scholarly journals The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

2002 ◽  
Vol 6 (5) ◽  
pp. 833-848 ◽  
Author(s):  
S. A. Watmough ◽  
P. J. Dillon
Keyword(s):  
Acid Deposition ◽  
Forest Soils ◽  
Critical Loads ◽  
Base Cation ◽  
Forest Harvesting ◽  
Case Scenario ◽  
Forested Catchments ◽  
South Central ◽  
The Impact ◽  
Sswc Model

Abstract. The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A) for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario). In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC) model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A) is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1) from forest soils can be maintained without any decrease in forest productivity. Calcium concentrations in the three lakes have decreased by between ∼10 and 25% over the past 20 years and calculations assume that calcium concentrations in lakes can fall to around 30% of their current values without any harmful effects on biota. Both these assumptions require urgent investigation. Keywords: acid deposition, calcium, critical loads, forests, harvesting, lakes

Potential impact of forest harvesting on lake chemistry in south-central Ontario at current levels of acid deposition

2003 ◽  
Vol 60 (9) ◽  
pp. 1095-1103 ◽  
Author(s):  
S A Watmough ◽  
J Aherne ◽  
P J Dillon
Keyword(s):  
Critical Load ◽  
Base Cation ◽  
Forest Harvesting ◽  
Lake Chemistry ◽  
South Central ◽  
Sulphate Deposition ◽  
Potential Impact ◽  
Whole Tree Harvesting ◽  
Whole Tree ◽  
Tree Harvesting

The potential impact of harvesting on lake chemistry was assessed for ~1300 lakes in south-central Ontario using a critical loads approach based on the steady-state water chemistry (SSWC) model. The critical load of acidity is currently only exceeded by bulk sulphate deposition in 9% of the lakes if harvesting does not occur. However, the percentage increases to 23%, 56%, and 72% under potential harvesting scenarios that assume wood-only (stem without bark), stem-only, or whole-tree harvesting, respectively. This increase in exceedance of critical load is due to the much lower base cation concentrations in lakes resulting from base cation removals during harvest. For example, only 0.3% of lakes will have Ca2+ concentrations <50 μequiv.·L–1 if harvesting does not occur, whereas 52% of lakes will have Ca2+ concentrations <50 μequiv.·L–1 if whole-tree harvesting occurs. Harvesting clearly has an enormous potential impact on lake chemistry, which will become more apparent as exchangeable base cation pools in soil decline and acid inputs can no longer be buffered.

Critical loads of acidity for surface waters in south-central Ontario, Canada: regional application of the Steady-State Water Chemistry (SSWC) model

2002 ◽  
Vol 59 (8) ◽  
pp. 1287-1295 ◽  
Author(s):  
A Henriksen ◽  
P J Dillon ◽  
J Aherne
Keyword(s):  
Steady State ◽  
Water Chemistry ◽  
Critical Load ◽  
Critical Loads ◽  
Lake Chemistry ◽  
Sulphur Deposition ◽  
South Central ◽  
State Water ◽  
Critical Loads Of Acidity ◽  
Sswc Model

Critical loads of acidity and the amount by which these critical loads are exceeded by atmospheric deposition (termed "exceedances") were estimated for 1469 lakes from five regions in south-central Ontario, Canada, using single lake chemistry measurements and sulphur deposition data for the period 1976–1999. Based on the Steady-State Water Chemistry (SSWC) model, four of the five regions had low critical loads, which is consistent with the underlying geology (silicate bedrock) and the thin glacial soils in these regions. Sulphur deposition in the study area showed a clear downward trend over the time period, with a decrease of approximately 50% to current levels of approximately 44 meq·m–2·year–1. As a result of the declining deposition, the portion of lakes with critical load exceedances has dropped substantially, from 74–82% in the four sensitive regions in 1976 to 11–26% in 1999. The pentile critical load is typically used as a regional target to account for uncertainties, but also to ensure that a sufficient percentage of lakes are protected (95%). This suggests that further reductions in emissions are required to reduce depositions to approximately 34 meq·m–2·year–1 (11 kg S·ha–1·year–1) to prevent critical load exceedance.

Do critical load models adequately protect forests? A case study in south-central Ontario

2003 ◽  
Vol 33 (8) ◽  
pp. 1544-1556 ◽  
Author(s):  
Shaun A Watmough ◽  
Peter J Dillon
Keyword(s):  
Critical Load ◽  
Soil Solution ◽  
Critical Loads ◽  
Base Cation ◽  
Base Saturation ◽  
Bulk Deposition ◽  
Molar Ratio ◽  
Critical Threshold ◽  
Soil Base ◽  
South Central

We calculated critical loads of acidity (S and S + N separately) for seven forested catchments in south-central Ontario, using a critical threshold designed to maintain the Ca/Al molar ratio above 1.0 or the base cation (BC; Ca + Mg + K) to Al molar ratio above 10 in soil solution. Critical loads are ~10–50% lower using the BC/Al ratio compared with the Ca/Al ratio, and harvesting greatly increases forest sensitivity to acid deposition. If forests are harvested, critical load calculations indicate that further reductions in S and N bulk deposition are required to maintain the BC/Al ratio in soil solution above 10, but reductions in S deposition are only mandatory for three of the seven catchments. However, S export exceeds inputs in bulk deposition by 40–100%. Our study indicates that setting the critical threshold of BC/Al at 10 may not maintain soil base saturation above 20%, and that N export is unpredictable at current deposition levels. We calculate that SO4 leaching (and therefore deposition) must be reduced by between 10 and 74% to maintain healthy, productive forests in catchments that are harvested. More reliable estimates of base cation removals during harvest, minimum Ca leaching losses from soils that can occur without affecting forest productivity, and critical limits for soil base saturation are needed to improve these critical load estimates.

scholarly journals Continuous cover forestry: possible implications for surface water acidification in the UK uplands

2004 ◽  
Vol 8 (3) ◽  
pp. 306-313 ◽  
Author(s):  
B. Reynolds
Keyword(s):  
Surface Water ◽  
Base Cation ◽  
Forest Harvesting ◽  
Environmental Data ◽  
Water Acidification ◽  
Surface Water Acidification ◽  
Continuous Cover Forestry ◽  
Forestry Commission ◽  
The Uk ◽  
The Impact

Abstract. The effects of widespread conifer afforestation on the acidity of lakes and streams in the acid sensitive uplands of the UK has been researched extensively and has contributed to the development and implementation of national forest management guidelines (e.g. Forest and Water Guidelines; Forestry Commission, 1993). However, a recent policy document (Woodlands for Wales; National Assembly for Wales, 2000) has proposed a major shift in the management of 50% of the Forestry Commission estate in Wales from the current system of patch clearfelling to Continuous Cover Forestry (CCF). This scale of change is without precedent in the UK; no studies in the UK forest environment have examined the likely environmental impacts of CCF. However, the wealth of environmental data from studies of UK forests managed by patch clearfelling enables an assessment of the impact of a change to CCF on three issues of particular relevance to surface water acidification in the uplands; forest harvesting, soil base cation depletion and atmospheric pollutant deposition. Whilst there is uncertainty as to how even-aged stands will be transformed to CCF in the UK, guiding principles for CCF on acidic and acid sensitive sites should focus on those aspects of management which minimise nitrate leaching, encourage base cation retention within the soil-plant system and enhance base cation inputs from external (atmospheric) and internal sources (weathering). CCF may provide opportunities to achieve this by reducing the scale of clearfelling, increasing species diversity, changing the structure of plantation forests and maintaining uninterrupted woodland cover. Keywords: acidification, forestry, continuous cover forestry, clearfelling

Modelling the impact of acid deposition and nutrient cycling on forest soils

1995 ◽  
Vol 79 (1-3) ◽  
pp. 231-254 ◽  
Author(s):  
W. de Vries ◽  
J. Kros ◽  
C. van der Salm
Keyword(s):  
Nutrient Cycling ◽  
Acid Deposition ◽  
Forest Soils ◽  
The Impact

scholarly journals Methods of Protection Forest Soils during Logging Operations (Review)

2021 ◽  
pp. 92-116
Author(s):  
Aleksey S. Ilintsev ◽  
◽  
Elena N. Nakvasina ◽  
Lars Högbom ◽  
◽  
...  
Keyword(s):  
Forest Soils ◽  
Forest Harvesting ◽  
Tree Regeneration ◽  
Soil Conditions ◽  
Forest Operations ◽  
Positioning Systems ◽  
Protection Forest ◽  
Wood Harvesting ◽  
Technical Solutions ◽  
The Impact

Public opinion has become increasingly critical of current logging methods and technologies, and there is a demand for standards to guide the operations of environmentally impactful industries. For many years, numerous researchers have studied the impact of logging on forest soils, revealing that there is a high risk of damaging forest soil during forest operations and terrain transport. Here we analyse and review a total of 105 publications in this area. This large body of work demonstrates the scientific interest that this field has attracted. Despite this, important areas of uncertainty concerning the impact of forest harvesting still remain. In particular, changes in soil conditions can affect soil properties in ways that are not well understood, with possible impacts on the physical, chemical, and biological properties of soils as well as the structure of the soil cover. While it is difficult to fully eliminate the negative impact of forest operations on forest soils, their adverse environmental consequences should be minimised because soil plays a vital role in tree regeneration and helps determine the productivity of future forest stands. Some of the most frequently cited measures and effective technological solutions to minimize damage to forest soils involve taking terrain and different technical solutions into account when organising logging operations. Potentially helpful technical solutions include selecting machines and mechanisms suitable for the site conditions, using larger and/or low-pressure tyres, using tyre pressure control, using anti-skid tracks, using track belts, meliorating wet areas, and using logging machinery incorporating global positioning systems and geographic information systems. Planning measures that can help minimize soil damage include choosing a suitable wood harvesting system and technology, accounting for seasonal factors when planning logging operations, planning networks of roads and trails in advance, leaving wood residues or mats on soil surface, training forest specialists, and reducing the number of machine passes over skid trails and strip roads. Despite active interest in applying sparing methods of wood harvesting, uptake of measures designed to reduce negative impacts on forest soils after logging has been limited. This may be due to a lack of scientific and technical information and the high cost of implementing best management practices. Moreover, economic factors and production plans may require wood harvesting throughout the year, irrespective of conditions. For citation: Ilintsev A.S., Nakvasina E.N., Högbom L. Methods of Protection Forest Soils during Logging Operations (Review). Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 92–116. DOI: 10.37482/0536-1036-2021-5-92-116

scholarly journals The impact of spousal violence on the children: A pastoral care approach

2014 ◽  
Vol 70 (2) ◽  
Author(s):  
Luvuyo G. Sifo ◽  
Maake J. Masango
Keyword(s):  
Pastoral Care ◽  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Spousal Violence ◽  
Post Traumatic Stress ◽  
Case Scenario ◽  
Care Approach ◽  
Post Traumatic ◽  
The Impact

This article investigates the impact of spousal violence on children. Spousal violence in the home affects children negatively and its impact goes beyond their childhood years into adulthood. Some children become dysfunctional in life as a result of their exposure to violence between their parents. These children may exhibit symptoms associated with post-traumatic stress disorder (PTSD) later on in life. A case study of a family exposed to violence was undertaken. Findings from this case scenario were measured against existing literature. A pastoral care method of responding to the victims is proposed in order for them to be healed.

scholarly journals Modeling dissolved organic carbon in temperate forest soils: TRIPLEX-DOC model development and validation

2014 ◽  
Vol 7 (3) ◽  
pp. 867-881 ◽  
Author(s):  
H. Wu ◽  
C. Peng ◽  
T. R. Moore ◽  
D. Hua ◽  
C. Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Forest Soils ◽  
Model Development ◽  
Terrestrial Ecosystems ◽  
Forest Harvesting ◽  
Biogeochemical Model ◽  
White Pine ◽  
C Cycling ◽  
Development And Validation

Abstract. Even though dissolved organic carbon (DOC) is the most active carbon (C) cycling in soil organic carbon (SOC) pools, it receives little attention from the global C budget. DOC fluxes are critical to aquatic ecosystem inputs and contribute to the C balance of terrestrial ecosystems, but few ecosystem models have attempted to integrate DOC dynamics into terrestrial C cycling. This study introduces a new process-based model, TRIPLEX-DOC, that is capable of estimating DOC dynamics in forest soils by incorporating both ecological drivers and biogeochemical processes. TRIPLEX-DOC was developed from Forest-DNDC, a biogeochemical model simulating C and nitrogen (N) dynamics, coupled with a new DOC process module that predicts metabolic transformations, sorption/desorption, and DOC leaching in forest soils. The model was validated against field observations of DOC concentrations and fluxes at white pine forest stands located in southern Ontario, Canada. The model was able to simulate seasonal dynamics of DOC concentrations and the magnitudes observed within different soil layers, as well as DOC leaching in the age sequence of these forests. Additionally, TRIPLEX-DOC estimated the effect of forest harvesting on DOC leaching, with a significant increase following harvesting, illustrating that land use change is of critical importance in regulating DOC leaching in temperate forests as an important source of C input to aquatic ecosystems.

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