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1.
Ambio ; 49(1): 74-84, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30666613

RESUMO

Forest transitions occur when net reforestation replaces net deforestation in places. Because forest transitions can increase biodiversity and augment carbon sequestration, they appeal to policymakers contending with the degrading effects of forest loss and climate change. What then can policymakers do to trigger forest transitions? The historical record over the last two centuries provides insights into the precipitating conditions. The early transitions often occurred passively, through the spontaneous regeneration of trees on abandoned agricultural lands. Later forest transitions occurred more frequently after large-scale crisis narratives emerged and spurred governments to take action, often by planting trees on degraded, sloped lands. To a greater degree than their predecessors, latecomer forest transitions exhibit centralized loci of power, leaders with clearly articulated goals, and rapid changes in forest cover. These historical shifts in forest transitions reflect our growing appreciation of their utility for countering droughts, floods, land degradation, and climate change.


Assuntos
Mudança Climática , Agricultura Florestal , Conservação dos Recursos Naturais , Florestas , Árvores
2.
Ambio ; 49(1): 299-309, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30900080

RESUMO

In this article, we focus on wellbeing as an important concept relating to bioenergy development in Canada. We use a three-dimensional or social approach to understanding wellbeing, which includes subjective and relational aspects in addition to the more traditional material dimension of wellbeing (e.g. financial resources, a healthy environment). Indigenous business leaders engaged in forestry, energy, and related resource sectors were recruited through our partner organization, the Canadian Council for Aboriginal Business, as a representative sample of key people to be engaged in the scoping of existing and future bioenergy partnerships in Canada. Participants often responded in ways that did not discretely fit into categories, but instead reflected a perspective on their own and their community's dimensions of social wellbeing, which we captured through open coding for emergent themes. Our findings on material wellbeing illustrate that relationships between different wellbeing dimensions need to be considered for community-appropriate bioenergy development.


Assuntos
Agricultura Florestal , Grupo com Ancestrais Oceânicos , Canadá , Meio Ambiente , Humanos
3.
Ambio ; 49(1): 85-97, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31055795

RESUMO

Retention forestry implies that biological legacies like dead and living trees are deliberately selected and retained beyond harvesting cycles to benefit biodiversity and ecosystem functioning. This model has been applied for several decades in even-aged, clearcutting (CC) systems but less so in uneven-aged, continuous-cover forestry (CCF). We provide an overview of retention in CCF in temperate regions of Europe, currently largely focused on habitat trees and dead wood. The relevance of current meta-analyses and many other studies on retention in CC is limited since they emphasize larger patches in open surroundings. Therefore, we reflect here on the ecological foundations and socio-economic frameworks of retention approaches in CCF, and highlight several areas with development potential for the future. Conclusions from this perspective paper, based on both research and current practice on several continents, although highlighting Europe, are also relevant to other temperate regions of the world using continuous-cover forest management approaches.


Assuntos
Ecossistema , Agricultura Florestal , Biodiversidade , Conservação dos Recursos Naturais , Europa (Continente) , Florestas , Árvores
4.
Sci Total Environ ; 698: 133761, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31493576

RESUMO

In Romania, natural Norway spruce forests are spread across upper mountain slopes (1300-1800 m). They perform multiple functions, being especially recognised for their economic value. However, where planted forests extend beyond the spruce's naturally occurring areas, they are frequently exposed to deleterious environmental factors. In Romania, forest planning is based on typological studies that were carried out between 1950 and 1970, and the regulations are applied in a somewhat flexible manner. In the context of the potential threats from climate change that could amplify induced destabilising phenomena, the risks to which these forests are becoming exposed can only be mediated through flexible management and the permanent adaptation of forest planning. For this reason, the purpose of this study was to develop a strategy for adapting forest management plan guidelines, with a view to improving ecosystem stability. A Norway spruce forest was chosen from the south-eastern Carpathians, which is included in the Natura 2000 Fagaras Mountains site. The models on which we based our current stand compositions resulted from long-term monitoring and analysis of species and stand structures. Stand structure - and forest structure, in general - is key to the continuous existence of stand functions and ecosystem services. Through design decisions, we promote biodiversity and the natural, better adapted, regeneration of local provenances. We highlight the rationale behind forest management planning and its regulations, with respect to the sustainable management of Norway spruce forests, which are vulnerable to potential changes in their structure as a result of climate change. Based on our findings, we propose the adaptation of measures used in forest management planning for Norway spruce forests to include protective functions that can be applied to all man-made Norway spruce forests introduced in former beech forest regions, and mixed coniferous/beech forests, that are vulnerable to changing environmental factors.


Assuntos
Mudança Climática , Agricultura Florestal/métodos , Florestas , Picea , Noruega , Romênia
5.
Sci Total Environ ; 698: 134129, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499344

RESUMO

Forest health status is negatively influenced by climate change, air pollution and other disturbances. Extreme droughts reduce stand productivity, increase vulnerability to pests, and can even provoke mortality. Growth dynamics at tree and forest stand levels are considered the main indicators of stability and productivity in forest ecosystem structures. The main climate drivers for tree growth were identified using basal area increment (BAI) as a synthetic indicator. BAI chronologies were obtained from increment cores for 1960-2012 period. Six species were analysed in an attempt to identify their growth limiting factors. For the most important oak species in Romania, resilience components were computed in order to analyse their response to drought events. Moreover, growth dynamics were analysed for two species in mixed and monoculture forests. The results suggest that - in comparison to Picea abies and Fagus sylvatica, the sensitivity of Quercus spp. is much higher (0.3-0.47). Oakspecies situated in the most drought-affected areas are sensitive to rainfall values from the previous autumn, current spring, and early summer, with April monthly values having the most significant effect on BAI increment (r = 0.47*) The most sensitive species to drought is Q. cerris and Q. frainetto. Their BAI reduction during drought is >50% compared with the BAI values before the drought period. The recovery capacity of tree growth following drought events is lower for Q. robur and Q. petraea and higher for Q. cerris and Q. frainetto. The mixed forest stands have not showed a constant higher resistance to drought.


Assuntos
Mudança Climática , Monitoramento Ambiental , Agricultura Florestal , Florestas , Árvores , Secas , Ecossistema , Fagus , Quercus , Romênia , Estações do Ano
6.
Zootaxa ; 4674(4): zootaxa.4674.4.6, 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31715996

RESUMO

A new species of xenodermatid snake, Achalinus yunkaiensis J. Wang, Y. Li Y.Y. Wang, sp. nov. was described based on a series of specimens collected from Dawuling Forestry Station located in the Yunkai Mountains of western Guangdong Province. It can be distinguished from known congeners by a significant genetic divergence at the mitochondrial CO1 gene fragment examined (p-distance ≥ 12.0%) and the following combination of characters: (1) dorsal scales strongly keeled, in 23 rows throughout the body, the most outer row on each side smooth and significantly enlarged; (2) tail relatively shorter, TaL/TL ratio 18.5-20.0%; (3) maxillary teeth 20-22; (4) length of suture between internasals subequal to that between the prefrontals; (5) nasal divided into two sections by nasal cleft, posterior one half as long as anterior; (6) loreal elongated, nearly twice as wide as high; (7) supralabials six; (8) infralabials six; (9) temporals 2+2+3 (rarely 2+2+4), the two anterior temporals in contact with eye; (10) ventrals 151-162, subcaudals 49-56 arranged in single row, not paired; (11) cloacal entire; (12) uniform brown (in adults) or black (in juveniles) above, tinged weakly iridescent, with a longitudinal dark-colored vertebral line; (13) light brown (in adults) or greyish white (in juveniles) beneath; and (14) dorsum with a longitudinal dark brown vertebral stripe from posterior margin of parietals to tail tip. Currently, 13 species are known in the genus Achalinus, with seven from mainland China.


Assuntos
Lagartos , Serpentes , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , China , Agricultura Florestal
7.
Nature ; 575(7781): 98-108, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695208

RESUMO

Much of the Earth's biosphere has been appropriated for the production of harvestable biomass in the form of food, fuel and fibre. Here we show that the simplification and intensification of these systems and their growing connection to international markets has yielded a global production ecosystem that is homogenous, highly connected and characterized by weakened internal feedbacks. We argue that these features converge to yield high and predictable supplies of biomass in the short term, but create conditions for novel and pervasive risks to emerge and interact in the longer term. Steering the global production ecosystem towards a sustainable trajectory will require the redirection of finance, increased transparency and traceability in supply chains, and the participation of a multitude of players, including integrated 'keystone actors' such as multinational corporations.


Assuntos
Biomassa , Ecossistema , Fontes Geradoras de Energia , Retroalimentação , Abastecimento de Alimentos , Atividades Humanas , Desenvolvimento Sustentável , Agricultura/economia , Animais , Comércio/economia , Fontes Geradoras de Energia/economia , Abastecimento de Alimentos/economia , Agricultura Florestal , Água Subterrânea/análise , Atividades Humanas/economia , Humanos , Desenvolvimento Sustentável/economia
8.
J Environ Manage ; 252: 109625, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31604183

RESUMO

Climate change is altering the nature and condition of vast areas in the boreal forest of Canada. There are great uncertainties concerning impacts on the forest, along with how policy and economic responses will translate effectively between local and macroscales. In particular, planting tree seedlings with improved characteristics following harvesting is one localized response strategy considered essential by policymakers. However, planting costs limit the macroscale adoption of this strategy which may result in trade-offs between profitability and reducing vulnerability. In this study, we developed a decision support tool (called Q3) that links stand-level decision making to the macroscale and applied this model to investigate the financial attractiveness of planting improved stocks under one climate change threat, drought-induced seedling mortality. Using several scenarios describing planting effort, improved yields and risk to drought-induced seedling mortality, we showed that adopting improved planting stock strategies across a macroscale (i.e., the western Boreal forest of Canada) can be financially attractive when considering stand-establishment constraints and drought risk. In particular, a proactive approach can be less costly than a reactive approach to drought-induced seedling mortality. To maximize profits, the forestry industry would need to prioritize younger stands closer to processing mills that had a smaller percentage of conifer growing stocks prior to harvest. This research improves the linkages between macroscale policies and forest management activities critical for recommending future development paths that the forestry industry could follow to decrease climate change vulnerabilities.


Assuntos
Mudança Climática , Agricultura Florestal , Canadá , Florestas , Árvores
9.
J Environ Manage ; 252: 109676, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31614263

RESUMO

In this paper we examine an example of a conservation conflict that is encountered in Ireland arising from the designation of Special Protection Areas (SPAs) for the Hen Harrier under the European Birds Directive (Directive, 2009/147/EC) and the consequent restrictions that are placed on forestry activities within these SPAs. We examine the causes of the Hen Harrier-forestry conflict; identify what stakeholders believe are the policy instruments and management strategies that may be useful in managing the conflict and finally identify plausible solutions that may be relevant to similar conflicts around multi-functional forests elsewhere in Europe and globally. Semi-structured interviews were conducted with key actors in this conflict. Drawing on Walker and Daniels' conflict triangle theory, a qualitative analysis of the transcripts of these interviews revealed that the conflict between Hen Harrier conservation and forestry in Ireland has a number of deep-rooted dimensions including those relating to the substance (e.g. restrictions on forest management activity in the SPAs), as well as procedural (e.g. lack of stakeholder engagement) and relationship dimensions (e.g. lack of trust). The polarisation of views in this conflict testifies to how entrenched stakeholders can become through lack of communication and trust. The policy instruments that stakeholders identified as having potential to address the conflict include the introduction of incentives/compensation scheme; changes to restrictions; more data and research on Hen Harrier bird surveys; implementation of landscape management models; and better communication and stakeholder engagement. The study highlights that conservation conflicts persist due to the multi-functional nature of forests and also due to repeated mistakes in terms of the lack of engagement with local stakeholders. Increasing the involvement of local actors has important substantive and instrumental benefits including improving the quality of decisions, as well as creating a greater chance of policies being better socially and politically acceptable. The need for more and better capacity-building across EU Member States for statutory and government agencies to learn from one another in terms of how to avoid repeating the same mistakes from one site to another is highlighted.


Assuntos
Conservação dos Recursos Naturais , Agricultura Florestal , Animais , Aves , Europa (Continente) , Irlanda
11.
Rev Med Suisse ; 15(669): 1974-1978, 2019 Oct 30.
Artigo em Francês | MEDLINE | ID: mdl-31663697

RESUMO

Tobacco has not only negative effects on health; it also has an environmental impact. Each year, tobacco production requires 22 000 billion liters of water, mainly for cultivation. Thousands hectares of forestland are cleared annually, largely for the desiccation of tobacco leaves. Cigarette production is responsible for 84 million tons of CO2 equivalent. This paper reviews the environmental impact of the production and consumption of cigarettes from tobacco growing and manufacturing to consumption and waste production, and compares it with current consumption data.


Assuntos
Produção Agrícola/estatística & dados numéricos , Meio Ambiente , Agricultura Florestal/estatística & dados numéricos , Produtos do Tabaco/provisão & distribução , Tabaco/crescimento & desenvolvimento , Dióxido de Carbono/metabolismo , Humanos , Tabaco/efeitos adversos , Tabaco/metabolismo , Produtos do Tabaco/efeitos adversos
13.
J Environ Manage ; 249: 109356, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445370

RESUMO

Determining appropriate management strategies to reduce greenhouse gas emissions using optimization techniques to understand how forest management activities affect the carbon dynamics is critical in implementing effective carbon management policies. This paper quantitatively analyzes the long-term effects of different management policies and silvicultural interventions using linear programming. In the analyses, afforestation targets for bare forest lands, tree species, carbon prices, planning approaches and sets of various targets and constraints on carbon dynamics were evaluated. The results were based on twenty-five forest management scenarios formulated for the Korucu Forest Planning Unit of Turkey. The results showed that, compared to timber-based planning strategies (TM), ecosystem-based planning approach (EM) contributes to a significant reduction in carbon sequestration in many cases. When different afforestation targets were incorporated into forest management strategies, cumulative carbon sequestration increased constantly compared to baseline scenario without any afforestation areas. In addition, the highest total carbon sequestration was observed when black pine (P. nigra) was used in afforestation activities rather than oak species (Quercus sp.) and other available tree species. While total timber production and timber net present value (NPV) decreased, carbon sequestration increased significantly with increasing carbon price. As a result of increasing carbon price from $20/ton to $100/ton, joint NPV increased by about five times. The results highlighted the importance of forest ecosystem and developing and implementing climate adaption measures into forest management activities in tackling climate change phenomenon.


Assuntos
Carbono , Agricultura Florestal , Sequestro de Carbono , Ecossistema , Florestas , Árvores , Turquia
14.
Sci Total Environ ; 687: 1164-1175, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412452

RESUMO

Biological homogenization is a process of biodiversity loss driven by the introduction and invasion of widespread species and the extinction of specialized, endemic species. This process has accelerated in recent years due to intensive human activities. We focused our study on large areas of forest vegetation that have not yet been intensively studied. Forest management, especially the planting of alien trees, could play a key role in the homogenization process because alien trees can act as habitat 'transformers' influencing vegetation through creating different environmental conditions. Several types of native forests (hardwood floodplain forests, oak forests, and oak-hornbeam forests) have in many regions been replaced by Robinia pseudoacacia plantations. The huge diversity of native broadleaved deciduous forests in the Pannonian and Carpathian regions, with many local differences and considerable geographical variability, could be exposed to the homogenization process due to the planting of Robinia pseudoacacia. We used 282 paired plots of Robinia pseudoacacia-dominated forests and native forests with a distance of 50-250 m among them under the same environmental conditions to avoid the influence of the variability of local environmental conditions on the forest undergrowth. We found out that the replacement of native forests by plantations of Robinia pseudoacacia plays a crucial role in the homogenization process in forest vegetation by unifying microenvironmental conditions of stands and removing the geographically specified variability of plant communities from previous four classes to single one. The replacement reduced total species pool from 422 to 372 species and supported the occurrence of widespread, generalist plant species in the undergrowth.


Assuntos
Florestas , Robinia/crescimento & desenvolvimento , Biodiversidade , Ecossistema , Europa (Continente) , Agricultura Florestal , Espécies Introduzidas , Plantas , Solo , Árvores
15.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2583-2590, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418181

RESUMO

We explored the effects of microtopography changes from artificial intervention of soil and water conservation (contour reverse-slope terrace, CRT) on tree growth in a degraded woodland on hillslope in water resource area of Songhua dam in Kunming City. The differences of the diameter at breast height (DBH), tree height, new branch increment, and leaf area index (LAI) of dominant tree species in different plots were compared through dynamic monitoring. Then, the causes of differences were analyzed by combining the soil water availability. The results showed that the maximum and mean values of DBH and height of Pinus yunnanensis (dominant species) in contour reverse-slope terrace plot were larger than those in control plot (CK), and the proportion of small-sized and low-dwarf trees in degraded forest community was higher, which indicated that the growth potential of new and seriously degraded forest was stimulated. The annual variation rate of the ave-rage new branch length and diameter of P. yunnanensis in different plots reached 72.4% and 39.1%, respectively. The changes of new branch growth of P. yunnanensis, LAI of plots, and the new branch growth rate were greater in CRT than those in CK. Soil water content was significantly correlated with both the new branch growth and LAI. The ratio of available water in plot (64.2%) was higher than that in CK (54.7%). During the rainy season (from May to September), the available water in CRT existed longer, which was conducive to tree growth and the improvement of plant community structure in degraded woodland.


Assuntos
Conservação dos Recursos Naturais/métodos , Florestas , Pinus/crescimento & desenvolvimento , Agricultura Florestal , Folhas de Planta , Solo , Árvores
16.
Environ Pollut ; 253: 636-645, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31330355

RESUMO

Timber harvest has many effects on aquatic ecosystems, including changes in hydrological, biogeochemical, and ecological processes that can influence mercury (Hg) cycling. Although timber harvest's influence on aqueous Hg transformation and transport are well studied, the effects on Hg bioaccumulation are not. We evaluated Hg bioaccumulation, biomagnification, and food web structure in 10 paired catchments that were either clear-cut in their entirety, clear-cut except for an 8-m wide riparian buffer, or left unharvested. Average mercury concentrations in aquatic biota from clear-cut catchments were 50% higher than in reference catchments and 165% higher than in catchments with a riparian buffer. Mercury concentrations in aquatic invertebrates and salamanders were not correlated with aqueous THg or MeHg concentrations, but rather treatment effects appeared to correspond with differences in the utilization of terrestrial and aquatic basal resources in the stream food webs. Carbon and nitrogen isotope data suggest that a diminished shredder niche in the clear-cut catchments contributed to lower basal resource diversity compared with the reference of buffered treatments, and that elevated Hg concentrations in the clear-cut catchments reflect an increased reliance on aquatic resources in clear-cut catchments. In contrast, catchments with riparian buffers had higher basal resource diversity than the reference catchments, indicative of more balanced utilization of terrestrial and aquatic resources. Further, following timber harvest THg concentrations in riparian songbirds were elevated, suggesting an influence of timber harvest on Hg export to riparian food webs. These data, coupled with comparisons of individual feeding guilds, indicate that changes in organic matter sources and associated effects on stream food web structure are important mechanisms by which timber harvest modifies Hg bioaccumulation in headwater streams and riparian consumers.


Assuntos
Cadeia Alimentar , Agricultura Florestal/métodos , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Biota , Carbono , Ecossistema , Invertebrados , Mercúrio/análise , Compostos de Metilmercúrio , Isótopos de Nitrogênio , Rios/química , Poluentes Químicos da Água/análise
17.
Oecologia ; 191(1): 241-252, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31352635

RESUMO

Emulation of natural disturbances is often regarded as a key measure to make forestry biodiversity-oriented. Consequently, extraction of logging residues is assumed to have little negative effect in comparison to extraction of dead wood mainly formed at natural disturbances. This is consistent with the evolutionary species pool hypothesis, which suggests that most species are evolutionary adapted to the naturally most abundant habitats. We tested this hypothesis for dead-wood-dependent macrofungi, lichens, and beetles in a boreal forest landscape in central Sweden, assuming that species are adapted to conditions similar to today's unmanaged forest. No occurrence patterns, for the species groups which we investigated, were consistent with the hypothesis. Overall, stumps and snags had the highest habitat quality (measured as average population density with equal weight given to each species) and fine woody debris the lowest, which was unexpected, since stumps were the rarest dead-wood type in unmanaged forest. We conclude that the evolutionary species pool concept did not explain patterns of species' occurrences, and for two reasons, the concept is not reliable as a general rule of thumb: (1) what constitute habitats harbouring different species communities can only be understood from habitat-specific studies and (2) the suitability of habitats is affected by their biophysical characteristics. Thus, emulation of natural disturbances may promote biodiversity, but empirical studies are needed for each habitat to understand how natural disturbances should be emulated. We also conclude that stump extraction for bioenergy is associated with larger risks for biodiversity than fine woody debris extraction.


Assuntos
Árvores , Madeira , Animais , Biodiversidade , Conservação dos Recursos Naturais , Ecossistema , Agricultura Florestal , Suécia
18.
Sci Total Environ ; 691: 516-527, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325852

RESUMO

European standards for the protection of forests from ozone (O3) are based on atmospheric exposure (AOT40) that is not always representative of O3 effects since it is not a proxy of gas uptake through stomata (stomatal flux). MOTTLES "MOnitoring ozone injury for seTTing new critical LEvelS" is a LIFE project aimed at establishing a permanent network of forest sites based on active O3 monitoring at remote areas at high and medium risk of O3 injury, in order to define new standards based on stomatal flux, i.e. PODY (Phytotoxic Ozone Dose above a threshold Y of uptake). Based on the first year of data collected at MOTTLES sites, we describe the MOTTLES monitoring station, together with protocols and metric calculation methods. AOT40 and PODY, computed with different methods, are then compared and correlated with forest-health indicators (radial growth, crown defoliation, visible foliar O3 injury). For the year 2017, the average AOT40 calculated according to the European Directive was even 5 times (on average 1.7 times) the European legislative standard for the protection of forests. When the metrics were calculated according to the European protocols (EU Directive 2008/50/EC or Modelling and Mapping Manual LTRAP Convention), the values were well correlated to those obtained on the basis of the real duration of the growing season (i.e. MOTTLES method) and were thus representative of the actual exposure/flux. AOT40 showed opposite direction relative to PODY. Visible foliar O3 injury appeared as the best forest-health indicator for O3 under field conditions and was more frequently detected at forest edge than inside the forest. The present work may help the set-up of further long-term forest monitoring sites dedicated to O3 assessment in forests, especially because flux-based assessments are recommended as part of monitoring air pollution impacts on ecosystems in the revised EU National Emissions Ceilings Directive.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Ozônio/análise , Conservação dos Recursos Naturais , Ecossistema , Agricultura Florestal , Florestas , Estômatos de Plantas
19.
Environ Monit Assess ; 191(8): 502, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31327078

RESUMO

The purpose of this study is to analyze the role of state ownership in forest governance in Turkey. It seeks to explore how property rights are affected by the complex, dynamic interplay of policies, economic influences, and the law. The historical development of state ownership, including its legal aspects, has been investigated in order to better understand the roots of current issues. An institutional approach has been followed. It is hypothesized that as the state exercises its property rights, it has both positive and negative effects on forest governance. This analysis confirms that state ownership may exceed its implementation capacity under the pressure of economic development objectives and that in areas where economic development is a priority, the loss of forests is inevitable. There is a need for a more adaptive approach to making policies related to property rights. The concept of the overriding public interest could be vital in achieving purposeful governance.


Assuntos
Política Ambiental , Agricultura Florestal/métodos , Florestas , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/legislação & jurisprudência , Monitoramento Ambiental , Agricultura Florestal/economia , Agricultura Florestal/legislação & jurisprudência , Humanos , Propriedade , Formulação de Políticas , Turquia
20.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1956-1964, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257768

RESUMO

The variation of forest canopy structure and understory light caused by natural or human disturbances might account for environmental heterogeneity and species diversity in the understory. These factors play an important role in driving the structure, process and pattern in forest ecosystem. We set up two 0.25 hm2 permanent plots in secondary Betula platyphylla-Populus davidiana forests on the Taoshan Forest Farm, one of which was thinned in 2012 and the other one remained natural. The canopy images of two plots were collected by hemispherical photography technology from 2012 to 2016 and 2018. Analysis of variance and Markov matrix were applied to examine the dynamics of canopy structure, understory light, and canopy closing process after thinning. The results showed that thinning was effective in adjusting canopy structure and understory light availability. Such process lasted for a long time and the adjusting effect decreased over time. After thinning, the change rate of canopy structure and understory light decreased over time. The tree canopy quickly closed during the first three years and then reached a stable state. Understory light availability was positively correlated with canopy openness and negatively correlated with leaf area index. The correlation between understory scattered radiation and canopy structural parameters was the strongest. The correlation between canopy structure and understory light in the thinning plot was stronger than that of the control plot. After thinning, the recovery rate of canopy structure was related to the canopy openness, with larger canopy openness being accompanied with higher recovery rate. Thus, less time was required for the transfer to smaller canopy openness. The Markov matrix model could simulate changes in distributions of canopy structure and could be used to predict the dynamics of the canopy structure.


Assuntos
Betula , Populus , Ecossistema , Agricultura Florestal , Florestas , Árvores
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