Optimal Location of New Forests in a Suburban Area

In this paper we develop a methodology to select a combination of forest sites that maximizes net social benefits taking into account restrictions on the total surface/size of new forest land. We use GIS technology to estimate for each site the major cost and benefit elements including lost agricultural output, timber and hunting values, carbon sequestration, non-use and recreation benefits. Special emphasis is placed on the recreational value of a potential site as this raises two issues. First, the recreation benefits of a base site estimated via the travel cost method need to be transferred to all potential sites. Second, the recreation benefit of each potential site depends on the existing sites and on the other sites that are in the selection. We show that the same ‘amount’ of afforestation (i.e. the same total surface divided into multiple sites at varying locations) creates a wide range of potential net social benefits due to the role of a varying set of recreation substitutes.We show that the net social benefit of new forest combinations respecting the area constraints may differ up to a factor 21. The substitution effect between forests, both new and existing, turned out to be the dominant factor in the benefit estimation. Compared to the existing literature, our paper improves the methodology by working with realistically feasible sites rather than grid sites, by including the complex recreation substitution effects between potential sites and by including all costs and benefits of afforestation bringing the analysis closer to a real cost benefit analysis.

Optimal location of new forests in a suburban region

This paper looks at the optimal location of new forests in a suburban region under area constraints. The GIS-based methodology takes into account use benefits such as timber, hunting, carbon sequestration and recreation, non-use benefits (both bequest and existence values), opportunity costs of converting agricultural land, as well as planting and management costs of the new forest. The recreation benefits of new forest sites are estimated using function transfer techniques. We show that the net social benefit of the total afforestation project may vary up to a factor 6, depending on the forest sites that are selected. We show that the recreation value of a forest site varies considerably with the available substitutes.Benefit transfer, travel cost analysis, cost-benefit analysis, forest recreation, Geographical Information Systems (GIS)

Optimal location of new forests in a suburban area

This paper looks for the optimal location of new forests in a suburban area under area constraints. The GIS-based methodology takes into account timber, hunting, carbon sequestration, non-use and recreation benefits and opportunity costs of converting agricultural land, as well as planting and management costs of the new forest. The recreation benefits of new forest sites are estimated using function transfer techniques. We show that the net social benefit of new forest combinations respecting the area constraints may differ up to a factor 21. The substitution effect between forests, both new and existing, turned out to be the dominant factor in the benefit estimation.Benefit transfer, travel cost analysis, cost-benefit analysis, forest recreation, Geographical Information Systems (GIS)

Unexpected understorey community development after 30 years in ancient and post-agricultural forests

1. Land-use change is considered one of the most radical and extensive disturbances that have influenced plant distributions and diversity patterns in forest understorey communities in much of Europe and eastern North America. In forests growing on former agricultural land, local species diversity and community differentiation among sites are generally reduced compared to ancient forests (i.e. forests with no historical record of agriculture). Yet, no study has determined how the compositional differences created by former land use change over time as the forest sites recover from former agricultural use. 2. Here we resurveyed 78 vegetation plots (half of the plots in ancient and half in post-agricultural forest) to demonstrate how three decades of forest development have changed the compositional differences between post-agricultural and ancient forest sites. The impact of land-use history and survey date was tested on two measures of species diversity and two measure of community divergence. 3. The data indicate that the imprint of former agricultural land use persisted over time, yet not through compositional stability. Parallel and strong vegetation shifts occurred in both ancient and post-agricultural forest: the species diversity decreased and local species cover strongly diverged, which indicates community drift. The observed understorey changes did thus not support the commonly accepted model of community development in post-agricultural forests, i.e. the diversity did not increase and the vegetation did not become more similar to the ancient forest vegetation over time. The changes in species composition were associated with an increase of common, competitive species at the expense of ancient forest indicator species. The source populations of ancient forest species have been gradually depleted, so the recovery of post-agricultural forests becomes even more precarious. 4. Synthesis. While land-use history is likely to persist as the primary predictor of local species diversity and community divergence, other environmental drivers may additionally structure forest understorey communities and lead to biotic impoverishment and pervasive species reordering on the time scale of only decades

Optimal location of new forests in a suburban region.

This paper looks at the optimal location of new forests in a suburban region under area constraints. The GIS-based methodology takes into account use benefits such as timber, hunting, carbon sequestration and recreation, non-use benefits (both bequest and existence values), opportunity costs of converting agricultural land, as well as planting and management costs of the new forest. The recreation benefits of new forest sites are estimated using function transfer techniques. We show that the net social benefit of the total afforestation project may vary up to a factor 6, depending on the forest sites that are selected. We show that the recreation value of a forest site varies considerably with the available substitutes.Benefit transfer; Travel cost analysis; Cost-benefit analysis; Forest recreation; Geographical Information Systems (GIS);

Do looks matter? A case study on extensive green roofs using discrete choice experiments

Extensive green roofs are a promising type of urban green that can play an important role in climate proofing and ultimately in the sustainability of our cities. Despite their increasingly widespread application and the growing scientific interest in extensive green roofs, their aesthetics have received limited scientific attention. Furthermore, several functional issues occur, as weedy species can colonize the roof, and extreme roof conditions can lead to gaps in the vegetation. Apart from altering the function of a green roof, we also expect these issues to influence the perception of extensive green roofs, possibly affecting their acceptance and application. We therefore assessed the preferences of a self-selected convenience sample of 155 Flemish respondents for visual aspects using a discrete choice experiment. This approach, combined with current knowledge on the psychological aspects of green roof visuals, allowed us to quantify extensive green roof preferences. Our results indicate that vegetation gaps and weedy species, together with a diverse vegetation have a considerable impact on green roof perception. Gaps were the single most important attribute, indicated by a relative importance of ca. 53%, with cost coming in at a close second at ca. 46%. Overall, this study explores the applicability of a stated preference technique to assess an often overlooked aspect of extensive green roofs. It thereby provides a foundation for further research aimed at generating practical recommendations for green roof construction and maintenance

Impact of mechanized harvesting on compaction of sandy and clayey forest soils : results of a meta-analysis

Nowadays, harvest operations are predominantly performed fully mechanized using heavy tractors or forestry machines. The resulting soil compaction may negatively affect the soil ecosystem. We wanted to draw general conclusions concerning the impact of mechanized harvesting on forest soil bulk density and the influencing factors. Therefore, we combined the data of several studies using a meta-analysis approach. The impact decreased from the surface towards deeper soil layers. At 0-10 cm depth, the impact on clayey soils was highest although not significantly different from the impact on sandy soils. Higher initial bulk densities, i.e., on already compacted forest soils, generally led to smaller extra increases of bulk density after machine traffic. For sandy soils, the impact was also significantly smaller when machines were lighter. No significant relationship was observed between the compaction degree and traffic intensity. We observed clear compaction on both clayey and sandy soils, especially in case of low initial soil compaction degrees and heavy machines. The compacted initial state of many forest soils, the long recovery period, and the generally high impact of the first passes that is frequently mentioned in literature all count in favour of designated skid trails and an adjustment of the machine type to the job

Travel cost and time measurement in travel cost models.

Cost; Measurement; Model; Models; Time; Working;

Former land use affects the nitrogen and phosphorus concentrations and biomass of forest herbs

The colonization rates of understorey plants into forests growing on former agricultural land differ remarkably among species. Different dispersal and recruitment largely account for the contrasting colonization rates, but different effects of the soil legacies of former agricultural land use on plant performance may also play a role. Seven herbaceous forest species were sampled in paired post-agricultural and ancient forest stands to study whether land-use history has an effect on the aboveground nutrient concentrations (N, P and N:P ratios) and biomass of forest herbs and, if so, whether slow and fast colonizing species respond differently. Results showed that P concentrations were significantly affected by former land use with higher concentrations in the post-agricultural stands. N concentrations were unaffected and N:P ratios were significantly higher in the ancient stands. Nutrient concentrations varied considerably among species, but the variation was unrelated to their colonization capacity. Six out of the seven species had higher biomass in the post-agricultural stands relative to the ancient stands, and the degree to which the species increased biomass was positively related to their colonization capacity, i.e., the fast colonizing species showed the strongest increase. Such differential responses to past land use may contribute to the contrasting colonization capacity of forest plants. Land-use history thus affected both the nutrient concentrations and biomass of forest herbs, and only the biomass response was related to colonization capacity