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Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption. Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine (Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0-0.3, 0.3-0.6, and 0.6-1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to 19:00 h and weighed every 2 h with 0.01 g precision for 10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105°C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6% of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.

This study presents a dynamic model for the prediction of diurnal changes in the moisture content of dead surface fuels in normally stocked Calabrian pine stands under varying weather conditions. The model was developed based on several empirical relationships between moisture contents of dead surface fuels and weather variables, and calibrated using field data collected from three Calabrian stands from three different regions of Turkey (Mugla, southwest; Antalya, south; Trabzon, north-east). The model was tested and validated with independent measurements of fuel moisture from two sets of field observations made during dry and rainy periods. Model predictions showed a mean absolute error (MAE) of 1.19% for litter and 0.90% for duff at Mugla, and 3.62% for litter and 14.38% for duff at Antalya. When two rainy periods were excluded from the analysis at Antalya site, the MAE decreased from 14.38% to 4.29% and R 2 increased from 0.25 to 0.83 for duff fuels. Graphical inspection and statistical validation of the model indicated that the diurnal litter and duff moisture dynamics could be predicted reasonably. The model can easily be adapted for other similar fuel types in the Mediterranean region.

Sweet chestnut (Castanea sativa Mill.) is one of the most important species in agro-forestry and horticulture. Turkey is an important C. sativa gene centre and fruit production region. The present study aimed to measure the variations in fruit width, length, thickness and weight in four different natural C. sativa populations in Turkey and determine the loss of fruit traits due to damage by chestnut weevil (Curculio elephas (Gyllenhal, 1836)) (Coleoptera: Curculionidae). Fruits were collected from four populations (Istanbul-Bahçeköy, Çanakkale-Bayramiç, Balıkesir-Erdek and Bursa-Uludağ) of phenotypically healthy sweet chestnut trees, measurements were taken, and the fruits were classified into those damaged by C. elephas and those not. Analysis revealed significant differences among and within the populations in all fruit traits, and between the sound and damaged fruits, with the average fruit width, length, thickness and weight being 24.8 mm, 23.1 mm, 15.3 mm and 3.4 g, respectively. Bursa-Uludağ population had the highest healthy fruit ratio (70%), with some individuals in the population yielding healthy fruits at ratios > 90%. In the Balıkesir-Erdek population, however, where the percentage of damaged fruits was the highest (54%), it was determined that some trees suffered more than 90% damage in contrast to the Bursa-Uludağ population. In the fruits infested by C. elephas, the approximate percentages of loss in fruit width, length, thickness and weight were 6, 4, 7 and 30%, respectively. The fruit weight loss percentages varied between 25% and 32% among the populations.

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