forest ◽  
Cercidiphyllum Japonicum ◽  
Species Recruitment ◽  
Individual Trees ◽  
Northern Japan

Dendroecological techniques were used to study the dynamics and species recruitment patterns, spanning nearly four centuries, for a mesic, montane, old-growth forest in Hokkaido, northern Japan. The forest is dominated by Abies sachalinensis (Masters), Acer palmatum (Thunb.),Quercus mongolica var. grosseserrata (Rehd.), and Cercidiphyllum japonicum (Sieb.). From 1620 to 1750 and 1820 to 1840, Q. mongolica exhibited continuous recruitment into the overstory. A lack of recruitment for all tree species from 1750 to 1820 followed a 1739 volcanic eruption 200 km from the study area. Release events for individual trees occurred almost every decade of the stand history, indicating that frequent small-scale disturbances coupled with infrequent large-scale disturbances, impact tree growth and species recruitment. From 1870 to 1950, canopy recruitment of Abies and Acer dominated the forest, while recruitment of Quercus ceased. These later successional species appeared to be replacing Quercus, suggesting that the syndrome of declining oak dominance is an increasingly global phenomenon. However, successional patterns in the forest are difficult to predict because intensive deer browsing has recently prevented canopy recruitment of all tree species and the possibility of future large-scale disturbances, such as fire and volcanic eruption.

On the dynamics of distribution of the American White Butterfly, Hyphantria cunea Drury, 1973 (Lepidoptera, Arctiidae), in Ukraine regarding the annual minimal air temperatures

2018 ◽  
Vol 14 (1) ◽  
pp. 44-57
Author(s):  
S. N. Shumov
Keyword(s):  
Air Temperature ◽  
Annual Reports ◽  
Complete Elimination ◽  
Hyphantria Cunea ◽  
White American ◽  
Gis Technologies ◽  
Data Analyses ◽  
Air Temperatures ◽  
Negative Temperatures

The spatial analysis of distribution and quantity of Hyphantria cunea Drury, 1973 across Ukraine since 1952 till 2016 regarding the values of annual absolute temperatures of ground air is performed using the Gis-technologies. The long-term pest dissemination data (Annual reports…, 1951–1985; Surveys of the distribution of quarantine pests ..., 1986–2017) and meteorological information (Meteorological Yearbooks of air temperature the surface layer of the atmosphere in Ukraine for the period 1951-2016; Branch State of the Hydrometeorological Service at the Central Geophysical Observatory of the Ministry for Emergencies) were used in the present research. The values of boundary negative temperatures of winter diapause of Hyphantria cunea, that unable the development of species’ subsequent generation, are received. Data analyses suggests almost complete elimination of winter diapausing individuals of White American Butterfly (especially pupae) under the air temperature of −32°С. Because of arising questions on the time of action of absolute minimal air temperatures, it is necessary to ascertain the boundary negative temperatures of winter diapause for White American Butterfly. It is also necessary to perform the more detailed research of a corresponding biological material with application to the freezing technics, giving temperature up to −50°С, with the subsequent analysis of the received results by the punched-analysis.

Old-growth forest reserves in Slovenia: the past, present, and future

2012 ◽  
Vol 163 (6) ◽  
pp. 240-246 ◽  
Author(s):  
Thomas A. Nagel ◽  
Jurij Diaci ◽  
Dusan Rozenbergar ◽  
Tihomir Rugani ◽  
Dejan Firm
Keyword(s):  
Stand Structure ◽  
Growth Conditions ◽  
Ecosystem Functions ◽  
Future Research ◽  
Old Growth ◽  
Forest Reserves ◽  
The Past ◽  
Old Growth Forest ◽  
Forest Remnants ◽  
Basic Characteristics

Old-growth forest reserves in Slovenia: the past, present, and future Slovenia has a small number of old-growth forest remnants, as well as many forest reserves approaching old-growth conditions. In this paper, we describe some of the basic characteristics of these old-growth remnants and the history of their protection in Slovenia. We then trace the long-term development of research in these old-growth remnants, with a focus on methodological changes. We also review some of the recent findings from old-growth research in Slovenia and discuss future research needs. The conceptual understanding of how these forests work has slowly evolved, from thinking of them in terms of stable systems to more dynamic and unpredictable ones due to the influence of natural disturbances and indirect human influences. In accordance with this thinking, the methods used to study old-growth forests have changed from descriptions of stand structure to studies that address natural processes and ecosystem functions.

scholarly journals Surface Water Temperature Predictions at a Mid-Latitude Reservoir under Long-Term Climate Change Impacts Using a Deep Neural Network Coupled with a Transfer Learning Approach

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1109
Author(s):  
Nobuaki Kimura ◽  
Kei Ishida ◽  
Daichi Baba
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Water Temperature ◽  
Transfer Learning ◽  
Air Temperature ◽  
Climate Models ◽  
Temporal Variations ◽  
Training Data ◽  
Surface Water Temperature

Long-term climate change may strongly affect the aquatic environment in mid-latitude water resources. In particular, it can be demonstrated that temporal variations in surface water temperature in a reservoir have strong responses to air temperature. We adopted deep neural networks (DNNs) to understand the long-term relationships between air temperature and surface water temperature, because DNNs can easily deal with nonlinear data, including uncertainties, that are obtained in complicated climate and aquatic systems. In general, DNNs cannot appropriately predict unexperienced data (i.e., out-of-range training data), such as future water temperature. To improve this limitation, our idea is to introduce a transfer learning (TL) approach. The observed data were used to train a DNN-based model. Continuous data (i.e., air temperature) ranging over 150 years to pre-training to climate change, which were obtained from climate models and include a downscaling model, were used to predict past and future surface water temperatures in the reservoir. The results showed that the DNN-based model with the TL approach was able to approximately predict based on the difference between past and future air temperatures. The model suggested that the occurrences in the highest water temperature increased, and the occurrences in the lowest water temperature decreased in the future predictions.

Sign in / Sign up

Export Citation Format

Share Document