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Journal ArticleDOI: 10.1111/BRV.12703

Producing wood at least cost to biodiversity: integrating Triad and sharing-sparing approaches to inform forest landscape management.

04 Mar 2021-Biological Reviews of The Cambridge Philosophical Society (John Wiley & Sons, Ltd)-Vol. 96, Iss: 4, pp 1301-1317
Abstract: Forest loss and degradation are the greatest threats to biodiversity worldwide. Rising global wood demand threatens further damage to remaining native forests. Contrasting solutions across a continuum of options have been proposed, yet which of these offers most promise remains unresolved. Expansion of high-yielding tree plantations could free up forest land for conservation provided this is implemented in tandem with stronger policies for conserving native forests. Because plantations and other intensively managed forests often support far less biodiversity than native forests, a second approach argues for widespread adoption of extensive management, or ‘ecological forestry’, which better simulates natural forest structure and disturbance regimes – albeit with compromised wood yields and hence a need to harvest over a larger area. A third, hybrid suggestion involves ‘Triad’ zoning where the landscape is divided into three sorts of management (reserve, ecological/extensive management, and intensive plantation). Progress towards resolving which of these approaches holds the most promise has been hampered by the absence of a conceptual framework and of sufficient empirical data formally to identify the most appropriate landscape-scale proportions of reserves, extensive, and intensive management to minimize biodiversity impacts while meeting a given level of demand for wood. In this review, we argue that this central challenge for sustainable forestry is analogous to that facing food-production systems, and that the land sharing–sparing framework devised to establish which approach to farming could meet food demand at least cost to wild species can be readily adapted to assess contrasting forest management regimes. We develop this argument in four ways: (i) we set out the relevance of the sharing–sparing framework for forestry and explore the degree to which concepts from agriculture can translate to a forest management context; (ii) we make design recommendations for empirical research on sustainable forestry to enable application of the sharing–sparing framework; (iii) we present overarching hypotheses which such studies could test; and (iv) we discuss potential pitfalls and opportunities in conceptualizing landscape management through a sharing–sparing lens. The framework we propose will enable forest managers worldwide to assess trade-offs directly between conservation and wood production and to determine the mix of management approaches that best balances these (and other) competing objectives. The results will inform ecologically sustainable forest policy and management, reduce risks of local and global extinctions from forestry, and potentially improve a valuable sector's social license to operate.

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Topics: Forest management (62%), Wood production (51%)
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Journal ArticleDOI: 10.1016/J.FORECO.2020.118902
Scott H. Harris1, Matthew G. Betts1Institutions (1)
Abstract: Tree plantations are integral for meeting society’s demand for wood products and are increasing in total area worldwide. It is therefore critical to understand how plantations affect native biodiversity. Our aim was to examine the degree to which plantations affect biodiversity by 1) quantifying songbird abundance across a gradient in forest stand age (stand initiation through canopy closure), 2) estimating the duration of early seral habitat, and 3) testing if forest structural and compositional elements prolong habitat availability. This approach is equivalent to the modeling of wood ‘yield curves’ common in forest management but applied to a biodiversity indicator. We used a chronosequence sampling design to survey songbirds and vegetation in 283 plantations aged 0–30 years in the Oregon Coast Range, USA. Stands were randomly selected within age strata and surveys were temporally replicated in order to use N-mixture models to estimate abundance after accounting for imperfect detection. The Coast Range is considered one of the most productive forest regions in the world and plantations occur on over 50% of the forested land base. Our chronosequence encompasses the assumed age of canopy closure, which we anticipated to be the point at which early seral biodiversity declines. We detected 5074 birds of 71 species during the 2018 and 2019 breeding seasons. Canopy closure occurred approximately 12 years following clearcut harvest and replanting. We found that bird abundance changed dynamically during this short early seral stage. Twenty species peaked in abundance either very early in stand development or with the approximate timing of canopy closure, and then subsequently declined to low levels by the end of the 30-year chronosequence. The estimated abundance of 3 species increased following canopy closure. We also found, contrary to our hypothesis, that the amount of broadleaf cover increased habitat longevity for only one species – Wilson’s warbler. To our knowledge, our study provides the first quantitative estimates for how bird species abundances change throughout the entire early seral stage in tree plantations in western North America – information that can be used to assess tradeoffs between timber production and biodiversity. We found that the duration of early seral habitat in plantations is short and generally cannot be ameliorated by managing for higher levels of broadleaf cover. This finding has important implications for early seral species in the rapidly shifting mosaic of tree plantation landscapes.

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Topics: Seral community (62%), Chronosequence (57%), Forest management (54%) ... read more

5 Citations


Journal ArticleDOI: 10.1002/EAP.2441
Abstract: Understanding how land-management intensification shapes the relationships between biodiversity, yield, and economic benefit is critical for managing natural resources. Yet, manipulative experiments that test how herbicides affect these relationships are scarce, particularly in forest ecosystems where considerable time lags exist between harvest revenue and initial investments. We assessed these relationships by combining 7 yr of biodiversity surveys (>800 taxa) and forecasts of timber yield and economic return from a replicated, large-scale experiment that manipulated herbicide application intensity in operational timber plantations. Herbicides reduced species richness across trophic groups (-18%), but responses by higher-level trophic groups were more variable (0-38% reduction) than plant responses (-40%). Financial discounting, a conventional economic method to standardize past and future cash flows, strongly modified biodiversity-revenue relationships caused by management intensity. Despite a projected 28% timber yield gain with herbicides, biodiversity-revenue trade-offs were muted when opportunity costs were high (i.e., economic discount rates ≥7%). Although herbicides can drive biodiversity-yield trade-offs, under certain conditions, financial discounting provides opportunities to reconcile biodiversity conservation with revenue.

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Topics: Forest management (55%), Forest ecology (51%), Discounting (50%)

1 Citations


Open accessJournal ArticleDOI: 10.3390/F12060755
08 Jun 2021-Forests
Abstract: In the past two decades, forest management has undergone major paradigm shifts that are challenging the current forest modelling architecture. New silvicultural systems, guidelines for natural disturbance emulation, a desire to enhance structural complexity, major advances in successional theory, and climate change have all highlighted the limitations of current empirical models in covering this range of conditions. Mechanistic models, which focus on modelling underlying ecological processes rather than specific forest conditions, have the potential to meet these new paradigm shifts in a consistent framework, thereby streamlining the planning process. Here we use the NEBIE (a silvicultural intervention scale that classifies management intensities as natural, extensive, basic, intensive, and elite) plot network, from across Ontario, Canada, to examine the applicability of a mechanistic model, ZELIG-CFS (a version of the ZELIG tree growth model developed by the Canadian Forest Service), to simulate yields and species compositions. As silvicultural intensity increased, overall yield generally increased. Species compositions met the desired outcomes when specific silvicultural treatments were implemented and otherwise generally moved from more shade-intolerant to more shade-tolerant species through time. Our results indicated that a mechanistic model can simulate complex stands across a range of forest types and silvicultural systems while accounting for climate change. Finally, we highlight the need to improve the modelling of regeneration processes in ZELIG-CFS to better represent regeneration dynamics in plantations. While fine-tuning is needed, mechanistic models present an option to incorporate adaptive complexity into modelling forest management outcomes.

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Topics: Forest management (56%)

Open accessPosted ContentDOI: 10.21203/RS.3.RS-686817/V1
14 Jul 2021-
Abstract: In many regions of the world, forest management has reduced old forest and simplified forest structure and composition via reliance on monoculture tree plantations. We hypothesized that such forest degradation has resulted in long-term habitat loss for forest-associated bird species of eastern Canada (130,017 km2) which, in turn, has affected bird population declines. Back-cast species distribution models revealed that despite little change in overall forest cover, breeding habitat loss occurred for 66% of the 54 most common species from 1985-2020. This habitat loss was strongly associated with population declines for 72% of species, as quantified in an independent, long-term dataset. Since 1985, net forest bird abundance has declined in this region by an estimated 33-104 million birds due to habitat loss alone. The effects of forest degradation may therefore be a primary cause of biodiversity decline in managed forest landscapes.

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Topics: Population (58%)


References
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107 results found


Open accessJournal ArticleDOI: 10.1126/SCIENCE.1187512
28 May 2010-Science
Abstract: In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of the state of biodiversity (covering species' population trends, extinction risk, habitat extent and condition, and community composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity (including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts) showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate of biodiversity loss does not appear to be slowing.

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Topics: Global biodiversity (65%), Biodiversity (60%), Convention on Biological Diversity (59%) ... read more

3,496 Citations


Open accessJournal ArticleDOI: 10.1126/SCIADV.1400253
01 Jun 2015-Science Advances
Abstract: The oft-repeated claim that Earth’s biota is entering a sixth “mass extinction” depends on clearly demonstrating that current extinction rates are far above the “background” rates prevailing between the five previous mass extinctions. Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis. We assess, using extremely conservative assumptions, whether human activities are causing a mass extinction. First, we use a recent estimate of a background rate of 2 mammal extinctions per 10,000 species per 100 years (that is, 2 E/MSY), which is twice as high as widely used previous estimates. We then compare this rate with the current rate of mammal and vertebrate extinctions. The latter is conservatively low because listing a species as extinct requires meeting stringent criteria. Even under our assumptions, which would tend to minimize evidence of an incipient mass extinction, the average rate of vertebrate species loss over the last century is up to 100 times higher than the background rate. Under the 2 E/MSY background rate, the number of species that have gone extinct in the last century would have taken, depending on the vertebrate taxon, between 800 and 10,000 years to disappear. These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way. Averting a dramatic decay of biodiversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts, but that window of opportunity is rapidly closing.

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Topics: Background extinction rate (71%), Extinction (61%), Extinction threshold (58%) ... read more

1,885 Citations


Journal ArticleDOI: 10.1038/NATURE13959
David Tilman1, Michael Clark2Institutions (2)
27 Nov 2014-Nature
Abstract: Diets link environmental and human health. Rising incomes and urbanization are driving a global dietary transition in which traditional diets are replaced by diets higher in refined sugars, refined fats, oils and meats. By 2050 these dietary trends, if unchecked, would be a major contributor to an estimated 80 per cent increase in global agricultural greenhouse gas emissions from food production and to global land clearing. Moreover, these dietary shifts are greatly increasing the incidence of type II diabetes, coronary heart disease and other chronic non-communicable diseases that lower global life expectancies. Alternative diets that offer substantial health benefits could, if widely adopted, reduce global agricultural greenhouse gas emissions, reduce land clearing and resultant species extinctions, and help prevent such diet-related chronic non-communicable diseases. The implementation of dietary solutions to the tightly linked diet–environment– health trilemma is a global challenge, and opportunity, of great environmental and public health importance.

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1,677 Citations


Journal ArticleDOI: 10.1126/SCIENCE.1106049
28 Jan 2005-Science
Abstract: World food demand is expected to more than double by 2050. Decisions about how to meet this challenge will have profound effects on wild species and habitats. We show that farming is already the greatest extinction threat to birds (the best known taxon), and its adverse impacts look set to increase, especially in developing countries. Two competing solutions have been proposed: wildlife-friendly farming (which boosts densities of wild populations on farmland but may decrease agricultural yields) and land sparing (which minimizes demand for farmland by increasing yield). We present a model that identifies how to resolve the trade-off between these approaches. This shows that the best type of farming for species persistence depends on the demand for agricultural products and on how the population densities of different species on farmland change with agricultural yield. Empirical data on such density-yield functions are sparse, but evidence from a range of taxa in developing countries suggests that high-yield farming may allow more species to persist.

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Topics: Agriculture (53%)

1,614 Citations


Open accessJournal ArticleDOI: 10.1073/PNAS.1019576108
Abstract: Developing countries are required to produce robust estimates of forest carbon stocks for successful implementation of climate change mitigation policies related to reducing emissions from deforestation and degradation (REDD). Here we present a “benchmark” map of biomass carbon stocks over 2.5 billion ha of forests on three continents, encompassing all tropical forests, for the early 2000s, which will be invaluable for REDD assessments at both project and national scales. We mapped the total carbon stock in live biomass (above- and belowground), using a combination of data from 4,079 in situ inventory plots and satellite light detection and ranging (Lidar) samples of forest structure to estimate carbon storage, plus optical and microwave imagery (1-km resolution) to extrapolate over the landscape. The total biomass carbon stock of forests in the study region is estimated to be 247 Gt C, with 193 Gt C stored aboveground and 54 Gt C stored belowground in roots. Forests in Latin America, sub-Saharan Africa, and Southeast Asia accounted for 49%, 25%, and 26% of the total stock, respectively. By analyzing the errors propagated through the estimation process, uncertainty at the pixel level (100 ha) ranged from ±6% to ±53%, but was constrained at the typical project (10,000 ha) and national (>1,000,000 ha) scales at ca. ±5% and ca. ±1%, respectively. The benchmark map illustrates regional patterns and provides methodologically comparable estimates of carbon stocks for 75 developing countries where previous assessments were either poor or incomplete.

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Topics: Carbon cycle (50%)

1,577 Citations