Small scale pH buffering in organic horizons of two boreal coniferous forest stands

1996 ◽  
Vol 179 (1) ◽  
pp. 99-107 ◽  
Author(s):  
U. Skyllberg
Keyword(s):  
Coniferous Forest ◽  
Small Scale ◽  
Forest Stands ◽  
Ph Buffering ◽  
Organic Horizons

Seed banks in five boreal forest stands originating between 1810 and 1963

1982 ◽  
Vol 60 (9) ◽  
pp. 1815-1821 ◽  
Author(s):  
Anders Granström
Keyword(s):  
Boreal Forest ◽  
Plant Species ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Soil Samples ◽  
Distribution Data ◽  
Forest Stands ◽  
Humus Layer ◽  
Seed Content ◽  
Organic Horizons

The viable seed content of soil samples from five coniferous forest stands in northern Sweden, aged 16–169 years, was determined by means of germination trials. The soil samples were separated into five fractions: three organic horizons and two mineral soil horizons. Seedlings of 15 phanerogam species emerged, representing densities of 239–763 seeds/m2 in the soils from the different stands. The depth distributions of the seeds varied with both plant species and forest stand. Most seeds were found at various depths in the humus layer, but in one stand an appreciable seed density of Luzula pilosa was present in the mineral soil. Most of the seedlings belonged to plant species present in the vegetation or with good means of dispersal. The depth distribution data, however, suggest that Luzula pilosa in particular may have a persistent seed bank. The role of persistent seeds in the vegetational composition of the boreal forest is discussed.

Spatial analysis of density dependent pattern in coniferous forest stands

Vegetatio ◽  
1985 ◽  
Vol 64 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Janet Franklin ◽  
Joel Michaelsen ◽  
Alan H. Strahler
Keyword(s):  
Spatial Analysis ◽  
Coniferous Forest ◽  
Forest Stands ◽  
Density Dependent

Small-scale processes with large-scale impacts: Investigating canopy structure controls on energy fluxes to the forest snowpack

2020 ◽  
Author(s):  
Giulia Mazzotti ◽  
Richard Essery ◽  
Johanna Malle ◽  
Clare Webster ◽  
Tobias Jonas
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Large Scale ◽  
Meteorological Data ◽  
Canopy Structure ◽  
Model Performance ◽  
Turbulent Fluxes ◽  
Temporal Variations ◽  
Small Scale ◽  
Forest Stands

<p>Forest canopies strongly affect snowpack energetics during wintertime. In discontinuous forest stands, spatio-temporal variations in radiative and turbulent fluxes create complex snow distribution and melt patterns, with further impacts on the hydrological regimes and on the land surface properties of seasonally snow-covered forested environments.</p><p>As increasingly detailed canopy structure datasets are becoming available, canopy-induced energy exchange processes can be explicitly represented in high-resolution snow models. We applied the modelling framework FSM2 to obtain spatially distributed simulations of the forest snowpack in subalpine and boreal forest stands at high spatial (2m) and temporal (10min) resolution. Modelled sub-canopy radiative and turbulent fluxes were compared to detailed meteorological data of incoming irradiances, air and snow surface temperatures. These were acquired with novel observational systems, including 1) a motorized cable car setup recording spatially and temporally resolved data along a transect and 2) a handheld setup designed to capture temporal snapshots of 2D spatial distributions across forest discontinuities.</p><p>The combination of high-resolution modelling and multi-dimensional datasets allowed us to assess model performance at the level of individual energy balance components, under various meteorological conditions and across canopy density gradients. We showed which canopy representation strategies within FSM2 best succeeded in reproducing snowpack energy transfer dynamics in discontinuous forests, and derived implications for implementing forest snow processes in coarser-resolution models.</p>

scholarly journals Storage and transformation of organic matter fractions in cryoturbated permafrost soils across the Siberian Arctic

2015 ◽  
Vol 12 (14) ◽  
pp. 4525-4542 ◽  
Author(s):  
N. Gentsch ◽  
R. Mikutta ◽  
R. J. E. Alves ◽  
J. Barta ◽  
P. Čapek ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Depth ◽  
Soil Conditions ◽  
Small Scale ◽  
Least Squares Regression ◽  
Siberian Arctic ◽  
Organic Horizons ◽  
Permafrost Soils ◽  
Co Precipitation ◽  
Transformation Of Organic Matter

Abstract. In permafrost soils, the temperature regime and the resulting cryogenic processes are important determinants of the storage of organic carbon (OC) and its small-scale spatial variability. For cryoturbated soils, there is a lack of research assessing pedon-scale heterogeneity in OC stocks and the transformation of functionally different organic matter (OM) fractions, such as particulate and mineral-associated OM. Therefore, pedons of 28 Turbels were sampled in 5 m wide soil trenches across the Siberian Arctic to calculate OC and total nitrogen (TN) stocks based on digital profile mapping. Density fractionation of soil samples was performed to distinguish between particulate OM (light fraction, LF, < 1.6 g cm−3), mineral associated OM (heavy fraction, HF, > 1.6 g cm−3), and a mobilizable dissolved pool (mobilizable fraction, MoF). Across all investigated soil profiles, the total OC storage was 20.2 ± 8.0 kg m−2 (mean ± SD) to 100 cm soil depth. Fifty-four percent of this OC was located in the horizons of the active layer (annual summer thawing layer), showing evidence of cryoturbation, and another 35 % was present in the upper permafrost. The HF-OC dominated the overall OC stocks (55 %), followed by LF-OC (19 % in mineral and 13 % in organic horizons). During fractionation, approximately 13 % of the OC was released as MoF, which likely represents a readily bioavailable OM pool. Cryogenic activity in combination with cold and wet conditions was the principle mechanism through which large OC stocks were sequestered in the subsoil (16.4 ± 8.1 kg m−2; all mineral B, C, and permafrost horizons). Approximately 22 % of the subsoil OC stock can be attributed to LF material subducted by cryoturbation, whereas migration of soluble OM along freezing gradients appeared to be the principle source of the dominant HF (63 %) in the subsoil. Despite the unfavourable abiotic conditions, low C / N ratios and high δ13C values indicated substantial microbial OM transformation in the subsoil, but this was not reflected in altered LF and HF pool sizes. Partial least-squares regression analyses suggest that OC accumulates in the HF fraction due to co-precipitation with multivalent cations (Al, Fe) and association with poorly crystalline iron oxides and clay minerals. Our data show that, across all permafrost pedons, the mineral-associated OM represents the dominant OM fraction, suggesting that the HF-OC is the OM pool in permafrost soils on which changing soil conditions will have the largest impact.

Natural regeneration determines wintering bird presence in wind-damaged coniferous forest stands independent of postdisturbance logging

2015 ◽  
Vol 45 (9) ◽  
pp. 1232-1237 ◽  
Author(s):  
Sinja A.B. Werner ◽  
Jörg Müller ◽  
Marco Heurich ◽  
Simon Thorn
Keyword(s):  
Natural Regeneration ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Economic Value ◽  
Coniferous Forest ◽  
Bird Species ◽  
Forest Stands ◽  
Bird Abundance ◽  
Coniferous Trees ◽  
Mature Forest

Natural disturbances in European production forests are undesired from an economic perspective but are important drivers of biodiversity. The removal of damaged timber to restore economic value is accompanied by negative effects on various species groups, particularly breeding bird communities, and can hinder natural regeneration. However, little is known about the effect of postdisturbance logging on bird assemblages in winter when temperatures are low and food resources are unpredictable. We conducted fixed-radius point counts of wintering birds in forest stands logged or unlogged after windthrows and in mature forest stands to test our predictions that bird species densities and abundances (i) are lower in postdisturbance logged stands and (ii) depend on the amount of natural regeneration, (iii) which differs between logged and unlogged stands. Our generalized linear mixed model did not support the expected differences in bird abundance or species densities between postdisturbance logged and unlogged stands but indicated that mature forest stands harbor the highest bird abundances and species densities. The number of regenerated coniferous trees significantly positively affected wintering bird abundances in both postdisturbance logged and unlogged stands. Hence, the number of coniferous trees appears to be a main predictor of wintering bird presence.

METODY PROWADZENIA ODNOWIEŃ NATURALNYCH SOSNY ZWYCZAJNEJ (PINUS SYLVESTRIS L.) W NADLEŚNICTWIE SKWIERZYNA

2020 ◽  
Vol XIII ◽  
pp. 1-1
Author(s):  
Maciej Hałuszczak
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Natural Regeneration ◽  
Coniferous Forest ◽  
Basic Method ◽  
Forest Stands ◽  
Clear Cutting ◽  
Forest District

For many years, the Skwierzyna Forest District has been a leader among 35 units of the Regional Directorate of State Forests in Szczecin in terms of the area of the obtained natural regeneration of Scots pine. In the Skwierzyna Forest District in the period 2010-2018, 522.93 ha of natural regeneration was recognized, which constitutes 43% of the total regeneration, the habitat of fresh mixed coniferous forest and fresh coniferous forest as optimal for obtaining regeneration of the natural pine. In the spring date of plowing, the forest plow LPz-75 is applied, as the best for obtaining satisfactory self-seeding. The basic method of natural regeneration of pine in the Skwierzyna Forest Inspectorate is the use of a strip-like clear cutting (Ib) in the form of classic narrow sheds, with a cutting width of up to 60 m. It is noteworthy that in the woodcutting the under-eaves undergrowths, arising in forest stands close to the harvest, are left intact and later used within the naturally renovated area.

Structure, composition, and diversity of old-growth black spruce boreal forest of the Clay Belt region in Quebec and Ontario

2003 ◽  
Vol 11 (S1) ◽  
pp. S79-S98 ◽  
Author(s):  
Karen Harper ◽  
Catherine Boudreault ◽  
Louis DeGrandpré ◽  
Pierre Drapeau ◽  
Sylvie Gauthier ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Picea Mariana ◽  
Black Spruce ◽  
Small Scale ◽  
Structural Development ◽  
Spruce Forest ◽  
Forest Stands ◽  
Old Growth ◽  
Old Growth Forest ◽  
Old Growth Forests

Old-growth black spruce (Picea mariana) boreal forest in the Clay Belt region of Ontario and Quebec is an open forest with a low canopy, quite different from what many consider to be "old growth". Here, we provide an overview of the characteristics of old-growth black spruce forest for three different site types on organic, clay, and coarse deposits. Our objectives were (1) to identify the extent of older forests; (2) to describe the structure, composition, and diversity in different age classes; and (3) to identify key processes in old-growth black spruce forest. We sampled canopy composition, deadwood abundance, understorey composition, and nonvascular plant species in 91 forest stands along a chronosequence that extended from 20 to more than 250 years after fire. We used a peak in tree basal area, which occurred at 100 years on clay and coarse sites and at 200 years on organic sites, as a process-based means of defining the start of old-growth forest. Old-growth forests are extensive in the Clay Belt, covering 30–50% of the forested landscape. Black spruce was dominant on all organic sites, and in all older stands. Although there were fewer understorey species and none exclusive to old-growth, these forests were structurally diverse and had greater abundance of Sphagnum, epiphytic lichens, and ericaceous species. Paludification, a process characteristic of old-growth forest stands on clay deposits in this region, causes decreases in tree and deadwood abundance. Old-growth black spruce forests, therefore, lack the large trees and snags that are characteristic of other old-growth forests. Small-scale disturbances such as spruce budworm and windthrow are common, creating numerous gaps. Landscape and stand level management strategies could minimize structural changes caused by harvesting, but unmanaged forest in all stages of development must be preserved in order to conserve all the attributes of old-growth black spruce forest. Key words: boreal forest, old growth, paludification, Picea mariana, structural development, succession.

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