1. Arita H, Ohkuro T (2007a) A maintenance system aimed to control wood vegetation of abandoned paddy field-study based on a survey of Ohshima-are Jouetsu-shi Niigata, Japan. Trans Jpn Soc Irrig Drain Rural Eng 249:255–260 (In Japanese with English summary)
2. Arita H, Ohkuro T (2007b) The expense of restoring abandoned paddy fields invaded by trees to a sound condition-study on a survey of Ohshima-are Jouetsu-shi Niigata, Japan. Trans Jpn Soc Irrig Drain Rural Eng 249:247–254 (In Japanese with English summary)
3. Bates D, Maechler M, Dai B (2008) Linear mixed-effects models using S4 classes. R package version 0.999375-28. http://lme4.r-forge.r-project.org/ . Accessed 13 Dec 2008
4. Cadenasso ML, Pickett STA (2000) Linking forest edge structure to edge function: mediation of herbivore damage. J Ecol 88:31–44
5. Catovsky S, Bazzaz FA (2002) Nitrogen availability influences regeneration of temperate tree species in the understory seedling bank. Ecol Appl 12:1056–1070