**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.

fire and the use of biocides are severely detrimental to soil quality due to the

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

than 25%, those soil erosion control techniques should always be considered.

tection, reduced evaporation, shading, field or path delimitation, etc.).

effects on biodiversity, economic and landscape values [51–54].

connectivity to existing nearby populations.

*Fragmentation of Forest Habitat.*

extinguishment.

**128**

**Box ².**

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

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

**5.4 Conservation of the forest itself: prevention against rural fires**

reduce the size of the fire, curb its progression and even promote its self-

The occurrence of mega-fires in recent decades, not only in Portugal (since the 1980s), but in other countries, introduces another problem to solve in landscape planning: rural fires. Admittedly, landscape management cannot solve all occurrences, especially when they are of criminal or negligent origin. Nevertheless, it can

As the forest is gradually fragmented, with patches of reduced size and increasing distance, the habitat

**5.3 Biodiversity conservation**

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

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 proAn analysis considering the patch size by forest type and the land morphology was performed.

**Table 1** presents several characteristics of the forest in Portugal and its comparison with Europe.

**Variables and indicators EU-27 Trend Portugal Trend Evaluation**

n/a 62 38

1.0

22 103 19 n/a n/a 144 n/a

5.5 23.3

77 (10–100) 44 /

0.2% 1995–2015

4 88 8

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

10 (2–41)

6 (0–30) 30 (1–248) 14 (3–31) 15 (1–81) 97 (4–476) 194 (7–1196) 300(77–1284)

18.1 (5–45) 21.1

Certified forest SFM *(% f. area*) 62 15.3 / Contribution GDP *(%)* 1.0 (0.2–5.0) 1.6 /

*Different forest types in relation to the land morphology (percentage in relation to each forest type) (collected data using [74]). In Portugal, forest land use covers 3.2 million ha (36.2% of land area) (2015, [71]). The forest and agroforest types and land percentage cover are eucalyptus, mostly* Eucalyptus globulus *Labill. (26.2%), maritime-pine* Pinus pinaster *Aiton. (22.2%), cork-oak* Quercus suber *L. (22.3%), holm-oak* Quercus rotundifolia *Lam. (10.8%), other oaks* Quercus *spp. (2.5%), stone-pine* Pinus pinea *L. (6.0%), chestnut* Castanea sativa *Mill. (1.5%), carob* Ceratonia siliqua *L. (<1%), acacia* Acacia *spp. (<1%), other*

Export – Import (*M euros*) 2106 1036 *Reference year 2010 [70–73]. Good/Fair; Need improvement; Bad/At risk.*

*Status and condition of the forests in Portugal, and comparison with Europe (EU-27).*

0.75 0.7

+0.8% 2000–10

Naturalness *(% f. area*) Undisturbed by man Semi-natural Plantations

Deadwood (*m<sup>3</sup> ha<sup>1</sup>*

(*average and range*)

(*average and range*)

Protected forests –

C.II *(% f. area*) Natura 2000 *(% f. area*)

*(% f. area*)

**Table 1.**

**Figure 7.**

**131**

*broadleaves (5.9%) and other conifers (1.6%).*

Biodiversity C.I & Landscape

Forest w/management plan

*landscape unit)*

Trees Birds Mammals Other vertebrates Other invertebrates Vascular plants Fungi

Forest connectivity index *(average normalized connectivity/*

Threatened species (*n°*) – 2005

)

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



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

#### **Table 1.**

An analysis considering the patch size by forest type and the land morphology

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

**Table 1** presents several characteristics of the forest in Portugal and its compar-

**Variables and indicators EU-27 Trend Portugal Trend Evaluation**

+2% 1990–10

+12% 1990–10

+0.7% 2000–10

+26.8% 1990–10

+19% 1990–10

9% 1990–10 9.6

+2.5% 1990–10 9.2

3164 35.5

3.0

50 44 6

53 25 22

102 32

64.7 7.5 5.5 <1 22.3

> 9.6 3.0

n/a 23.7 140 7.8

31.6 16.4

38.0 0.17 4.2 n/a

28.0 +14%

1995–2015

/

/

/

/

/

2.5% 1995–15

27.4 /

154 27% 1990–10

177,757 38.0 (10.8–76.6)

805.6 (13–3466)

> 9.8 (0–48)

25.8 (0–95)

> 29 51 20

5.0 (0–70)

> 56 34 10

292 (23–1405) 44

> 61.9 9.7 12.2 2.0 14.2

> 16.9 2.6

405 (15.0) 429 (15.9) 376 (13.9) 169 (6.3) 242 (8.9)

> 25.3 17.4

2.8 2.2 0.05 0.2 1.7

Desertification (*% f. area at risk)* n/a 60

was performed.

ison with Europe.

*(range)*

Forest area – 2010 *(x 1000 ha) % land area (average)*

Coppice forest (*% forest area*) (*average and range*)

Irregular stands *(% f. area*) (*average and range*)

Tree species composition (*% forest area*) 1 species 2–3 species ≥4 species

Introduced species *(% f. area*)

Carbon stock – above gr (*MtC*) (*average/country and range*)

Forest functions *(% f. area*) (*primary function*) Production

Protection soil and water Conservation biodiversity

(*average/forest area, m<sup>3</sup> ha<sup>1</sup>*

Products (*sum & average*) Roundwood (*M m<sup>3</sup>*

Mushrooms (*M kg*) Fruits (*M kg*) Cork (*M kg*) Honey (*M kg*)

Soil condition (*C/N*) Organic floor mineral 0-10 cm

Forest damage (*% f. area*) Insects and diseases Grazing and wildlife Invasive trees Fire Storms

**130**

) (*average*)

)

)

(*average and range*)

Planting Coppice

(*average t C/ha*)

Social services Protection area

Fellings (*M m<sup>3</sup>*

Regeneration *(% f. area*) Natural regeneration

)

Growing stock (*M m3*

(*average and range*)

*Status and condition of the forests in Portugal, and comparison with Europe (EU-27).*

#### **Figure 7.**

*Different forest types in relation to the land morphology (percentage in relation to each forest type) (collected data using [74]). In Portugal, forest land use covers 3.2 million ha (36.2% of land area) (2015, [71]). The forest and agroforest types and land percentage cover are eucalyptus, mostly* Eucalyptus globulus *Labill. (26.2%), maritime-pine* Pinus pinaster *Aiton. (22.2%), cork-oak* Quercus suber *L. (22.3%), holm-oak* Quercus rotundifolia *Lam. (10.8%), other oaks* Quercus *spp. (2.5%), stone-pine* Pinus pinea *L. (6.0%), chestnut* Castanea sativa *Mill. (1.5%), carob* Ceratonia siliqua *L. (<1%), acacia* Acacia *spp. (<1%), other broadleaves (5.9%) and other conifers (1.6%).*

**Figure 7** shows the relation between each forest type and its location in land morphology, using categories defined by [75]: valley bottoms, hillslopes and large hilltops. The location of the forest in the Portuguese landscape not always fulfills the best soil and water conservation goals. Most forest species and the two species with the higher occupation and use (eucalyptus and maritime-pine plantations) are mostly located in slopes above 25%, which normally represent the less suitability for forestry production, due to the high susceptibility to soil erosion and other issues, considering the silvicultural practices that have been applied.

conservation, biodiversity conservation and conservation of the forest itself, such as many others related to the human activities (accessibility, urban

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

The former text highlights the following keywords: water retention, infiltration, headwater system, land morphology, lithology, permeability, species, combustibility, leaf litter, margins, floodwaters and springs, soil and its texture and structure, building and/or compaction, erosion, cultural practices, continuity, landscape fireprevention network. All these keywords give an idea of the complexity of the

The areas of the river basin where nature conservation issues (*latu sensu*) must be addressed have already been mentioned and constitute the materials of the landscape plan (**Figure 10**). In addition to the location, the species to be used must be defined as well as cultural practices and management models. The species to be used must correspond to their ecological suitability [76], and depending on the role, a specie or mixture of species can perform in the ecosystem [49]. As for the most combustible species, such as *Pinus pinaster* Aiton. and *Eucalyptus globulus* Labill., in case of use, a place may be reserved for them, and always outside areas where nature conservation or ecological restoration is a priority [77], such as extremely

In Portugal, the native species were almost banned, in the name of an economy linked to paper pulp and other wood products, opting for faster growing species managed in monospecific stands that constitute deserts, both animals and people. This model has had severe consequences on the depopulation of the countryside, with emigration and exodus to the cities, living in unhealthy settlements and underpaid jobs, leading to the current high risk of rural fires. It is important to take technical and political measures to improve and valuate native broadleaved species by their several goods and services, combined with management techniques that

*Conceptual scheme of landscape intervention on a river basin. The valley bottom and streams should be used for agriculture, grazing and/or riparian species; headwater systems should be covered by hardwoods which might be interspersed with void fields intended for grazing purposes. Hillslopes might be covered with woods for production interspersed with longitudinal and transversal autochthonous hardwood species, depending on the*

*slope length (d, d1) and along the contours (adapted from Magalhães et al. [66]).*

provide better profitability and contributing to sustainability.

settlements, etc.).

degraded areas.

**Figure 10.**

**133**

subject of the landscape/land-use planning.

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

The study of the dimension of the forest stand also shows that the current landscape has extensive areas of fire-prone eucalyptus and pine plantations and monocultures, with patches over 100 ha (**Figures 8** and **9**) (collected data using [74]). The large amount and contribution to the total forest cover of these forest areas are mainly eucalyptus (18%) and maritime-pine (17%) (**Figure 8**).

#### **Figure 8.**

*Forest type and patch size in relation to total forest area in Portugal (contribution of each forest type and patch size to the total country forest area).*

#### **Figure 9.**

*Distribution of patch size for different forest types (percentage in relation to each forest type).*

#### **6.1 The landscape plan**

The landscape plan that will define the composition and location of the forest in the landscape must respond to the aspects mentioned: soil conservation, water

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

conservation, biodiversity conservation and conservation of the forest itself, such as many others related to the human activities (accessibility, urban settlements, etc.).

The former text highlights the following keywords: water retention, infiltration, headwater system, land morphology, lithology, permeability, species, combustibility, leaf litter, margins, floodwaters and springs, soil and its texture and structure, building and/or compaction, erosion, cultural practices, continuity, landscape fireprevention network. All these keywords give an idea of the complexity of the subject of the landscape/land-use planning.

The areas of the river basin where nature conservation issues (*latu sensu*) must be addressed have already been mentioned and constitute the materials of the landscape plan (**Figure 10**). In addition to the location, the species to be used must be defined as well as cultural practices and management models. The species to be used must correspond to their ecological suitability [76], and depending on the role, a specie or mixture of species can perform in the ecosystem [49]. As for the most combustible species, such as *Pinus pinaster* Aiton. and *Eucalyptus globulus* Labill., in case of use, a place may be reserved for them, and always outside areas where nature conservation or ecological restoration is a priority [77], such as extremely degraded areas.

In Portugal, the native species were almost banned, in the name of an economy linked to paper pulp and other wood products, opting for faster growing species managed in monospecific stands that constitute deserts, both animals and people. This model has had severe consequences on the depopulation of the countryside, with emigration and exodus to the cities, living in unhealthy settlements and underpaid jobs, leading to the current high risk of rural fires. It is important to take technical and political measures to improve and valuate native broadleaved species by their several goods and services, combined with management techniques that provide better profitability and contributing to sustainability.

#### **Figure 10.**

**Figure 7** shows the relation between each forest type and its location in land morphology, using categories defined by [75]: valley bottoms, hillslopes and large hilltops. The location of the forest in the Portuguese landscape not always fulfills the best soil and water conservation goals. Most forest species and the two species with the higher occupation and use (eucalyptus and maritime-pine plantations) are mostly located in slopes above 25%, which normally represent the less suitability for forestry production, due to the high susceptibility to soil erosion and other issues,

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

The study of the dimension of the forest stand also shows that the current landscape has extensive areas of fire-prone eucalyptus and pine plantations and monocultures, with patches over 100 ha (**Figures 8** and **9**) (collected data using [74]). The large amount and contribution to the total forest cover of these forest

*Forest type and patch size in relation to total forest area in Portugal (contribution of each forest type and patch*

The landscape plan that will define the composition and location of the forest in

the landscape must respond to the aspects mentioned: soil conservation, water

*Distribution of patch size for different forest types (percentage in relation to each forest type).*

areas are mainly eucalyptus (18%) and maritime-pine (17%) (**Figure 8**).

considering the silvicultural practices that have been applied.

**6.1 The landscape plan**

**Figure 9.**

**132**

**Figure 8.**

*size to the total country forest area).*

*Conceptual scheme of landscape intervention on a river basin. The valley bottom and streams should be used for agriculture, grazing and/or riparian species; headwater systems should be covered by hardwoods which might be interspersed with void fields intended for grazing purposes. Hillslopes might be covered with woods for production interspersed with longitudinal and transversal autochthonous hardwood species, depending on the slope length (d, d1) and along the contours (adapted from Magalhães et al. [66]).*

It is now necessary to reverse this landscape organization model, through a new paradigm that will take at least three decades to implement and that has to be actively funded by the government.

tree size and age. The existence of trees with cavities and dead wood is of particular interest to many specialist species. The tree species also plays an important role, and there is interest in certain species by their naturalness, kind of tree-related microhabitats and associated species. Silviculture should allow the maintenance of large trees, dead wood as well as certain species, which exhibit certain features of interest for biodiversity. Trees without economic value may be maintained by its biological value, without decreasing stand production, and avoiding harvesting costs, and, on the other hand, contribute to a better functioning of the ecosystem, with positive

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

Besides ecosystems and species diversity, biodiversity also involves genetic diversity. Genetic diversity in a given population of trees is determined by the long evolutionary history and population dynamics. A genetic diversity, in terms of intra- and interpopulation variability, is also an aspect to consider in silviculture given its importance to various levels as element of biodiversity in forest growth and production and survival and adaptability and as a vital part of the ecosystem functioning. This is important in terms of reproductive success, adaptability with

The tree regeneration is a key process that influences the genetic diversity of the

Habitat loss, overexploitation and inadequate silviculture are the main factors of the Mediterranean forest degradation (e.g., Chiatante et al. [82]). Some practices such as clearcutting and fragmentation might have negative effects for soil and water status, as well on the stand regeneration. In turn, an excessive fragmentation can have negative effects on the tree seed predation and dispersion as shown by

Reducing fragmentation through appropriate silviculture helps to maintain biodiversity and the ability of forest natural adaptation. The recommended solutions resulting from specific studies vary depending on the biological groups, the forest type, the site characteristics, the distribution pattern and targets [55, 85]. Measures to solve fragmentation should also be combined with actions for forest fire prevention, particularly: actions at the social level; forest partitioning or segregation with other forms of land use (agriculture, agro-forestry and pasture); utilization of forest species more resistant to fire, with a lower combustibility and

Several programs related to the conservation and promotion of biodiversity have highlighted the importance of an integrated approach in silviculture. Some studies have shown that biodiversity conservation involves combining different types of strategies and measures applied at different scales. The level of integration of conservation measures will depend on several factors, namely, related to the ecosystem characteristics, conservation needs and forest management objectives. Several authors (e.g., Kohm and Franklin [86]; Lindenmayer and Franklin [4]) indicate the promotion or maintenance of the following key elements for the biodiversity conservation and its relationship with the landscape: stand structural complexity, connectivity and landscape heterogeneity. Continuity in space and time is an essential element to support populations, since there is a wide range of life

Silviculture should enable the development of these elements at the tree, stand and landscape levels. Different values can be achieved or involve different spatial

stand population, affecting adaptation and demographic processes. The natural regeneration improves genetic diversity and enables continuous adaptation and evolution of the population in a given location. Evaluations conducted on the application of selective cuts show that natural regeneration has positive effects in

effects on the production of the stand.

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

genetic diversity [80, 81].

fire propagation.

**135**

strategies and habitat requirements.

scales. This can create heterogeneity and spatial variability.

implications for evolution, and climate change adaptation.

Santos and Tellería [83] and Morán-López et al. [84].
