Home arrow Articles arrow Fred's Tips arrow Tree Physiology and Its Implications for the Bonsai Enthusiast

Most Recent Articles

Tree Physiology and Its Implications for the Bonsai Enthusiast PDF Print E-mail
Written by Fred Nowak   
Tuesday, 05 August 2008
What does a tree use to grow?  It uses the carbohydrates thathave been stored in the roots and trunk.  No, the fertilizeris not food for the tree.  Fertilizer permits the tree tobetter utilize the food that is available to it. Sometimes I think thatfertilizers are vitamins to the growing, living process. The window oftime and season to produce carbohydrates from the carbon dioxide of theair and water is really quite limited for deciduous trees. Through the process of photosynthesis, that carbon dioxide and waterare converted into carbohydrates, the food that plants and treesrequire. What is the window of food production and storage for a typicaldeciduous tree?  It really is quite short.  It isdone in about 5-6 months and depending on the availability of sun,about 8 hours a day.  That is a pretty short time for the treeto prepare for the winter and next yearsgrowth.                                   

On the graph, one can see that the carbohydrates produced in the summermonths must carry the tree for an extended period of time. Question. What are the implications of this process for bonsaienthusiasts?

There is a seasonal pattern of carbohydrate "deposition andmobilization".  Review the chart below and see, perhaps evenbetter, the implications for the bonsai enthusiast.

Beginning with tree no. 4, one can see a tree is fully satiated withcarbohydrates. The carbs are stored in the roots and trunk (#5) and arethen available in early spring for the tree to pull up the carbs (#1)and prepare for the emergence of leaves. With spring comes leafemergence and the carbs become quite depleted. By mid-summer, the treeis replenishing the depleted carbs. Again, what are the implications ofthis process for the bonsai enthusiast for fertilization and pruning.?
What happens when the rate of tree respiration (using the carbs andthis goes on throughout the year) exceeds the rate ofphotosynthesis?  Yep, the tree vigor declines and treemortality eventually occurs. Have you ever had a tree die because ofthis occurence?  What happens when you remove healthyphotosynthesizing limbs (particularly during the growingseason)?  What does this tell you about pruning? How does rootpruning (a regular bonsai task) affect the livelihood (physiology) ofthe tree?

Questions are being asked but answers not provided.  Theanswers to the questions should be obvious to the bonsai enthusiast.Perhaps there should be discussion about these matters at a meeting ofthe Memphis Bonsai Society.

There is another bit of information to cause you to think about theabove processes and their implications. Trees allocate their carbs tosupport five different processes, in priority order (Oliver and Larson1996.

    * Maintenance of living tissue (stayingalive-respiration)
    * Production of fine roots and leaves
    * Flower and seed production
    * Primary growth (elongation of branchesand roots)
    * Secondary growth (diameter growth,i.e. wood)

In a healthy tree, each of these processes is sufficiently "fueled" bycarbohydrates.  "Life is good."  Gradual mortality ofa tree can be observed by examining these processes in reverse order.

Charts and most materials are from Dr. David Mercker, University ofTennessee Extension, West Tennessee Forester; presentations by JimVolgas, Master Gardener and ISA Certified Arborist and others at theShelby County Urban Forester Training Program 2008
Last Updated ( Thursday, 08 October 2009 )
 
< Prev   Next >
[ Back ]