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Posts tagged ‘Canopy’

Dec 23

Reforestation Challenges Around the World

In the conclusion of our three part series on the reforestation of Banguet province in the Philippines, we asked Dr. Anthony S. Davis, Tom Alberg and Judi Beck Chair in Natural Resources at the University of Idaho, Loreca Stauber, one of the visionaries behind the project, and Kea Woodruff, former U of I Nursery Production and Logistics Associate, now at Harvard University, to explain some challenges associated with teaching reforestation to different cultures.

Ground view of a forest of bamboo looking up

Even with increased environmental awareness, we’re still losing almost thirty million acres of forest globally every year.

What are some of the cultural challenges?

Anthony: As I spend more and more time looking at international forests, I realize that we’re losing forests at a phenomenal rate. Even with all of our awareness about where we get supplies, where trees come from, where wood comes from, and where paper comes from, we’re still losing almost thirty million acres of forest globally every year. That’s terrifying to me. What’s even worse is that most of it comes from countries that don’t have environmental controls.  They don’t have systems in place that keep them from cutting down all the trees. Often, when we cut trees down for forestry, we replant. But, when you start to work in countries where that’s not valued or not part of the culture or the system, then a huge problem emerges.

How do you teach people to grow trees that can survive in their native terrain?

Anthony: There isn’t a lot of knowledge globally about how to grow high-quality tree seedlings. I’ve gotten really interested in the question of how to take a tree seedling which is grown in a nursery, where it essentially has all of the water and all of the nutrients it could possibly ask for, and get it into a condition where it’s likely to survive somewhere extremely harsh: with limited nutrients and water.  How do you get it to the point where it’s able to overcome those challenges?

There are two ways to look at that. One is to get more water to that seedling after it’s planted. The other is to make sure that the seedling you’re planting has its best possible chance of developing a root system that can access water that might not normally be available in those six inches where healthy roots are located when it’s first planted. Based on work that’s be done here at the University of Idaho in graduate student projects over the years, we found that if you can grow a seedling in a healthy manner in the nursery, it’s more likely to grow roots or access water that previously they might not have been able to access.

Researcher works on one of the water tanks that will supply water to the Benguet nursery in the Philippines

Working on one of the water tanks that will supply water to the Benguet nursery in the Philippines. The project is proceeding nicely after a series of setbacks: a destructive typhoon, slides that had to be cleared, 2 deaths, 1 funeral, and electrical power interruptions.

What challenges the plants after they leave the nursery?

Anthony: If that seedling can get roots down and access water, it starts to grow.  The beauty of reforestation, in general, is that it’s very simple; it can be very easy to get trees to grow. However, what often happens is you have a social element that overlaps the biological element. Some of it could be a lack of education, where people don’t understand that a large amount of foliage or leaves on a tree means that you need more water. You think about that image of success: people want to plant the biggest tree possible. That might work in a yard, but it really doesn’t work in a reforestation situation.

What are the challenges of establishing a nursery in a place like the Philippines?

Kea: In the place like the Philippines where resources aren’t necessarily as available, it becomes a huge challenge just finding the right kind of media or container. Also, there’s a decentralization of the knowledge resource itself. While we were there, we had the opportunity to meet with different government agencies, and there are definitely people who know a lot about the species that are available and how to grow them, but in terms of that information being disseminated and widely available to the public, that’s a challenge. The techniques that will be needed to actually produce a seedling resource need to be addressed.  

Loreca:  The basic thing is a good nursery. That has been a problem. In the past, the government, in an effort to green the Philippines, has given seedlings, but oftentimes, these seedlings are so poor in quality that they don’t survive in out planting.

Coffee beans thriving in the tropical Philippines

Coffee beans will thrive in the tropical Philippines.

How can you help other cultures to succeed at reforestation?

Anthony: During some work I was doing in the Middle East, in Lebanon, we found that communicating to people what a high-quality seedling became really important. You teach them about quality, defining it in terms of how much water a plant needs to survive, or how a plant has to grow in order to colonize a site.  We had a lot of success with the project there, getting people to understand that there was a problem in only looking at above ground information in terms of what makes a high-quality seedling. Really, when the roots are what’s driving survival, they’re looking at the wrong part of the picture.

How do you teach people to think beyond the nursery?

Anthony: Our work in Lebanon coincided with a project in Haiti. In Haiti, we had a former student who had been here at the University of Idaho who asked for help starting a nursery. These same conversations occurred: what is a healthy seedling, what is likely to survive, where do you get your seed, how long do you grow it for, when do you plant it?  We were able to have conversations around all of the elements that go into growing trees.

I remember clearly the “aha” moment where this young woman said, “We’ve been doing it wrong! We’ve always focused on growing as many seedlings as possible, and we haven’t worried about quality.”

See it live

Watch a video where Anthony talks about his work.

 

You can learn more about the reforestation programs that the University of Idaho nursery is involved with here.

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Dec 17

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Philippines Part 2: Overcoming Native Challenges with Remote Data

In one of the first agroforestry efforts in mountainous terrain, Moscow, Idaho community leader Loreca Stauber, Dr. Anthony S. Davis, Tom Alberg and Judi Beck Chair in Natural Resources at the University of Idaho, and their partners have initiated a program where U of I students travel overseas to work with farmers of Banguet province in the Philippines to develop the skills needed to grow high quality tree seedlings.  Local vegetable farmers have historically terraced the mountains that have been forested so they could grow monoculture crops, causing serious erosion (read about it here).  The land has degraded so much that the Philippine government has stepped in: warning farmers to begin conservation techniques, or they will take away the land and manage it themselves.

People building a local nursery in Benguet

Building a local nursery in Benguet.

Inspiring Students to Look at the Big Picture

One of the steps in helping local farmers to solve this problem is to create a local nursery where they can start growing native plants and trees.  Fortunately, the University of Idaho has operated a tree nursery for over one hundred years, and they understand how to grow trees. Dr. Davis specializes in setting up native nurseries for growing native plants all over the world. He says, “I want our students to be exposed to this because we’re graduating students who should be problem solvers, who should be able to look at the biggest challenges and contribute their own ideas towards resolving those challenges.”

Loreca Stauber adds, “We are part of the world and the world is part of us. The students can do more than just get their degree and find a job. Anthony and Kea, when they do this, inspire students to look at a bigger world than they are currently living in.”

Training Students to Understand Native Terrain and Resources

Davis says a good plan needs to take local conditions into account:  “The principles of growing trees are actually universal. It doesn’t matter whether you’re in Haiti, Lebanon, Idaho, or in the Philippines. Those principles are the same and they’re readily transferable. It’s how you adapt them to unique local situations that makes a difference.”

Close up on bamboo stalks

“It’s not really about the best way to grow a plant in a greenhouse environment; It’s about the best way to grow a plant that will also survive on its outplanting site.”

Kea Woodruff, former U of I Nursery Production and Logistics Associate, now at Harvard University, says they train the students who go overseas on the “target plant” concept:  designing a growing regime based on what the plant is going to need in its future home. She says, “It’s not really about the best way to grow a plant in a greenhouse environment; It’s about the best way to grow a plant that will also survive on its outplanting site. Determining what the outplanting site is and what each species will need to survive on that outplanting site is what determines greenhouse operations.”

Dr. Davis says you need to consider native resources when doing these types of projects.  “There could be plumbing there, but there’s no guarantee that when you turn the system on, the tap water will come out. That depends on the seasonality of the rains. It’s part of why we wanted the project partners (the farmers) to have data loggers: so we could look at the data together and get a better feel for when water is most abundant and when it’s most scarce, so it can be stored for later use.”

Overcoming Native Challenges with Remote Data

Decagon (now METER) donated data loggers to the program so that Dr. Davis and other people on the team could look at data with the farmers in the Philippines and advise them when to irrigate.  Davis says, “One of the things that’s most important in trying to set up a very remote nursery and manage the production in that nursery from approximately four flights, twelve hours, and twelve time zones away, is knowing what’s going on. There are things that are really easy to ask, like could you send me a picture every Wednesday and Saturday of the nursery, or could you measure the height and the diameter of the seedlings? What’s much harder to tell is how much water is coming in, or what the temperature was during the day or night, because those require people to be monitoring things at a greater frequency than is often possible. If we know how much water is coming into the nursery from rainfall, we can build collection systems so that we can manage where that water goes later on.”

Managing data for both the short and long term is critical, says Davis, because it’s often whether there was rainfall in the predicted amount, and at the right time, that determines whether a seedling establishes or not.

Next week:  The conclusion of our three part series: an interview with Dr. Davis and Kea Woodruff, discussing the cultural challenges of reforestation in different countries.

Acknowledgements:  The SEAGAA agroforestry project in Benguet is agro and forest; the farmers received a grant from the Rufford Foundation based in the UK to build a greenhouse and much of the water catchment system and auxiliary structure that go with a nursery facility.  They also received a sizable grant from the Philippine government to launch mushroom growing as a necessary complement to help support long-term agroforestry. The project is beyond reforestation – it is the growing of trees, shrubs, ground cover, the restoring of watersheds, creating livelihoods, the rebuilding of soil fertility and integrity, the revival of springs which have vanished with the removal of perennial flora, and the restoring biodiversity to bring back the natural checks and balances of a natural ecosystem.

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Dec 11

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Reforestation in the Philippines (Part 1)

In the mountainous Benguet province of the Philippines, farmers grow up to three crops of vegetables a year. Their mountain vegetable farms exist at the expense of original forest cover, causing tremendous erosion difficulties. To counteract erosion and preserve the watershed as well as promote reforestation, the Philippine government issued a mandate: farmers must find alternatives that restore the watershed or lose their land.

Arial view of rice terraces in the Philippines

Rice terraces in the Philippines

An Agroforestry Alternative

Loreca Stauber is no scientist, but she loves Benguet, and a letter from her friend, a scientist living in the Philippines, inspired her with the vision of teaching farmers to reforest the mountains and grow vegetables amongst the trees.  

Her friend writes, “We envision mountain farms as forest ecosystems whose primary social responsibility to the communities around and below is to be part of responsible watersheds that court, catch, store and gradually share water. We see mountain farms that are not prone to soil erosion or leaching: cultivated with minimal chemical inputs and tillage that will allow the natural buildup of biomass, organic matter, helpful organisms and fauna. We think of forest ecosystems that may not make millionaires of its farmers for one generation and heavy debtors even before the next. Rather, we envision forest farm ecosystems that are self-sufficient and self-sustaining. We are working on demonstrating forest ecosystems that can substitute for monocrop vegetable farms that deplete and leach the soil, pollute watersheds and are self-destructing.”  

Realizing the problem in the Philippines could be solved by reforestation, Loreca emailed Dr. Anthony S. Davis, Tom Alberg and Judi Beck Chair in Natural Resources in the University of Idaho’s Department of Forest, Rangeland, and Fire Sciences.  The U of I operates a 100-year-old nursery specializing in growing hardy tree seedlings. Dr. Davis recalls, “The email she sent me said, “I think you should do something about this,”  and I thought, “Actually I agree. I think we should do something about this.  So we began to screen the idea, asking: are there partners?  Is it a good idea?  Does it fit with this little thing that we do really well, which is essentially teaching people how to grow tree seedlings, and is there an educational component that’s valuable for our students?  When those check boxes lined up, then it was a matter of taking advantage of that opportunity and seeing where it could go.”

Green forested mountains in the Philippines

Forested mountains in the Philippines

Determining What Already Works

Together, they and other partners started a program in which U of I students went overseas to teach the people of Benguet how to grow trees, with the goal of moving the land toward agroforestry.  They wanted to grow a forest ecosystem (trees, shrubs, and ground cover) along with annual crops. Kea Woodruff, former U of I Nursery Production and Logistics Associate, now at Harvard University, traveled to the Philippines with an interdisciplinary team of undergraduate and graduate students to look at what agroforestry projects were already working and to conduct a needs assessment.    She says, “I saw a wide variety of landscapes in the areas that we were. One woman decided on her own that she was going to practice agroforestry, and people come and view her land as a demonstration site. It has mature bamboo, coffee trees, and mature Benguet pine. It really looks like what you would expect the native forest to look in an area like the Philippines.”

Kea said there were also intermediate sites where there are Benguet pines and some coffee with row crops blended in, such as strawberries and squash. She adds, “There’s clearly great potential to grow different species on these lands if we can help figure out the best way to use the resources that are available.”

Next week: Learn how partners in the project have been able to use native resources in the quest to reforest erosion-plagued Benguet.

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Dec 4

Understanding the Influence of Coastal Fog on the Water Relations of a California Pine Forest

Forests along the California coast and offshore islands experience coastal fog in summer, when conditions are otherwise warm and dry. Since fog-water inputs directly augment water availability to forests during the dry season, a potential reduction of fog due to climate change would place trees at a higher risk of water stress and drought-induced mortality.  Dr. Sara Baguskas completed her Ph.D. research in the geography department at UC Santa Barbara on how variation in fog-water inputs impact the water relations of a rare, endemic tree species, Bishop pine, located on Santa Cruz Island in Channel Islands National Park. The goal of her study was to enhance our ability to predict how coastal forests may respond to climate change by better understanding how fog-water inputs influence the water budget of coastal forests.

Fog on Trees

Dr. Baguskas’ study seeks a better understanding of how fog-water inputs influence the water budget of coastal forests.

Fog Manipulation

Santa Cruz Island supports the southern extent of the species range in California, thus it is where we would expect to see a reduction in the species range in a warmer, drier, and possibly less foggy future. To advance our mechanistic understanding of how coastal fog influences the physiological function of Bishop pines, Dr. Baguskas conducted a controlled greenhouse experiment where she manipulated fog-water inputs to potted Bishop pine saplings during a three-week drydown period. She installed soil moisture (VWC) sensors horizontally into the side of several pots of sapling trees at two different depths (2 cm and 10 cm) and exposed the pines to simulated fog events with a fog machine.

In one group of plants, Baguskas let fog drip down to the soil, and in another treatment, she prevented fog drip to the soil so that only the canopies were immersed in fog.  She adds, “Leaf wetness sensors were an important complement to soil moisture probes in the second treatment because I needed to demonstrate that during fog events, the leaves were wet and soil moisture did not change.” Additionally, Baguskas used a photosynthesis and fluorescence system to measure photosynthetic rates in each group.

Fog in pine trees from the ground

The fog events had a significant, positive effect on the photosynthetic rate and capacity of the pines.

Results

Dr. Baguskas found that the fog events had a significant, positive effect on the photosynthetic rate and capacity of the pines.  The combination of fog immersion and fog drip had the greatest effect on photosynthetic rates during the drydown period, so, in essence, she determined that fog drip to the soil slows the impact of drydown.  

“But,” she says, “when I looked at fog immersion alone, when the plant canopies were wet by fog with no drip to the soil, I also saw a significant improvement in the photosynthetic rates of these plants compared to the trees that received no fog at all, suggesting that there could have been indirect foliar uptake of water through these leaves which enhanced performance.”  An alternative interpretation of that, Baguskas adds, is that nighttime fog events reduced soil evaporation rates, resulting in less evaporative loss of soil moisture.

Dr. Baguskas says her “canopy immersion alone” data are consistent with other research: Todd Dawson, Gregory Goldsmith, Kevin Simmonin, Carter Berry, and Emily Limm have all found that when you wet plant leaves, it has a physiological effect, suggesting the plants are taking water up through their leaves and not relying as much on soil moisture.  (These authors performed different types of experiments, but their papers serve as reference studies). Baguskas says, “My results suggest that is what’s going on, but it’s not as definitive as other studies that have actually worked on tracking the water through leaves using a stable isotope approach.”  

Lessons Learned

Though Dr. Baguskas did not monitor soil temperature in this study, she says that in the future, she will always combine temperature data with soil moisture data.  She comments, “Consistently, the soil moisture in the “canopy-immersed only” plants was slightly elevated over the soil moisture in the control plants.  It made me wonder if this was a biologically meaningful result. Does it support the fact that if plants are taking up water through their leaves, they don’t rely on as much soil moisture?  Or did my treatment change soil temperature, and is that having a confounding effect on my results?  What I’ve learned from this, is that in the future I will always use soil probes with temperature sensors because you may not know until you see your results if temperature might be important.”

Future Fog Studies

Baguskas is a USDA-NIFA postdoctoral Research Fellow working with Dr. Michael Loik in the Environmental Studies Department at UC Santa Cruz. She continues to study coastal fog, but now in strawberry fields. Her current research questions are focused on integrating coastal fog into water-use decisions in coastal California agriculture. She loves the work and continues to rely on soil moisture sensors to make meaningful and reliable environmental measurements in the field and greenhouse.

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Sep 25

Can a Leaf Wetness Sensor Distinguish Fog From Dew?

The Namib Desert on the Southwestern coast of Africa is hyper-arid in terms of rainfall but experiences frequent coastal fog events.  The fog has been suggested to provide sufficient water for survival to certain plants which are endemic to the Namib, some of which occur only in the fog zone (up to 60 km inland).

Orange sand with bush grass everywhere

Dr. Keir Soderberg wanted to measure how much fog water plants were taking up either through surficial roots or their leaves.

Dr. Keir Soderberg, former researcher at the University of Virginia (now a consultant at S.S. Papadopulos & Associates), wanted to use stable isotopes to measure how much fog water plants were taking up either through surficial roots or their leaves. To enrich his data set, he decided to use leaf wetness sensors to show when the fog was occurring.  He also wondered if he could use the leaf wetness sensors to distinguish between fog and dew.

Large orange sand mounds

The Namib Desert

Keir set up five fog monitoring stations along a climate gradient in the central Namib. Each measured leaf wetness, air temperature, and relative humidity measurements along with solar radiation and soil parameters (moisture, temperature, and electrical conductivity).  Stable isotope analysis of samples was also used to help quantify the amounts of fog, groundwater, and soil water that plants were using.

Dew or Fog:

Keir says, “We began collecting one-minute data to look at the different patterns of how the water was being deposited on the leaf wetness sensor. The dew tended to be more of a gradual wetting, but with the fog you would see these cyclical waves of steep wetting and then a little bit of a drying on the sensor.”  Keir says he could look at those patterns and correlate them with visual evidence from his visits to the Namib during fog or dew events, though those wetting patterns may be specific to this location.

Rain, fog, and dew totals from (July 2008 to June 2009) from the Gobabeb weather station

Measuring Volume:

Keir also tried to determine the volume of water deposited on the leaf wetness sensors. He did a calibration in the lab by spraying water on the sensor and then weighing it. He said, “It was sort of a trial and error thing.  I found the performance was definitely sensor specific.  You have to get an individual calibration, but I felt the uncertainty could be controlled.”  

In comparing different methods of measuring fog deposition, Keir concluded that it is difficult to compare across measurement methods. “There’s a lot of variability between methods, even if you are confident in your own device and its accuracy.”  This gives the advantage to the most common measurement device, the Standard Fog Collector, since much of the work done through the years has used these instruments. However, the cylindrical-style collectors have the advantage of being insensitive to wind direction.

Volume of water deposited for three fog events on a vertical collector and a leaf wetness sensor diagram

Future Data:

In spite of this, Keir admits he’s still interested in seeing if he can get good dew collection data from leaf wetness sensors.  He says, “I went on from Namibia to a research station in Kenya where we had an eddy covariance flux tower.  Though there is no fog in Kenya, I convinced them to put leaf wetness sensors up and down the tower to collect data on dew deposition.  We left the sensors out there and have been collecting one-minute data for a while. There’s this massive dataset out there that we still need to look at.”

Keir collaborated on a paper for The Journal of Arid Environments, called “The Nature of Moisture at Gobabeb, in the Central Namib Desert,” a compilation of different fog and dew collection techniques over the years, including leaf wetness sensors, for automating the identification of fog events.  You can find it here.  New fog monitoring stations are going up in the Namib through the programs FogLife and FogNet.

For a basic understanding of the role that fog plays in plant and ecosystem processes, read this article by Dr. Chris Still, who has studied this issue for many years in the Channel Islands National Park off of the coast of California.

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Aug 22

Author Interview: Soil Physics with Python

The new book Soil Physics with Python: Transport in the Soil-Plant-Atmosphere System written by Dr. Marco Bitteli, Dr. Gaylon S. Campbell, and Dr. Fausto Tomei presents concepts and problems in soil physics as well as solutions using original computer programs.

Picture of the cover of the book "Soil Physics with Python" by Marco Bittelli, Gaylon S. Campbell, and Fausto Tomei

Soil Physics with Python

In contrast to the majority of the literature on soil physics, this text focuses on solving, not deriving, differential equations for transport. Numerical methods convert differential equations into algebraic equations, which can be solved using conventional methods of linear algebra.  Here, Dr. Campbell interviews about this update to his classic book Soil Physics with BASIC.

Why did you write the first book, Soil Physics with BASIC?

Soil physics classes were always frustrating for me because you would spend time writing fancy equations on the chalkboard, and in the end, you couldn’t do anything with them.  You couldn’t solve any of the problems because, even though they involved difficult mathematics, the math was still so simplified that it didn’t apply to anything that went on in nature.

When I taught my first graduate soil physics class, I determined that we were going to be able to do something by the time we finished.  Luckily, in the mid-1970s, personal computers were being developed, and I realized this was the answer to my problem.  Numerical methods could solve any problem with any geometry in it.  It wasn’t limited to problems that fit the assumptions needed to derive a complex differential equation.  I could write computer programs that simplified the mathematics for the students and teach them how to solve those problems using numerical methods.  By the end of the semester, my students would have a set of tools that they could use to solve problems in the real world.  

Did this book come from class notes or some other source?  

I wrote two textbooks and they both came the same way.  When I first started teaching, I had a textbook that was inadequate, so I began writing notes of my own and handing them out to the students.   After two years, I turned these notes into An Introduction to Environmental Biophysics.  Soil Physics with BASIC came about by the same process, but I enlisted the help of my daughter, Julia, to type it up. It was in the early days of word processing so entering equations was quite difficult.  It all went well for her until chapter eight, which was a nightmare of greek symbols. After she finished slogging for days through the material, we somehow lost the chapter.  She retyped it, and we lost it again, making her type it three times!  We didn’t have spreadsheets then either, so the figures were all hand-drawn by my daughter, Karine.

Red soil in the desert with trees and brush around

Marco [Bitteli] has added two and three-dimensional flow problems, so you can model whole landscapes and water behavior in an entire terrain.

What does Soil Physics with Python add to the conversation?

First, it updates the programming language.  BASIC was a language invented at Dartmouth and intended to be a simple teaching language.  It was never supposed to be a scientific computer language.  Python (13:26.) is a newer language, and there are many open source programs for it, making it a better language to use for science.

Secondly, the old book had one-dimensional flow problems in it for the most part, but Marco [Bitteli] has added two and three-dimensional flow problems, so you can model whole landscapes and water behavior in an entire terrain.

In addition, Dr. Bitteli describes the process and analysis of soil treated as fractals as well as soil image analysis.  There are a lot of extensions and updates that weren’t in the original book.  

Will it be accessible across all disciplines?

To some extent, different disciplines speak different languages.  A soil physicist talks about water potential, and a geotechnical engineer talks about soil suction. Thus, there may be some translation of discipline-specific terms, but it’s intended to be a book that people in the plant sciences can use along with people in the soil sciences.

Dr. Marco Bitteli earned his PhD at Washington State University and was Dr. Campbell’s former student.  This book is a product of their continued collaboration. Dr. BBitteli is now a professor at University of Bologna, the oldest university in operation in the world.  Soil Physics with Python  is available at Amazon.com.

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Aug 14

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The Potential of Drones in Research

Someday soon,  multi-rotors will execute pre-programmed flight paths over several hundred research plots collecting daily data and sending it back to a computer while researchers sip their morning coffee.  Researchers and growers won’t need to know anything about flying: the drones will fly themselves.  This is the dream.

One UAV (unmanned air vehicle) industry leader at the above drone demonstration commented, “The truth is that this is where agriculture (and research) is going, and I don’t mean ‘Tomorrowland’ going–I mean it’s pretty much there.  The only thing that’s holding us back is a permit from the FAA for autonomy, and that’s because the FAA is slowly backing into this UAV piece because we have the busiest general aviation sky in the world. But really, what you should have in your mind is multiple units operating with a single operator in a control vehicle.”  The above UAV was extensively tested in California’s NAPA valley with results soon to be published online.

In this blog, a METER scientist and an instrumentation engineer give their perspectives on what needs to happen before drones reach their full research potential.  

Drone hexacopter flying against a blue sky

Drone Hexacopter

What are the advantages of drones for researchers?

Dr. Colin Campbell, research scientist-

One of the biggest challenges of work in the field is variability: low spots, high spots, sandy soil, clay soil, hard pans beneath the surface in some areas and not in others.  This results in highly variable performance in crops.  In addition to that, even when you have good homogeneity in a field, you might have differences due to irrigation or rainfall. If we want to improve agriculture, one thing that we have to do is be able to come out with better tools to be able to visualize the field in more than a single dimension. In order to do this right now, students go out and take plant measurements all day, every day, all summer long. The advantage of a drone is that you could do flyovers of a field, monitoring the traits that you’re interested in using reflectance indices that would normally take days of work.

What are the obstacles to progress?

Greg Kelley, mechanical engineer, and drone hobbyist-   

Recently, the FAA has come out with a set of guidelines for the industrial use of drones:  flying machines have to stay under a certain ceiling (500 ft; 150 m), and they have to be flown in the line of sight of the operator.  The naive thing about those policies is: how much control does the operator have over the drone anyway?  It used to be that with your remote control, you were moving the control surfaces (flaps, rudder, etc) on the aircraft, but this is changing.  The onboard computer performs things like holding a stable altitude, maintaining a GPS location, or auto-stabilization (it keeps the aircraft level, even when a gust of wind comes).  Those are degrees of control that have been taken away from the operator. Thus, according to the level of automation that the operator has built into the system, he may not be in direct control at all times. In fact, these machines are being developed so that they can fly themselves. From my perspective, the FAA regulations are going to have to evolve along with the automation of drones in order to allow the development of this technology in an appropriate way.

Drone with eight rotors sitting on a landing pad

Drone with eight rotors.

What needs to happen before drones reach their full potential?

Dr. Colin Campbell–  

Even if we get the flexibility required with drones, we’ve got to get the right sensor on the drone. On the surface, this seems relatively simple.  Sensors to measure spectral reflectance are available in a package size that should easily mount on a drone platform. But, there are still many challenges.  First, current spectral reflectance sensors make a passive reflectance measurement, meaning we’re at the mercy of the reflected sunlight.  Clouds, sun angle, and leaf orientation, among other things, will all affect the measurement. There are several groups working on this (just search “drone NDVI” on the internet), but it’s a difficult problem to solve.  Second, drones create a spectral reflectance “map” of a field that needs to be geo-referenced to features on the ground to match measurements with position.  Once data are collected, the behavior of “plot A” can only be determined by matching the location and spectral reflectance of “plot A.”  Different from the first challenge, this is more related to programming than science but is still a major hurdle.

Despite these challenges, drones promise incredible benefits as an agricultural and environmental measurement tool. As one industry leader at the drone demonstration put it, “the complexity of the problems that agriculture faces and the opportunities for efficiencies are vast.  It will require ongoing engagement, next year and the year after that. There are a lot of questions to be answered and the efficacy is yet to be determined, but it’s exciting to watch the UAV helicopter and where it’s going.”  Both Campbell and Kelley agree that significant advances will be made within the next few years.

Read about an ROI calculator that’s been created to help growers quantify whether the benefits of using a drone will exceed their costs.

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May 23

Gore-Tex, House Wrap, and Stomatal Conductance

Want to develop an appreciation for Gore-Tex?  All you need is five minutes in a rubber raincoat.  But how do you know whether the North Face knock-off you’ve just purchased in China for a ridiculously low price is Gore-Tex or rubber?  If you’re a METER researcher, you dash back to your hotel room and clamp a porometer onto the fabric.

The leaf porometer was designed to measure stomatal conductance in leaves.  It’s typically used by canopy researchers to relate stomatal resistance to canopy attributes like water use, water balance, and uptake rates of herbicides, ozone, and pollutants.  Yet, from the beginning, Dr. Gaylon Campbell, the porometer’s designer, saw the possibilities:  “Give this to someone with only a passing interest in research, a ten-year-old kid for example, and they’ll go around the garden and come back with some really interesting observations,” he said.  “There are lots of questions about what loses water and what doesn’t that you can answer with this instrument.”

Researcher Clamping a LEAF POROMETER onto a Leaf in a Forest

SC1 Leaf Porometer

Dr. Campbell was probably thinking the questions would be about organic material—but it hasn’t always turned out that way.  By putting a wet paper towel on one side of an inorganic material and clamping the towel and the material into the porometer head, you can measure how well water vapor diffuses through the material.  Using this strategy, the researcher in China discovered that his raincoat was pretty much impermeable (unlike real Gore-Tex, which is a good vapor conductor).  Spotting the fake North Face coat is now a favorite part of METER’s canopy seminar.  And the coat is not the only leafless item that has been tested. “People will clamp the porometer on just about anything,” Doug Cobos, a METER research scientist, admitted. He himself grabbed it when a local contractor brought in a sample of some supposedly unique house wrap.

Siding is supposed to protect a house from the elements, but most building codes now require that houses be wrapped under the siding.  House wraps provide a secondary defense against liquid water and increase energy efficiency by preventing drafts.  As with raincoats, high-performance house wrap needs to repel water and stop wind while remaining permeable to water vapor.

A House Under Construction with Trees Around it

House under construction with protective wrap under the siding.

The practice of applying a sheathing of tar paper under siding is a hundred years old, but in the last fifteen years, high tech house wraps made from polypropylene in combination with a push towards energy efficiency have made the house wrap market big and competitive.  Upstart wraps try to gain market share through innovation and the one brought in by the local contractor came along with an outlandish claim.  According to the manufacturer’s rep, this plastic wrap would allow water vapor to diffuse out while preventing any from diffusing in.  Some builders might have scratched their heads and moved on.  Our local man decided to check it out.  He brought a sample of the mystical wrap to Decagon.  Out came the porometer and a quick scientific study of house wrap was born.

Dr. Cobos tested industry standard Tyvek house wrap along with the great one-way pretender.  The results?  “The vapor conductance of the new material was basically the same, regardless of which side of the material faced wet filter paper,” Dr. Cobos said.  “And, in fact, the material didn’t diffuse well at all.  Its conductance was similar to cheap perforated plastic.  It didn’t come close to the performance of Tyvek.” Ultimately, the newfangled wrap was retested by the manufacturer and taken off the market.

Probably the porometer’s best and highest use is still in canopy research, but it still gets pulled out to measure whatever seems interesting, organic and inorganic alike.  That dovetails with Dr. Campbell’s vision of it as a tool for routine use in canopy studies—and everywhere else.  Can you use it on yourself?  “Oh sure,” says Dr. Campbell.  “People clamp the porometer on their fingers all the time.  That’s a quick way to see if it’s working.”  He grins.  “Maybe you could use it as a lie detector on your kids.”

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May 15

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What is the Future of Sensor Technology?

Dr. John Selker, hydrologist at Oregon State University and one of the scientists behind the Trans African Hydro and Meteorological Observatory (TAHMO) project, gives his perspective on the future of sensor technology.

Researcher Pointing to Something while Walking through a Forest

Dr. John Selker (Image: andrewsforest.oregonstateuniversity.edu)

What sparked your interest in science?

I was kind of an accidental scientist in a sense. I went into water resources having experienced the 1985 drought in Kenya. I saw that water was transformative in the lives of people there. I thought there were lots of things we could do to make a difference, so I wanted to become a water resource engineer. It was during my graduate degree process that I got excited about science.

What was the first sensor you developed?

I’ve been developing sensors for a long time.  I worked at some national labs on teams developing sensors for physics experiments. The first one I developed myself was as an undergraduate student in physics. I was the lab instructor for the class, and I wanted to do something on my own while the students were busy. I made a non-contact bicycle speedometer which was much like an anemometer. I took an ultrasonic emitter, trained it on the tire, and I could get the beat frequency between emitted sound and the backscatter to get the bicycle speed.

What’s the future of sensor technology?

Communication

Right now one of the very exciting advances in technology is communication. Having sensors that can communicate back to the scientists immediately makes a huge difference in terms of knowing how things are going, making decisions on the fly, and getting good quality data.  Oftentimes in the past, a sensor would fail and you wouldn’t know about it for months.  Cell phone technology and the ability to run a station on a few AA batteries for years has been the most transformative aspect of technological development.  The sensors themselves also continue to improve: getting smaller and using less energy, and that’s excellent progress as well.

A Picture of a Orange Maple Leaf in the middle of Fall

What often happens is that you install a solar sensor, and then a leaf or a dust grain falls on it, and you lose your accuracy.

Redundancy

I think the next big thing in sensing technology is how to use what we might call “semi-redundant” sensing.  What often happens is that you install a solar sensor, and then a leaf or a dust grain falls on it, and you lose your accuracy.  However, if you had a solar panel and a solar sensor, you could then do comparisons.  Or if you were using a wind sensor and an accelerometer you could also compare data. We now have the computing capability to look at these things synergistically.

Accuracy

What I would say in science is that if we can get a few more zeros: a hundred times more accurate, or ten times more frequent measurements, then it would change our total vision of the world.  So, what I think we’re going to have in the next few years, is another zero in accuracy.  I think we’re going to go from being plus or minus five percent to plus or minus 0.5 percent, and we are going to do that through much more sophisticated intercomparisons of sensors.  As sensors get cheaper, we can afford to have more and more related sensors to make those comparisons.  I think we’re going to see this whole field of data assimilation become a critical part of the proliferation of sensors.

What are your thoughts on the future of sensor technology?

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Nov 13

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Complex Scientific Questions Yield Better Science in Desert FMP Project

The Desert FMP project originated from a discussion between pretty divergent scientists: Rick Gill, a BYU ecologist, another scientist who works on soil microbes, a plant physiologist, and a mammalogist who researches small mammals.

Desert FMP

Tree fire in Rush Valley

In an interview Rick said, “We started talking one day about the transformations that have occurred in the arid West over the past 100 years.  One of the things we are really interested in is fire.  How do ecosystems recover after fire? What’s the role of water in rangeland recovery? And the unique piece of this is: what’s the role of small mammals in this process?  We may never have thought of that question, or the complexity of researching how all of our questions work together in a system, if scientists from different disciplines hadn’t decided to collaborate.”

Desert FMP

Rush Valley research site. Five replications with four treatments: burned/unburned and small mammal/no small mammal. What’s interesting for us is that you can see that in the burned plots (the light brown) there are strong differences in the amount of the bright green plant—halogeton—that was present and it is systematically associated with the presence of small mammals. Here is the logic: In the spring, the presence of small mammals suppressed the cheatgrass and to some extent halogeton; in the absence of halogeton, cheatgrass ran wild. The cheatgrass transpired away all of the water and the halogeton that had germinated all died before it could flower.

As the experiment unfolds it is becoming clear that small mammals play a larger role in ecosystem recovery from fire than originally thought.  The scientists have used their observations to hypothesize that small mammals eat the seeds and seedlings of two invasive species. This ends up setting the vegetation along a very different trajectory than when small mammals are absent following fire.  Rick says, “We have discovered this complex but interesting interaction between water, fire, and small mammals. The first year after the fire, a really nasty range forb moved in called halogeton, which is toxic to livestock. Halogeton also accumulates salts in the upper soil profile that will cause failure in native plant germination.  Cheatgrass has also moved in which makes the area more prone to fire as it connects the sagebrush plants with flammable material. But what’s interesting is in treatments where mammals were present, the densities of both halogeton and cheatgrass were much lower than where small mammals were absent.

Desert FMP

Plot water potential comparison using matric potential sensors between Mammal (blue) and no mammal (red) over time. With no mammals to control cheatgrass, it depleted soil water availability below no mammal treatment and consequently halogeten was not able to grow.

 “The other really important thing is that cheatgrass and halogeton have different growth patterns.  Cheatgrass germinates in the Fall.  It reaches peak biomass early in the growing season and then dies off leaving a blanket of dead, highly flammable vegetation.  Halogeton germinates early in the growing season and remains relatively small until early Autumn when it bolts.  These are things that will be really easy to pick up using NDVI sensors, which are sensitive to the amount of green vegetation within the field of view of the sensor.  We are also using a system that we’ve designed to manipulate precipitation input.   This will enable us to connect water availability to the success of two invasive plants that have negative impacts on rangelands.  And with these same treatments we’re going to be able to tease out when in the year and to what extent small mammals are influencing the ecosystem by eating the seeds or the plant and at what stage.”

“Until I saw it in the field, the question of mammals being influential in rangeland fire recovery had never occurred to me.  We only discovered that piece of the puzzle because scientists from differing disciplines are working together.”

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