Effects of forest floor organic layer and root biomass on soil respiration following boreal forest fire

2008 ◽  
Vol 38 (4) ◽  
pp. 647-655 ◽  
Author(s):  
S. Singh ◽  
B. D. Amiro ◽  
S. A. Quideau
Keyword(s):  
Soil Respiration ◽  
Boreal Forest ◽  
Layer Thickness ◽  
Forest Floor ◽  
Root Biomass ◽  
Mineral Soil ◽  
Spatial And Temporal Variation ◽  
Organic Layer ◽  
Grid Pattern ◽  
Significant Difference

Soil respiration and its spatial and temporal variation were studied at three boreal forest sites in central Saskatchewan, Canada, burned in 1998, 1989, and 1977. Soil respiration, soil temperature, and organic layer thickness were measured at 100 points in a grid pattern of 2 m × 2 m at each site in 2004 and 2005. The mean within-site spatial coefficient of variation was 35%, and the measurements were not spatially autocorrelated. We found no significant difference in variance between the two youngest sites (P > 0.05), whereas the older site showed significantly lower variance (P < 0.05). Soil respiration was not correlated with the forest floor organic layer thickness at any of the sites (R2 < 0.1). Removal of the forest floor layer reduced the soil respiration by 17% to 38%, depending on the site. Thus, the respiration from the mineral soil seemed to contribute a major fraction of the total soil respiration (62%–83%). Soil respiration was positively linearly related to the fine root biomass (R2 = 0.63–0.85, P < 0.05) at all sites. We conclude that variation in root biomass has a larger effect than differential forest floor organic layers on variation in soil respiration in young boreal postfire forests.

scholarly journals Thinning and Burning Effects on Long-Term Litter Accumulation and Function in Young Ponderosa Pine Forests

2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard
Keyword(s):  
Ponderosa Pine ◽  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Pine Forests ◽  
Organic Layer ◽  
Litter Accumulation ◽  
Ponderosa Pine Forests ◽  
Essential Components

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.

scholarly journals Contrasting Root System Structure and Belowground Interactions between Black Spruce (Picea mariana (Mill.) B.S.P) and Trembling Aspen (Populus tremuloides Michx) in Boreal Mixedwoods of Eastern Canada

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 127 ◽  
Author(s):  
Claudele Ghotsa Mekontchou ◽  
Daniel Houle ◽  
Yves Bergeron ◽  
Igor Drobyshev
Keyword(s):  
Nutrient Uptake ◽  
Resource Use ◽  
Root Biomass ◽  
Competitive Exclusion ◽  
Fine Root ◽  
Black Spruce ◽  
Mineral Soil ◽  
Organic Layer ◽  
Mixed Stands ◽  
Boreal Mixedwoods

This study explored the underground interactions between black spruce and trembling aspen in pure and mixed stands to understand how their soil resource use help these species coexist in the boreal mixedwoods of Western Quebec. We analyzed species-specific fine root foraging strategies (root biomass and root tissue density) along three soil layers (organic, top 0–15 cm, and bottom 15–30 cm mineral soil), using 180 soil cores. We collected cores in three sites, each containing three 20 × 50 m2 plots of pure spruce, pure aspen, and mixed spruce and aspen stands. Spruce had a shallow rooting, whereas aspen had a deep rooting in both types of stands. Compared to pure spruce stands, spruce had a lower fine root biomass (FRB) and a higher root tissue density (RTD) in the organic layer of mixed stands. Both patterns were indicative of spruce’s more intensive resource use strategy and competitive advantage over aspen in that layer. Aspen FRB in the organic soil did not differ significantly between pure and mixed stands, but increased in the mineral soil of mixed stands. Since we did not observe a significant difference in the nutrient content of the mineral soil layer between pure aspen and mixed stands, we concluded that aspen may experience competitive exclusion in the organic layer by spruce. Aspen exhibited an extensive nutrient uptake strategy in the organic layer of mixed stands: higher FRB and lower RTD than spruce. In mixed stands, the differences in aspen rooting patterns between the organic and mineral layers suggested the use of contrasting nutrient uptake strategies along the soil profile. We speculate that the stronger spatial separation of the roots of spruce and aspen in mixed stands likely contribute to a higher partitioning of their nutrient uptake along the soil profile. These results indicate the competitive exclusion of aspen by spruce in boreal mixedwoods, which likely occurs in the soil organic layer.

Distribution of water-soluble organic carbon in an aspen forest soil

1996 ◽  
Vol 26 (7) ◽  
pp. 1266-1272 ◽  
Author(s):  
W.Z. Huang ◽  
J.J. Schoenau
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Water Soluble ◽  
Organic Layer ◽  
Litter Fall ◽  
Organic C ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Prince Albert National Park ◽  
Aspen Forest

The purpose of this study was to characterize the quantity, distribution, and variance of water-soluble organic C (WSOC) in a soil under trembling aspen (Populustremuloides Michx.) in the southern boreal forest of Canada. WSOC was determined monthly from May to October 1994 in the forest floor horizons (L, F, H) and mineral soil (Ae) of an aspen stand in Prince Albert National Park, Saskatchewan. The concentration of WSOC varied considerably with profile depth, but varied little among the slope positions and aspects. The L horizon had the highest WSOC concentration (425–8690 mg•kg−1 ovendried soil), followed by the F, H, and Ae horizons. The concentration of WSOC in the Ae horizon was significantly related to the concentration in forest floor horizons above. Water-soluble organic C in the Ae horizon likely was derived from the overlying organic layer by leaching. In a laboratory incubation, the rate of WSOC release (the net result of release and uptake) during incubation decreased continuously over time, but in the field, the rate of WSOC release decreased slightly early in the growing season, but increased later in the season as new litter fall reached the forest floor. This indicates that litter fall is a major factor in the replenishment of WSOC in aspen forest stands.

scholarly journals Bioturbation by wild boar increases the stability of forest soil carbon

2019 ◽  
Author(s):  
Axel Don ◽  
Christina Hagen ◽  
Erik Grüneberg ◽  
Cora Vos
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Carbon ◽  
Wild Boar ◽  
Forest Soils ◽  
Forest Floor ◽  
Mineral Soil ◽  
Organic Layer ◽  
Carbon Transfer ◽  
The Stability

Abstract. Most forest soils are characterised by a steep carbon gradient from the forest floor to the mineral soil, indicating that carbon is prevented from entry into the soil. Bioturbation can help incorporate litter-derived carbon into the mineral soil. Wild boar are effective at mixing and grubbing in the soil and wild boar populations are increasing in many parts of the world. In a six-year field study, we investigated the effect of wild boar bioturbation on the stocks and stability of soil organic carbon in two forest areas. Regular bioturbation mimicking grubbing by wild boar was performed artificially in 23 plots and the organic layer and mineral soil down to 15 cm depth were then sampled. No significant changes in soil organic carbon stocks were detected in the bioturbation plots compared with non-disturbed reference plots. However, around 50 % of forest floor carbon was transferred with bioturbation to mineral soil carbon and the stock of stabilised mineral-associated carbon increased by 28 %. Thus, a large proportion of the labile carbon in the forest floor was transformed into more stable carbon. Carbon saturation of mineral surfaces was not detected, but carbon loading per unit mineral surface increased by on average 66 % in the forest floor due to bioturbation. This indicates that mineral forest soils have non-used capacity to stabilise and store carbon. Transfer of aboveground litter into the mineral soil is the only rate-limiting process. Wild boar can help to speed up this process with their grubbing activity.

scholarly journals Carbon, nitrogen, and phosphorus stoichiometry of organic matter in Swedish forest soils and its relationship with climate, tree species, and soil texture

2021 ◽  
Author(s):  
Marie Spohn ◽  
Johan Stendahl
Keyword(s):  
Organic Matter ◽  
Boreal Forest ◽  
Forest Soils ◽  
Soil Texture ◽  
Tree Species ◽  
Mineral Soil ◽  
Stand Age ◽  
Organic Layer ◽  
Mean Annual Temperature ◽  
P Concentration

Abstract. While the carbon (C) content of temperate and boreal forest soils is relatively well studied, much less is known about the ratios of C, nitrogen (N), and phosphorus (P) of the soil organic matter, and the abiotic and biotic factors that shape them. Therefore, the aim of this study was to explore carbon, nitrogen, and organic phosphorus (OP) contents and element ratios in temperate and boreal forest soils and their relationships with climate, dominant tree species, and soil texture. For this purpose, we studied 309 forest soils with a stand age >60 years located all over Sweden between 56° N and 68° N. The soils are a representative subsample of Swedish forest soils with a stand age >60 years that were sampled for the Swedish Forest Soil Inventory. We found that the N stock of the organic layer increased by a factor of 7.5 from −2 °C to 7.5 °C mean annual temperature (MAT), it increased almost twice as much as the organic layer stock along the MAT gradient. The increase in the N stock went along with an increase in the N : P ratio of the organic layer by a factor of 2.1 from −2 °C to 7.5 °C MAT (R2 = 0.36, p < 0.001). Forests dominated by pine had higher C : N ratios in the litter layer and mineral soil down to a depth of 65 cm than forests dominated by other tree species. Further, also the C : P ratio was increased in the pine-dominated forests compared to forests dominated by other tree species in the organic layer, but the C : OP ratio in the mineral soil was not elevated in pine forests. C, N and OP contents in the mineral soil were higher in fine-textured soils than in coarse-textured soils by a factor of 2.3, 3.5, and 4.6, respectively. Thus, the effect of texture was stronger on OP than on N and C, likely because OP adsorbs very rigidly to mineral surfaces. Further, we found, that the P and K concentrations of the organic layer were inversely related with the organic layer stock. The C and N concentrations of the mineral soil were best predicted by the combination of MAT, texture, and tree species, whereas the OP concentration was best predicted by the combination of MAT, texture and the P concentration of the parent material in the mineral soil. In the organic layer, the P concentration was best predicted by the organic layer stock. Taken together, the results show that the N : P ratio of the organic layer was most strongly related to MAT. Further, the C : N ratio was most strongly related to dominant tree species, even in the mineral subsoil. In contrast, the C : P ratio was only affected by dominant tree species in the organic layer, but the C : OP ratio in the mineral soil was hardly affected by tree species due to the strong effect of soil texture on the OP concentration.

Responses of fine roots to experimental nitrogen addition in a tropical lower montane rain forest, Panama

2010 ◽  
Vol 27 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Markus Adamek ◽  
Marife D. Corre ◽  
Dirk Hölscher
Keyword(s):  
Rain Forest ◽  
Root Biomass ◽  
Fine Root ◽  
Mineral Soil ◽  
N Fertilization ◽  
Fine Root Biomass ◽  
Organic Layer ◽  
N Addition ◽  
Ingrowth Cores ◽  
Montane Rain Forest

Abstract:Nitrogen (N) availability is a major control on fine-root growth and distribution with depth in forest soils. We investigated fine-root dynamics in response to N addition in a montane rain forest with N-limited above-ground production. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were laid out in a paired-plot design with four replicates (each 40 × 40 m). During 1.5 y of treatment, fine root-biomass, necromass and production were assessed by sequential coring at three soil depths (organic layer, 0–10 cm and 10–20 cm mineral soil), whereas fine-root redistribution with depth was assessed by ingrowth cores. Total fine-root biomass, necromass and production in the controls were 458 ± 21 g m−2, 101 ± 9 g m−2 and 324 ± 33 g m−2 y−1, respectively. No significant difference at any depth was detected under N fertilization. Fine-root biomass in the organic layer decreased over time under N addition. At 10–20 cm in the mineral soil, fine-root biomass in ingrowth cores increased significantly after 1.5 y of N fertilization compared with the control. The increased available N may have induced the change in fine-root distribution to explore the deeper mineral soil for other nutrients which may cause additional limitation to above-ground production once N limitation is alleviated.

Impacts of harvesting and mechanical site preparation on soil chemical properties of mixed-wood boreal forest sites in Alberta

1996 ◽  
Vol 76 (4) ◽  
pp. 531-540 ◽  
Author(s):  
M. G. Schmidt ◽  
S. E. Macdonald ◽  
R. L. Rothwell
Keyword(s):  
Boreal Forest ◽  
Mineral Soil ◽  
Chemical Properties ◽  
Site Preparation ◽  
Available Phosphorus ◽  
Organic Layer ◽  
Mechanical Site Preparation ◽  
Forest Sites ◽  
Mineralizable Nitrogen ◽  
Surface Mineral

We examined the impacts of harvesting and mechanical site preparation (MSP) on soil chemical properties of mixed-wood boreal forest sites in west central Alberta. Treatments included: 1) disc trencher, hinge, and trench microsites; 2) ripper plow, hinge, and trench microsites; 3) blading thin (organic layer depth < 2 cm), and thick (organic layer depth > 2 cm) microsites; 4) harvested with no site preparation; and 5) unharvested. Twenty months after harvesting, the forest floor of harvested areas with no MSP (vs. unharvested) had higher carbon:nitrogen ratios lower pH, and lower concentrations of total and mineralizable nitrogen, available phosphorus, and exchangeable bases Fifteen months after MSP, treated areas had either reduced or unchanged concentrations of total nitrogen and carbon, available phosphorus, and mineralizable nitrogen in the surface mineral soil, compared with harvested sites with no site preparation. The MSP-treated areas also had increased or unchanged pH, base saturation, and exchangeable base concentrations. Microsites adjacent to the displaced forest floor (hinge for disc and ripper treatments) or with a thicker organic layer (thick for blading) generally had higher concentrations of total nitrogen and carbon, and mineralizable nitrogen in the surface mineral soil as compared to trench and thin microsites. Key words: Forest soils, mechanical site preparation, harvesting, N, P, mixed-wood boreal forest

The role of mineral soil topography on the spatial distribution of organic layer thickness in a paludified boreal landscape

Geoderma ◽  
2014 ◽  
Vol 221-222 ◽  
pp. 70-81 ◽  
Author(s):  
Ahmed Laamrani ◽  
Osvaldo Valeria ◽  
Nicole Fenton ◽  
Yves Bergeron ◽  
Li Zhen Cheng
Keyword(s):  
Spatial Distribution ◽  
Layer Thickness ◽  
Mineral Soil ◽  
Organic Layer ◽  
Boreal Landscape
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