1. Aiken LS, West SG (1991) Multiple regression: testing and interpreting interactions, 2nd edn. Sage, CA
2. Alméras T, Fournier M (2009) The gravitropic control of woody stems orientation: biomechanical parameters involved and consequences for stem allometry. In: Thibaut B (ed) Proceedings of the sixth plant biomechanics conference in Cayenne, French Guyana, French, pp 314–321
3. Anonymous (2001) Hyvän metsänhoidon suositukset. Publications of Forestry Development Centre Tapio, Libris Oy, Helsinki (in Finnish)
4. Aphalo PJ, Ballaré CL (1995) On the importance of information-acquiring systems in plant–plant interactions. Funct Ecol 9:5–14
5. Aphalo PJ, Rikala R (2006) Spacing of silver birch seedlings grown in containers of equal size affects their morphology and its variability. Tree Physiol 26:1227–1237