scholarly journals Carbon Limitation and Drought Sensitivity at Contrasting Elevation and Competition of Abies pinsapo Forests. Does Experimental Thinning Enhance Water Supply and Carbohydrates?

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1132 ◽  
Author(s):  
Victor Lechuga ◽  
Vinicio Carraro ◽  
Benjamín Viñegla ◽  
José Antonio Carreira ◽  
Juan Carlos Linares
Keyword(s):  
Regional Scale ◽  
Secondary Growth ◽  
Stand Density ◽  
High Elevation ◽  
Carbon Limitation ◽  
Flow Density ◽  
Xylem Water Potential ◽  
Local Climate ◽  
Water Balances ◽  
Abies Pinsapo

Stand-level competition and local climate influence tree responses to increased drought at the regional scale. To evaluate stand density and elevation effects on tree carbon and water balances, we monitored seasonal changes in sap-flow density (SFD), gas exchange, xylem water potential, secondary growth, and non-structural carbohydrates (NSCs) in Abies pinsapo. Trees were subjected to experimental thinning within a low-elevation stand (1200 m), and carbon and water balances were compared to control plots at low and high elevation (1700 m). The hydraulic conductivity and the resistance to cavitation were also characterized, showing relatively high values and no significant differences among treatments. Trees growing at higher elevations presented the highest SFD, photosynthetic rates, and secondary growth, mainly because their growing season was extended until summer. Trees growing at low elevation reduced SFD during late spring and summer while SFD and secondary growth were significantly higher in the thinned stands. Declining NSC concentrations in needles, branches, and sapwood suggest drought-induced control of the carbon supply status. Our results might indicate potential altitudinal shifts, as better performance occurs at higher elevations, while thinning may be suitable as adaptive management to mitigate drought effects in endangered Mediterranean trees.

scholarly journals Terrestrial Carbon Stock Potential in Selected Forest in Bhutan, India and Nepal

2021 ◽  
pp. 21-32
Author(s):  
Kezang Choden ◽  
Bhagat Suberi ◽  
Purna Chettri
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Carbon Stock ◽  
Sustainable Forest Management ◽  
Regional Scale ◽  
Stand Density ◽  
Forest Products ◽  
Forest Types ◽  
Sequestration Potential ◽  
The Government

Forests are natural carbon reservoirs that play an important role in the global carbon cycle for storing large quantities of carbon in vegetation and soils. Carbon stored in pool helps in mitigating climate change by carbon sequestration. The vulnerable countries to changing climate such as Bhutan, Nepal, and India require a full understanding of carbon dynamics as well as baseline data on carbon stock potential to mitigate anticipated risks and vulnerabilities (RVs) through climate change. The scope of such RVs are trans boundary in nature, however, the comparative studies at regional scale are still scanty. Therefore, the aim of this review is to assess the carbon stock potentials of selected forest types in the eastern Himalayan area, with an emphasis on Bhutan, India, and Nepal. This review paper is based on published articles, information from websites and considerable data from National forestry reports of India and Bhutan; emphasizing on aboveground biomass and soil organic carbon stock. The review showed that carbon stock potential is highly dependent on stand density, above-ground biomass, species richness and forest types. The sub-tropical forest was found to have larger carbon capacity and sequestration potential. SOC concentration and tree biomass stocks were significantly higher at the high altitude where there is less human disturbance. In general, forest coverage has increased compare to previous year in Bhutan, India and Nepal which ultimately leads to higher carbon stock potential. It is mainly due to strong policies and different strategies for conservation of forest management have reduced mass destruction despite a growing population. Despite the rules, deforestation continues to occur at various scales. However, it can be stated that the government and citizens are working hard to increase carbon stock potential, mostly through afforestation and community forest creation. In addition, it is recommended to practice sustainable forest management, regulated and planned cutting of trees and proper forest products utilization.

Explaining the exceptional 4270 m high elevation limit of an evergreen oak in the south-eastern Himalayas

2020 ◽  
Vol 40 (10) ◽  
pp. 1327-1342 ◽  
Author(s):  
Yang Yang ◽  
Hang Sun ◽  
Christian Körner
Keyword(s):  
Safety Margin ◽  
High Elevation ◽  
Carbon Limitation ◽  
Range Limit ◽  
The South ◽  
Freezing Resistance ◽  
Eastern Himalayas ◽  
Alpine Treeline ◽  
South Eastern ◽  
Stressful Environment

Abstract Unlike the well-understood alpine treeline, the upper range limits of tree taxa that do not reach the alpine treeline are largely unexplained. In this study, we explored the causes of the exceptionally high elevation (4270 m) occurrence of broad-leaved evergreen oaks (Quercus pannosa) in the south-eastern Himalayas. We assessed the course of freezing resistance of buds and leaves from winter to summer at the upper elevational limit of this oak species. Linked to leaf phenology, we analyzed freezing resistance and assessed minimum crown temperature for the past 65 years. We also examined potential carbon limitation at the range limit of this species. Last season buds and leaves operated at a safety margin of 5.5 and 11 K in mid-winter. Once fully dehardened early in July, last season foliage is damaged at −5.9 and new foliage at −4.6 °C. Bud break is timed for late June to early July when low temperature extremes historically were never below −3.0 °C. The monsoon regime ensures a long remaining season (149 days), thus compensating for the late onset of shoot growth. Compared with a site at 3450 m, specific leaf area is reduced, foliar non-structural carbohydrate concentrations are similar and the δ13C signal is higher, jointly suggesting that carbon limitation is unlikely at the range limit of this species. We also show that these oaks enter the growing season with fully intact (not embolized) xylem. We conclude that the interaction between phenology and freezing tolerance results in safe flushing, while still facilitating shoot maturation before winter. These factors jointly determine the upper range limit of this oak species. Our study illuminates an exceptional case of broad-leaved evergreen tree performance near the treeline, and by exploring a suite of traits, we can underpin the central role of flushing phenology in such a stressful environment.

scholarly journals The climate sensitivity of Antarctic blue-ice areas

1995 ◽  
Vol 21 ◽  
pp. 157-161 ◽  
Author(s):  
Richard Bintanja ◽  
Michiel R. Van Den Broeke
Keyword(s):  
Mass Balance ◽  
Time Scales ◽  
Climate Sensitivity ◽  
High Elevation ◽  
Surface Mass Balance ◽  
Snow Surface ◽  
Local Climate ◽  
Surface Mass

On time-scales of less than about 100 years, when the ice topography can be considered stationary, the extent of Antarctic blue-ice areas is governed mainly by the surface mass balance. In and near high-elevation blue-ice areas, ablation is due entirely to sublimation. An estimate of the mass-balance profile ranging from a blue-ice area to the adjacent snow surface is presented. By considering changes in sublimation induced by variations in local climate, the deviation from the mass-balance profile is evaluated. It is concluded that even for considerable changes in local climate these deviations remain relatively small and have only little effect on the extent of a blue-ice area. This can be attributed mainly to the steep mass-balance profile.

scholarly journals Evaluation method of ecosystem service value under complex ecological environment: A case study of Gansu Province, China

2020 ◽  
Author(s):  
Xiaojiong Zhao ◽  
Jian Wang ◽  
Junde Su ◽  
Wei Sun
Keyword(s):  
Ecosystem Service ◽  
Regional Difference ◽  
Evaluation Method ◽  
Regional Scale ◽  
Gansu Province ◽  
Ecological Environment ◽  
Ecosystem Service Value ◽  
Local Climate ◽  
Service Value ◽  
Service Function

AbstractScientific assessment of regional ecosystem service value (ESV) is helpful to make scientific ecological protection plan and compensation policy. The evaluation method has not been established that is adapted to the complex and diverse characteristics of the ecological environment. This paper takes Gansu Province as an example, on the basis of fully considering the regional differences of ecosystem service function, the five correction index of value equivalent factor per unit area were constructed in the provincial scale, and the regional difference adjustment index of 11 kinds of ES was constructed in regional scale, in the way, the value evaluation model based on regional difference was established. The results show that in 2015, the total ESV reached 2239.555 billion Yuan in Gansu Province, ESV gradually increased from the northeast to the southwest, and the high-value areas of service function located in Qilian Mountain and Longnan Mountain, of which the forest and grassland ecosystem contributed the most to the value. From the perspective of value composition, local climate regulation and biodiversity maintenance function are the main service functions of Gansu Province. From 2000 to 2015, ESV increased by 3.426 billion Yuan in Gansu Province, the value of forest and urban ecosystem continued increasing, while the value of cultivated land ecosystem continue decreasing. From the spatial characteristics of service value change, the area of value reduction gradually moved from the central part of Gansu Province to the surrounding area. In general, although this study needs further improvement, the constructed evaluation method provides a relatively comprehensive evaluation scheme for the spatiotemporal dynamic evaluation of ESV in Gansu Province. This study provided a more overall research idea for the evaluation of ESV under complex ecological environment.

scholarly journals Scaling up local climate action: A survey of climate policy priorities in the Vancouver Island and Coastal Communities region

2021 ◽  
Vol 2021 ◽  
pp. 36-69
Author(s):  
Ekaterina Rhodes ◽  
Tamara Krawchenko ◽  
Katherine Pearce ◽  
Karena Shaw
Keyword(s):  
Climate Policy ◽  
Local Governments ◽  
Regional Scale ◽  
Vancouver Island ◽  
Climate Impacts ◽  
Coastal Communities ◽  
Local Climate ◽  
Climate Action ◽  
Barriers And Opportunities ◽  
Upper Level

Regional planning can help functionally-connected communities share expertise and the costs of climate action and amplify collective concerns and needs to upper-level governments. Understanding communities’ climate impacts, policies and barriers to action is foundational to the development of regional-scale climate planning. In support of a nascent climate strategy in the Vancouver Island and Coastal Communities region of British Columbia, our study employs a web-based survey of local government officials (n=106) to identify the existing climate impacts, policy priorities, barriers, and opportunities that guide climate policy-making in the region, including the impacts of the COVID-19 pandemic. We find that nearly all communities have experienced climate-related impacts and have implemented a variety of climate policies. However, local governments face substantial barriers—including a lack of financial resources, authority and staffing capacity—to pursue climate action and planning.

scholarly journals Future runoff regime changes and their time of emergence for 93 catchments in Switzerland

2020 ◽  
Author(s):  
Regula Muelchi ◽  
Ole Rössler ◽  
Jan Schwanbeck ◽  
Rolf Weingartner ◽  
Olivia Martius
Keyword(s):  
Climate Change ◽  
Strong Influence ◽  
Climate Model ◽  
High Elevation ◽  
Snow Accumulation ◽  
Seasonal Patterns ◽  
Climate Projections ◽  
Local Climate ◽  
Runoff Change ◽  
Runoff Changes

Abstract. Assessments of climate change impacts on runoff regimes are essential for adaptation and mitigation planning. Changing runoff regimes and thus changing seasonal patterns of water availability have strong influence on various sectors such as agriculture, energy production or fishery. In this study, we use the most up to date local climate projections for Switzerland (CH2018) that were downscaled with a post-processing method (quantile mapping). This enables detailed information on changes in runoff regimes and their time of emergence for 93 rivers in Switzerland under three emission pathways RCP2.6, RCP4.5, and RCP8.5. Changes in seasonal patterns are projected with increasing winter runoff and decreasing summer and autumn runoff. Spring runoff is projected to increase in high elevation catchments and to decrease in lower lying catchments. Despite strong increases in winter and partly in spring, the yearly mean runoff is projected to decrease in most catchments. Results show a strong elevation dependence for the signal and magnitude of change. Compared to lower lying catchments, runoff changes in high elevation catchments (above 1500 masl) are larger in winter, spring, and summer due to the strong influence of reduced snow accumulation and earlier snow melt as well as glacier melt. Under RCP8.5 (RCP2.6) and for catchments with mean altitude below 1500 masl, average relative runoff change in winter is +27 % (+5 %), in spring −5 % (−6 %), in summer −31 % (−4 %), in autumn −21 % (−6 %), and −8 % (−4 %) throughout the year. For catchments with mean elevation above 1500 masl, runoff changes on average by +77 % (+24 %) in winter, by +28 % (+16 %) in spring, by −41 % (−9 %) in summer, by −15 % (−4 %) in autumn, and by −9 % (−0.6 %) in the yearly mean. The changes and the climate model agreement on the signal of change increase with increasing global mean temperatures or stronger emission scenarios. This amplification highlights the importance of climate change mitigation. Under RCP8.5, early times of emergence in winter (before 2065; period 2036–2065) and summer (before 2065) were found for catchments with mean altitudes above 1500 masl. Significant changes in catchments below 1500 masl emerge later in the century. However, not all catchments show a time of emergence in all seasons and in some catchments the detected significant changes are not persistent over time.

scholarly journals Using ForeStereo and LIDAR data to assess fire and canopy structure-related risks in relict Abies pinsapo Boiss. forests

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10158
Author(s):  
Álvaro Cortés-Molino ◽  
Isabel Aulló-Maestro ◽  
Ismael Fernandez-Luque ◽  
Antonio Flores-Moya ◽  
José A. Carreira ◽  
...  
Keyword(s):  
Stand Structure ◽  
Secondary Growth ◽  
Canopy Structure ◽  
Airborne Lidar ◽  
Distribution Area ◽  
Lidar Data ◽  
Fire Simulation ◽  
Entire Area ◽  
Fuel Models ◽  
Abies Pinsapo

In this study we combine information from aerial LIDAR and hemispherical images taken in the field with ForeStereo—a forest inventory device—to assess the vulnerability and to design conservation strategies for endangered Mediterranean fir forests based on the mapping of fire risk and canopy structure spatial variability. We focused on the largest continuous remnant population of the endangered tree species Abies pinsapo Boiss. spanning 252 ha in Sierra de las Nieves National Park (South Andalusia, Spain). We established 49 sampling plots over the study area. Stand structure variables were derived from ForeStereo device, a proximal sensing technology for tree diameter, height and crown dimensions and stand crown cover and basal area retrieval from stereoscopic hemispherical images photogrammetry. With this information, we developed regression models with airborne LIDAR data (spatial resolution of 0.5 points∙m−2). Thereafter, six fuel models were fitted to the plots according to the UCO40 classification criteria, and then the entire area was classified using the Nearest Neighbor algorithm on Sentinel imagery (overall accuracy of 0.56 and a KIA-Kappa Coefficient of 0.46). FlamMap software was used for fire simulation scenarios based on fuel models, stand structure, and terrain data. Besides the fire simulation, we analyzed canopy structure to assess the status and vulnerability of this fir population. The assessment shows a secondary growth forest that has an increasing presence of fuel models with the potential for high fire spread rate fire and burn probability. Our methodological approach has the potential to be integrated as a support tool for the adaptive management and conservation of A. pinsapo across its whole distribution area (<4,000 ha), as well as for other endangered circum-Mediterranean fir forests, as A. numidica de Lannoy and A. pinsapo marocana Trab. in North Africa.

scholarly journals A Validation of ERA5 Reanalysis Data in the Southern Antarctic Peninsula—Ellsworth Land Region, and Its Implications for Ice Core Studies

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 289 ◽  
Author(s):  
Dieter Tetzner ◽  
Elizabeth Thomas ◽  
Claire Allen
Keyword(s):  
Wind Speed ◽  
Antarctic Peninsula ◽  
Ice Core ◽  
Regional Scale ◽  
Surface Air Temperature ◽  
Reanalysis Data ◽  
Near Surface ◽  
Local Climate ◽  
Proxy Records ◽  
Wind Regimes

Climate reanalyses provide key information to calibrate proxy records in regions with scarce direct observations. The climate reanalysis used to perform a proxy calibration should accurately reproduce the local climate variability. Here we present a regional scale evaluation of meteorological parameters using ERA-Interim and ERA5 reanalyses compared to in-situ observations from 13 automatic weather stations (AWS), located in the southern Antarctic Peninsula and Ellsworth Land, Antarctica. Both reanalyses seem to perform better in the escarpment area (>1000 m a.s.l) than on the coast. A significant improvement is observed in the performance of ERA5 over ERA-Interim. ERA5 is highly accurate, representing the magnitude and variability of near-surface air temperature and wind regimes. The higher spatial and temporal resolution provided by ERA5 reduces significantly the cold coastal biases identified in ERA-Interim and increases the accuracy representing the wind direction and wind speed in the escarpment. The slight underestimation in the wind speed obtained from the reanalyses could be attributed to an interplay of topographic factors and the effect of local wind regimes. Three sites in this region are highlighted for their potential for ice core studies. These sites are likely to provide accurate proxy calibrations for future palaeoclimatic reconstructions.

Coupling the delta-h parametrization with melt beneath a supraglacial debris cover: an evaluation across 54 glaciers in the southern European Alps

2021 ◽  
Author(s):  
Francesco Avanzi ◽  
Simone Gabellani ◽  
Edoardo Cremonese ◽  
Umberto Morra di Cella ◽  
Matthias Huss
Keyword(s):  
Mass Balance ◽  
Regional Scale ◽  
High Elevation ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Hydrological Models ◽  
Elevation Gradients ◽  
Ice Flow ◽  
Thickness Change ◽  
Debris Cover

&lt;p&gt;Glacier mass balance is an essential component of the water budget of high-elevation and high-latitude regions, and yet this process is rather oversimplified in most hydrological models. This oversimplification is particularly relevant when it comes to representing two mechanisms: ice flow dynamics and melt beneath a supraglacial debris cover. In 2010, Huss et al. proposed a parsimonious approach to account for&amp;#160; glacier dynamics in hydrological models without solving complex equations of three-dimensional ice flow, the so-called delta-h parametrization. On the other hand, accounting for melt of debris-covered ice is still challenging as&amp;#160; estimates of debris thickness are rare.&amp;#160;&lt;/p&gt;&lt;p&gt;Here, we leveraged a distributed dataset of glacier-thickness change to derive a glacier-specific delta-h parametrization for 54 glaciers across the Aosta Valley (Italy), as well as&amp;#160; develop a novel approach for modeling melt beneath supraglacial debris based on residuals between locally observed change in thickness and that expected by regional elevation gradients. This approach does not require any on-the-ground data on debris cover, and as such it is particularly suited for ungauged regions where remote sensing is the only, feasible source of information for modeling.&amp;#160;&lt;/p&gt;&lt;p&gt;We found an expected, significant variability in both the delta-h parametrization and residuals over debris-covered ice across glaciers, with somewhat steeper orographic gradients in the former compared to the curves originally proposed by Huss et al. for Swiss glaciers. At a regional scale, the glacier mass balance showed a clear transition between a regime dominated by active glacier flow above 2,300 m ASL and a debris-dominated regime below this elevation threshold, which makes accounting for melt in the debris-covered area essential to correctly capture the future fate of low-elevation glaciers. Implementing the delta-h parametrization and our proposed approach to melt beneath supraglacial debris into S3M, a distributed cryospheric model, yielded an improved realism in estimates of future changes in glacier geometry&amp;#160; compared to assuming non-dynamic downwasting.&lt;/p&gt;

Postglacial vegetation, fire, and climate history of the Siskiyou Mountains, Oregon, USA

2005 ◽  
Vol 64 (1) ◽  
pp. 44-56 ◽  
Author(s):  
Christy E. Briles ◽  
Cathy Whitlock ◽  
Patrick J. Bartlein
Keyword(s):  
Environmental History ◽  
Fire Regime ◽  
Regional Scale ◽  
Natural Disturbance ◽  
High Elevation ◽  
Early Holocene ◽  
Climate History ◽  
Fire Activity ◽  
History Of ◽  
Siskiyou Mountains

AbstractThe forests of the Siskiyou Mountains are among the most diverse in North America, yet the long-term relationship among climate, diversity, and natural disturbance is not well known. Pollen, plant macrofossils, and high-resolution charcoal data from Bolan Lake, Oregon, were analyzed to reconstruct a 17,000-yr-long environmental history of high-elevation forests in the region. In the late-glacial period, the presence of a subalpine parkland of Artemisia, Poaceae, Pinus, and Tsuga with infrequent fires suggests cool dry conditions. After 14,500 cal yr B.P., a closed forest of Abies, Pseudotsuga, Tsuga, and Alnus rubra with more frequent fires developed which indicates more mesic conditions than before. An open woodland of Pinus, Quercus, and Cupressaceae, with higher fire activity than before, characterized the early Holocene and implies warmer and drier conditions than at present. In the late Holocene, Abies and Picea were more prevalent in the forest, suggesting a return to cool wet conditions, although fire-episode frequency remained relatively high. The modern forest of Abies and Pseudotsuga and the present-day fire regime developed ca. 2100 cal yr B.P. and indicates that conditions had become slightly drier than before. Sub-millennial-scale fluctuations in vegetation and fire activity suggest climatic variations during the Younger Dryas interval and within the early Holocene period. The timing of vegetation changes in the Bolan Lake record is similar to that of other sites in the Pacific Northwest and Klamath region, and indicates that local vegetation communities were responding to regional-scale climate changes. The record implies that climate-driven millennial- to centennial-scale vegetation and fire change should be considered when explaining the high floristic diversity observed at present in the Siskiyou Mountains.

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