Approaches linking biodiversity assessment with landscape structure are necessary in the framework of sustainable rural development. The present paper describes a methodology to estimate plant diversity involving landscape structure as a proportional weight associated with different plant communities found in the landscape mosaic. The area occupied by a plant community, its patch number or its spatial distribution of patches are variables that could be expressed in gamma plant diversity of a territory. The methodology applies (1) remote sensing information, to identify land cover and land use types; (2) aspect, to discriminate composition of plant communities in each land cover type; (3) multi-scale field techniques, to asses plant diversity; (4) affinity analysis of plant community composition, to validate the stratified random sampling design and (5) the additive model that partitions gamma diversity into its alpha and beta components. The method was applied to three Spanish rural areas and was able to record 150-260 species per ha. Species richness, Shannon information index and Simpson concentration index were used to measure diversity in each area. The estimation using Shannon diversity index and the product of patch number and patch interspersion as weighting of plant community diversity was found to be the most appropriate method of measuring plant diversity at the landscape level.

The methodology previously used to study the afforestations by terraces with Pinus sylvestris L. in Castilla y León is extended in this paper to study in more detail the impact on physical soil properties of the afforestations by terraces with Scots pine in the northern area of the Iberian Range of Soria. The values of soil parameters are obtained from 5 profile types: non-afforested, next to the cutting, next to the embankment, between terraces and in Scots pine mature stands, located in seven plot series, and then compared. The soil parameters are evaluated as follows: fine earth, sand, silt and clay, both in the whole profile and in the upper layer of the profile, permeability, equivalent moisture and water holding capacity of the soil profile, and erodibility. After 16-17 years, no significant changes have occurred in the physical properties that define the soil habitat of the Pinus sylvestris in Spain. Significant fine particle retention, nonoutstanding decrease of permeability, considerable improvement of water holding capacity, no increase of erodibility and progress toward ecological conditions similar to the soils with mature stands are detected, with values within those of the present central habitat of the species in Spain. Regarding to the changes in the soil physical properties, this method result appropriate for afforesting with Pinus sylvestris the above-mentioned region.

Partial and preliminary results obtained from a Spanish forest formation dynamics study are presented in this paper. Seven land squares located in different land classes and selected according to a fitoclimatological gradient (Allue, 1990), have been diacronically analyzed using aerial photointerpretation and spatial analysis with G.I.S. techniques. As an overall trend, polarization in forest pattern evolution has been detected: Fragmentation and diversification have occurred in coastal and/or periurban areas, and homogenization and extensification have occurred in inner and remote areas.