Abstract The preparation method used for forage samples after collection is important when obtaining their nutritive value with acceptable accuracy and precision. This study was conducted to evaluate the effect of oven drying (40°C) or freeze drying on the nutritional components of forage samples collected: (1) from a shrubland, at monthly intervals through the year; and (2) from woody species at various stages of maturity. Collection occurred both by hand plucking and via oesophageally fistulated goats. The woody species tested were kermes oak ( Quercus coccifera L.), oriental hornbeam ( Carpinus orientalis Mill.), manna ash ( Fraxinus ornus L.), oak species ( Quercus pubescens Wild.) and rock-rose ( Cistus incanus Rchb.). Oven-dried fistula samples produced artificially increased levels of neutral detergent fibre and lignin, while the in vitro organic matter digestibility was underestimated in comparison with freeze-dried samples during all grazing periods. A similar pattern was observed for the hand-clipped samples during the rapid growing season, when the moisture content was high while during the remaining periods of the year, no significant differences were detected. For nutritional studies, when samples contain high proportions of moisture, the only acceptable method is freeze drying.