Impacts of the sustainable forestry initiative landscape level measures on hydrological processes

The effects on hydrological processes of the application of the landscape level measures included in the sustainable forestry initiative (SFI) program were analyzed through simulation. A landscape scenario where limitation of harvesting units’ size, imposition of a green-up interval, and establishment of streamside management zones (SMZ) were simulatedwas compared with a reference scenario where no SFI rules were followed. An intensively managed forested landscape located in East Texas, USA, was used as the study area. The HARVEST landscape model was used to simulate landscape pattern and a modified version of the APEX model was used to simulate hydrological processes. Water and sediment yields were generally small within the observation period and most of the runoff and erosion observed occurred during intense storm events. Water and sediment yield at the subarea level and water yield at the watershed level were similar in both scenarios. However, sediment yield at the watershed level was higher in the non-SFI scenario. The differences were due to the reduction in channel erosion resulting from the presence of SMZs. The effect of buffer zones in terms of sediment deposition was not different between scenarios, which can be attributed to the level slopes of the study area. Landscape measures of the SFI program, namely buffer zones, seem important in reducing channel degradation, particularly during major storm events, in intensively managed forest landscapes in East Texas.PRODEP II

Effects of the sustainable forestry initiative on the quality, abundance, and configuration of wildlife habitats

We analyzed the effects of landscape measures within the Sustainable Forestry Initiative (SFI) program on the suitability, abundance and spatial pattern of vertebrate habitats based on modeling and simulation of landscape and stand structure in a forested watershed in East Texas. Eight vertebrate species representing guilds established according to breeding and foraging requirements were selected: American beaver (Castor canadensis), American woodcock (Scolopax minor), pine warbler (Dendroica pinus), downy woodpecker (Picoides pubescens), barred owl (Strix varia), wild turkey (Meleagris gallopavo silvestris),fox squirrel (Sciurus niger) and gray squirrel (Sciurus carolinensis). Habitat suitability of the landscape in general increased with the implementation of SFI measures and habitat conditions were more diverse and even. Fragmentation and establishment of narrow and elongated habitat areas in a network configuration were the main consequences of the implementation of SFI measures in terms of habitat spatial structure. These changes were usually not limiting for the species analyzed. Mature pine and hardwood stands were absent from the simulated landscapes limiting the habitat for species like downy woodpecker or barred owl.Most of the species considered in this work benefited particularly from the implementation of streamside management zones (SMZs)

Análise da sustentabilidade de sistemas florestais à escala da paisagem

Neste trabalho apresentamos uma metodologia para a análise da sustentabilidade em paisagens florestais. Tomando como base os critérios e indicadores habituais em programas de sustentabilidade, designadamente dos processos de Montreal e Helsínquia, associaram-se uma série de modelos de várias origens e estruturas no sentido de simular os efeitos da implementação de medidas de gestão sustentável na estrutura e funcionamento da paisagem. Esta metodologia tem por base um modelo de ordenamento de unidades de gestão florestal que permite definir sequências de corte de forma espacialmente explícita de acordo com regras de gestão dos povoamentos e da paisagem. Informação relativa a atributos estruturais particulares dos povoamentos é fornecida por modelos de crescimento ajustados a condições particulares de composição, idade e produtividade locais. A integração desta informação num sistema de informação geográfica permite conhecer ao nível da paisagem as distribuições espaciais dos atributos relevantes para a modelação dos parâmetros relacionados com os critérios em consideração: conservação da biodiversidade, do solo e da água. A biodiversidade é avaliada com base em modelos de habitats de espécies seleccionadas. Erosão e escoamento ao nível de bacias de diferentes ordens são modelados a partir de um modelo hidrológic

Assessment of sustainability in intensively managed forested landscapes: a case study in Eastern Texas.

We developed a methodology to analyze the effects of management practices on landscape structure and function to be used in the assessment of sustainability in intensively managed forest landscapes. It is based on modeling and simulation of landscape and stand structure as well as biological and physical processes. The methodology includes a landscape structure model and several forest stand-level models to simulate the dynamics of landscapes and stands as a function of management rules. It also includes habitat models to evaluate landscape quality and spatial characteristics of vertebrate habitat, and a hydrologic model to simulate water and sediment yield at the subarea and watershed levels. The application of this methodology to the Sustainable Forestry Initiative (SFI) program in eastern Texas indicated that this is an effective way to evaluate effects of sustainable forestry programs on landscape structure and processes. During simulation years, the habitat of pine warbler, the species used as an example to illustrate the methodology, became apparently fragmented under the SFI scenario. This fragmentation was caused mainly by narrow, forested streamside management zones dissecting pine stands and should have little negative influence on the pine warbler habitat. Sediment yield at the landscape level decreased by the implementation of SFI measures, particularly by the reduction of channel degradation

Effects of the Sustainable Forestry Initiative on Landscape Pattern and Processes

We used simulation modeling to study the changes in landscape pattern and function resulting from the application of the Sustainable Forestry Initiative (SFI) program in East Texas, USA. Changes in landscape structure were examined by comparing landscapes with different management histories. The effects of pattern on processes were analyzed considering vertebrate habitat quality and configuration and hydrological processes such as water and sediment yield. Landscapes managed according to the SFI program presented increased general fragmentation. The application of measures under SFI increased habitat diversity in the landscape as well as Habitat Suitability Index (HSI) values for most of the species. Habitat for species requiring large patches of mature forest was almost absent. Landscapes managed under the SFI program showed lower sediment yield at the watershed level than those under the non-SFI program due to higher channel erosion related to the absence of buffer strips in the non-SFI scenario

The role of the sustainable forestry Initiative in forest landscape changes in Texas, USA

We studied the changes in landscape pattern and function resulting from the application of the Sustainable Forestry Initiative (SFI) in East Texas, USA. Changes in landscape structure were studied by comparing land-scapes with different management histories. A methodology to integrate landscape and stand pattern dynamics with processes was developed based upon modeling and simulation. The effects of pattern on processes were analyzed with this methodology considering the quality, quantity and con-figuration of vertebrate habitat and hydrological processes. Comparisons among landscapes revealed that forest management has a strong influence on landscape structure. The SFI program has increased overall fragmentation with an increase in number of patches, length of edges and shape complexity and a decrease in patch size, and number and size of core areas. Management according to the SFI program resulted generally in higher habitat suitability for many of the species analyzed and higher habitat di-versity in the landscape. The SFI program induced fragmentation of the habitat of pine warbler and the establishment of narrow and elongated habitats in a network structure for most of the remaining species. Land-scapes managed under the SFI program showed lower sediment yield at the watershed level than those under the non-SFI program due to lower channel erosion. The effects of the SFI program at the landscape level are related to the network of buffer strips. In general we conclude that relevant measures at the landscape level improve the sustainability of forested landscapes in East Texas

Effects of the sustainable forestry Initiative on landscape function as measured by patterns of vertebrate habitats

The Sustainable Forestry Initiative (SFI) adopted in 1995 by the American Forest and Paper Association is currently applied over 90% of industrial forests in the US. This program has potential effects on forest landscape structure and function, including biodiversity. Here we analyze the effects of SFI application on the abundance and spatial pattern of vertebrate habitats in a 6,000-ha forested watershed in East Texas. Simulations of landscape structure changes in the study area were conducted based on forest inventory data and SFI rules such as regeneration harvest areas limits of 49 ha for pine and 12 ha for hardwoods, streamside management zones 30 m or more wide, and a three-year green-up interval. The 266 species (83 herps, 132 birds, 51 mammals) of vertebrates potentially occurring in the study area were grouped into 12 clusters based upon their habitat requirements. One species per cluster was selected as the indicator species for the cluster. Habitat Suitability Index models were used to develop habitat suitability maps for the indicator species based on the landscape simulations. Habitat abundance and spatial characteristics for individual vertebrate species were evaluated at different points of time to assess the effects of the SFI on vertebrate habitats as compared to reference scenarios

Universality of the thermodynamic Casimir effect

Recently a nonuniversal character of the leading spatial behavior of the thermodynamic Casimir force has been reported [X. S. Chen and V. Dohm, Phys. Rev. E {\bf 66}, 016102 (2002)]. We reconsider the arguments leading to this observation and show that there is no such leading nonuniversal term in systems with short-ranged interactions if one treats properly the effects generated by a sharp momentum cutoff in the Fourier transform of the interaction potential. We also conclude that lattice and continuum models then produce results in mutual agreement independent of the cutoff scheme, contrary to the aforementioned report. All results are consistent with the {\em universal} character of the Casimir force in systems with short-ranged interactions. The effects due to dispersion forces are discussed for systems with periodic or realistic boundary conditions. In contrast to systems with short-ranged interactions, for $L/\xi \gg 1$ one observes leading finite-size contributions governed by power laws in $L$ due to the subleading long-ranged character of the interaction, where $L$ is the finite system size and $\xi$ is the correlation length.Comment: 11 pages, revtex, to appear in Phys. Rev. E 68 (2003

Critical structure factor in Ising systems

We perform a large-scale Monte Carlo simulation of the three-dimensional Ising model on simple cubic lattices of size L^3 with L=128 and 256. We determine the corresponding structure factor (Fourier transform of the two-point function) and compare it with several approximations and with experimental results. We also compute the turbidity as a function of the momentum of the incoming radiation, focusing in particular on the deviations from the Ornstein-Zernicke expression of Puglielli and Ford.Comment: 16 page