A study was made of the total pollen production per individual tree in
ten anemophilous arboreal species (including wild, cultivated and orn
amental species) of considerable aerobiological importance: Pinus pina
ster, Ulmus minor, Juglans regia, Platanus hispanica, Quercus rotundif
olia, Salix atrocinerea, Populus nigra, Acer negundo, Olea europaea an
d Fraximus angustifolia. For each species three isolated well-shaped s
pecimens of medium height were chosen, and the number of flowers per i
ndividual tree and the number of pollen grains per anther was estimate
d. The values of total pollen production varied between a little over
1000 million grains in Juglans regia and more than 500,000 million in
one single tree in Quercus rotundifolia. For the production of pollen
grains per anther, the values oscillated between 3000 grains in Juglan
s, regia and 100,000 in Olea europaea. There is an exponential correla
tion between the size of the anthers and the number of pollen grains t
hey contain. A linear correlation is also evident between the volume o
f the tree crown and the total production of inflorescences, Bowers, a
nthers and pollen grains per individual tree. Based on this, a mean co
efficient of the number of grains/meter of diameter of the tree crown
is obtained which varies between 3.4 x 10(8) for Juglans regia and 550
.9 x 10(8) for Quercus rotundifolia. The ratio between the number of a
nthers per inflorescence and the number of pollen grains per anther ca
rries out a hyperbolic function; thus, the inflorescences with the mos
t anthers have the anthers with the least pollen and vice-versa. This
ratio is also manifest between the number of grains per flower and the
number of flowers per tree, as well as the number of grains per inflo
rescence and the number of inflorescences per tree.