Trade-offs between competition and facilitation: a case study of vegetation management in the interior cedar–hemlock forests of southern British Columbia

2006 ◽  
Vol 36 (10) ◽  
pp. 2486-2496 ◽  
Author(s):  
Suzanne Simard ◽  
Alan Vyse
Keyword(s):  
British Columbia ◽  
Management Practices ◽  
Forest Policy ◽  
Structural Diversity ◽  
Vegetation Management ◽  
Facilitative Effect ◽  
Trade Offs ◽  
Substantial Risk ◽  
Population Sizes ◽  
Paper Birch

Vegetation-management practices are applied in temperate-zone forests on the assumption that changing the competitive environment between conifers and unwanted vegetation will improve conifer productivity. We review this assumption using research examining interactions between paper birch (Betula papyrifera Marsh.) and conifers in the highly productive Interior Cedar Hemlock zone of British Columbia. We have found that both competition and facilitation are important in young plantations, where paper birch competes for light, reducing growth of shade-intolerant conifers, but having a facilitative effect on shade-tolerant conifers. This facilitative effect may result from greater ectomycorrhizal diversity, population sizes of Armillaria ostoyae (Romagn.) Herink antagonistic bacteria, and associative nitrogen fixation in plantations where interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) is mixed with paper birch. Where paper birch is manually cut or girdled, conifers grow faster in diameter, but more die as a result of A. ostoyae root disease, and these responses increase with increasing weeding intensity. The weeding treatments do not affect plant community species richness but reduce paper birch dominants and increase understory structural diversity. British Columbia forest policy has been slow to respond to these findings, and we suggest that as a result, the forested landscape incurs substantial risk. We propose additional pathways for managing Interior Cedar Hemlock mixtures to ensure that the natural mix of forest types in the landscape is maintained.

scholarly journals Broadleaves in the Interior of British Columbia: Their extent, use, management and prospects for investment in genetic conservation and improvement

2009 ◽  
Vol 85 (4) ◽  
pp. 528-537 ◽  
Author(s):  
Alan Vyse ◽  
Suzanne W Simard
Keyword(s):  
British Columbia ◽  
Management Practices ◽  
Genetic Research ◽  
Genetic Conservation ◽  
Trembling Aspen ◽  
Conifer Species ◽  
Black Cottonwood ◽  
Ecological Zones ◽  
Balsam Poplar ◽  
Paper Birch

The principal broadleaves in Interior British Columbia (trembling aspen, paper birch, balsam poplar and black cottonwood) are well distributed across all of the major Interior ecological zones but their occurrence is greatest in the northern areas. Their utilization has gradually increased over the last 20 years, especially in the north. Economic values are low compared to conifer species but shortage of conifer timber as a result of the mountain pine beetle epidemic could drive demand for broadleaves higher. The ecological and non-timber values of broadleaves are very high; however, management practices still favour conifer species. Retention of broadleaves in harvesting and reforestation programs is widely implemented, but at a very low intensity and with little attention to broadleaf silvics. Future management of broadleaves is likely to be based largely on natural regeneration of broadleaves and not nursery production. Investments in genetic research should focus on genecology and gene conservation, as well as facilitated migration studies and investigation of pest resistance. Key words: broadleaves, trembling aspen, paper birch, black cottonwood, balsam poplar, management, genetic conservation, genetic improvement

scholarly journals Effect of Pheromone Blend Components, Sex Ratio, and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Abeysinghe Mudiyanselage Prabodha Sammani ◽  
Dissanayaka Mudiyanselage Saman Kumara Dissanayaka ◽  
Leanage Kanaka Wolly Wijayaratne ◽  
William Robert Morrison
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Management Practices ◽  
Mating Disruption ◽  
Current Knowledge ◽  
Mating Status ◽  
Cadra Cautella ◽  
Synthetic Chemicals ◽  
Population Sizes ◽  
Lepidoptera Pyralidae

Abstract The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.

scholarly journals Trade-Offs among Release Treatments in Jack Pine Plantations: Twenty-Five Year Responses

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 370
Author(s):  
Holly D. Deighton ◽  
Frederick Wayne Bell ◽  
Nelson Thiffault ◽  
Eric B. Searle ◽  
Mathew Leitch ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Boreal Forests ◽  
Pinus Banksiana ◽  
Vegetation Management ◽  
Jack Pine ◽  
Forest Diversity ◽  
Trade Offs ◽  
Jack Pine Forests ◽  
Stand Yield ◽  
Forest Managers

We assessed 27 indicators of plant diversity, stand yield and individual crop tree responses 25 years post-treatment to determine long-term trade-offs among conifer release treatments in boreal and sub-boreal forests. This research addresses the lack of longer-term data needed by forest managers to implement more integrated vegetation management programs, supporting more informed decisions about release treatment choice. Four treatments (untreated control, motor-manual brushsaw, single aerial spray, and complete competition removal) were established at two jack pine (Pinus banksiana Lamb.) sites in Ontario, Canada. Our results suggest that plant diversity and productivity in boreal jack pine forests are significantly influenced by vegetation management treatments. Overall, release treatments did not cause a loss of diversity but benefitted stand-scale yield and individual crop tree growth, with maximum benefits occurring in more intensive release treatments. However, none of the treatments maximized all 27 indicators studied; thus, forest managers are faced with trade-offs when choosing treatments. Research on longer term effects, ideally through at least one rotation, is essential to fully understand outcomes of different vegetation management on forest diversity, stand yield, and individual crop tree responses.

scholarly journals Identifying Sustainable Nitrogen Management Practices for Tea Plantations

Nitrogen ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 43-57
Author(s):  
Rhys Rebello ◽  
Paul J. Burgess ◽  
Nicholas T. Girkin
Keyword(s):  
Management Practices ◽  
Synergistic Effects ◽  
Soil Health ◽  
N Leaching ◽  
N2o Emissions ◽  
Nitrification Inhibitors ◽  
Financial Barriers ◽  
Trade Offs ◽  
High Yields ◽  
N Management

Tea (Camellia sinensis L.) is the most widely consumed beverage in the world. It is mostly grown in the tropics with a heavy dependence on mineral nitrogen (N) fertilisers to maintain high yields while minimising the areas under cultivation. However, N is often applied in excess of crop requirements, resulting in substantial adverse environmental impacts. We conducted a systematic literature review, synthesising the findings from 48 studies to assess the impacts of excessive N application on soil health, and identify sustainable, alternative forms of N management. High N applications lead to soil acidification, N leaching to surface and groundwater, and the emission of greenhouse gases including nitrous oxide (N2O). We identified a range of alternative N management practices, the use of organic fertilisers, a mixture of organic and inorganic fertilisers, controlled release fertilisers, nitrification inhibitors and soil amendments including biochar. While many practices result in reduced N loading or mitigate some adverse impacts, major trade-offs include lower yields, and in some instances increased N2O emissions. Practices are also frequently trialled in isolation, meaning there may be a missed opportunity from assessing synergistic effects. Moreover, adoption rates of alternatives are low due to a lack of knowledge amongst farmers, and/or financial barriers. The use of site-specific management practices which incorporate local factors (for example climate, tea variety, irrigation requirements, site slope, and fertiliser type) are therefore recommended to improve sustainable N management practices in the long term.

Current issues and controversies in assessing the environmental impacts of livestock production.

2021 ◽  
Vol 16 (044) ◽  
Author(s):  
Judith L. Capper
Keyword(s):  
Environmental Impacts ◽  
Resource Use ◽  
Management Practices ◽  
Ghg Emissions ◽  
Livestock Production ◽  
Environmental Indicators ◽  
Environment Impact ◽  
Trade Offs ◽  
Specific Practice ◽  
Over Time

Abstract The environment impact of livestock production is one of the most significant issues within agriculture. Global concerns over climate change, resource use, pollution and other environment indicators means that producers must implement practices and systems to reduce environmental impacts, yet this may only be achieved through assessments that allow impacts to be quantified, benchmarked and improved over time. Although environmental indicators are widely accepted, the metrics by which these are assessed continue to evolve over time as assessment objectives gain clarity and focus, and as the science relating to controversial topics (e.g. global warming or carbon sequestration) becomes more refined. however, significant negative trade-offs may occur between different metrics and denominators such that a specific practice or system may appear to have greater or lesser impacts, depending on assessment methodology. A number of tools and models have been developed to empower producers in quantifying environmental impacts, which will be increasingly important is satisfying future consumers' hunger for information as well as food. These tools must be supplied in tandem with information as to the potential consequences of changing management practices and systems. At present however, tools available are based on differing methodologies, are often opaque in their background calculations and do not necessarily account for all the factors that influence environmental impacts from livestock. There is a clear need for robust tools that can be used as standards for assessing environmental impacts from the global livestock industry and that go beyond GHG emissions to produce a more rounded holistic assessment.

scholarly journals Unimodal Relationships of Understory Alpha and Beta Diversity along Chronosequence in Coppiced and Unmanaged Beech Forests

Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 101 ◽  
Author(s):  
Sándor Bartha ◽  
Roberto Canullo ◽  
Stefano Chelli ◽  
Giandiego Campetella
Keyword(s):  
Beta Diversity ◽  
Management Practices ◽  
Multiple Scales ◽  
Forest Succession ◽  
Spatial Scales ◽  
Alpha Diversity ◽  
Structural Diversity ◽  
Diversity Indices ◽  
Alpha And Beta Diversity ◽  
Coppice Management

Patterns of diversity across spatial scales in forest successions are being overlooked, despite their importance for developing sustainable management practices. Here, we tested the recently proposed U-shaped biodiversity model of forest succession. A chronosequence of 11 stands spanning from 5 to 400 years since the last disturbance was used. Understory species presence was recorded along 200 m long transects of 20 × 20 cm quadrates. Alpha diversity (species richness, Shannon and Simpson diversity indices) and three types of beta diversity indices were assessed at multiple scales. Beta diversity was expressed by a) spatial compositional variability (number and diversity of species combinations), b) pairwise spatial turnover (between plots Sorensen, Jaccard, and Bray–Curtis dissimilarity), and c) spatial variability coefficients (CV% of alpha diversity measures). Our results supported the U-shaped model for both alpha and beta diversity. The strongest differences appeared between active and abandoned coppices. The maximum beta diversity emerged at characteristic scales of 2 m in young coppices and 10 m in later successional stages. We conclude that traditional coppice management maintains high structural diversity and heterogeneity in the understory. The similarly high beta diversities in active coppices and old-growth forests suggest the presence of microhabitats for specialist species of high conservation value.

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