scholarly journals Effects of Mechanical Site Preparation on Microsite Availability and Growth of Planted Black Spruce in Canadian Paludified Forests

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 670 ◽  
Author(s):  
Mohammed Henneb ◽  
Osvaldo Valeria ◽  
Nelson Thiffault ◽  
Nicole J. Fenton ◽  
Yves Bergeron
Keyword(s):  
Organic Matter ◽  
Treatment Effectiveness ◽  
Black Spruce ◽  
Wood Fiber ◽  
Site Preparation ◽  
Planting Density ◽  
Organic Layer ◽  
Mechanical Site Preparation ◽  
Decomposition Of Organic Matter ◽  
Successful Establishment

Low productivity caused by paludification in some parts of the closed black spruce (Picea mariana (Mill.) B.S.P) dominated boreal forest threatens the provision of ecosystem services, including wood fiber production. The accumulation, over time, of organic matter in paludified soils leads to an anaerobic environment that reduces microbial activity, decelerates decomposition of organic matter, and generates nutrient-poor microsites for regeneration. Consequently, it results in significant impacts on site productivity. Considering its ability to disturb the soil, mechanical site preparation (MSP) is viewed as a potential treatment that can help restore productivity of paludified sites following harvesting. We conducted a field experiment to verify if (1) the availability of microsites conducive to reforestation varies with MSP, microtopography (slope and aspect) and initial OLT conditions; (2) the growth of planted seedlings depends on the intensity of mechanical disturbance of the organic layer, type of microsite, planting density, presence of Ericaceae, and the planting position and depth; (3) there are direct and indirect causal relationships between microsites availability after MSP, OLT, microtopography, planting quality and seedlings growth; and (4) if mechanical site preparation and microsite type exposed affect the Ericaceae cover after planting. Our results confirmed that MSP is effective in establishing conditions that permit a productive regeneration cohort on these paludified sites. To ensure successful establishment of plantations on these sites, it is necessary, however, to distinguish between those that are slightly or moderately paludified from those that are highly paludified, as treatment effectiveness of different MSP types depends on organic layer thickness. Our results also show that preference should be given to some microsite types as clay and mixed-substrate microsites for planting to ensure sufficient availability of water and nutrients for seedlings.

scholarly journals Mechanical site preparation: Key to microsite creation success on Clay Belt paludified sites

2015 ◽  
Vol 91 (02) ◽  
pp. 187-196 ◽  
Author(s):  
Mohammed Henneb ◽  
Osvaldo Valeria ◽  
Nicole J. Fenton ◽  
Nelson Thiffault ◽  
Yves Bergeron
Keyword(s):  
Organic Matter ◽  
High Water ◽  
Site Preparation ◽  
Tree Regeneration ◽  
High Water Content ◽  
Organic Layer ◽  
Forest Sector ◽  
Mechanical Site Preparation ◽  
Rooting Zone ◽  
Before And After

Paludification is the accumulation of partially decomposed organic matter over saturated mineral soils. It reduces tree regeneration and growth, mainly because of low temperatures and high water content in the rooting zone, reduced organic matter decomposition, and hence, low nutrient availability. On the Clay Belt of western Québec and eastern Ontario, forests tend to paludify naturally but this process might be promoted by logging methods. Our objective was to identify which of two commonly used mechanical site preparation (MSP) techniques is best adapted to reduce organic layer thickness (OLT) and generate favourable planting microsites post-harvest in paludified sites. Nine experimental blocks (between 20 ha–61 ha each) were delimited within a 35 km2 forest sector with variable levels of paludification. The forest sector was harvested by careful logging to protect advance growth and soils and subsequently the nine experimental blocks were treated with either forest harrowing, disc trenching (T26) or left as untreated controls (harvesting only) with three replicate blocks per treatment. We measured OLT before and after MSP and determined planting microsite quality within each block. Results revealed significant differences in OLT between MSP treatments and harvesting only. Overall, harrowing was the best technique, as it reduced OLT more than T26 scarification and generated the highest percent of good microsites, except where initial OLT was 44 cm–56 cm. Our results contribute to the successful use of MSP in paludified forests.

The effect of mechanical site preparation on ectomycorrhizae of planted white spruce seedlings in conifer-dominated boreal mixedwood forest

2008 ◽  
Vol 38 (7) ◽  
pp. 2072-2079 ◽  
Author(s):  
Lance W. Lazaruk ◽  
S. Ellen Macdonald ◽  
Gavin Kernaghan
Keyword(s):  
Picea Glauca ◽  
Untreated Control ◽  
White Spruce ◽  
Site Preparation ◽  
Organic Layer ◽  
Root Tips ◽  
Mechanical Site Preparation ◽  
Clear Cut ◽  
Mixed Treatment ◽  
Boreal Mixedwood Forest

We characterized the ectomycorrhizae (ECM) of planted white spruce ( Picea glauca (Moench) Voss) seedlings as affected by mechanical site preparation (MSP) of clear-cut conifer-dominated boreal mixedwood forest. Relative abundance, richness, and composition of the ECM community were compared among untreated control, mixed, mounded, and scalped site preparation treatments. On >11 000 root tips, we observed 16 ECM morphotypes. Those common to the nursery in which the seedlings were raised were most abundant ( Thelephora americana , Wilcoxina -like (E-strain), Amphinema byssoides , Phialocephala -like (MRA)). Seedlings in the untreated controls had lower abundances of these, but higher abundances of other ECM, which were not present in the nursery of origin but were indigenous to these forest stands. In terms of ECM composition, the “mixed” treatment was most similar to the untreated control, while the “scalped” and “mound” treatments showed significantly different ECM communities than the controls. Our results suggest that MSP may facilitate continued dominance by ECM that establish on seedlings in the nursery while slowing the natural succession towards the natural forest ECM. MSP treatments that leave some surface organic matter relatively intact may impact ECM less than those that remove or bury the organic layer.

Paludification dynamics in the boreal forest of the James Bay Lowlands: effect of time since fire and topography

2009 ◽  
Vol 39 (3) ◽  
pp. 546-552 ◽  
Author(s):  
Martin Simard ◽  
Pierre Y. Bernier ◽  
Yves Bergeron ◽  
David Paré ◽  
Lakhdar Guérine
Keyword(s):  
Organic Matter ◽  
Boreal Forest ◽  
Black Spruce ◽  
Forest Productivity ◽  
Organic Layer ◽  
Layer Depth ◽  
Potential Productivity ◽  
Organic Matter Accumulation ◽  
Soil Organic Layer ◽  
Time Since Fire

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.

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

scholarly journals Intensive Mechanical Site Preparation to Establish Short Rotation Hybrid Poplar Plantations—A Case-Study in Québec, Canada

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 785 ◽  
Author(s):  
Nelson Thiffault ◽  
Raed Elferjani ◽  
François Hébert ◽  
David Paré ◽  
Pierre Gagné
Keyword(s):  
Wood Fiber ◽  
Hybrid Poplar ◽  
Site Preparation ◽  
Nutrient Concentrations ◽  
Management Approach ◽  
Mechanical Site Preparation ◽  
Positive Effects ◽  
Growing Seasons ◽  
Short Rotation ◽  
Poplar Plantations

Because they generate more wood per area and time, short rotation plantations are likely to play an increasing role in meeting the global increase in the demand for wood fiber. To be successful, high-yield plantations require costly intensive silviculture regimes to ensure the survival and maximize yields. While hybrid poplar (Populus spp.) is frequently used in intensive, short rotation forestry, it is particularly sensitive to competition and resource levels. Mechanical site preparation is thus of great importance to create microsites that provide sufficient light levels and adequate soil water and nutrient availability. We conducted an experiment in Québec (Canada) to compare two intensive site preparation treatments commonly used to establish hybrid poplar. We compared the effects of double-blade site preparation (V-blade), mounding and a control on hybrid poplar growth and nutritional status four growing seasons after planting on recently harvested forested sites. We also evaluated the effects of site preparation and planted poplar on inorganic soil N. Our results confirmed general positive effects of site preparation on the early growth of hybrid poplar clones. After four growing seasons, survival was higher in the mounding treatment (99%) than in the V-blade (91%) and the control (48%). Saplings planted in the V-blade and in the mounding treatments had mean diameters that were respectively 91% and 155% larger than saplings planted in the control plots. Saplings were 68% taller in the mounding treatment than the control plots, but differences between the V-blade and controls were not significant. We did not detect significant effects of site preparation or the presence of planted hybrid poplar on soil inorganic N. Sapling foliar nutrient concentrations were not influenced by the site preparation treatments. Based on these results, mounding appears to be a good management approach to establish hybrid poplar plantations under the ecological conditions we have studied, as it is less likely to cause erosion because of the localized nature of the treatment. However, these environmental benefits need to be balanced against economic and social considerations.

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