Strawberry Shake Botanical Lesson

I had a strawberry shake with my supper tonight.  Boy, it sure was good!  It even had chunks of real strawberries and occasionally the straw would get blocked.  This always brings to mind a spring time botanical lesson.  

Trees are very interesting organisms.  They breath, they grow, they make food, and they multiple.  This time of the year trees are coming back to life after their long winters nap.  Have you ever thought about the mechanics behind the bud?  

Before the bud grows and flowers the sap has to start moving in the tree.  Warm days and cool nights start this process along its way.  But how does the sap move throughout the tree?  By tiny straws found in the vascular cambium.  

The vascular cambium is the special growing part of the tree that is sandwiched between the bark and the wood of the tree.  Two types of tubes are found in the vascular cabium- xylem and phloem.  Xylem carries the water and nutrients from the roots upward to the limbs of the tree and phloem carries the food from the limbs down to the roots for storage.  But, in the spring time when the sap starts following both tubes carry the sap upwards during the day and down into the ground during the night.   

The sap moving upward provides food to the buds, which causes them to grow, leaf out and sometimes flower.  

But to get back to the strawberry milkshake.  Have you ever had a strawberry stuck in the straw and no matter how hard you try that strawberry will just not move through the straw?  

That is what happens to the xylem and phloem tubes in the trees when they get older.  When the xylem tube get blocked, those tubes turn into wood.  When phloem tubes get blocked, they turn into bark.  And that is just part of the story of how a tree grows.