Paula Soares

Evaluating a growth model for forest management using continuous forest inventory data

Abstract Model evaluation should include qualitative as well as quantitative examinations of the model. The qualitative parts should comprise a critical appraisal of model logic as well as theoretical and biological realism of the model. The quantitative parts should comprise statistical tests and comparisons of predictions with observations independent of those used to fit the model. Comprehensive model evaluation requires several alternative approaches and criteria. Model evaluation is not one simple procedure, but consists of a number of interrelated steps that should not be separated from each other or from model construction. It is stressed that models can only be evaluated in relative terms, and their predictive value is always open to question. Thus, model evaluation is an ongoing process. A case study with the PBRAVO growth model for maritime pine (Pinus pinaster Ait.) in the Leiria forest, Portugal, illustrates the utility of selected criteria and graphical techniques. Based on theoretical examinations and tests with data from continuous forest inventories, we conclude that the Leiria version of the PBRAVO model does not adequately represent reality and that forecasts lack sufficient accuracy for forest management purposes.

Effect of tree, stand, and site variables on the allometry of Eucalyptus globulus tree biomass.

The objective of this study was to develop a system of compatible equations to estimate eucalyptus (Eucalyptus globulus Labill.) tree aboveground biomass and biomass of tree components for forest biomass prediction across regional boundaries. Data came from 441 trees sampled on several sites (99 and 14 plots in planted and coppice regenerated stands, respectively) representative of the eucalyptus expansion area in Portugal. The system of equations, simultaneously fitted using seemingly unrelated regression, was based on the allometric model for the biomass of stem wood, stem bark, leaves, and branches. Total aboveground biomass was expressed as the sum of the biomass of the respective tree components. The study allowed the following conclusions: (i) there is a significant increase in the predictive ability of the models that include height (stem components) or crown length (crown components) as an additional predictor to diameter at 1.30xa0m; (ii) there is a clear effect of the stage of development of the s...

Height–diameter equation for first rotation eucalypt plantations in Portugal

Abstract A height–diameter equation for eucalypt plantations was developed based on a tree dataset from trials and permanent plots located in the north and central coastal regions of Portugal. The total dataset was split into two datasets through restricted random sampling at the plot level. The equations selected in one data subset were evaluated with the other subset and vice versa. Harrison equation, fitted with the iteratively reweighted least squares method, in both versions—restricted and not restricted to pass through the point diameter–height (0, 1.30)—was selected. The first version was recommended for young plantations; it is age dependent and requires a measure of stand productivity. The second version was appropriate to use in commercial forest inventory where trees smaller than 4xa0cm diameter are not measured; it is age independent, density dependent and, also requires a measure of stand productivity.

Impact of pelvic radiotherapy on female sexuality

PurposeTo assess physical and psychological morbidity, sexual functioning and social and relationship satisfaction among women treated with pelvic radiotherapy.MethodsObservational (case–control) study of 199 women: 98 submitted to pelvic radiotherapy for the treatment of uterine, rectal or anal cancers and 101 without a personal history of cancer and similar socio-demographic variables. These completed a socio-demographic and clinical questionnaire, and validated measures of psychological health (DASS: Lovibond and Lovibond in Behav Res Ther 33:353–343, 1995), sexual function (FSFI: Rosen et al. in J Sex Marital Ther 26:191–208, 2007), social support (ESSS: Ribeiro in Analise Psicologica 3:547–558, 1999) and relationship satisfaction (IMS: Hudson in The WALMYR assessment scales scoring manual 1992).ResultsWomen submitted to pelvic irradiation reported a higher rate of adverse physical symptoms in the last month: fatigue 59 versus 25% (pxa0<xa00.001), lack of strength 42 versus 20% (pxa0=xa00.001), diarrhoea 24 versus 12% (pxa0=xa00.032), vaginal discharge 17 versus 7% (pxa0=xa00.024), skin erythema 9 versus 2% (pxa0=xa00.026). Levels of depression, anxiety and stress were higher among radiotherapy patients, but only reach statistical significance for the stress parameter (6.1 vs. 4.0, pxa0=xa00.012). Also these women reported lower scores of satisfaction with social support (57.2 vs. 62.2, pxa0=xa00.005) and sexual function (8.5 vs. 13.5, pxa0=xa00.049). No statistically significant differences occurred between the two groups regarding scores of relationship satisfaction (20.8 vs. 19.9, pxa0=xa0n.s.).ConclusionsOur results suggested that pelvic radiotherapy had a negative impact on female sexuality. Thus, interventions that would help to reduce this impact need to be designed and integrated into routine clinical practice.

Airborne Lidar Estimation of Aboveground Forest Biomass in the Absence of Field Inventory

The scientific community involved in the UN-REDD program is still reporting large uncertainties about the amount and spatial variability of CO2 stored in forests. The main limitation has been the lack of field samplings over space and time needed to calibrate and convert remote sensing measurements into aboveground biomass (AGB). As an alternative to costly field inventories, we examine the reliability of state-of-the-art lidar methods to provide direct retrieval of many forest metrics that are commonly collected through field sampling techniques (e.g., tree density, individual tree height, crown cover). AGB is estimated using existing allometric equations that are fed by lidar-derived metrics at either the individual tree- or forest layer-level (for the overstory or underneath layers, respectively). Results over 40 plots of a multilayered forest located in northwest Portugal show that the lidar method provides AGB estimates with a relatively small random error (RMSE = of 17.1%) and bias (of 4.6%). It provides local AGB baselines that meet the requirements in terms of accuracy to calibrate satellite remote sensing measurements (e.g., the upcoming lidar GEDI (Global Ecosystem Dynamics Investigation), and the Synthetic Aperture Radar (SAR) missions NISAR (National Aeronautics and Space Administration and Indian Space Research Organization SAR) and BIOMASS from the European Space Agency, ESA) for AGB mapping purposes. The development of similar techniques over a variety of forest types would be a significant improvement in quantifying CO2 stocks and changes to comply with the UN-REDD policies.

Impact of neoadjuvant chemoradiation on pathologic response and survival of patients with locally advanced rectal cancer.

BACKGROUNDnThe impact of neoadjuvant chemotherapy (CT) and radiotherapy (RT) on overall survival (OS) has been controversial. Some studies have pointed to an improvement in OS and disease-free survival (DFS) in patients with pathologic complete response (pCR).nnnAIMnTo evaluate the therapeutic response and impact on survival of preoperative RT, alone or combined with CT, in patients with locally advanced rectal cancer (LARC).nnnMATERIALS AND METHODSnA set of 132 patients with LARC were treated preoperatively. GROUP 1: RT alone, 19 patients. GROUP 2: RT and concomitant oral CT (Capecitabine or UFTxa0+xa0leucovorin), 68 patients. GROUP 3: RT and concomitant CT with 5-FU in continuous infusion, 45 patients. 58.2% of patients were submitted to adjuvant CT.nnnRESULTSnGROUP 1: no pCR, tumoral downstaging was 26.7%. GROUP 2: pCR in 16.9%; tumoral downstaging was 47.7%. GROUP 3: pCR in 11.9%; tumor downstaging was 52.4%. The loco-regional control (LRC) was 95%. The 5-year OS (pxa0=xa00.038) and DFS (pxa0=xa00.05) were significantly superior in patients treated with CTxa0+xa0RT. Patients with pCR had a significant increase on DFS (pxa0=xa00.019). Patients cT3-4 that had a tumoral downstaging to ypT0-2, showed an increase on DFS, OS and LRC.nnnCONCLUSIONSnCT combined with RT has increased tumoral response and survival rate. Nodal downstaging and pCR were higher in the GROUP 2. The 5-year OS and DFS were significantly superior in CTxa0+xa0RT arms. Patients with pathologic response showed a better DFS. Adjuvant CT had no impact on LRC, DFS nor on OS.

Canopy Density Model: A New ALS-Derived Product to Generate Multilayer Crown Cover Maps

The canopy density model (CDM), a new product interpolated from airborne laser scanner (ALS) data and dedicated to forest structure characterization is presented. It exploits both the multiecho capability of the ALS and a nonparametric density estimation technique called kernel density estimators (KDEs). The CDM is used to delineate the outmost perimeter of vegetation features and to compute forest crown cover (CrCO). Contrary to other works that focus on single-layer forest canopies, CrCo is derived here for each layer, namely, the overstory, the understory, and ground vegetation. The root-mean-square error of prediction determined by using field data acquired over 44 forest stands in a forest in Portugal allows the testing of the reliability of the method: It ranges from 6.21% (overstory) to 13.76% (ground vegetation). In addition, we investigate the ability of the CDM to map the CrCo for individual trees. Finally, two existing methods have been applied to our study site in order to assess improvements, advantages, and drawbacks of our approach.

Comparing small-footprint lidar and forest inventory data for single strata biomass estimation - A case study over a multi-layered mediterranean forest

Current methods for accurately estimating vegetation biomass with remote sensing data require extensive, representative and time consuming field measurements to calibrate the sensor signal. In addition, such techniques focus on the topmost vegetation canopy and thus they are of little use over multi-layered forest ecosystems where the underneath strata hold considerable amounts of biomass. This work is the first attempt to estimate biomass by remote sensing without the need for massive in situ measurements. Indeed, we use small-footprint airborne laser scanning (ALS) data to derive key forest metrics, which are used in allometric equations that were originally established to assess biomass using field measurements. Field- and ALS-derived biomass estimates are compared over 40 plots of a multi-layered Mediterranean forest. Linear regression models explain up to 99% of the variability associated with surface vegetation, understory, and overstory biomass.

Assessment of the indirect impact of wildfire (severity) on actual evapotranspiration in eucalyptus forest based on the surface energy balance estimated from remote-sensing techniques

ABSTRACT Wildfires have a strong impact on the environment, changing its structure, soil properties, and microclimate and subsequently its water cycle with implications on the surface energy fluxes. Persisting droughts and catastrophic forest fires initiated this case study of pure eucalyptus stands in north-central Portugal. Although many studies have investigated changes in actual evapotranspiration (ETa), surface energy flux patterns, and the related physical parameters, only a few concentrated on the fire-driven changes in pure eucalyptus stands in the Mediterranean climate. This study aims to understand the consequences of wildfires on the water cycle, namely the ETa, and the surface energy heat fluxes by applying a simplified two-source energy balance model in combination with medium-resolution imagery (Landsat 8). A total of 21 different burnt locations were evaluated, which burned between 2011 and 2013. Estimated surface energy fluxes and daily ETa were compared to nearby control sites (unburnt) during satellite overpass for the time after the fire (2013–2015). The fire scars were classified into their burn severity, using the differenced Normalized Burn Ratio. The absolute difference of ETa ( ETa) between unburnt and burnt locations was used to identify fire-driven changes in magnitude and its evolution over time. Our results show that for the unburnt stands, the contributions to the total latent heat flux were around 80% from the canopy and 20% from the soil, while for the burnt site the contributions were around 30% (canopy) and 70% (soil) shortly after the fire. Inter-annually, the difference in ETa increased during the rainy season, which was related to the epicormic shooting, the fast regrowth rate of foliage, and the abundance of water. Generally, smaller differences in ETa were related to the severity classification and stand properties (i.e. tree species and soil characteristics). Two to three years after the fire events, ETa became non-significant for all severity classes, leading to an impact on the total water cycle smaller in comparison to other post-fire studies.

Observation of tumor morphological changes in lung irradiation with orthogonal ray imaging: RTmonitoring - A simulation study

Orthogonal ray imaging is a new potential technique that consists in detecting radiation dispersed in the patient and emitted perpendicularly to the beam axis. RTmonitoring aims at real time radiotherapy (RT) monitoring. OrthoCT addresses low-dose patient morphologic imaging, mainly on-board for assisting RT (not studied here). We report Geant4 simulations analyzing the capability of RTmonitoring to detect (1) a lung tumor deviation of 9.36mm, (2) a tumor shrinkage of 9.36mm, and (3) a tumor growth of 30mm. The original spherical tumor has the density of water and a diameter of ca 30mm. In RT treatment planning security margins are added around the tumor to be irradiated in order to account for these and other RT disturbing mechanisms. Here, despite not addressing a real treatment plan, we simulate the aforementioned tumor morphological changes to investigate whether an RTmonitoring system can be useful in detecting such changes. Indeed, tumor dislocation/modification in the lung represents a topic of strong research and development worldwide for all forms of RT. A beam missing the dislocated tumor will represent an underdosage that may be strongly correlated with tumor relapse. On the other hand, the detection of tumor shrinkage in lung RT may allow for a reduction of the dose field, which represents an important relief of the dose burden to the surrounding healthy lung. It is known that healthy lung tissue subjected to RT doses result at times in fibrosis which impairs respiratory function. Finally, detection of tumor growth represents equally an important asset in RT due to the evident tumor underdosage if such scenario is missed. We show that the counts distributions obtained with RTmonitoring result in a very high visual correlation both with the simulated, original dose distribution, and with the tumor location. Therefore, this technique is likely to represent a high potential asset for image-guided RT, adaptive RT, and real-time RT dose verification.