Farmers who grow food in greenhouses are constantly monitoring temperature and humidity to optimize growth rates. The ability to monitor these two data sets is inexpensive enough that it is perhaps the first and easiest observations to apply to forest protection via remote sensing.
Currently remote sensing in forestry is primarily based on aerial and satellite imagery, camera traps and water quality monitoring stations downstream. But as the cost of on site monitoring equipment goes down one of the first methods to be pushed for by RFPFs will be the creation of long term charts of a forest’s temperature and humidity at different canopy heights. This data will allow us to accurately calculate VPD.
Vapor pressure deficit is a measure of how dry or humid the air is. The difference between how much water vapor the air can hold and how much it actually contains is called the vapor pressure deficit, or VPD. Incremental changes in vapor pressure deficit due to climate change are linked to interrelated threats.
For example, high VPD can impact the health of forests, as trees and other vegetation require a certain amount of moisture to grow and thrive. Increases in VPD since the late 90’s have led to increasing forest drought and tree mortality. As dry air and dry vegetation create ideal conditions for fire to spread, high VPD also leads to an increase in wildfire risk.” https://blog.ucsusa.org/pablo-ortiz/californias-thirsty-future-the-role-of-vapor-pressure-deficit-in-our-changing-climate-and-drought/
So what if we were constantly monitoring VPD at different heights in a forest canopy at specific sites and only allowed an increase in canopy openings (RFPFs prefer branch pruning to whole tree cutting) only if VPD numbers were low enough to allow it?
This new method would create greater accountability when it comes to optimizing tree growth, rather than just arguing what the text books teach about optimizing tree growth.
With Optimization Modeling we can do much more than just create new forest protection laws that require a minimum amount of canopy cover, or a minimum restocking standard for number of live tree seedlings per acre.
When making decisions, humans are not always rational: besides the use of expertise and experience, we tend to use our intuition and many heuristics to simplify the process, as we have brought up in this insight. Even if in most cases this is helpful, sometimes these heuristics and our intuition may result in inappropriate decisions, due to the existence of some biases. The use of an optimization model reduces the existence of such biases and noise in the decision-making process.” https://www.cassotis.com/insights/what-are-the-main-benefits-of-an-optimization-model
Commercial foresters have always complained that site specifics are a better way to define responsible forestry rather than broad catch all regulations that may not apply to some sites. However this notion has meant that baked into most governmental oversight of logging is the need for “flexibility” to address unique challenges of a site and too often this means laws, rules and guidelines don’t have to be enforced as long as Best Management Practices (BMPs) are applied.
Too often BMPs allow entry into areas that are protected by law, but in the name of “flexibility” via BMPs it can often mean that once protected area can now be destroyed.
So what if logging was no longer allowed in a forest if site specific VPD numbers from long term remote sensing and forecasting of humidity and temperature showed that the growth of the trees would be compromised if the canopy was opened up further? At RFPF that’s what we aim to help develop in coming years.
Delightful post. Fascinating to think, if I’m understanding correctly, of canopy opening as opening a vapor pressure release valve.
The discussion of optimization brings to mind something I read from the UN last week about Monitoring and Evaluation. You might appreciate this: “ M&E involves looking at adaptation measures and assessing their effectiveness, impact, efficiency and sustainability and the extent to which they have fulfilled specific objectives (for example, reducing vulnerability, increasing resilience, or increasing adaptive capacity).
But it is so much more. We would be wasting the information collected, if we didn’t also use it for learning _–_ that is, applying it, and _sharing_ it, for us to improve what we do. https://www.undp.org/blog/powerhouse-strong-adaptation-systems-monitoring-evaluation-and-learning
That looks like a checklist to me.
Yes, but when it comes to keeping green leaves alive the less those valves are opened, the less those leaves require their roots to pump water out of the ground to keep them wet and alive. And just as the shade of taller trees can help keep the vapor pressure deficit lower (more closed valves) leaves themselves have their own valves and can close their pores and shut down respiration in times of low humidity and high temps as well. Of course when they’re closed they no longer respirate, which means during times of high heat and droughts they aren’t absorbing carbon and producing oxygen as much.
Right on, thanks for clarifying.