# How does one calculate the amount of oxygen produced by trees?

I'm currently working on a project to measure the impact of tree planting. Calculating the amount of oxygen seems harder than I imagined.

Of-course there's the type and size of the tree and the environment (soil and air consistency), but there are plenty of other variables in play of which I have no knowledge of (being an engineer, not a biologist).

From a computational standpoint I'm looking for rough and finer methods of calculation for the amount of oxygen the following produce:

• A tree
• A large forest
• Multiple countries with their forest

The one tree can be calculated exact, given enough variables. Oxygen during the day, during the night, tracked over it's age, etc.

A large forest will be calculated more approximate. Extra relevant would be how growth and oxygen production are influenced by tree density (trees per square mile).

Calculating multiple countries would be a whole other problem. It looks like it's very hard to prevent estimations from completely destroying the accuracy of calculations.

Basically I've written down some concerns and now I'm looking for a way of actually calculating these numbers and preferably some real numbers to validate against. The internet is crawling with estimates ((1)(2)(3)(4) and many, many more), but finding decent sources to compare your calculations seems hard.

How does one usually tackle this calculation problem?

• You can look into paper showing oxygen produced by non invasive and traditional method. Nov 9, 2015 at 17:21
• Apparently, we are working on the similar task regarding the measuring the impact of tree planting and decided to reach you out to ask you for help. I’ve been running a local startup project on a tree planning. We personalize trees and now our next move is to calculate amount of oxygen each baby tree produces. Surely, we take all external environmental factors in consideration. I’ve been looking for answers in internet and suddenly reached your post. What I’m asking for is to share your experience how you dealt with this issue. That would be a tremendous support. Dec 20, 2016 at 10:22

## 1 Answer

With detailed mechanistic models. There are a huge number of variables here, and you'll need to account for nearly all of them. Here is a similar project for crops.

You could try this model for a single tree but I don't envy trying to scale that up to entire countries.

Just to ballpark some figures, you could consider photosynthetic efficiency, average insolation, and shading effects. X amount of light falls on this country on average, and of that light .1% is converted into oxygen, so that's how much oxygen is made.

You could also approach it from the other direction and estimate how much each tree weighs. Tree dry weight is going to be mostly carbon, and necessarily nearly all of those carbon atoms were once carbon dioxide and represent one O2 molecule each. This approach has the advantage of taking into account respiration, unlike the light approach. The light approach measures total oxygen produced, but the carbon approach measures total oxygen released.