How does a tree's energy allocation shift due to nitrogen fertilization?

Nitrogen fertilization plays a significant role in a tree's energy allocation by enhancing growth processes. When trees receive additional nitrogen, they often redirect more energy toward vegetative growth, including increased leaf production and overall size, as nitrogen is a critical nutrient for synthesizing amino acids and proteins necessary for growth.

This shift occurs because nitrogen is a vital component of chlorophyll, which is essential for photosynthesis. With improved nitrogen availability, trees can produce more chlorophyll, leading to higher rates of photosynthesis and ultimately, vigorous growth. However, this emphasis on growth can come at the expense of the tree's defense mechanisms, such as the production of secondary metabolites that help protect against pests or diseases.

Consequently, a tree that receives nitrogen fertilization may grow rapidly and produce more foliage, but it may also become more vulnerable to threats because it is not allocating sufficient resources toward defense strategies. This trade-off highlights the complex balance between growth and defense in the plant health and ecology of trees.