Where Do Trees Get Their Mass From?

If you were to consider how trees actually get to the enormous size that some of them are able to achieve, you might believe that most of this is the result of the soil in which they are plant, growing from seedlings. If you think about the largest trees in the world such as the redwoods and the sequoias, it makes sense that the soil plays a large role in delivering the nutrients that are necessary to help manifest these natural giants. However, there might be other factors involved. Let’s look at where trees actually get their mass from, and it may not just be from the surrounding soil.

What Most People Think

If you were to interview random people about how trees are able to grow to their enormous size, it is very common for people to reference the soil that they are planted in. A good question to ask is, if they are using the soil in order to grow, why is there not a huge hole around all trees where the soil has been extracted and used. It is also common sense to assume that the soil plays a large role because of the enormous roots that can sometimes be seen above the ground, seemingly digging into the soil as a source of not only nutrients, but the water that is in the ground. However, there might be another answer to this question, one that makes more sense, in regard to how trees become so enormous.

Early Research On The Topic

A scientist by the name of Johann Baptista Van Helmholt decided to figure out this exact question and started with a simple pot of soil. He planted a tree in the pot of soil after measuring the weight of the soil, and took care of a tree for five years. He was very careful to not allow any soil to escape the pot, nor did he add any additional soil during this five year period. At the end of the experiment, the tree had grown, weighing 70 kg, but only 60 g of soil was missing from the pot, clearly showing that the tree did not get its mass directly from the soil.

So What Is The Answer?

Many people believe that the water and nutrients may actually contribute to the enormous size that trees can become. Johann Baptista Van Helmholt actually concluded after his experiment that trees are almost entirely made of air. Others began to realize that perhaps beyond the soil and water that another process was occurring, the process of photosynthesis. It was determined that sunlight was needed to build the mass within the trees, despite the fact that sunlight is not actually matter. Oxygen is another possibility, but what research finally determined is that 95% of all of the mass of a tree is the result of carbon dioxide. This is the gas that humans exhale, as well as most other animals, through the respiration process. In the same way that trees produce oxygen for us that we need to breathe in order to grow, the carbon dioxide has the same effect with trees, helping them to build their mass.

In conclusion, animals breathe out carbon dioxide and lose water, and this is how we lose mass. Conversely, trees take in carbon dioxide and water, and this is how they build mass. And in a strange sense, through this process, we are actually becoming part of the trees.