Dear Chris Slade

_Male_ willows are the only ones to provide _pollen_ (and nectar) during spring,
females only provide nectar.
So size does not matter here :=)

Nectar is only energy source, pollen contains proteins and other substances taht
the beehive desperately needs during spring for the colony build-up.

Biofuel-Energy _is_ the main objective of energy belts, however, I have to
addresse the related, indirect (external) effects, too in my work.

Interannual variations play a role, but I cannot assess their importance at the
moment.

Mixtures of different willows are important also because of pest-attack-risk
minimisation strategies.


Sincerely
Med venlig hilsen


Bernd Kuemmel

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Bernd Kuemmel, stud.lic. (PhD.stud.)
Royal Veterinary and Agricultural University (KVL)
Agrovej 10           +  DK-2630 Taastrup
V: (+45) 35 28 35 33  +  F: (+45) 35 28 21 75
http://www.agsci.kvl.dk/~bek/cfehtml.htm