Improving management decisions in portuguese forests through fire behaviour modeling: guidelines to support a sustainable landscape

PosterUnderstanding wildfire behavior at the landscape-level is critical to address wildfire impacts in Portuguese forest management planning. Thus, fire spread was simulated in three forested landscape to assist forest managers in identifying high-risk areas for actively integrating stand-level fuel treatments with explicit landscape-level management planning and develop fire prevention priorities. Specifically, several modeling applications to detect significant fire-landscape interactions between stand-level features and fire behavior were fitted to classify Portuguese forests to fire risk levels and create guidelines to support hazard-reduction silvicultural practiceN/

Evaluacion de la probabilidad de ocurrencia de fuegos en rodales de Pinus pinaster Ait en Portugal

Maritime pine (Pinus pinaster Ait.) is an important conifer from the western Mediterranean Basin extending over 22% of the forest area in Portugal. In the last three decades nearly 4% of Maritime pine area has been burned by wildfires. Yet no wildfire occurrence probability models are available and forest and fire management planning activities are thus carried out mostly independently of each other. This paper presents research to address this gap. Specifically, it presents a model to assess wildfire occurrence probability in regular and pure Maritime pine stands in Portugal. Emphasis was in developing a model based on easily available inventory data so that it might be useful to forest managers. For that purpose, data from the last two Portuguese National Forest Inventories (NFI) and data from wildfire perimeters in the years from 1998 to 2004 and from 2006 to 2007 were used. A binary logistic regression model was build using biometric data from the NFL Biometric data included indicators that might be changed by operations prescribed in forest planning. Results showed that the probability of wildfire occurrence in a stand increases in stand located at steeper slopes and with high shrubs load while it decreases with precipitation and with stand basal area. These results are instrumental for assessing the impact of forest management options on wildfire probability thus helping forest managers to reduce the risk of wildfire

A three-step approach to post-fire mortality modelling in maritime pine (Pinus pinaster Ait.) stands for enhanced forest planning in Portugal

Maritime pine (Pinus pinaster Ait) is a very important timber-producing species in Portugal with a yield of ~67.1 million m3 year21. It covers ~22.6 per cent of the forest area (710.6 × 103 ha). Fire is the most significant threat to maritime pine plantations. This paper discusses research aiming at the development of post-fire mortality models for P. pinaster Ait stands in Portugal that can be used for enhanced integration of forest and fire management planning activities. Post-fire mortality was modelled using biometric and fire data from 2005/2006 National Forest Inventory plots and other sample plots within 2006–2008 fire perimeters. A three-step modelling strategy based on logistic regression methods was used. Firstly, the probability of mortality to occur after a wildfire in a stand is predicted and secondly, the degree of mortality caused by a wildfire on stands where mortality occurs is quantified. Thirdly, mortality is distributed among trees. The models are based on easily measurable tree characteristics so that forest managers may predict post-fire mortality based on forest structure. The models show that relative mortality decreases when average d.b.h. increases, while slope and tree size diversity increase the mortalityinfo:eu-repo/semantics/publishedVersio

Developing wildfire risk probability models for Eucalyptus globulus stands in Portugal

This paper presents a model to predict annual wildfire risk in pure and even-aged eucalypt stands in Portugal. Emphasis was in developing a management-oriented model, i.e., a model that might both: (a) help assess wildfire occurrence probability as a function of readily available forest inventory data; and (b) help predict the effects of management options (e.g., silvicultural treatments) on the risk of fire in eucalypt stands. Data from both the 1995/1998 and the 2005/2006 Portuguese National Forest Inventories as well as wildfire perimeters’ data were used for modeling purposes. Specifically, this research considered 1122 inventory plots with approximately 1.2 million trees and 85 wildfire perimeters. The model to predict the probability of wildfire occurrence is a logistic function of measurable and controllable biometric and environmental variables. Results showed that wildfire occurrence probability in a stand increases with the ratio basal area/quadratic mean diameter and with the shrubs biomass load, while it decreases with stand dominant height. They further showed that the probability of wildfire occurrence is higher in stands that are over 1 Km distant from roads. These results are instrumental for assessing the impact of forest management options on wildfire risk levels thus helping forest managers develop plans that may mitigate wildfire impacts

Fluorescence Spectroscopy of Porphyrins and Phthalocyanines: Some Insights into Supramolecular Self-Assembly, Microencapsulation, and Imaging Microscopy

The molecular interactions of anionic tetrasulfonate phenyl porphyrin (TPPS) with poly(amido amine) (PAMAM) dendrimers of generation 2.0 and 4.0 (G2 and G4, respectively) forming H- or J-aggregates, as well as with human and bovine serum albumin proteins (HSA and BSA), were reviewed in the context of self-assembly molecular complementarity. The spectroscopic studies were extended to the association of aluminum phthtalocyanine (AlPCS4) detected with a PAMAM G4 dendrimer with fluorescence studies in both steady state and dynamic state, as well as due to the fluorescence quenching associated to electron-transfer with a distribution of lifetimes. The functionalization of TPPS with peripheral substituents enables the assignment of spontaneous pH-induced aggregates with different and well-defined morphologies. Other work reported in the literature, in particular with soft self-assembly materials, fall in the same area with particular interest for the environment. The microencapsulation of TPPS studies into polyelectrolyte capsules was developed quite recently and aroused much interest, which is well supported and complemented by the extensive data reported on the Imaging Microscopy section of the Luminescence of Porphyrins and Phthalocyanines included in the present review

Modelling post-fire mortality in pure and mixed forest stands in Portugal

Assessing impacts of management strategies may allow designing more resistant forests to wildfires. Planning-oriented models to predict the effect of stand structure and forest composition on mortality for supporting fire-smart management decisions, and allowing its inclusion in forest management optimization systems were developed. Post-fire mortality was modeled as a function of measurable forest inventory data and projections over time in 165 pure and 76 mixed forest stands in Portugal, collected by the 5th National Forest Inventory plots (NFI) plus other sample plots from ForFireS project, intercepted within 2006–2008 wildfire perimeters’ data. Presence and tree survival were obtained by examining 2450 trees from 16 species one year after the wildfire occurrence. A set of logistic regression models were developed under a three-stage modeling system: firstly multiple fixed-effects at stand-level that comprises a sub-model to predict mortality from wildfire; and another for the proportion of dead trees on stands killed by fire. At tree-level due to the nested structure of the data analyzed (trees within stands), a mixed-effect model was developed to estimate mortality among trees in a fire event. The results imply that the variation of tree mortality decreases when tree diameter at breast height increases. Moreover, the relative mortality increases with stand density, higher altitude and steeper slopes. In the same conditions, conifers are more prone to die than eucalyptus and broadleaves. Pure stands of broadleaves exhibit noticeably higher fire resistance than mixed stands of broadleaves and others species composition

Fluorescent dye nano-assemblies by thiol attachment directed to the tips of gold nanorods for effective emission enhancement

The conjugation of dye-labelled DNA oligonucleotides with gold nanorods has been widely explored for the development of multifunctional fluorescent nanoprobes. Here, we show that the functionalization route is crucial to achieve enhanced emission in dye nano-assemblies based on gold nanorods. By using a tip-selective approach for thiol attachment of dye molecules onto gold nanorods, it was possible to effectively increase the emission by more than 10-fold relatively to that of a free dye. On the other hand, a non-selective approach revealed that indiscriminate surface functionalization has a detrimental effect on the enhancement. Simulations of discrete dipole approximation gave further insight into the surface distribution of plasmon-enhanced emission by confirming that tip regions afford an effective enhancement, while side regions exhibit a negligible effect or even emission quenching. The contrast between dye nano-assemblies obtained from tip- and non-selective functionalization was further characterized by single-particle fluorescence emission. These studies showed that tip-functionalized gold nanorods with an average of only 30 dye molecules have a comparable to or even stronger emission than non-selectively functionalized particles with approximately 10 times more dye molecules. The results herein reported could significantly improve the performance of dye nano-assemblies for imaging or sensing applications.UID/BIO/04565/2019, UID/QUI/00100/2019, UID/Multi/04326/2019, PD/BD/113630/2015, SFRH/BPD/111906/2015info:eu-repo/semantics/publishedVersio

Enhanced-Fluorescence of a Dye on DNA- assembled Gold Nano-Dimers Discriminated by Lifetime Correlation Spectroscopy

We have employed DNA-directed assembly to prepare dimers of gold nanoparticles and used their longitudinally coupled plasmon mode to enhance the fluorescence emission of an organic red-emitting dye, Atto-655. The plasmon- enhanced fluorescence of this dye using dimers of 80 nm particles was measured at single molecule detection level. The top enhancement factors were above 1000-fold in 71% of the dimers within a total of 32 dimers measured, and, in some cases, they reached almost 4000-fold, in good agreement with model simulations. Additionally, fluorescence lifetime correlation analysis enabled the separation of enhanced from non-enhanced emission simultaneously collected in our confocal detection volume. This approach allowed us to recover a short relaxation component exclusive to enhanced emission that is attributed to the interaction of the dye with DNA in the interparticle gaps. </div