The Betula Tree - Adaptations to the Winter

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Across
  1. 3. these fall off the tree in the Autumn
  2. 5. the English name for the Betula Tree
  3. 7. these are lost from the tree, when
Down
  1. 1. frost causes this to stop being taken up by the tree, so the trees drops it leaves to preserve this
  2. 2. is the birch tree deciduous or evergreen?
  3. 4. the tree does this in winter, a bit like some animals
  4. 6. this takes a lot of energy to make, so the trees stops making it in Autumn/Winter, when the rate of PNS is low