1. Al Afas N, Marron N, Ceulemans R (2007) Variability in Populus leaf anatomy and morphology in relation to canopy position, biomass production, and varietal taxon. Ann For Sci 64:521–532. doi: 10.1051/forest:2007029
2. Apple M, Tiekotter K, Snow M, Young J, Soeldner A, Phillips D, Tingey D, Bond BJ (2002) Needle anatomy changes with increasing tree age in Douglas-fir. Tree Physiol 22:129–136
3. Blanco A, Castroviejo M, Fraile JL, Bandullo JM, Muñoz LA, Sánchez O (1989) Estudio ecológico del pino canario. Serie Técnica No. 6. ICONA, Madrid
4. Calamassi R (1986) Identification of provenances of Pinus halepensis Mill. on the basis of the anatomical and morphological needle structures. Ann For Sci 43:281–298. doi: 10.1051/forest:19860301
5. Calamassi R, Puglisi SR, Vendramin GG (1988) Genetic variation in morphological and anatomical needle characteristics in Pinus brutia Ten. Silvae Genet 37:199–206