scholarly journals Climate Variability May Delay Post-Fire Recovery of Boreal Forest in Southern Siberia, Russia

2021 ◽  
Vol 13 (12) ◽  
pp. 2247
Author(s):  
Qiaoqi Sun ◽  
Arden Burrell ◽  
Kirsten Barrett ◽  
Elena Kukavskaya ◽  
Ludmila Buryak ◽  
...  

Prolonged dry periods and increased temperatures that result from anthropogenic climate change have been shown to increase the frequency and severity of wildfires in the boreal region. There is growing evidence that such changes in fire regime can reduce forest resilience and drive shifts in post-fire plant successional trajectories. The response of post-fire vegetation communities to climate variability is under-studied, despite being a critical phase determining the ultimate successional conclusion. This study investigated the responses of post-fire recruited species to climate change and inter-annual variability at 16 study sites that experienced high-severity fire events, mostly in early 2000, within the Scots pine forest-steppe zone of southeastern Siberia, Russia. These sites were originally dominated by Scots pine, and by 2018, they were recruited by different successional species. Additionally, three mature Scots pine stands were included for comparison. A Bayesian Additive Regression Trees (BART) approach was used to model the relationship between Landsat-derived Normalized Difference Vegetation Index (NDVI) time series, temperature and precipitation in the 15 years after a stand-replacing fire. Using the resulting BART models, together with six projected climate scenarios with increased temperature and enhanced inner-annual precipitation variability, we simulated NDVI at 5-year intervals for 15 years post-fire. Our results show that the BART models performed well, with in-sample Pseudo-R2 varying from 0.49 to 0.95 for fire-disturbed sites. Increased temperature enhanced greenness across all sites and across all three time periods since fires, exhibiting a positive feedback in a warming environment. Repeatedly dry spring periods reduced NDVI at all the sites and wetter summer periods following such dry springs could not compensate for this, indicating that a prolonged dry spring has a strong impact consistently over the entire early developmental stages from the initial 5 years to 15 years post-fire. Further, young forests showed higher climate sensitivity compared to the mature forest, irrespective of species and projected climatic conditions. Our findings suggest that a dry spring not only increases fire risk, but also delays recovery of boreal forests in southern Siberia. It also highlights the importance of changing rainfall seasonality as well as total rainfall in a changing climate for post-fire recovery of forest.

2021 ◽  
Author(s):  
Minchao Wu ◽  
Giulia Vico ◽  
Stefano Manzoni ◽  
Zhanzhang Cai ◽  
Maoya Bassiouni ◽  
...  

<p> Recent accelerating global warming with increasing climate variability exerts a strong impact on terrestrial carbon budgets, but the ecosystem response to the changing climate and the overall climate-vegetation coupling remain largely unclear during different stages of the growing season. The timing of growing seasons can be modulated by different environmental conditions (e.g., thermal and hydrological changes) and affect the overall interpretation of regional climate-vegetation coupling. Here, we analyse the climate-vegetation coupling for Europe during 1982–2014 using a grid-wise definition of the growing season period based on remote sensing data. We quantify sub-seasonal anomalies of vegetation greenness from long-term vegetation indices (Normalized Difference Vegetation Index and two-band Enhanced Vegetation Index), and their relationships with corresponding local growing conditions (2m temperature, downwards surface solar radiation and root-zone soil moisture); and with multiple climate variability indices that reflect the large-scale climatic conditions over Europe. We find that early growing season anomalies in vegetation greenness tend to be large during the first two months of the growing season and that the coupling of these anomalies with large-scale climate largely determines the full-year climate-vegetation coupling. The North Atlantic Oscillation (NAO) and Scandinavian Pattern (SCA) phases evaluated one to two months before the start of growing season are the dominant drivers of the early growing season climate-vegetation coupling over large parts of boreal and temperate Europe. However, the sign of the effect of these indices on vegetation greenness is opposite. The East Atlantic Pattern (EA) evaluated several months in advance of the growing season is instead a main controlling factor on the temperate belt and the Mediterranean region. These findings highlight the importance of accounting for the spatial heterogeneity of growing season periods using location-specific definitions when studying large-scale land-atmosphere interactions.</p>


2014 ◽  
Vol 11 (5) ◽  
pp. 7685-7719 ◽  
Author(s):  
M. Broich ◽  
A. Huete ◽  
M. G. Tulbure ◽  
X. Ma ◽  
Q. Xin ◽  
...  

Abstract. Land surface phenological cycles of vegetation greening and browning are influenced by variability in climatic forcing. Quantitative information on phenological cycles and their variability is important for agricultural applications, wildfire fuel accumulation, land management, land surface modeling, and climate change studies. Most phenology studies have focused on temperature-driven Northern Hemisphere systems, where phenology shows annually reoccurring patterns. Yet, precipitation-driven non-annual phenology of arid and semi-arid systems (i.e. drylands) received much less attention, despite the fact that they cover more than 30% of the global land surface. Here we focused on Australia, the driest inhabited continent with one of the most variable rainfall climates in the world and vast areas of dryland systems. Detailed and internally consistent studies investigating phenological cycles and their response to climate variability across the entire continent designed specifically for Australian dryland conditions are missing. To fill this knowledge gap and to advance phenological research, we used existing methods more effectively to study geographic and climate-driven variability in phenology over Australia. We linked derived phenological metrics with rainfall and the Southern Oscillation Index (SOI). We based our analysis on Enhanced Vegetation Index (EVI) data from the MODerate Resolution Imaging Spectroradiometer (MODIS) from 2000 to 2013, which included extreme drought and wet years. We conducted a continent-wide investigation of the link between phenology and climate variability and a more detailed investigation over the Murray–Darling Basin (MDB), the primary agricultural area and largest river catchment of Australia. Results showed high inter- and intra-annual variability in phenological cycles. Phenological cycle peaks occurred not only during the austral summer but at any time of the year, and their timing varied by more than a month in the interior of the continent. The phenological cycle peak magnitude and integrated greenness were most significantly correlated with monthly SOI within the preceding 12 months. Correlation patterns occurred primarily over north-eastern Australia and within the MDB predominantly over natural land cover and particularly in floodplain and wetland areas. Integrated greenness of the phenological cycles (surrogate of productivity) showed positive anomalies of more than two standard deviations over most of eastern Australia in 2009–2010, which coincided with the transition between the El Niño induced decadal droughts to flooding caused by La Niña. The quantified spatial-temporal variability in phenology across Australia in response to climate variability presented here provides important information for land management and climate change studies and applications.


2019 ◽  
Vol 92 (5) ◽  
pp. 648-658 ◽  
Author(s):  
J Routa ◽  
A Kilpeläinen ◽  
V -P Ikonen ◽  
A Asikainen ◽  
A Venäläinen ◽  
...  

Abstract The aim of this study was to examine how intensified silviculture affects timber production (sawlogs and pulpwood) and its economic profitability (net present value [NPV], with 2 per cent interest rate) based on forest ecosystem model simulations. The study was conducted on Norway spruce and Scots pine stands located on medium-fertile upland forest sites under middle boreal conditions in Finland, under current climate and minor climate change (the RCP2.6 forcing scenario). In intensified silviculture, improved regeneration materials were used, with 10–20 per cent higher growth than the unimproved materials, and/or nitrogen (N) fertilization of 150 kg ha−1, once or twice during a rotation of 50–70 years. Compared to the baseline management regime, the use of improved seedlings, alone or together with N fertilization, increased timber production by up to 26–28 per cent and the NPV by up to 32–60 per cent over rotation lengths of 60–70 years, regardless of tree species (although more in spruce) or climate applied. The use of improved seedlings affected timber yield and NPV more than N fertilization. Minor climate change also increased these outcomes in Scots pine, but not in Norway spruce.


2017 ◽  
pp. 120-127
Author(s):  
S.M. Svyderska

An important element of climate change is to assess changes in agro-climatic growing conditions of crops and the impact of these changes on their performance. Agriculture is the most vulnerable sector of  Ukraine's economy to fluctuations and climate change. Given the inertial nature of agriculture and the dependence of the efficiency on the weather, now need to make timely and adequate solutions to complex problems caused by climate change. Due to the expected increase in air temperature of the Northern Hemisphere food security Ukraine will largely depend on how effectively adapting agriculture to future climate change. This includes advance assessment of the impact of the expected climate change on agro-climatic conditions for growing crops. Potatoes - perennial, herbaceous, plant, but in nature is treated as an annual plant, so that the life cycle, beginning with germination and ending with the formation of bubbles and the formation of mature tubers, is one growing season. Potato is one of the most important crops grown and diversified use in almost all parts of our country. But the main focus areas of potatoes in Polesie and Forest-steppe. We consider the relative performance of the photosynthetic productivity of potato and agro-climatic conditions for growing potatoes for the period 1986 to 2005, and expected their changes calculated by the climate change scenarios A1B and A2 for the period 2011 to 2050 in Eastern and Western Forest-Steppe. We consider the agrometeorological and agro-climatic conditions in which there may be a maximum performance of potato.


Author(s):  
A. M. Polevoy ◽  
L. E. Bozhko ◽  
E. A. Barsukova

The influence of the climate change on the agro-climatic growth conditions, development and formation of productivity of meadow and steppe vegetation in the forest-steppe zone of Ukraine for three periods has been studied: 2021–2030, 2031–2040, 2041–2050. The calculations of the expected conditions have been performed according to the climate change scenarios RCP4.5 and RCP8.5. The paper provides an assessment of the agro-climatic conditions for the formation of productivity of meadow and steppe vegetation in the current global warming and further climate change conditions until 2050. The assessment has been performed by comparing the average long-term agro-climatic indicators (1980–2010) of the productivity of wild phytocenoses with the same indicators for the future over decades. The calculations of both average long-term productivity of grasses and productivity of grasses in the conditions of climate change are executed according to four types of productivity: potential productivity which in case of optimum maintenance of plants with heat, moisture and mineral food is defined by solar radiation; meteorologically possible yield, which is provided by the temperature regime and the regime of humidification of the territory; really possible yield capacity, which is provided by the natural fertility of the soil; actual yield capacity in the natural conditions. Key words: meadow, steppe vegetation, productivity, humus balance, photosynthetic potential, agroecological categories of yields, climate change.


2020 ◽  
Vol 10 (2) ◽  
pp. 60-69
Author(s):  
Mariya Mihaylova ◽  
Mikhail Chernyshov

The indicators characterizing growth, productivity and living conditions of forest-steppe and steppe ecotypes of Scots pine in provenance trial plantation of Stupinsky Pole training ground in the Voronezh Region, obtained in 2019 on temporary sample plots, have been analyzed. The object of comprehensive research are forest-steppe and steppe ecotypes of Scots pine in 60-year-old provenance trial plantations growing in the Ramonsky district forestry of the Voronezh forestry. The studied cultures were laid on the lands after agricultural use in 1959 under the guidance of Professor M. M. Veresin. The planting material was 2-year-old standard seedlings of Scots pine, planted manually under Kolesov's planting iron. The type of growing conditions is A2 and B2. No additional planting was made. Based on the materials of 13 test plots laid according to the standard method, some features of the growth of forest-steppe and steppe pine ecotypes has been revealed. Their productivity and living condition have been evaluated. The highest average height is a characteristic of the steppe ecotype from the seeds of the Valsky forestry of the Saratov region and the forest-steppe ecotype from the seeds of the Platonov forestry of the Tambov region. The lowest average height is in crops of the forest-steppe ecotype from the seeds of the Monastic forestry of the Penza region. Local ecotypes (seeds from the Khrenovsky forestry) have the largest average diameter. The steppe ecotypes from the Saratov Region have the smallest diameter. The variability of the diameters of the preserved 60-year-old trees at a height of 1.3 m and at the surface of the soil was estimated as average - 16.99-31.09% and 19.50-29.94%, respectively. It is also typical for ordinary forest plantations. All the trees are classified as industrial trees. The stock of raw wood depends on the stand density. The largest stock was recorded in cultures from the Bryansk region (Krasnoslobodskoye forestry) due to the greater number of preserved trees. The smallest is among forest-steppe ecotypes of the Belgorod region. The analysis of the vital state of the surviving plants has showed that the best indicators have forest-steppe ecotypes from adjacent areas with similar climatic conditions. At the same time, the amount of preserved pine trees of all ecotypes per 1 ha is not large. Their preservation is 3.8-10.2% of the trees planted in 1959. Preservation varies greatly in ecotypes. Edaphic conditions for the growth of maternal stands where seeds were harvested have a significant impact on the living conditions of pine provenance trial plantations


2017 ◽  
Author(s):  
Michael Klinge ◽  
Choimaa Dulamsuren ◽  
Stefan Erasmi ◽  
Dirk Nikolaus Karger ◽  
Markus Hauck

Abstract. In northern Mongolia, at the southern boundary of the Siberian boreal forest belt, the distribution of steppe and forest is generally linked to climate and topography, making this region highly sensible to climate change. Detailed investigations on the limiting parameters of forest and steppe occurrence in different ecozones provide necessary information for environmental modelling and scenarios of potential landscape change. In this study, remote sensing data and gridded climate data were analyzed in order to identify distribution patterns of forest and steppe in Mongolia and to detect driving ecological factors of forest occurrence and vulnerability against environmental change. With respect to anomalies in extreme years we integrated the climate and land cover data of a 15 year period from 1999–2013. Forest distribution and vegetation vitality derived from the normalized differentiated vegetation index (NDVI) were investigated for the three ecozones with boreal forest present in Mongolia (taiga, subtaiga, and forest-steppe). In addition to the entire ecozone areas, the analysis focused on different subunits of forest and non-forested areas at the upper and lower treeline, which represent ecological borderlines of site conditions. The total cover of boreal forest in Mongolia was estimated at 73 818 km2. The upper treeline generally increases from 1800 m above sea level (a.s.l.) in the Northeast to 2700 m a.s.l. in the South. The lower treeline locally emerges at 1000 m a.s.l. in the northern taiga and is rising southward to 2500 m a.s.l. The latitudinal trend of both treelines turns into a longitudinal trend in the east of the mountains ranges due to more aridity caused by rain-shadow effects. Less vital trees were identified by NDVI at both, the upper and lower treeline in relation to the respective ecozone. The mean growing season temperature (MGST) of 7.9–8.9 °C and a minimum of 6 °C was found to be a limiting parameter at the upper treeline but negligible for the lower treeline and the total ecozones. The minimum of the mean annual precipitation (MAP) of 230–290 mm yr−1 is an important limiting factor at the lower treeline but at the upper treeline in the forest-steppe ecotone, too. In general, NDVI and MAP are lower in grassland, and MGST is higher compared to the forests in the same ecozone. An exception occurs at the upper treeline of the subtaiga and taiga, where the alpine vegetation is represented by meadow mixed with shrubs. Comparing the NDVI with climate data shows that increasing precipitation and higher temperatures generally lead to higher greenness in all ecological subunits. While the MGST is positively correlated with the MAP of the total ecozones of the forest-steppe, this correlation turns negative in the taiga ecozone. The subtaiga represents an ecological transition zone of approximately 300 mm yr−1 precipitation, which occurs independently from the MGST. Nevertheless, higher temperatures lead to higher vegetation vitality in terms of NDVI values. Climate change leads to a spatial relocation of tree communities, treelines and ecozones, thus an interpretation of future tree vitality and biomass trends directly from the recent relationships between NDVI and climate parameters is difficult. While climate plays a major role for vegetation and treeline distribution in Mongolia, the disappearing permafrost needs to be accounted for as a limiting factor for tree growth when modeling future trends of climate warming and human forest disturbance.


Author(s):  
G. V. Kuznetsova ◽  
N. V. Astrakhantseva

Changes in the radial growth Pinus sibirica Du Tour and Pinus cembra L. grafts and Scots pine (Pinus sylvestris L.) rootstocks were observed in comparison with control (non-grafted) trees of the corresponding species, whichindicated the mutual influence of the grafting components on each other. The smaller width of the annual rings in Pinuscembra grafts compared to Siberian cedar grafts is due to their species features. In general, the phloem was more conservative in structure than the xylem and in the grafts union zone retained the species characteristics, sometimes manifestedin the form of jagged junction of two types of bark, while in the xylem in the union zone were cells with an intermediatestructure. The study of seasonal dynamics showed that, in comparison with the rootstocks of Scots pine (Pinus sylvestrisL.), the scions of Stone pine quickly passed to the process of maturation of tracheids, especially the scions of Pinus sibirica Du Tour, which also completed the development of xylem annual ring faster. The similarity of some parameters of theanatomical structure, reactions to climatic conditions, synchronization of the development of the annual ring in the scion of the P. cembra with the stock of the Scots pine explain the higher safety of grafts of the P. cembra in comparison withthe P. sibirica.


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