scholarly journals Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change

2014 ◽  
Vol 41 (3) ◽  
pp. 983-990 ◽  
Author(s):  
Christopher E. Doughty ◽  
Lyla L. Taylor ◽  
Cecile A. J. Girardin ◽  
Yadvinder Malhi ◽  
David J. Beerling
2008 ◽  
Vol 24 (4) ◽  
pp. 397-406 ◽  
Author(s):  
Nathalie Soethe ◽  
Johannes Lehmann ◽  
Christof Engels

AbstractWe measured macronutrient concentrations in soils and leaves of trees, shrubs and herbs at 1900, 2400 and 3000 m in an Ecuadorian tropical montane forest. Foliar N, P, S and K concentrations in trees were highest at 1900 m (21.7, 2.2, 1.9 and 10.0 mg g−1). At 2400 and 3000 m, foliar concentrations of N, P, S and K were similar to nutrient concentrations in tropical trees with apparent nutrient deficiency, as presented in literature. Unlike foliar nutrient concentrations, the amounts of plant-available nutrients in mineral soil were not affected by altitude or increased significantly with increasing altitude. High C:N ratios (25:1 at 2400 m and 34:1 at 3000 m) and C:P ratios (605:1 at 2400 m and 620:1 at 3000 m) in the soil organic layer suggested slow mineralization of plant litter and thus, a low availability of N and P at high altitudes. Foliar N:P ratios were significantly higher at 2400 m (11.3:1) than at 3000 m (8.3:1), indicating that at high altitudes, N supply was more critical than P supply. In conclusion, the access of plants to several nutrients, most likely N, P, S and K, decreased markedly with increasing altitude in this tropical montane forest.


2009 ◽  
Vol 39 (3) ◽  
pp. 546-552 ◽  
Author(s):  
Martin Simard ◽  
Pierre Y. Bernier ◽  
Yves Bergeron ◽  
David Paré ◽  
Lakhdar Guérine

In many northern forest ecosystems, soil organic matter accumulation can lead to paludification and forest productivity losses. Paludification rate is primarily influenced by topography and time elapsed since fire, two factors whose influence is often confounded and whose discrimination would help forest management. This study, which was conducted in the black spruce ( Picea mariana (Mill.) BSP) boreal forest of northwestern Quebec (Canada), aimed to (1) quantify the effect of slope and time since fire on paludification rates, (2) determine whether soil organic layer depth could be estimated by surface variables that can potentially be remotely sensed, and (3) relate the degree of paludification to tree productivity. In this study, soil organic layer depth was used as an estimator of the degree of paludification. Slope and postfire age strongly affected paludification dynamics. Young stands growing on steep slopes had thinner organic layers and lower organic matter accumulation rates compared with young stands growing on flat sites. Black spruce basal area and Sphagnum cover were strong predictors of organic layer depth, potentially allowing mapping of paludification degree across the landscape. Tree productivity was negatively related to organic layer depth (R2 = 0.57). The equations developed here can be used to quantify forest productivity decline in stands that are undergoing paludification, as well as potential productivity recovery given appropriate site preparation techniques.


2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.


2011 ◽  
Vol 91 (6) ◽  
pp. 965-968
Author(s):  
B. Wilske ◽  
E. A. Johnson

Wilske, B. and Johnson, E. A. 2011. Measuring unsaturated hydraulic conductivity (K(ψm)) of the F and H soil organic layers at small matric potential (ψm). Can. J. Soil Sci. 91: 965–968. K(ψm) of the soil organic layers is a key parameter to assess water redistribution in cold-climate forests. This study tested the twin suction disc apparatus (TSD) as a new method to measure K(ψm) of the F and H layers directly. We compared the results to two studies. One represents a large data base, the other used similar sample locations; but both derived K(ψm) from combining two methods, i.e., pressure plate measurements combined with the instantaneous profile technique or the constant head approach. The TSD data are consistent with previous results considering the large variability in K(ψm) from the combined methods. This suggests that the TSD method represents an alternative to determine K(ψm) of the soil organic layer.


2007 ◽  
Vol 37 (6) ◽  
pp. 1012-1023 ◽  
Author(s):  
David F. Greene ◽  
S. Ellen Macdonald ◽  
Sybille Haeussler ◽  
Susy Domenicano ◽  
Josée Noël ◽  
...  

We compared prefire and postfire organic-layer depths in boreal forest types (14 fires) across Canada, and examined tree recruitment as a function of depth. There was extensive within-stand variation in depth, much of it due to clustering of thinner organic layers around boles. There were no significant differences in postfire organic-layer depth among sites with different prefire forest species composition, but sites in the eastern boreal region had thicker postfire organic layers than those in the western boreal region. Mean organic-layer depth was much greater in intact stands than after fires; overall, fire reduced organic-layer depth by 60%, largely because of increases in the area of thin (<3 cm) organic layers (1% in intact stands vs. 40% in postfire stands). There was more variation in organic-layer depth within postfire than within prefire stands; notably, some areas in postfire stands were deeply combusted, while adjacent parts were only lightly combusted. We speculate that the diminished role of energy loss to latent heat around tree boles increased organic-layer consumption around tree boles. Seedlings were clustered around burned tree bases, where organic layers were thinner, and the dependence of a species on thin organic layers was an inverse function of seed size.


2013 ◽  
Vol 66 ◽  
pp. 51-59 ◽  
Author(s):  
Aino Smolander ◽  
Veikko Kitunen ◽  
Mikko Kukkola ◽  
Pekka Tamminen

2011 ◽  
Vol 8 (5) ◽  
pp. 1279-1289 ◽  
Author(s):  
M. Häkkinen ◽  
J. Heikkinen ◽  
R. Mäkipää

Abstract. Changes in the soil carbon stock can potentially have a large influence on global carbon balance between terrestrial ecosystems and atmosphere. Since carbon sequestration of forest soils is influenced by human activities, reporting of the soil carbon pool is a compulsory part of the national greenhouse gas (GHG) inventories. Various soil carbon models are applied in GHG inventories, however, the verification of model-based estimates is lacking. In general, the soil carbon models predict accumulation of soil carbon in the middle-aged stands, which is in good agreement with chronosequence studies and flux measurements of eddy sites, but they have not been widely tested with repeated measurements of permanent plots. The objective of this study was to evaluate soil carbon changes in the organic layer of boreal middle-aged forest stands. Soil carbon changes on re-measured sites were analyzed by using soil survey data that was based on composite samples as a first measurement and by taking into account spatial variation on the basis of the second measurement. By utilizing earlier soil surveys, a long sampling interval, which helps detection of slow changes, could be readily available. The range of measured change in the soil organic layer varied from −260 to 1260 g m−2 over the study period of 16–19 years and 23 ± 2 g m−2 per year, on average. The increase was significant in 6 out of the 38 plots from which data were available. Although the soil carbon change was difficult to detect at the plot scale, the overall increase measured across the middle-aged stands agrees with predictions of the commonly applied soil models. Further verification of the soil models is needed with larger datasets that cover wider geographical area and represent all age classes, especially young stands with potentially large soil carbon source.


2018 ◽  
Vol 409 ◽  
pp. 872-889 ◽  
Author(s):  
Mélanie Court ◽  
Gregory van der Heijden ◽  
Serge Didier ◽  
Claude Nys ◽  
Claudine Richter ◽  
...  

2018 ◽  
Vol 27 (2) ◽  
pp. 125 ◽  
Author(s):  
Xanthe J. Walker ◽  
Jennifer L. Baltzer ◽  
Steven G. Cumming ◽  
Nicola J. Day ◽  
Jill F. Johnstone ◽  
...  

Increased fire frequency, extent and severity are expected to strongly affect the structure and function of boreal forest ecosystems. In this study, we examined 213 plots in boreal forests dominated by black spruce (Picea mariana) or jack pine (Pinus banksiana) of the Northwest Territories, Canada, after an unprecedentedly large area burned in 2014. Large fire size is associated with high fire intensity and severity, which would manifest as areas with deep burning of the soil organic layer (SOL). Our primary objectives were to estimate burn depth in these fires and then to characterise landscapes vulnerable to deep burning throughout this region. Here we quantify burn depth in black spruce stands using the position of adventitious roots within the soil column, and in jack pine stands using measurements of burned and unburned SOL depths. Using these estimates, we then evaluate how burn depth and the proportion of SOL combusted varies among forest type, ecozone, plot-level moisture and stand density. Our results suggest that most of the SOL was combusted in jack pine stands regardless of plot moisture class, but that black spruce forests experience complete combustion of the SOL only in dry and moderately well-drained landscape positions. The models and calibrations we present in this study should allow future research to more accurately estimate burn depth in Canadian boreal forests.


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