Gonzalez-Rodriguez V.,Area de Ecologia |
Villar R.,Area de Ecologia |
Casado R.,Area de Ecologia |
Suarez-Bonnet E.,Area de Ecologia |
And 2 more authors.
Annals of Forest Science | Year: 2011
Introduction : The great spatial and temporal heterogeneity of Mediterranean ecosystems can influence establishment success in woody species, whose natural regeneration occurs to a very small extent. In this work, the effect of the spatial pattern of environmental variables (light availability, soil moisture and herbaceous production) on seedling emergence, growth, survival and establishment success was examined by using a spatially explicit approach. Methods : Seeds of four Quercus species differing in leaf longevity (Quercus ilex, Quercus suber, Quercus faginea and Quercus pyrenaica) were sown in two plots located in a holm oak forest (southern Spain). The spatial pattern of the studied variables was examined by Spatial Analysis by Distance Indices. Results : All environmental variables exhibited an aggregated spatial pattern. There was no clear spatial association between the environmental variables and emergence and survival. Only soil moisture during the dry season was spatially associated with the establishment success of all the species. Species also differed in survival and establishment success, with evergreens having higher percentages than deciduous. No aggregated spatial pattern for growth and morphological traits was apparent, these being more dependent on seed mass than on environmental factors. Identifying which microsites facilitate regeneration may provide useful hints with a view in focusing restoration endeavours on microenvironments with high survival percentage. © 2011 INRA and Springer Science+Business Media B.V.
Lopez F.J.,Edificio Leonardo da Vinci |
Pinzi S.,Edificio Leonardo da Vinci |
Ruiz J.J.,Edificio Leonardo da Vinci |
Lopez A.,Edificio Leonardo da Vinci |
Dorado M.P.,Edificio Leonardo da Vinci
Fuel | Year: 2010
Biomass from olive tree pruning could be used as fuel for heating systems in boiler, thus helping to mitigate CO2 emissions and reducing the dependence on fossil fuels. It also helps to reap secondary benefits, such as the creation of employment in rural areas. In the present study, an economic viability analysis about the use of olive tree pruning as fuel for heating systems in public schools of Lucena (Andalusia, Spain) have been carried out. This town has been selected due to its proximity to olive tree plantations. The heat cost calculations were based on the standard VDI 2067. Eventually, a sensitivity analysis to assess the effect of prices variation over the time needed to recover the investment has been carried out. It can be concluded that, in many cases, subsidies are needed to promote modern biomass technologies, to compensate for non-internalized external costs of fossil fuel systems. In case a subsidy up to 50% of the investment is applied, payback is reduced, thus biomass boiler using olive tree chips is strongly recommended. Energy cost using olive tree chips is highly dependent on the high variability of the boilers working period. In all case studies, based on the sensitivity analysis, a maximum radius of 5 km of olive trees cuttings is enough to feed the public school boilers of the town. Also, it can be seen that the cost of energy considering either olive tree chips or olive pits is similar. © 2009 Elsevier Ltd. All rights reserved.