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 Fertilizing
with too much nitrogen makes a tree larger and weaker (less
stored energy and lower defense chemicals). |
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Fertilizing Trees the Benefits and the Pitfalls
Tree fertilization is an important service that provides trees
with the basic building blocks to maximize their genetic potential.
It essentially replaces soil minerals needed by a tree that are
in short supply in the soil. However there are some misconceptions
about fertilizer.
Common Fertilizer Misconceptions
- Fertilizer is not food, but soil elements.
- Fertilizer is not a health treatment - But is a method of
replacing elements the tree needs that are not present in the
soil.
- Nitrogen fertilizer forces a tree to use stored carbohydrates
(energy) to grow foliage and add mass. This increases its need
for energy and other resources.
- Fertilizer can feed soil and tree pathogens, making them
stronger. Stressed or weak trees should be fertilized with caution.
Where is Fertilizer an Important Tool?
- Trees growing in yards that systematically have their leaves
removed.
- Small trees where the purpose is fast growth.
- Replacement of elements in situations where soil tests have
shown them lacking in the soil.
- Low nitrogen fertilizer should always be used with mature
trees to avoid stimulating an unhealthy growth increase.
Nitrogen Makes Trees Grow Faster and Often Makes Them Weaker
Most fertilizers contain nitrogen. Research has shown that fertilizing
with too much nitrogen increases the size of the tree at the expense
of stored energy. Larger trees require more energy and greater
resources to support their larger mass. This makes them more susceptible
to environmental stresses.
Faster growing trees are basically less durable than slower growing
trees (See the chart below)
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For
many mature yard trees, the deficiency level of the growing
site is already past this stress threshold. By reducing the
trees growth rate - health and longevity can be restored. |
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Cambistat Increases the Lifespan and Durability of Yard Trees
Cambistat works by making the tree more conservative. Slower growth
rate means energy is shunted into increased root mass, increased
defenses, thicker leaves, and increased storage. A slower growing
tree needs fewer resources - including water, minerals and energy.
This reduced resource need raises the threshold of stress needed
to injure the tree. For many mature yard trees, the deficiency
level of the growing site is already past this stress threshold.
By reducing the tree's growth rate - health and longevity can
be restored.
As can be seen in the chart below, reducing a tree's growth rate
with Cambistat will:
1. Reduce it's sensitivity to stress
2. Decrease it's need for resources
3. Increase its energy reserves
4. Increase it's tissue defense
5. Reduce it's attractiveness to organisms
6. Give it longer lasting leaves
7. Make it more durable
Fast Growth or Slow Growth - Differences in Tree Health and Longevity
In the Tree Care Industry article "Why Do Trees Vary in Suitability
to Diseases and Insects", Clive Jones explores the relationship
between how fast a tree grows and its longevity. Basically, fast
growing trees are more susceptible to damage from stress than
slower growing trees. See the chart below for the differences
in tree characteristics of fast versus slow growing trees.
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Tree
Characteristics
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Inherent
Growth Rate
|
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Fast
|
Slow
|
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Growth Strategy
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Live fast, Die Young
|
Live Slow, Live Long
|
|
Nitrogen Demand
|
High
|
Low
|
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Carbon Allocation
|
To Growth
|
To Storage
|
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Stored Reserves
|
Low
|
High
|
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Root to Shoot Ratio
|
Low
|
High
|
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Leaf Longevity
|
Short
|
Long
|
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Leaf Fiber
|
Low
|
High
|
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Leaf Tannin
|
Low
|
High
|
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Tissue Nitrogen
|
High
|
Low
|
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Tissue Defense
|
Low
|
High
|
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Food Quality to Organisms
|
High
|
Low
|
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Sensitivity to Resource Availability
|
High
|
Low
|
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Sensitivity to Stress & Damage
|
High
|
Low
|
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Insect Herbivory
|
High
|
Low
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