- Author: Jeannette Warnert
Reposted from the UCANR Green Blog
To help California forest property owners adapt to the changing climate, UC Agriculture and Natural Resources (UC ANR) has produced a 13-page peer-reviewed paper that outlines actions owners can take to sustain their forests' value even when temperatures rise.
“Managers of forest land have always had to adapt to changing conditions – such as markets, urban encroachment, droughts and floods,” said Susie Kocher, UC Cooperative Extension forestry and natural resources advisor. “We wrote this paper to help forest managers better understand the evolving science of climate change and how they can help their forests adapt to the climate of the future.”
Forests are shaped by the climates in which they grow. The current rapid pace of climate change has not happened for thousands of years, according to climate scientists. Nevertheless, the authors assure forest landowners that there are land management decisions they can make to ensure the resiliency of their resources, and perhaps even improve them.
“Some trees may grow faster under the warmer conditions we experience with climate change,” Kocher said, “especially those at highest elevation where there is adequate precipitation.”
The paper details the solid scientific evidence that indicates the rise in global average temperatures over the past 100 years. The temperatures, it says, “will likely continue to rise in the future, with impacts on natural and human systems.”
The document provides specific recommendations for care of three common types of forest in California: mixed conifer, oak woodland and coastal redwood forests.
Mixed conifer forests – typically composed of white fir, sugar pine, ponderosa pine, incense cedar and California black oak – are susceptible to moisture stress caused by warmer temperatures and reduced snow and rain. The drier conditions make the trees more vulnerable to fire and insect attack.
The drought of 2010-2016 has already had a substantial impact on mixed conifer forests in the Sierra Nevada. Aerial detection surveys show that more than 102 million trees have died since 2010; more than 62 million died in 2016 alone.
The UC ANR climate change adaptation paper suggests reducing competition for water by thinning trees and managing for species and structural diversity. The authors suggest property owners consider the source of seedlings when planting new trees.
“Select seedlings adapted to a slightly lower elevation or latitude than your property,” Kocher said. “These would be more likely to thrive under the 3- to 5-degree warmer temperatures we expect in 50 years or so.”
Oak woodlands are widely distributed and diverse in California, which gives them moderate to high capacity to adapt to climate change. Mature oaks are more resilient than young trees and seedlings.
One potential impact of climate change on oak woodlands is increasing precipitation variability and increasing spring rains. The moisture change could increase the spread and prevalence of Sudden Oak Death (SOD), a disease caused by a bacterium that was introduced into California from outside the U.S. SOD is primarily a concern in areas with tanoaks in Central to Northern California coastal areas.
“To reduce the spread of sudden oak death, land owners should prevent the movement of infected leaves, wood and soil,” according to the paper.
The primary concern for coastal redwood forests is the decline in fog. Fog frequency in coastal redwoods is 33 percent lower now compared to the early 20th Century. Less fog and rain plus warmer temperatures would leave coastal areas where redwoods typically thrive drier. But that doesn't mean redwoods will disappear. Areas with deep soil and areas close to streams and rivers may provide refuge for redwood forests.
The new publication, Adapting Forests to Climate Change, can be downloaded free from the UC ANR Catalog. It is the 25th in the Forest Stewardship series, developed to help forest landowners in California learn how to manage their land. It was written by Adrienne Marshall, a doctoral student at the University of Idaho; Susie Kocher, UC Cooperative Extension forestry and natural resources advisor; Amber Kerr, postdoctoral scholar with the UC John Muir Institute of the Environment; and Peter Stine, U.S. Forest Service.
- Author: Jeannette Warnert
This winter, a generous amount of rain and snow has fallen on California, but it can't erase the brown swaths of dead and dying trees in the Sierra Nevada caused by five years of drought and decades of forest mismanagement.
Fire suppression and the harvest of the largest and most resilient trees in the forest led to a large population of weak trees. The prolonged drought further weakened the trees' defenses against native insects. Aerial detection surveys show that more than 102 million trees have died since 2010; more than 62 million died in 2016 alone. Public and private landowners are now struggling to recover from this natural disaster.
UC Cooperative Extension forester and natural resources advisor Susie Kocher recommends dead trees be removed and the landscape reevaluated.
“The dead trees will eventually fall,” Kocher said. “Removing trees around homes and other buildings is especially important for safety. Also, when they fall on the ground they become large fuels on the forest floor, leading to more intense fires.”
The cost of removing the trees can be substantial. The State of California is funneling disaster relief funds through California counties, utilities are felling trees that pose a threat to power lines, and local jurisdictions are removing trees that could fall on roads and other public infrastructure. However, most tree removal is the responsibility of private landowners.
When the dead trees are gone, before considering replanting, Kocher suggests Sierra residents carefully assess what has survived.
“There is often a lot of live vegetation remaining,” Kocher said. “Make a map and mark where you find living trees and shrubs and identify them by species and size. If you have a significant number of trees left, you may not need to replant.”
Kocher suggests nurturing the remaining young trees.
“You may want to thin trees out so that available sun and soil moisture are focused on the healthiest individuals. Some watering in the summer may help counter stress caused by increased solar radiation,” she said.
If removing the dead trees leaves the landscape too bare, replanting native conifers is a good strategy. Conifers include pine, cedar and fir trees, but in California's dense forests, firs and cedars – which do well in shady conditions – are beginning to dominate. Replanting may be a time to give native pines – such as Jeffrey, ponderosa and sugar pines – a chance to recover ground.
“The fact that many pines have died does not necessarily mean they are no longer adapted to your location, even with our warming climate,” Kocher said. “There may be a few locations that are less suitable for trees that have grown there in the past, but for most areas, local growing conditions should support native conifers in the near future.”
Native plants and shrubs that died during the drought or were damaged during tree removal will likely come back on their own without replanting. Shrubs and oaks can re-sprout and native herbaceous plants generally store seed in the soil that will grow under native rainfall conditions.
Replanting of trees also gives landowners the chance to shape the landscape for best effect. Kocher offers the following recommendations on replanting trees in natural landscapes:
- Space trees at least 10 feet apart.
- Trees and flammable vegetation should be kept at least 10 feet away from the home, planted sparsely within 30 feet of the home and spaced widely enough in the 30 to 100-food zone so the crowns of the trees will not touch when they are mature. Beyond 100 feet, trees can fill into a more natural looking forest.
- Plant trees at least 10 feet from power lines.
- Do not plant trees within the road right of way to prevent interference with snow clearance, maintenance and construction projects.
- Plant pines where there is a lot of sun. Do not plant sugar pine on the driest sites.
- Avoid planting where the mature trees will block desired views.
- Author: Jeannette Warnert
Reposted from the UCANR Green blog
After conducting extensive forest research and taking into consideration all aspects of forest health – including fire and wildlife behavior, water quality and quantity – a group of distinguished scientists have concluded that enough is now known about proposed U.S. Forest Service landscape management treatments for them to be implemented in Sierra Nevada forests.
“There is currently a great need for forest restoration and fire hazard reduction treatments to be implemented at large spatial scales in the Sierra Nevada,” the scientists wrote. “The next one to three decades are a critical period: after this time it may be very difficult to influence the character of Sierra Nevada forests, especially old forest characteristics.”
The scientists' recommendation is in the final report of a unique, 10-year experiment in collaboration: the Sierra Nevada Adaptive Management Project (SNAMP). A 1,000-page final report on the project was submitted to the U.S. Forest Service at the end of 2015. In it, scientists reached 31 points of consensus about managing California forests to reduce wildfire hazards and protect wildlife and human communities.
“SNAMP was founded on a desire to work collaboratively to protect the forests of the Sierra Nevada,” said John Battles, professor of forest ecology in the Department of Environmental Science, Policy and Management at UC Berkeley and SNAMP principle investigator. “The challenges are multifaceted with a huge diversity of perspective among the public, among managers, and among scientists. SNAMP tried to bring all these interests and talents together to safeguard a vital resource and a natural wonder."
SNAMP was created to help develop a collaborative management and monitoring plan consistent with the Sierra Nevada Forest Plan Amendment, signed by regional forester Jack Blackwell on Jan. 21, 2004. The amendment called for the use of fuel reduction treatments – such as prescribed burning, mechanical chopping of underbrush, and harvesting certain trees – in strategically placed areas to slow down potential wildfires and improve forest health.
Because of disagreements over forest treatments in the past, which often led to lawsuits that languished in court for years, the U.S. Forest Service, U.S. Fish and Wildlife Service and the California Natural Resources Agency decided to take a new approach in 2005. They asked the University of California to provide unbiased scientific assessments of the impacts of the proposed treatments. UC was also charged with engaging the public concerned about repercussions of the forest treatments on wildlife habitat and water quality.
The scientific efforts and the forest treatments were all conducted in an open and transparent process. To ensure the greatest number of stakeholders were taking part, SNAMP included a public participation team of social scientists and UC Cooperative Extension outreach professionals to conduct and study the collaboration process.
Susan Kocher, UC Agriculture and Natural Resources Cooperative Extension forestry advisor in the Central Sierra, was a member the project since 2008 and served as the leader of the public participation team during the final two years, succeeding Kimberly Rodrigues, a UC forestry scientist who is now the director of the UC Hopland Research and Extension Center in Mendocino County. Kocher said having outreach and public participation included as a funded part of a science project is unusual.
“We were able to make great strides in getting everybody on the same page,” Kocher said. “That's what our data shows, too.”
A large volume of new scientific information was generated by the science team, and was published in 46 journal articles. The science spread fast and far, according to citation analysis conducted by the public participation team.
“We found that the average time it took for a SNAMP publication to be cited in another journal was about seven months,” Kocher said. “Citations to our articles came from all over the United States and around the globe.”
In addition, SNAMP science-based information was immediately useful to forest managers, according to a 14-page response to the SNAMP final report by the Forest Service, Fish and Wildlife and the California Natural Resources Agency. For example, an excerpt of the response submitted by California Fish and Wildlife noted that “SNAMP proved successful at modifying treatment methodology to meet the ever-changing reality of forest management.”
“The results were able to prove useful for managers past and future regarding how management can be implemented, in the face of wildfires while still retaining important owl nesting/roosting and foraging habitat features in and near owl activity features,” the document said.
SNAMP – funded with $15 million in grants mainly from the U.S. Forest Service, with support from U.S. Fish and Wildlife, California Natural Resources Agency and University of California – ran from 2007 to 2015. The project ended with the submission of the final report that contains details about the study areas, the treatment processes and reports from each of the six science teams. The science teams and their final reports are:
- Fire and forest ecosystem health
- Spatial - The study of forest canopy and understory with remote sensing technology called lidar, which uses reflected light for analysis.
- Wildlife: California spotted owl – A bird that is dependent on high-canopy forests.
- Wildlife: Pacific fisher – A weasel-like nocturnal animal that roams a wide area and nests in the hollows of old-growth trees.
- Water quality and quality
- Public participation
A key chapter in the publication is titled Integrated Management Recommendations. In it, the 31 points of consensus are outlined.
“The integration in this project is also unique,” Kocher said. “Scientists tend to work in their own focus areas, but we can learn a lot from each other's research projects.”
Working together, the scientists looked at all the research outcomes. The first 18 recommendations in the chapter are the direct result of scientific research conducted in SNAMP projects; the remainder of the recommendations are based on other scientific work and research.
Each of the recommendations is linked to a management goal. Some goals may conflict with achieving one or more of the other management goals. This approach to organizing the recommendations was taken to demonstrate that, while many of the management recommendations do not clash, a few may. For example, suggesting treatments across a landscape in a way that minimizes the negative effects on wildlife might reduce the efficiency of treatments aimed at reducing wildfire behavior and impacts.
The next steps are for the U.S. Forest Service to consider and adapt the SNAMP results and recommendations to continue to restore and protect the natural resources at risk in the Sierra.
“My hope is the SNAMP will be seen as a promising first try to apply adaptive management in the Sierra Nevada,” Battles said. “We gained important new insights about the ecology of these forests and we learned how to conduct applied research in an inclusive manner that engages not only scientists from multiple disciplines but also managers and the public."
- Author: Susie Kocher
The fourth winter in a row of disappointing precipitation has triggered a die off of trees in the Sierra Nevada, most of which is now in ‘exceptional drought' status. The US Forest Service conducted aerial monitoring surveys by airplane in April 2015 and observed a large increase in tree mortality in the Southern Sierra (from Sonora south). Surveyors flew over 4.1 million acres of public and private forest land and found that about 20 percent had tree mortality on it, totaling over 10 million dead trees.
The Forest Service found severe mortality in many pine species especially ponderosa pine. On private lands along the foothills of the Sierras, surveyors found extensive areas of dead pines. Large areas of blue and live oak mortality were also suspected though it was too early in the season to be sure.
On the Stanislaus National Forest, areas with dead trees doubled since last year. Pine mortality, mostly caused by western pine beetle, was common at lower elevations. Over 5 million trees were killed on the Sierra and Sequoia National Forests up from the 300,000 trees killed last year in the same area. Conifer mortality was scattered at higher elevation, though surveyors note that the survey was conducted too early in the year to detect the full extent of mortality levels.
The insects killing trees in the Sierra are all native insects that are multiplying because of drought conditions. Native insects are a necessary part of the forest ecosystem that speed decay of wood back into nutrients, prey on other insects, and provide food for wildlife. They are normally present at low levels and cause tree mortality only in localized areas.
However, drought weakens trees and reduces their ability to withstand insect attacks. Normally trees use pitch to expel beetles that attempt to burrow into the tree through the bark. Weakened trees cannot produce the pitch needed to repel these beetles which are able to enter under the bark and lay eggs. Larvae feed on a tree's inner bark cutting off the tree's ability to transport nutrients and eventually kill it. Attacking beetles release chemicals called pheromones that attract other beetles until a mass attack overcomes the tree. Many beetles also carry fungi that weaken the tree's defenses.
Western pine beetle is one of the main culprits killing pines in the Sierra during this drought. It is a bark beetle, one of a genus of beetles named Dendroctonus which literally means ‘tree-killer'. Adult beetles are dark brown and about a quarter-inch long. Adults bore into ponderosa pines, lay eggs which develop into larvae in the inner bark then complete development in the outer bark. When beetle populations are high, such as during drought periods, even healthy trees may not be able to produce enough pitch to ward off hundreds of beetle attacks.
Western pine beetle often attacks in conjunction with other insects. Other beetles causing tree mortality in Sierra forests include mountain pine beetle, red turpentine beetle, Jeffrey pine beetle, engraver beetles (Ips) and fir engravers. Forests with a higher diversity of tree species are typically less affected because beetles often have a preference for specific tree species. Some species may attack only one tree type. For example Jeffrey pine beetles attack only Jeffrey pine.
Signs that bark beetles are affecting a tree include pitch tubes (streams or tubes of pitch visible on the trunk), small holes through the bark, or boring dust. If the tree is extremely water-stressed and cannot produce pitch, boring dust may be the only visible sign. Trees with needles that have turned from green to red are dead. Most beetles have emerged by the time trees turn red.
The best defense against bark beetles is to keep trees healthy so they are able fight off insects themselves. Widely spaced trees are typically less susceptible to successful attack by bark beetles since they face less competition for moisture, light, and nutrients compared to densely growing and overcrowded trees. Forest health can be promoted by thinning to reduce overcrowding (so each tree has access to more resources) and removing high risk trees during thinning (such as those that are suppressed or unhealthy).
For landscape trees of high value close to a home, watering may be one option to increase tree vigor against bark beetle attacks. Apply about 10 gallons of water for each inch of tree diameter (measured at chest height) around the dripline of the tree once or several times a month during dry weather.
There are some insecticides registered for bark beetle control, but all are preventative only. Carbaryl may prevent attack for up to two years, while pyrethroids can deter attack for up to a year. Spraying can be tricky because the chemical must be applied up to 50 feet up the trunk of the tree usually while standing on the ground. Since misapplication may have toxic consequences, any insecticide must be administered by a licensed pesticide applicator. All applications must follow the label. Though some systemic treatments applied to the soil or inserted into the tree may work in some cases, there is not a lot of documented evidence that they are effective against western pine beetle. No insecticide can prevent tree death once a tree has been successfully attacked.
- Author: Brook Gamble
Reprinted from the UCANR Green Blog
Over a dozen UC Agriculture and Natural Resources (UC ANR) California Naturalists, fire ecology experts, wildlife biologists, resource managers, educators, and artists met at UC Berkeley's Blodgett Forest Research Station and the adjacent El Dorado National Forest April 23 and 24, and not one of them complained about the much-needed deluge of rain and intermittent hail that soaked the group. The weekend's ambitious goal? To dive deeply into a UC California Naturalist Program and California Fire Science Consortium advanced training workshop on the subject of wildfire effects on Sierran mixed conifer forests.
With the 2014 El Dorado National Forest's King Fire as a case study, a mix of lectures, field studies, art, field journaling techniques, and Native American story telling were used to examine land management practices that influence fire behavior and explore how the landscape recovers from fire. UC ANR Cooperative Extension Central Sierra's forestry advisor Susie Kocher and community education specialist Kim Ingram organized and facilitated the workshop.
Workshop participants were treated a lecture and field studies of basic fire ecology concepts by Scott Stephens, professor of fire science at UC Berkeley. Stevens lectured in class, and later demonstrated on a number of wet, lush forested treatment plots in the field, topics ranging from fire policy, fuels management options and objectives, and carbon sequestration to fire suppression consequences, fire behavior and severity, soil stability, and post-fire forest structure. Stephens is a researcher with the Sierra Nevada Adaptive Management Project (SNAMP), a long-term collaborative research project investigating how forest fuels thinning impacts fire behavior, fire risk, wildlife, forest health, and water. Fire is a vital to maintaining healthy California forests and ecosystems and Stephens's work demonstrates that both prescribed fire and its mechanical thinning replacements can successfully change forest structure and fuel loads, resulting in potential overall improvement of forest health. He finds that treated forest stands are more resistant and resilient to high-intensity wildfire and that these treatments have minor to negligible negative impacts on birds and small mammals, understory plant diversity, exotic plant invasions, and insect attack. Current and future research is in part focused on the impact and feasibility of treatments across the landscape.
Also joining participants was Sheila Whitmore from the University of Wisconsin-Madison. Whitmore is the assistant project leader on SNAMP's owl team, which studies how fuel reduction treatments affect California spotted owl survival, forest occupancy, and reproductive success. The California spotted owl is one of three sub-species of spotted owls and the only spotted owl that has not yet been placed on the endangered species list, although its population is widely thought to be declining. Late in the evening, accompanied by Whimore, three nocturnal field technicians, and armed with tools of the trade like bird call whistles and flashlights, participants quietly slogged deep into the forest along the 22-mile system of El Dorado Irrigation District canals, listening for the territorial four-note hoot of the California spotted owl. While the crew eventually found one female owl on the night hike, the owl team has just started surveying breeding territories this spring and are uncertain how and if the owls will be impacted by the King Fire. Modeling efforts and a radio telemetry study seek answers to questions about demography, habitat, individual range size, and foraging preferences, given different levels of severity in burned forests.
Day two of the workshop, under warm sunshine, began with a discussion of Native American fire ecology and traditional stories shared by Kimberly Shiningstar Petree. Petree is a Tumelay Nissenan Miwok, the cultural preservation officer for her tribe, and the founder of the Cosumnes Culture and Waterways, a non-profit dedicated to promoting, preserving, and stewarding Indigenous Culture and waterways of their land. As told by a descendant of the first stewards of the area's forests and a carrier of an ancient oral tradition, the fire stories that Petree shared with the group were both relevant to today's fire management practices, and moving, setting a positive tone for the rest of the day.
Patricia Trimble, El Dorado National Forest's Georgetown district ranger, and Laurie Wigham, illustrator, painter and art teacher, accompanied participants on field activities. Trimble took participants on a road-based tour of the King Fire, demonstrating the effects of low, moderate and severe fire on the landscape. She shared information on consequences of long-term fire suppression, fire impacts, Forest Service strategies for protecting cultural resources, forest replanting and erosion abatement efforts, National Environmental Policy Act regulations, and public perception of fire. More than seven months after the fire, the Forest Service has just opened the burn back up to the public, and the public was out in force mushroom hunting, fishing, and cutting firewood within the high severity areas of the King Fire.
Wigham thoughtfully braided art and field journaling techniques seamlessly into the stops along the way. She shared inexpensive and novel ways to document the landscape in a group or individual setting at difference scales. She offered low-tech tricks to help participants deepen their ability to absorb dense and technical information, observe nature closely and scientifically, and to connect with feelings about a place and time in nature.
Lectures, field study, art, field journaling techniques, knowledge sharing, and Native American story telling: supported by a solid framework of current science topics and research results, they all had their place in this advanced training workshop. Each individual piece of the fire ecology workshop was enriching and informative, and forced participants to move deeper and more thoughtfully into their understanding of the dense topic than they might on their own. The regeneration of the El Dorado National Forest after the King Fire will undoubtedly provide inspiration, research, and education opportunities far into the future.
The UC California Naturalist Program uses a science curriculum, hands-on learning and service to inspire stewardship of the state's natural resources. The public and UC-certified Naturalists alike may sign up for future California Naturalist Advanced Trainings here.