The odd bear or delivery from a stork briefly in short tree (6)
I believe the answer is:
baobab
'briefly in short tree' is the definition.
'baobab' can be an answer for 'tree' (I've seen this before). I'm not sure about the 'briefly in short' bit.
'the odd bear or delivery from a stork' is the wordplay.
'the odd' means one should take alternating letters.
'delivery from a stork' becomes 'bab' (I can't justify this - if you can you should give a lot more credence to this answer).
'bear'+'or'='bearor'
The alternate letters of 'bearor' are 'bao'.
'bao'+'bab'='BAOBAB'
Can you help me to learn more?
(Other definitions for baobab that I've seen before include "Thick-trunked tree" , "Gigantic tropical tree with very thick trunk" , "Tree indigenous to Africa and Australia" , "African or Australian tree with very thick trunk" , "The monkey bread tree" .)