Impacts of meteorology and precursor emission change on O3 variation in Tianjin, China from 2015 to 2021

Deterioration of surface ozone (O₃) pollution in Northern China over the past few years received much attention. For many cities, it is still under debate whether the trend of surface O₃ variation is driven by meteorology or the change in precursors emissions. In this work, a time series decomposition method (Seasonal-Trend decomposition procedure based on Loess (STL)) and random forest (RF) algorithm were utilized to quantify the meteorological impacts on the recorded O₃ trend and identify the key meteorological factors affecting O₃ pollution in Tianjin, the biggest coastal port city in Northern China. After “removing” the meteorological fluctuations from the observed O₃ time series, we found that variation of O₃ in Tianjin was largely driven by the changes in precursors emissions. The meteorology was unfavorable for O₃ pollution in period of 2015-2016, and turned out to be favorable during 2017-2021. Specifically, meteorology contributed 9.3 µg/m³ O₃ (13%) in 2019, together with the increase in precursors emissions, making 2019 to be the worst year of O₃ pollution since 2015. Since then, the favorable effects of meteorology on O₃ pollution tended to be weaker. Temperature was the most important factor affecting O₃ level, followed by air humidity in O₃ pollution season. In the midday of summer days, O₃ pollution frequently exceeded the standard level (>160 µg/m³) at a combined condition with relative humidity in 40%-50% and temperature > 31°C. Both the temperature and the dryness of the atmosphere need to be subtly considered for summer O₃ forecasting.     

Underlying cause of fire: Different form of land tenure conflicts in Sumatra

One of the social phenomena that have arisen in Indonesia in the post-Reformasi period (mid-1998) is the increase in land tenure conflicts between local communities and tree plantation companies, and between local communities and the forestry department. Land tenure conflicts often trigger forest and land fires, which is both a symptom and a cause of increasing conflict over tenure and use rights. If the tenure issue is not appropriately addressed, it will continue to result in unwanted fires and forest degradation, related smoke and gas emissions, and environmental and economic losses. A recent study in Sumatra revealed that, in many cases, (1) tenure conflicts between companies and communities, resulting from past government policies and practices, often trigger forest and land fires because of frustrations by the communities of being unable to have their claims heard in a fair and transparent judicial system; and (2) even with the use of military force, forest policy and management has largely failed to protect forest resources when local communities were not involved. The nature of the partnership between communities and companies in land use development is also an important factor in influencing the incidence and control of fire.     

南岳森林土壤的研究——Ⅱ.化学性状和土壤有机质

本文介绍了南岳森林土壤与母岩的化学性状,以了解气候和植被对土壤的影响;介绍了土壤有机质的作用、含量、分布;讨论了影响土壤有机质含量的因素并给出了循环模型。     

Static modeling of dynamic recreation behavior: Implications for prediction and welfare estimation

This paper examines the consequences of using a static model of recreation trip-taking behavior when the underlying decision problem is dynamic. Specifically we examine the implications for trip forecasting and welfare estimation using a panel dataset of Lake Michigan salmon anglers for the 1996 and 1997 fishing seasons. We derive and estimate both a structural dynamic model using Bellman's equation, and a reduced-form static model with trip probability expressions mimicking those of the dynamic model. We illustrate an inherent identification problem in the reduced-form model that creates biased welfare estimates, and we discuss the general implications of this for the interpretation of preference parameters in static models. We then use both models to simulate trip taking behavior and show that although their in-sample trip forecasts are similar, their welfare estimates and out-of-sample forecasts are quite different.     

200 years of sustainability in forestry: Lessons from history

Since the end of the 1980s the concept of sustainable development has gained general acceptance, but much uncertainty still exists on how to operationalize this concept. In forestry the concept of sustainability has been an accepted principle since the 18th century. The experiences with its application in forestry may contribute towards obtaining a better insight into the implications and operational significance of the concept of sustainability. This article describes the history of sustainability in forestry, including the various social values on which its interpretation has been based. The original principle of sustained yield has gradually been broadened to a more inclusive principle of sustainable forest management. The dynamics in social valuation of forest resources resulted in various attempts at practical operationalization of the principle. Notwithstanding 200 years of efforts to operationalize the concept of sustainability, its exact application in forestry remains troublesome. Three lessons are drawn: (1) the need to recognize the different nature of ecological limits and social dynamics, (2) the role of dynamic social values with respect to forest resources, and (3) the significance of operational experiences in trying to attain sustainability within a concrete context.     

An introduction to digital methods in remote sensing of forested ecosystems: Focus on the Pacific Northwest,USA

Aerial photography has been routinely used for several decades by natural resource scientists and managers to map and monitor the condition of forested landscapes. Recently, along with the emergence of concepts in managing forests as ecosystems, has come a significant shift in emphasis from smaller to larger spatial scales and the widespread use of geographic information systems. These developments have precipitated an increasing need for vegetation information derived from other remote sensing imagery, especially digital data acquired from high-elevation aircraft and satellite platforms. This paper introduces fundamental concepts in digital remote sensing and describes numerous applications of the technology. The intent is to provide a balanced, nontechnical view, discussing the shortcomings, successes, and future potential for digital remote sensing of forested ecosystems.     

The Delphi approach to the mediation of environmental disputes

Environmental disputes, in many countries, have taken on a ritualistic character. Their persistence, even after prolonged analysis and debate, suggests that they result from ideological rather than factual differences. Since no single ideological position holds a monopoly on the truth, effective environmental management would seem to require an integration of views, the problem being how to achieve this. One approach to this problem is illustrated in this article. Two factions in the spruce budworm dispute in New Brunswick, Canada, were engaged in a mediation exercise using the Delphi method. Details of the design and execution of this form of mediation are provided, together with an evaluation of the Delphi's effectiveness in this context.     

Scale-dependent inconsistencies in the effects of trampling on a forest understory community

The response of forest understory vegetation to trampling applied at different temporal and spatial scales was determined in a cliff-edge forest in Ontario, Canada. Three frequencies (0, 50, 500 passes per year) of short-term trampling (one year) were applied to plots previously undisturbed. Existing trails that had received three frequencies (approx. 100, 500, 25,000 passes per year) of long-term trampling (18 years) were also studied. Community composition, species richness, and individual species frequency were recorded in plots within 4 m and (or) 1 m of the patch centerline. The quantitative and qualitative form of plant response to increased trampling was compared for short-term and long-term treatments, both within 4 m and within 1 m of the path centerline, to judge the consistency of trampling effects at different temporal and spatial scales. As trampling frequency increased, community composition changed progressively, but consistently, in plots both within 4 m and 1 m of the path centerline. Species richness was less affected by trampling and only decreased within 1 m of the path centerline at the highest level of trampling (25,000 passes per season for 18 years). Effects of trampling on individual species frequency were much less consistent at different temporal and spatial scales of trampling. The scale-dependence results suggest that field workers and resource managers both should try explicitly to include and define multiple scale components when trying to ascertain the response of vegetation to human disturbance factors.