scholarly journals Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation

2015 ◽  
Vol 5 (4) ◽  
pp. 948-960 ◽  
Author(s):  
Per-Ola Hedwall ◽  
Jerry Skoglund ◽  
Sune Linder
Keyword(s):  
Boreal Forest ◽  
Soil Temperature ◽  
Forest Floor ◽  
Life Form ◽  
Nutrient Status ◽  
Successional Stage ◽  
Specific Effects ◽  
Forest Floor Vegetation

scholarly journals Influence of forest floor vegetation on the total forest reflectance and its implications for LAI estimation using vegetation indices

2021 ◽  
Author(s):  
Terhikki Manninen ◽  
◽  
Pauline Stenberg ◽  
Keyword(s):  
Boreal Forest ◽  
Wavelength Range ◽  
Forest Floor ◽  
Forest Canopy ◽  
Vegetation Indices ◽  
Single Scattering ◽  
Relative Contribution ◽  
Bidirectional Reflectance Factor ◽  
Simple Ratio ◽  
Forest Floor Vegetation

Recently a simple analytic canopy bidirectional reflectance factor (BRF) model based on the spectral invariants theory was presented. The model takes into account that the recollision probability in the forest canopy is different for the first scattering than the later ones. Here this model is extended to include the forest floor contribution to the total forest BRF. The effect of the understory vegetation on the total forest BRF as well as on the simple ratio (SR) and the normalized difference (NDVI) vegetation indices is demonstrated for typical cases of boreal forest. The relative contribution of the forest floor to the total BRF was up to 69 % in the red wavelength range and up to 54 % in the NIR wavelength range. Values of SR and NDVI for the forest and the canopy differed within 10 % and 30 % in red and within 1 % and 10 % in the NIR wavelength range. The relative variation of the BRF with the azimuth and view zenith angles was not very sensitive to the forest floor vegetation. Hence, linear correlation of the modelled total BRF and the Ross-thick kernel was strong for dense forests (R2 > 0.9). The agreement between modelled BRF and satellite-based reflectance values was good when measured LAI, clumping index and leaf single scattering albedo values for a boreal forest were used as input to the model.

Spatial variability of the net ecosystem production and its component fluxes across a managed boreal forest landscape in Sweden: A biometric and chamber data-based analysis

2020 ◽  
Author(s):  
Eduardo Martínez García ◽  
Mats B. Nilson ◽  
Hjalmar Laudon ◽  
Jörgen Wallerman ◽  
Johan E.S. Fransson ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Boreal Forest ◽  
Forest Floor ◽  
Forest Landscape ◽  
Northern Sweden ◽  
Age Classes ◽  
Old Growth ◽  
Ecosystem Production ◽  
Spruce Stands ◽  
Forest Floor Vegetation

<p>A managed boreal forest landscape is a diverse successional mosaic of clear-cuts to old-growth stands of different species growing on a variety of soil types. Consequently, this high spatial heterogeneity strongly impacts the forest net ecosystem production (NEP) across the managed landscape. However, the quantification of the variability of NEP and its component fluxes across forested landscapes is currently highly uncertain due to the complex interactions between forest structure and physiological processes and their changes over time.</p> <p>Here, we assessed the spatial variability of NEP and its component fluxes during a 3-year period (2016-2018) over a boreal forest landscape (<em>ca.</em> 68 km<sup>2</sup>) located within the Krycklan catchment (64°14′N, 19°46′E) in northern Sweden. For this purpose, we selected 50 representative forest plots (10 m radius) across the catchment spanning various tree species (pine- and spruce-dominated stands) and forest age classes (from clear-cuts to old-growth forests). In each plot, forest floor CO<sub>2</sub> fluxes were manually measured with custom-made closed chambers in monthly intervals during the growing seasons 2016-2018. Measurements were carried out across natural (both light/dark measurements) and trenching/vegetation removal plots (0.45 × 0.45 m) to partition the net forest-floor exchange (NE<sub>FF</sub>) into its contributing components, i.e., gross primary production (GPP<sub>FF</sub>) and respiration (ER<sub>FF</sub>). ER<sub>FF</sub> was further separated into plant autotrophic and soil heterotrophic respiration (Ra<sub>FF</sub> and Rh<sub>FF</sub>). Plot-level biometric measurements were conducted to determine the net primary production of trees and forest floor vegetation (NPP<sub>T</sub> and NPP<sub>FF</sub>) as well as heterotrophic dead wood respiration (decomposition, Rh<sub>DW</sub>). Finally, NEP was calculated as NEP = NPP<sub>T</sub> + NPP<sub>FF</sub> – Rh<sub>FF</sub> – Rh<sub>DW</sub>.</p> <p>Our results showed that NPP<sub>T</sub> consistently increased with forest ageing, while an opposite pattern was observed for NPP<sub>FF</sub>. In general, spruce stands showed lower NPP<sub>T</sub> compared to spruce stands at each given age class. In contrast, pine stands showed consistently higher NE<sub>FF</sub>, GPP<sub>FF</sub>, ER<sub>FF</sub>, Rh<sub>FF</sub>, Ra<sub>FF</sub>, and NPP<sub>FF</sub> compared to spruce stands. The forest floor was a net CO<sub>2</sub> source, which increased with stand age due to the progressive decrease in GPP<sub>FF</sub>, while the ER<sub>FF</sub> remained similar among all the age classes. In addition, an analogous age-related pattern was observed in Rh<sub>FF</sub>. Our findings also depicted an increasing NEP with forest age from about ≈ 54±67 g C m<sup>-2</sup> yr<sup>-1</sup> during the initial stages of development (i.e., 5-30 years-old) to a maximum of ≈ 170±68 g C m<sup>-2</sup> yr<sup>-1</sup> in middle-aged stands (i.e., 60-100 years-old). Higher NEP was generally observed for pine compared to spruce stands. Interestingly, we found that the old-growth forests steadily continue to accumulate C, which is contrary to the common view that they become C neutral or sources.</p> <p>Overall, this comprehensive study improves our understanding of the spatial variability of the C balance over the heterogeneous regional forest landscape in northern Sweden, identifying tree species, forest floor vegetation and forest ageing as key drivers.</p>

Comparison of soil respiration among three temperate forests in Changbai Mountains, China

2010 ◽  
Vol 40 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Xu Wang ◽  
Yanling Jiang ◽  
Bingrui Jia ◽  
Fengyu Wang ◽  
Guangsheng Zhou
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Secondary Forest ◽  
Temperature Response ◽  
Stand Age ◽  
Changbai Mountains ◽  
Primary Forest ◽  
Plantation Forest ◽  
Successional Stage ◽  
Coniferous Plantation

CO2 efflux from forest soils is an important process in the global carbon cycle; however, effects of stand age and successional status remain uncertain. We compared soil respiration and its relationship to soil carbon content, forest floor mass, root biomass, soil temperature, and soil moisture content among three temperate forest ecosystems in Changbai Mountains, northeastern China, from 2003 to 2005. Forest types included an old-growth, mixed coniferous and broad-leaved primary forest (MN), a middle-aged, broad-leaved secondary forest (BL), and a young coniferous plantation forest (CP). Average annual soil CO2 efflux at BL (1477.9 ± 61.8 g C·m–2·year–1) was significantly higher than at CP (830.7 ± 48.7 g C·m–2·year–1) and MN (935.4 ± 53.3 g C·m–2·year–1). Differences in soil temperature among those sites were not statistically significant but contributed to the differences in annual CO2 efflux. In addition, the temperature response of soil CO2 efflux was higher at MN (Q10 = 2.78) than that at BL (Q10 = 2.17) and CP (Q10 = 2.02). Our results suggest that successional stage affects soil respiration by the differences in substrate quantity and quality, environmental conditions, and root respiration.

scholarly journals Microbial Substrate Utilization and Vegetation Shifts in Boreal Forest Floors of Western Canada

2021 ◽  
Vol 4 ◽  
Author(s):  
Emily Lloret ◽  
Sylvie Quideau
Keyword(s):  
Boreal Forest ◽  
Microbial Communities ◽  
Forest Floor ◽  
Microbial Respiration ◽  
Substrate Utilization ◽  
Utilization Efficiency ◽  
Western Canada ◽  
Spruce Forest ◽  
Vegetation Shifts ◽  
Forest Floors

Boreal forest soils are highly susceptible to global warming, and in the next few decades, are expected to face large increases in temperature and transformative vegetation shifts. The entire boreal biome will migrate northward, and within the main boreal forest of Western Canada, deciduous trees will replace conifers. The main objective of our research was to assess how these vegetation shifts will affect functioning of soil microbial communities and ultimately the overall persistence of boreal soil carbon. In this study, aspen and spruce forest floors from the boreal mixedwood forest of Alberta were incubated in the laboratory for 67 days without (control) and with the addition of three distinct 13C labeled substrates (glucose, aspen leaves, and aspen roots). Our first objective was to compare aspen and spruce substrate utilization efficiency (SUE) in the case of a labile C source (13C-glucose). For our second objective, addition of aspen litter to spruce forest floor mimicked future vegetation shifts, and we tested how this would alter substrate use efficiency in the spruce forest floor compared to the aspen. Tracking of carbon utilization by microbial communities was accomplished using 13C-PLFA analysis, and 13C-CO2 measurements allowed quantification of the relative contribution of each added substrate to microbial respiration. Following glucose addition, the aspen community showed a greater 13C-PLFA enrichment than the spruce throughout the 67-day incubation. The spruce community respired a greater amount of 13C glucose, and it also had a much lower glucose utilization efficiency compared to the aspen. Following addition of aspen litter, in particular aspen leaves, the aspen community originally showed greater total 13C-PLFA enrichment, although gram positive phospholipid fatty acids (PLFAs) were significantly more enriched in the spruce community. While the spruce community respired a greater amount of the added 13C-leaves, both forest floor types showed comparable substrate utilization efficiencies by Day 67. These results indicate that a shift from spruce to aspen may lead to a greater loss of the aspen litter through microbial respiration, but that incorporation into microbial biomass and eventually into the more persistent soil carbon pool may not be affected.

scholarly journals Outbreeding and inbreeding strategies in herbaceous-shrubby communities in the Venezuelan Gran Sabana Plateau

AoB Plants ◽  
2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Nelson Ramírez ◽  
Omaira Hokche
Keyword(s):  
Plant Species ◽  
Carbon Metabolism ◽  
Life Form ◽  
Sex Expression ◽  
Perennial Herb ◽  
Sexual System ◽  
Dioecious Species ◽  
Successional Stage ◽  
Sexual Systems ◽  
Perennial Herbs

Abstract Breeding system, sexual system, temporal variation in sex expression and herkogamy were evaluated in seven herbaceous-shrubby communities from the Gran Sabana Plateau, Venezuela. This analysis was conducted considering the life form, substrate type, succulence, carbon metabolism, nutritional relation, successional stage, pollination system specificity and endemism of plant species. Of the 348 plant species studied, 73.8 % were hermaphrodite, 16.9 % were monoecious and 9.2 % were dioecious. Plant sexual systems such as dichogamy and herkogamy were associated with life form, nutritional relations, carbon metabolism and pollination systems. Most species were adichogamous, followed by protandrous and protogynous. Protandry was high for perennial herbs, annual herbs and trees, and protogyny was most frequent in perennial herbs. Protandrous and protogynous species were frequently anemophilous. Herkogamy was higher than non-herkogamy. Herkogamy was higher for trees, shrubs and liana; higher in monophilous and lower in anemophilous species. Most of the hermaphrodites were herkogamous and adichogamous species. In contrast, monoecy were commonly perennial herb and dichogamous species and frequently associated with anemophily. Dioecious species were trees and shrubs and with polyphilous pollination. Dioecy was the most frequent sexual system for endemic species. Hermaphrodite species were similarly distributed across plant communities. Monoecy was slightly higher for savanna and fallow than the other communities, and dioecy was higher for shrublands and secondary bushland. Most plant species were non-agamospermous, non-spontaneous self-pollinated and xenogamous. Partially self-incompatible dominated, followed by self-incompatible, partially cross-incompatible and the lowest frequency corresponded to cross-incompatible species. All these results are discussed in the context of evolutionary and ecological trends.

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