scholarly journals Ground-layer composition affects tree fine root biomass and soil nutrient availability in jack pine and black spruce forests under extreme drainage conditions

2017 ◽  
Vol 47 (4) ◽  
pp. 433-444 ◽  
Author(s):  
Marine Pacé ◽  
Nicole J. Fenton ◽  
David Paré ◽  
Yves Bergeron

In the boreal forest, long-lasting canopy gaps are associated with lichens on dry sites and with Sphagnum spp. on wet sites. We hypothesize that ground-layer composition plays a role in maintaining gaps through its effects on fine root biomass (diameter ≤ 2 mm) and soil nutrient availability. Along gradients of canopy openness in both jack pine (Pinus banksiana Lamb.) – lichen and black spruce (Picea mariana (Mill.) B.S.P.) – moss forests, the relationships between canopy closure, ground-layer composition, tree fine root biomass, and soil nutrients were analyzed and decomposed using path analysis. The effects of lichen and Sphagnum spp. removal on tree fine root biomass and soil nutrients were tested in situ. Although variations in pine fine root biomass were mainly explained by stand aboveground biomass, lichen removal locally increased fine root biomass by more than 50%, resin extractable soil potassium by 580%, and base cations by 180%. While Sphagnum cover was identified as a key driver of stand aboveground biomass reduction in paludified forest sites, its removal had no short-term effects on spruce fine root biomass and soil nutrients. Our results suggest that lichens, more than Sphagnum spp., affect tree growth via direct effects on soil nutrients. These two different patterns call for different silvicultural solutions to maintain productive stands.

2005 ◽  
Vol 35 (12) ◽  
pp. 2934-2941 ◽  
Author(s):  
Matthew A Neatrour ◽  
Robert H Jones ◽  
Stephen W Golladay

We investigated the relationship between soil nutrients and fine-root biomass at broad (among ecosystem types) and fine (within a 20 m × 20 m plot) spatial scales in forested wetlands of the southeastern United States. We selected three replicates each of high-fertility floodplain swamps, low-fertility depressional swamps, and intermediate-fertility river swamp sloughs and measured soil nutrient availability (NO3-N, NH4-N, and PO4-P) and fine-root biomass. At one replicate of each wetland type, a dense network of sampling points was used to measure variability (variance and coefficient of variation) of soil nutrients and fine-root biomass. At the broad scale, fine-root biomass was lower in floodplain swamps than in either river swamp sloughs or depressional swamps. Also, multiple linear regression and Spearman's rank correlations indicated a negative relationship between soil nutrient availability and fine-root biomass. Fine-scale correlates between soil nutrient availability and fine-root biomass were generally weak. Fine-scale variability of NO3-N and NH4-N was greatest in the floodplain swamps, but nutrients were not spatially patchy at any of the sampled sites. We conclude that soil nutrient availability may control fine-root biomass at the broad scale, but it is unclear if the same is true at fine spatial scales.


1998 ◽  
Vol 78 (1) ◽  
pp. 163-169 ◽  
Author(s):  
J. S. Bhatti ◽  
N. W. Foster ◽  
P. W. Hazlett

Vertical distribution of fine root biomass and nutrient content was examined within a black spruce (Picea mariana) stand growing on a boreal peat soil in northeastern Ontario. The influence of site physical and chemical properties on fine root biomass production was assessed. More then 80% of the fine roots were present in moss plus the top 10 cm of peat where nutrients and aeration are most favourable. The fine root biomass (W/V) was significantly higher with alder (5.9 kg m−3) (Alnus rugosa) as understory vegetation compared to non-alder locations (2.9 kg m−3). Total nutrient content in fine roots was 54, 3.2, 5.4, 63 and 5.7 kg ha−1 on the alder site and 20, 1.4, 2.3, 28 and 4.2 kg ha−1 of N, P, K, Ca, and Mg on the non-alder site, respectively. The mass (W/V) of nutrients in fine roots was strongly dependent upon the availability of nutrients in the peat. Fine root content had a strong positive relationship with peat available P and exchangeable K contents suggesting that P and K may be limiting nutrients for black spruce in this peat soil. Key words: Nitrogen, phosphorus, potassium, boreal peatlands, aeration, water table


Trees ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 441-449 ◽  
Author(s):  
Kyotaro Noguchi ◽  
Yojiro Matsuura ◽  
Stephen D. Sparrow ◽  
Larry D. Hinzman

2018 ◽  
Vol 12 (3) ◽  
pp. 531-541
Author(s):  
F Leland Russell ◽  
Gregory R Houseman

Abstract Aims Identifying factors that drive variation in herbivore effects on plant populations can provide insight for explaining plant distributions and for limiting weeds. Abiotic resource availability to plants is a key explanation for variation in herbivore effects on individual plants, but the role of resources in determining herbivore effects on plant populations is largely unexplored. We tested the hypothesis that soil nutrient availability drives variation in insect and mammal herbivore effects on tall thistle (Cirsium altissimum) population growth. Methods In a Kansas USA restored tallgrass grassland that experienced prescribed fires, we manipulated soil nutrients, through fertilizer addition, and presence of insect and mammal herbivores, using combinations of insecticide and fencing, in experimental plots. Over 7 years, we quantified herbivore damage to reproductive tall thistles, tall thistle seed production and population growth rates. Important Findings Seed production was reduced by insect herbivores and increased by fertilizer addition, but treatment effects were independent. Herbivore effects on tall thistle population growth depended upon soil nutrients in only one of seven annual transitions. Herbivores reduced thistle population growth in two of three annual transitions that included prescribed fire, whereas they reduced population growth in only one of four transitions without fire. Soil nutrient availability does not provide a general explanation for variation in herbivore effects on tall thistle population growth rates. Disturbance regime may be a more important aspect of ecological context for influencing herbivore effects on tall thistle populations in mesic grasslands.


2013 ◽  
Vol 36 (7) ◽  
pp. 645-654 ◽  
Author(s):  
Yun-Ke LIU ◽  
Chuan FAN ◽  
Xian-Wei LI ◽  
Yin-Hua LING ◽  
Yi-Gui ZHOU ◽  
...  

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