**5. Forest ecosystems in the landscape**

The forest has vital importance at the landscape scale, going far beyond the production of materials and energy, called *tradable goods*. The other functions of the forest in the landscape are the conservation of water, soil and biodiversity. These supporting ecosystem services are interrelated with other forest-related ecosystem services, such as climate regulation, bioclimatic comfort and other cultural services (landscape contemplation, recreation and cultural heritage). The quality of the ecosystem services provided depends on the principles of landscape planning, followed by the technicians and policy-makers, which will also determine the sustainability of the forest.

The adequate provision of forest ecosystem services, without disturbing the landscape equilibrium, depends on the understanding of the ecological and cultural landscape context. For this, the forest planning needs to be defined in articulation with other uses considering the river basin context. The river basin is a fundamental landscape unit of planning because everything flows in it: water, sediments, nutrients, air, through the local breezes (mountain and valley), and even man and goods. This flow of energy and materials depends on the land morphology of the river basin [43], but also ecological components, invisible or unnoticeable to an ordinary observer, such as the lithology, the characteristics of soil and the land cover types existing in the basin with different behaviors in the rainwater infiltration. This last aspect of the land cover is also crucial in the thermal and water balance of the atmosphere, because if there is a change on the land cover and land use, there is a changing of the planetary albedo, meaning a change on the reflection coefficient for solar radiation. Albedo is a crucial climate factor. Thus, climate change should be discussed in an integrated way [44] concerning the impact of land use and land cover changes.

**5.1 Water conservation**

*DOI: http://dx.doi.org/10.5772/intechopen.91701*

**5.2 Soil conservation**

**127**

The main objective regarding water conservation in a river basin is to maximize its

At the river basin scale, it is also essential to address the areas where infiltration is ensured, even at low permeability. It is vital to infiltrate and retain water in the headwater systems [48] and, as much as possible, in the upper third of the basin. In this regard, Molchanov [49] indicates a minimum size of 40% of the basin's affor-

Another measure to achieve water retention is the selection of vegetation species that can contribute to good soil that has water retention capacity and also to produce a highly absorbent organic layer of soil (leaf litter and humus). In this regard, Molchanov recommends a combination of hardwoods and *Cupressaceae*. The species to be used must be autochthonous, meaning that, in each case, research is needed on the best leaf litter to obtain. As for soil capable of better retaining water, it will be developing in the

concentration time, meaning to increase its retention as long as possible before arriving into the sea through the rivers. This objective is most important in the Mediterranean climate, as in the case of Portugal, where precipitation occurs in the cold season when plants are at vegetative rest, so there is an imperative need to store rainwater in winter so that it can be used in summer. The best storage is underground, that is, in aquifers, because this prevents evaporation losses and provides better water quality due to the effects of filter and buffering capacity of the soil. In order for water to get to aquifers, it must be retained so that it has time to infiltrate. Infiltration can be achieved in two ways: a natural mode and a forced mode, that is, with active measures in that direction. Natural infiltration requires knowledge of

*Spatial and Temporal Variability Regarding Forest: From Tree to the Landscape*

the combined permeability of lithology, soil and slope degree [47].

following point, which is a common feature of all landscape-system layers.

Other areas of the river basin where water conservation is required are the streams, their banks, and floodplains, and also the springs. The banks and springs should be lined with vegetation from the riparian gallery, from various strata, from aquatic herbaceous plants to the tree layer. Floodplains, depending on the time of year, are wetlands, or even subject to flooding. They should be reserved for suitable crops or riverside trees and never have buildings (other than small irrigation or other support infrastructures). Depending on their situation in the river basin (upstream or downstream), these areas usually do not infiltrate water, especially in the rainy season, when the lower section has already depleted the infiltration capacity. Floods that occur downstream of the basin, depending on conditions, can to a large extent be controlled or mitigated by basin planning, especially in the upper third, either with appropriate coverings or with forced measures.

Soil plays a crucial role in the capacity to retain water. This capacity depends on the texture of the soil (coarser textures seep more water, while the finer textures retain it until the soil reaches field capacity, after which it begins to shed water and needs to be drained to support the plants) and depends on the soil structure. Only a well-structured soil can retain water through the clay-humic complexes and for that it has to have organic matter, including lignin, and a balanced microbial life, in which all microorganisms play an essential role, including fungi due to mycelia and

These characteristics are usually ignored by people, but also by technicians who advocate soil-destroying cultural practices. These include soil loss by building or compaction, but also by soil tillage or tillage techniques, contributing to water evaporation and erosion, especially as the slope increases. Also, the practice of prescribed

their role in improving the conditions of nutrient use by plants.

estation area, ensuring a convenient full water flow.

The location of the forest and the type of species used should, therefore, be planned to take into account all these aspects, through a landscape design that articulates them in patterns of occupation (mosaics) capable of also ensuring other functions previously described, such as continuity and stand fragmentation.

The methodology that has been developed considering the integration of different components of the landscape system is being studied in the SCAPEFIRE project (**Box 1**). The conceptual approach is to include layers by objectives and then develop their spatial integration. In order to ensure the ecological sustainability of the landscape, the layers considered are (i) water conservation, (ii) soil conservation and (iii) biodiversity conservation. To these is added one more layer concerning the sustainability of the forest by itself: (iv) the prevention of rural fires. The areas from (i), (ii) and (iii) are included in the landscape ecological network [43, 45, 46] and need to be carefully planned.

The overarching goal of the SCAPEFIRE Project is to propose a landscape planning model that contributes to the prevention of rural fires, considering the ecological, economic and social sustainability of the landscape. Some Portuguese landscapes are highly combustible due to the last four decades of inadequate policies. Despite the importance of spatial planning as a core component in the rural fire prevention, mentioned in the media and the political discourse, its definition and implementation are still to be accomplished. The proposed project is based on the assumption that a paradigm shift in the land use is needed in favor of a lesser "fire-prone" and a more sustainable model. Acknowledging the current economic importance of the most fire-prone species, the aim is to create a landscape protection structure against rural fires that ensures soil, water and biodiversity conservation and socio-economic viability. This structure will be adapted to each type of landscape. In addition to the proposal for a new land-use planning model, the economic evaluation of multifunctional agroforestry systems will be carried out. Moreover, by improving and valuating native broadleaved species by their multiple goods and services, they provide with higher comparable profitability. Therefore, this project aims to integrate the sectoral themes in a landscape/landuse plan. Its main innovation lies in the transdisciplinarity that has not been usual, either in the field of rural fire research or in public and political discussion. The core project team consists of a permanent group of researchers based at LEAF/ISA/ULisbon, where coordination is located. This team will bring together researchers across several Portuguese research centers and other national institutions and the Pau Costa Foundation with extensive knowledge on fire ecology and operational fire management at landscape level. Stakeholder participation will be present throughout the Project, through a group of researchers, public entities linked to land-use planning, at national level (Directorate General of the Territory), and local (municipalities), but also owners and the Portuguese Federation of Local Development Associations (MINHA TERRA).

**Box ¹.** *Species movement.* *Spatial and Temporal Variability Regarding Forest: From Tree to the Landscape DOI: http://dx.doi.org/10.5772/intechopen.91701*

### **5.1 Water conservation**

The adequate provision of forest ecosystem services, without disturbing the landscape equilibrium, depends on the understanding of the ecological and cultural landscape context. For this, the forest planning needs to be defined in articulation with other uses considering the river basin context. The river basin is a fundamental landscape unit of planning because everything flows in it: water, sediments, nutrients, air, through the local breezes (mountain and valley), and even man and goods. This flow of energy and materials depends on the land morphology of the river basin [43], but also ecological components, invisible or unnoticeable to an ordinary observer, such as the lithology, the characteristics of soil and the land cover types existing in the basin with different behaviors in the rainwater infiltration. This last aspect of the land cover is also crucial in the thermal and water balance of the atmosphere, because if there is a change on the land cover and land use, there is a changing of the planetary albedo, meaning a change on the reflection coefficient for solar radiation. Albedo is a crucial climate factor. Thus, climate change should be discussed in an integrated way [44] concerning the impact of land use and land

*Spatial Variability in Environmental Science - Patterns, Processes, and Analyses*

The location of the forest and the type of species used should, therefore, be planned to take into account all these aspects, through a landscape design that articulates them in patterns of occupation (mosaics) capable of also ensuring other functions previously described, such as continuity and stand fragmentation.

tion and (iii) biodiversity conservation. To these is added one more layer

[43, 45, 46] and need to be carefully planned.

The methodology that has been developed considering the integration of different components of the landscape system is being studied in the SCAPEFIRE project (**Box 1**). The conceptual approach is to include layers by objectives and then develop their spatial integration. In order to ensure the ecological sustainability of the landscape, the layers considered are (i) water conservation, (ii) soil conserva-

concerning the sustainability of the forest by itself: (iv) the prevention of rural fires. The areas from (i), (ii) and (iii) are included in the landscape ecological network

The overarching goal of the SCAPEFIRE Project is to propose a landscape planning model that contributes to the prevention of rural fires, considering the ecological, economic and social sustainability of the landscape. Some Portuguese landscapes are highly combustible due to the last four decades of inadequate policies. Despite the importance of spatial planning as a core component in the rural fire prevention, mentioned in the media and the political discourse, its definition and implementation are still to be accomplished. The proposed project is based on the assumption that a paradigm shift in the land use is needed in favor of a lesser "fire-prone" and a more sustainable model. Acknowledging the current economic importance of the most fire-prone species, the aim is to create a landscape protection structure against rural fires that ensures soil, water and biodiversity conservation and socio-economic viability. This structure will be adapted to each type of landscape. In addition to the proposal for a new land-use planning model, the economic evaluation of multifunctional agroforestry systems will be carried out. Moreover, by improving and valuating native broadleaved species by their multiple goods and services, they provide with higher comparable profitability. Therefore, this project aims to integrate the sectoral themes in a landscape/landuse plan. Its main innovation lies in the transdisciplinarity that has not been usual, either in the field of rural fire research or in public and political discussion. The core project team consists of a permanent group of researchers based at LEAF/ISA/ULisbon, where coordination is located. This team will bring together researchers across several Portuguese research centers and other national institutions and the Pau Costa Foundation with extensive knowledge on fire ecology and operational fire management at landscape level. Stakeholder participation will be present throughout the Project, through a group of researchers, public entities linked to land-use planning, at national level (Directorate General of the Territory), and local (municipalities), but also owners and the Portuguese Federation of Local Development Associations

cover changes.

(MINHA TERRA).

**Box ¹.** *Species movement.*

**126**

The main objective regarding water conservation in a river basin is to maximize its concentration time, meaning to increase its retention as long as possible before arriving into the sea through the rivers. This objective is most important in the Mediterranean climate, as in the case of Portugal, where precipitation occurs in the cold season when plants are at vegetative rest, so there is an imperative need to store rainwater in winter so that it can be used in summer. The best storage is underground, that is, in aquifers, because this prevents evaporation losses and provides better water quality due to the effects of filter and buffering capacity of the soil. In order for water to get to aquifers, it must be retained so that it has time to infiltrate.

Infiltration can be achieved in two ways: a natural mode and a forced mode, that is, with active measures in that direction. Natural infiltration requires knowledge of the combined permeability of lithology, soil and slope degree [47].

At the river basin scale, it is also essential to address the areas where infiltration is ensured, even at low permeability. It is vital to infiltrate and retain water in the headwater systems [48] and, as much as possible, in the upper third of the basin. In this regard, Molchanov [49] indicates a minimum size of 40% of the basin's afforestation area, ensuring a convenient full water flow.

Another measure to achieve water retention is the selection of vegetation species that can contribute to good soil that has water retention capacity and also to produce a highly absorbent organic layer of soil (leaf litter and humus). In this regard, Molchanov recommends a combination of hardwoods and *Cupressaceae*. The species to be used must be autochthonous, meaning that, in each case, research is needed on the best leaf litter to obtain. As for soil capable of better retaining water, it will be developing in the following point, which is a common feature of all landscape-system layers.

Other areas of the river basin where water conservation is required are the streams, their banks, and floodplains, and also the springs. The banks and springs should be lined with vegetation from the riparian gallery, from various strata, from aquatic herbaceous plants to the tree layer. Floodplains, depending on the time of year, are wetlands, or even subject to flooding. They should be reserved for suitable crops or riverside trees and never have buildings (other than small irrigation or other support infrastructures). Depending on their situation in the river basin (upstream or downstream), these areas usually do not infiltrate water, especially in the rainy season, when the lower section has already depleted the infiltration capacity. Floods that occur downstream of the basin, depending on conditions, can to a large extent be controlled or mitigated by basin planning, especially in the upper third, either with appropriate coverings or with forced measures.

#### **5.2 Soil conservation**

Soil plays a crucial role in the capacity to retain water. This capacity depends on the texture of the soil (coarser textures seep more water, while the finer textures retain it until the soil reaches field capacity, after which it begins to shed water and needs to be drained to support the plants) and depends on the soil structure. Only a well-structured soil can retain water through the clay-humic complexes and for that it has to have organic matter, including lignin, and a balanced microbial life, in which all microorganisms play an essential role, including fungi due to mycelia and their role in improving the conditions of nutrient use by plants.

These characteristics are usually ignored by people, but also by technicians who advocate soil-destroying cultural practices. These include soil loss by building or compaction, but also by soil tillage or tillage techniques, contributing to water evaporation and erosion, especially as the slope increases. Also, the practice of prescribed fire and the use of biocides are severely detrimental to soil quality due to the destruction they cause of their biome. The issue of erosion should be addressed in the presence of soil erosion maps [50] in order to propose the best land cover to provide pedogenesis and water infiltration. In the absence of these maps, it is well known that, among the factors involved in erosion, the slope is decisive, so depending on the soil types and the evidence of erosion, it is necessary to evaluate which slopes from which erosion control techniques should be programmed. However, on slopes greater than 25%, those soil erosion control techniques should always be considered.

One of the critical components of fire behavior is known to be basin morphology, including slope, aspect and altitude [59–61]. The slopes exposed to the north, with slopes >25%, are the least burning [62]. The speed of fire progression doubles for each 10° increase in slope [63] and is reduced when it reaches the top, due to the local wind from the opposite slope. When it reaches the ridge, if it does not progress in the opposite slope, the fire begins to plow toward the lower slope, more slowly than when the slope rises. Given this pattern of fire behavior, it is essential to create a landscape fire-prevention network directly related to the watershed morphology that contains or extinguishes the fire. Agee et al. [64] propose the installation of shaded fuel breaks as low-fuel vegetation strips or areas (note that they do not correspond to the fuel management strips provided for in Portuguese law, with no vegetation and bare soil). These authors propose that these shaded fuel breaks be networked, according to the site, and say they are more efficient if they are wide

*Spatial and Temporal Variability Regarding Forest: From Tree to the Landscape*

The key areas of the river basin in which to intervene for this purpose are the structuring lines of the landscape‑the streams and the ridges. According to Povak et al. [65], the waterlines and associated valley bottoms are more important for this purpose than the ridges. If the slope is too long, one or more fire retardant strips should be introduced downhill along the slope to avoid top-down and down-up fire [61]. To complete the structure, it is also necessary to create strips transverse to the slope. In the hillslope, the streams and the secondary ridges alternate, so it is in these secondary lines that these fire-retardant strips should be

Concerning the species to be used, there is a considerable debate about the higher or lower combustibility of species. In Portugal, *Eucalyptus globulus* Labill. and *Pinus pinaster* Aiton. have occupied the country and are currently the two species with the present main commercial value, since the industries related to the transformation of autochthonous species have practically disappeared, which discourages the owners for their use. The simple empirical observation of fires and their consequences, as well as the analyses carried out on the species that burned the most, allows to say that these two tree species are more combustible than the autochthonous tree species. From the available literature, Silva et al. [67] verified a tendency toward fire, in decreasing order of: pinewood, eucalyptus forests, broadleaf forests, unspecified coniferous forests, cork oak forests, chestnut orchards and holm oak. They also concluded that stand composition is the most important variable to explain the probability of fire. Calviño-Cancela et al. [68] also state that autochthonous species are more fire-resistant, as well as the studies concerning leaf litter combustibility [69]. In this context, it has to be admitted that species are not equally combustible and that, as might be expected, hardwoods other than eucalyptus are more fire-resistant and therefore can be regarded as fire-retardant. The landscape fire-prevention network should, therefore, be planned with different tree species, always avoiding monocultures. In this network, it is also possible to have the agricultural fields, pastures and, ultimately, voids (without shrub or tree vegetation) that, however, should be covered with herbaceous plants so as not to leave

**6. Evaluation of the forest condition in Portugal: analysis and results**

Different characteristics and variables concerning the forest of Portugal were evaluated to provide an overview of their status and condition. Data were collected considering different sources and analyzed, taking into consideration the main features related to the sustainable forest management goals and including the forest landscape features in relation to the habitat mosaic and connectivity.

and have surface fuel control bands.

*DOI: http://dx.doi.org/10.5772/intechopen.91701*

the soil uncovered and prevent its erosion.

created [66].

**129**

#### **5.3 Biodiversity conservation**

Concerning the conservation of biodiversity, much has already been mentioned. With regard to the landscape, aspects that still need to be considered, apart from those for water and soil conservation, are the fragmentation and continuity necessary for the conservation of life flows (plants and animals) (**Box 2**). Continuity should be ensured in the main structural lines of the landscape (ridges and waterlines), creating links with existing forest areas. Where there is no forest, both in rural and urban areas, continuity should be achieved by partitioning the landscape through linear biodiverse structures (hedges) consisting of shrubs and tree species, depending on the functions to be obtained, in addition to biodiversity (wind protection, reduced evaporation, shading, field or path delimitation, etc.).

An important aspect about the variability and biodiversity is related to the landscape and fragmentation of the forest habitat. Many studies, including in the Mediterranean region, have shown that an excessive forest fragmentation is another element of fragility and vulnerability of the forest with adverse effects on biodiversity, economic and landscape values [51–54].

As the forest is gradually fragmented, with patches of reduced size and increasing distance, the habitat became increasingly more isolated. This has a major impact on habitat loss, on the different biotic communities, the population dynamics and processes of the forest ecosystem. Habitat connectivity has an important effect on the persistence and abundance of different species [55, 56]. The gradual fragmentation may also lead to the extinction of species of different biological groups that are more sensitive to this process. The colonization of a species results from the combination of dispersion and recruitment. Certain species of slow dispersion are affected by excessive fragmentation. For certain species, with a narrow ecological niche or limited dispersal ability, habitat reduction leads to risk of extinction of local populations. On the other hand, small fragments are more susceptible to degradation factors. In smaller fragments, the edge effect is larger.

Habitat destruction leads to biodiversity loss not only in the affected areas but also in the fragments due to the population size reduction, the disruption in the movement and interactions [52]. The functional connectivity is a crucial factor in the viability of certain populations, the dynamics and interspecific interactions (e.g., Tilman and Kareiva [57]). Species movement and dispersal, genetic exchange and other ecological flows in a given area are important for the survival and viability of many species [19]. Some studies show that as the proportion of a given habitat reduces, the colonization possibilities of the remaining fragments decrease (e.g., With et al. [42]). Fragmentation has also effects on the stand genetic variability [58]. Recovery after a disturbance will be heavily influenced by the availability of seedlings and the connectivity to existing nearby populations.
