- Author: Pam Kan-Rice
"Trees are poems that the earth writes upon the sky,” wrote Kahlil Gibran. But trees falling into power lines have sparked catastrophic fires and falling trees have injured nature lovers.
To prevent power outages, PG&E looks for trees near power lines that need to be trimmed or removed. To prevent power outages and other mishaps caused by failing trees, Matteo Garbelotto, UC Cooperative Extension forest pathology specialist at UC Berkeley, has incorporated science into a mobile application that can be used to determine whether a tree presents a hazard and should be removed.
“PG&E was doing tree surveys with pencil and paper,” said Garbelotto, who saw the manual process as fraught with opportunities for error. A paper record needs to be sent to a central collection site where it is transcribed. In the transcription process, mistakes can be made. And there's no way of verifying if a person actually examined the tree to fill out the form.
“Why don't you do a digital survey?” he asked a PG&E tree surveyer. “Using a tablet or phone, the data could be shipped directly, in real time, to the San Francisco office. Using a phone or GPS device, you will know the precise location of the tree and know the worker did the job. If there's a fire, you have proof.”
PG&E Corporation Foundation, the philanthropic arm of the utility, gave Garbelotto a $70,000 grant to develop the app he envisioned for determining which trees are hazards. The tree disease expert created a list of questions that help evaluate tree health.
For example, in addition to asking if the tree leaning toward a power line, surveyers are asked, Are there obvious signs of internal decay? Is there a large wound on the tree?
“If a tree has a wound of 5 inches or more, there is a good chance there is significant decay behind the wound,” Garbelotto said. “If there is a mushroom or conk growing on the tree, that portion of the tree is dead and the branch or whole tree may fall down.”
The app, which Garbelotto has dubbed “Evalutree,” can be used for more than powerline safety.
UC Berkeley Ph.D. student Michael Johnson has been using the app to evaluate different species of trees.
“We have just started our third field season using the app on a project for the Department of Defense that quantifies the health and economic value of the oak woodlands on the 100,000-acre Vandenberg Air Force Base,” said Johnson. “We started with coast live oak the first summer, added tanoak the second summer, and have expanded to bishop pine this summer.”
The mobile app has simplified data collection for Johnson, who is in the Forest Pathology and Mycology Lab at UC Berkeley.
“I used pencil and paper studying postfire aspen regeneration on Forest Service land in Northern Arizona in 2012-2013, where I also did my master's work on ponderosa pine decay in 2013-2015,” Johnson said.
He described his undergraduate work collecting data with pencil and paper carried in a tatum, a 8.5-inch by 12-inch metal case with a clipboard, compared with working with the Evalutree phone app.
“Each day would start with making sure that we had all of our data sheets packed in our bulky field tatums,” Johnson said, “making sure our GPS points were preloaded in a separate, expensive GPS device, making sure that our camera had batteries and that we had dry erase markers for our small white board so that we could indicate which plot each photograph belonged to.
“After the fieldwork was complete, we would spend weeks doing data entry, trying to make out the scrawled numbers and notes – smeared with charcoal and raindrops – and sorting and compiling the data, photos and GPS points. It was time-consuming and painstaking, to say the least.”
For his graduate research, Johnson was able to enter data directly into a spreadsheet on a field computer. “At the end of the field work, I would just have to compile the data from the computer, photos from the camera, and GPS points from the Garmin to make a report,” he said.
“Evalutree has changed all of that. Instead of field tatums and multiple bulky devices, I walk out into the field with a lab cell phone. The app has preloaded survey questions, the ability to connect photographs to specific plots, and drops GPS points at each plot and tree that I survey.”
Working in the U.S. Defense Department's sprawling, undeveloped landscapes, Johnson said, “We are often in the field all day without internet or phone connectivity. The app is prepared to meet this challenge and relies on our phone's internal storage and pre-existing GPS functionality to order and store our data with precision accuracy. At the end of the day – when we have returned to civilization and technology – we simply upload all of our surveys for the day and I immediately have my data and reports in multiple formats, including pdf, xls and kml files, at my fingertips.
“Within minutes, I can update my maps to show the exact location of all of the day's surveys, start crunching data in Excel, or print out a report with the photographs from each plot for my boss,” Johnson said.
Garbelotto, the UC Cooperative Extension specialist, would like to make the technology available to cities and companies that manage trees.
“The app can be used by any agency or government that owns or manages a significant number of trees and needs to run surveys on a regular basis to ensure these trees are not at risk of failing, causing property damage or, worse, casualties or injuries to people,” Garbelotto said.
“The surveys can be easily customized for different projects,” he said. “It can be used for campgrounds or parks to calculate the likelihood of a tree failing and likelihood of causing damage. You could have an answer within minutes of submitting the survey.”
- Author: Jeannette Warnert
Reposted from UCANR News
Given California's changing climate, should Sierra Nevada residents replant pine trees after so many died during the 2010-2016 drought? The short answer is yes, says Susie Kocher, UC Cooperative Extension forestry advisor.
“We have every reason to believe that pines will continue to be an important part of mixed conifer forests in the Sierras,” Kocher said.
Kocher spoke at a meeting for UC Master Gardeners, volunteers who provide landscape advice to the public in California. Questions have been coming in to Master Gardener hotlines from mountain residents wondering what to do after unprecedented tree loses in the last few years.
Most California forests are suffering from severe overcrowding due to 100 years of aggressive fire suppression and selective harvesting of the largest and most resilient trees. They were then subjected to five years of drought.
“There were just too many stems in the ground,” Kocher said. “The drought was very warm, so trees needed more water, but got less. These were optimal conditions for bark beetles.”
Western pine beetle is a native pest that attacks larger ponderosa pine and Coulter pine trees weakened by disease, fire, injury or water stress. Bark beetles are tree species specific, so other beetles target other species of trees in California's mixed conifer forests. Typically, bark beetles bore through tree bark and create long winding tunnels in the phloem. An aggregating pheromone attracts additional bark beetles to the tree, and heavily attacked trees invariably die.
During the drought, 102 million Sierra Nevada trees died from bark beetle attack or simply lack of water; 68 million of those died in 2016 alone. But after the abundant rainfall in the 2016-17 season, the bark beetle population seems to have crashed.
Landowners with 20 acres or more may be eligible for a state cost-sharing program to remove trees, reduce the fire hazard and replant new seedlings. Landowners in mountain communities who wish to revitalize their properties can contact local UC Master Gardeners for recovery advice.
UC Master Gardeners are plant enthusiasts who have passed an intense training program presented by UC academics. They participate in continuing education annually to update and maintain their knowledge. More than 60 Master Gardeners from Mariposa, Madera and Fresno counties gathered in Oakhurst in October to learn from UC scientists how to work with mountain homeowners whose towering trees have died. Similar training sessions, all funded by a grant from UC Agriculture and Natural Resources, were held in El Dorado and Tuolumne counties in June.
“There is life after beetles,” said Jodi Axelson, UC Cooperative Extension forestry specialist at UC Berkeley.
“Eco systems are stretched, and then they come back,” she said. “You must remember the time scale of forest change is long and pines have been a major species in the Sierra Nevada for at least 28,000 years. As long as there have been pines, there have been bark beetles.”
The scientists suggest that people who own forestland take a step back and assess the landscape after their dead trees have been removed.
“We're seeing a lot of young cedar and white fir surviving the drought. Oaks seems to be doing really well,” Kocher said.
She suggests landowners thin young trees so available sun and soil moisture are focused on the healthiest trees. Water seedlings that are receiving more sun than before to reduce stress. Planting native conifers is the best option. Due to climate change, she recommends choosing trees from a slightly lower elevation to hedge against warmer temperatures in the future.
Pines are adapted to the California forest, but may need help to regenerate. When the ground is moist in the late fall or spring, plant seedlings 10 to 14 feet apart. New trees should be planted well away from homes to maintain defensible space and at least 10 feet from power lines.
“Please don't set them up for future torture,” Kocher said. “That's just sad.”
To help the new trees become established, cover the ground around the tree, but not touching the bark, with two or three inches of mulch and irrigate weekly during the dry season for the first few years.
Questions about special circumstances may be directed to local UC Master Gardeners. Find the local program here: http://mg.ucanr.edu/FindUs/
- Author: ESPM News
In response to California's growing tree mortality crisis, the Little Hoover Commission held a public hearing on California Forest Management yesterday (January 26) at the state capital in Sacramento.
Professor Scott Stephens, a fire scientist in the department of environmental science, policy, and management, delivered the opening remarks. He provided background on the causes and magnitude of tree losses happening across the state. "Our forests are not in a resilient condition," he said. "Past management actions, including fire suppression and logging focused on large trees have produced forests today that are much more vulnerable to fire and drought-related mortality." Stephens made suggestions for legislation, policy, and forest management techniques that could help restore resilience to California's forest ecosystems and prevent future mortality crises. He also offered ideas on how the state could better work with private landowners as well as the federal government to promote healthier forests.
- Author: Robert Sanders
Reposted from UC Berkeley News
Todd Dawson's field equipment always includes ropes and ascenders, which he and his team use to climb hundreds of feet into the canopies of the world's largest trees, California's redwoods.
It's laborious work, but he'll soon be getting a little help. From drones.
The need is urgent, Dawson said. Since 2010, more than 102 million trees, mostly pines and firs, have died in California because of drought, 62 million in 2016 alone. Why are pines and firs succumbing, but the thousand-year-old sequoias surviving, and will that continue into the future?
In August, he and Gregory Crutsinger, a plant ecologist and head of scientific programs at Parrot, performed the first test of a drone, a quadcopter, equipped with a state-of-the-art multispectral camera that takes photos in red, green and two infrared bands. Called the Sequoia, the camera works like more expensive satellite and airborne sensors, measuring the sunlight reflected by vegetation in order to assess physiological activity or plant health.
“Before, a team of five to seven people would climb and spend a week or more in one tree mapping it all around,” Dawson said. “With a drone, we could do that with a two-minute flight. We can map the leaf area by circling the tree, then do some camera work inside the canopy, and we have the whole tree in a day.”
After the data and photos were stitched together by a software program called Pix4D, Dawson and Crutsinger ended up with a three-dimensional representation of the foliage that his team had never seen before – information that will be used to determine how much carbon the tree takes up each day and how much water it uses, the basis for assessing what might happen with higher carbon dioxide levels in the atmosphere and less water on and in the ground.
“With repeat flights you can watch a forest grow without ever actually measuring any trees in the forest,” Dawson said. “I think drone technology holds a lot of promise to do some very innovative science over time and in three-dimensional space with a relatively cheap tool. It is really pretty amazing.”
Monitoring the health of the state's iconic sequoias is just one instance of how drones, combined with state-of-the-art sensors, can benefit science, Crutsinger said.
“Drone technology is getting much cheaper, but stitching and photogrammetry are innovating at the same time,” he said, referring to the science of making measurements from photos. “That is the backbone of the whole new commercial drone industry: not just the ability to capture the data, but also to process very high-resolution photos into millions of points that generate a three-dimensional model. This is going to help science but also environmental monitoring, agriculture and even construction sites.”
Crutsinger, a former Miller postdoctoral fellow at UC Berkeley, is asking other scientists to propose research collaborations with Parrot in exchange for free drones, cameras and analysis software. These Climate Innovation Grants are open to any student or researcher around the world.
Monitoring a changing environment
Dawson is now assessing how best to use the initial data and the drone and camera to answer questions in plant ecology. For the giant sequoias (Sequoiadendron giganteum), which he studies in the University of California's 320-acre Whitaker Forest just outside Sequoia-Kings Canyon National Park, he anticipates learning a lot more about their physiology than can be achieved by roping onto the canopy. Knowing the leaf area alone is a key advance, since he and his team have been able to model only the trees' branches and twigs, from which they estimate leaf surface.
“If we know how much area is there, I can tell you how many tons of carbon per meter squared per day was fixed by that forest, and how much water was used by that leaf area per day. You can start to get at rates of carbon exchanged between the tree and the atmosphere and then at rates of carbon sequestration,” he said. “These are important numbers for our forecasting models, so we can say, ‘If the climate goes up by 2 degrees, or it gets drier by 10 percent, what the hell is going to happen to that productivity?' All of a sudden you have power to really measure the pulse of the Earth, which is a really hard thing to do at large scales.”
Dawson is keen to see how drones and specialized sensors can aid his other research, which involves not only giant sequoias but also coastal redwoods, California's oaks and the canopy epiphytes in the clouds forest of Costa Rica. But he also sees a wealth of other possibilities.
“I think this is one of the tools for ‘change detection' that we are going to find is a game changer,” he said. “We can do this quickly and accurately over natural lands and agricultural lands and forest that burned and places that were hit by hurricanes or droughts, and look at the changes taking place and why they are taking place much more easily than we did before.”
Dawson doesn't plan to give up climbing trees, though. Some data will still need to be captured in the tree tops, if only to connect drone observations with tree physiology and ecology.
“The low-hanging fruit right now is really, what basic-level things that take up a lot of time can we replace with the drone, and what do we still need to do with boots on the ground in the field,” Crutsinger said. “If we can just save time and person power, that is most of the cost of doing scientific research, particularly in ecology. We are looking to augment what already happens on the ground — or in this case the crown — and then think about what new questions we can ask as well.”
- Author: Jeannette Warnert
Reposted from the UCANR News Blog
Even though there has been a deficit of fire in California forests for decades, their future is not hopeless, said UC Berkeley fire science professor and UC Agriculture and Natural Resources researcher Scott Stephens in an interview with Craig Miller on KQED Science.
"The next 25 to 30 years are paramount. If you begin to do restoration, reduce density, make forests more variable in pattern, and less fuel, when you have episodes of drought and fire, it's going to be fine. The forests have been doing this for millennia. It's going to be fine," Stephens said.
However, under current conditions, in which fires have been regularly suppressed, the situation is dire.
"The forests used to burn every 12 to 15 years, but most places haven't been touched for 50 to 100 years. Today we have areas with 300 or 400 trees per acre, where you used to have 50 to 80," he said.
Even though, Stephens said he is an optimist. "There's still opportunity today to do restoration, so that when it does get warmer and warmer, as projected, the forests will be able to deal with that, deal with insects and disease and keep themselves intact."