- Author: Steve Dreistadt
Brooms are shrubs introduced into North America from Europe in the mid-1800s. Common species include Scotch broom (Cytisus scoparius) and Portuguese broom (Cytisus striatus). Brooms initially were introduced as ornamentals, but then used extensively for erosion control along roadsides and in mined areas.
Now throughout California forests, roadsides, and wildlands they are weeds that increase the risk of wildfire and crowd out desirable vegetation. They form impenetrable thickets that invade other vegetation, shade out tree seedlings, and make reforestation difficult. They burn readily, increase the intensity of fire, and carry fire to the tree canopy. They are toxic to cattle and horses and unpalatable to most wildlife. Brooms produce abundant, long-lived seed and are able to fix atmospheric nitrogen, giving them competitive advantage over native plants.
Invasive species that create a dangerous wildfire hazard and crowd out desirable vegetation and wildlife are examples of why this book emphasizes vegetation management and pesticide handling, including correct equipment calibration and effective herbicide application. The second edition also provides broader coverage of insects, plant pathogens, vertebrate pests, and the various practices to manage them, recognizing that lands commonly have multiple uses and when and how pests are managed depends on many considerations with sometimes conflicting goals.
Experts with Cal-Fire, Caltrans, PG&E, USDA Forest Service, private industry, the University of California (UC) Berkeley and Davis campuses, UC County Cooperative Extension offices, and the California Department of Pesticide Regulation (DPR) contributed to Forest and Right-of-Way Pest Control, prepared by UC ANR's Statewide Integrated Pest Management Program.
Forest and Right-of-Way Pest Control is available for $35 online in the UC ANR Catalog. The table of contents and more information about the book are available on the UC IPM website. You can also preview and electronically search the contents on Google Books.
- Author: Bill Tietje
Bill Tietje is a UC Cooperative Extension area natural resources specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. He is based in San Luis Obispo.
UC Cooperative Extension's Master Gardeners have received many calls during the past few months concerning the poor condition of many California native oak trees, in both urban and rural landscapes. Many evergreen oaks, including coast live oaks, have brown leaves and thin foliage. Adding to the unattractiveness, a deciduous oak, the blue oak, dropped its leaves ahead of schedule. Although a tree may look unhealthy, it can recover.
Early leaf drop is a deciduous tree's adaptation for conserving water that it otherwise would lose through transpiration from its leaves, which can occur as long as the leaves are green.
More recently, another deciduous oak, the valley oak, kept its brown, dead leaves longer than usual. This could be due to the virtual lack of rainfall and wind last fall and early winter, both of which typically contribute to an earlier leaf drop.
So why are these things happening?
As you know, it's dry out there! In fact, the past 12 months have been the driest on record, going back to 1870. Not surprisingly, many oaks are under water stress—and they show it.
This situation reminds one of the conditions during the drought of 1988-1990, one of the most widespread and severe droughts in the state's history. Coincidentally during that time in three counties on the Central Coast, UC Cooperative Extension was conducting a study that included the monitoring of coast live oak, blue oak, and valley oak trees on study plots scattered throughout Monterey, San Luis Obispo and Santa Barbara counties. Many of the oaks looked stressed. Some of the trees succumbed to the drought. Small oak trees in the undergrowth and on steep terrain with southern exposure, and shallow, infertile soil, were most vulnerable. Such sites are typically drier than other slopes and orientations. However, large, mature trees—or, large branches on these trees—on more gentle slopes, also died. Usually there is not only a single factor that causes the decline and mortality of oak trees. Drought stress lowers the trees' defense, making the trees more susceptible to mortality factors such as decay fungi and boring beetles. Most likely the drought caused early death of some oak trees that would have persisted otherwise.
What can be done?
Surely our native oaks have been through droughts before. So the oak trees, other than the very small or very old trees, should be okay. Nonetheless, given the very low rainfall this year it may be prudent to give a valued tree in the urban landscape a “deep watering”.
A deep watering can be accomplished by moving a hose around under the tree's canopy during the day for a day or two at a low flow or a trickle stream, such that the water percolates into the soil, not simply run down the hill. Water a few feet away from the base of the tree to avoid inviting damage from crown rot caused by the fungi Phytophthora cinnamomi. Water-saturated soil increases the chances of infection of the tree trunk.
A deep watering followed by soil drying for a month or two should not harm the tree. In fact, a deep watering may be the best recommendation for invigorating your thirsty oak tree, thus providing some insurance that the tree will survive this current drought.
I should mention that unless California receives normal or better rainfall the rest of the rainfall season, it is likely that early leaf drop will occur next summer. Remember, as suggested above, the early browning and fall of leaves does not mean that your tree will die. This is simply the tree's way of adapting to conserve water when soil moisture is low. Unless the tree is severely weakened by some other cause, it will leaf out normally the following spring.
For more information: Tietje, W., W. Weitkamp, W. Jensen, and S. Garcia. 1993. Drought takes toll on Central Coast's native oaks. California Agriculture 47(6):4-6.
- Author: Jeanette Warnert
- Posted by: Susie Kocher
Reprinted from the UCANR Green Blog
Every year, the day after Thanksgiving, Susie Kocher bundles up her children, gathers the extended family and hikes into the Lake Tahoe Basin forest to find a Christmas tree.
“It’s my favorite part of the season,” Kocher said. “Having the fresh, living thing in the house really symbolizes the holiday. You can’t do it with a fake tree.”
Kocher, a forester and the natural resources advisor for UC Cooperative Extension in the Central Sierra, lives and works in Lake Tahoe. The Lake Tahoe Basin Management District is one of nine national forests in California, all of them in the northern part of the state, where the U.S. Forest Service allows Christmas tree cutting with a $10 permit.
Though some people mourn the death of any tree, Kocher says careful selection and removal of Christmas trees is an enchanting family tradition that enriches forest health.
“We have a lot of small trees on public lands because of fire suppression,” Kocher said. “They’re all competing with one another and many will ultimately die. A smart harvest of Christmas trees can improve the forest by helping with thinning.”
People with permits to cut down Christmas trees in national forests must follow strict guidelines. The trees must be within 10 feet of another living tree, the base of the trunk cannot be more than six inches wide and it must be cut within six inches of the ground. Some national forests limit the harvest to certain tree species.
Despite committing to these guidelines when obtaining a permit, Kocher said she has seen some Christmas tree harvesters make ill-advised choices.
“Some are too lazy to find a good tree and will cut the top off a large tree,” Kocher said. “You can be driving around and see what looks like a poor old Dr. Suess tree, which is what grows from the ugly remnant left behind in the forest.”
Such irresponsible Christmas tree cutting has led some forests to discontinue Christmas tree harvesting for personal use.
Kelly Hooten, information specialist with the Sierra National Forest, said the organization stopped issuing Christmas tree cutting permits because people would tend to cut down only healthy, strong trees.
“It’s really the sickly, Charlie Brown trees that we would prefer to thin in our forest,” Hooten said.
The El Dorado National Forest does not allow Christmas tree cutting because there are more than 30 Christmas tree farms in the vicinity where visitors can choose and cut down their own trees.
“Allowing Christmas tree cutting in forests would hurt these farmers economically,” said Lynn Wunderlich, UCCE advisor in the Central Sierra office. Many Christmas tree farmers also provide food, crafts, activities and visits with Santa.
“Families can visit the farmer year after year as their children grow, so that’s part of the experience,” Wunderlich said.
There has been ongoing debate about whether a fake tree or real tree is more environmentally friendly, but for Kocher, there is no question.
“Fresh real trees are a renewable resource, fake trees are not,” she said. “It’s an agricultural product. You can contribute to a local farmers’ income or you can help thin the forest. Picking and bringing home a fresh tree, decorating it and smelling it defines the season for me. Without it, I don’t think it would feel like Christmas.”
- Author: Kim Ingram
- Posted by: Susie Kocher
Reposted from the UCANR Green Blog
Thinning a forest of woody materials has multiple objectives. It can increase the resiliency of the remaining trees from the effects of fire, drought, pest and disease; it can improve habitat quality for wildlife including watersheds; and it can make it easier for firefighters to protect human lives and livelihoods when a fire is burning. There are several ways thinning is carried out: cable logging, feller bunching, conventional tractor skidding, hand-thinning and piling, and mastication. One of the issues with thinning is the disposal of biomass that is non-merchantable (e.g., branches, tree tops, small diameter trees). Typically this material goes into large slash piles. For the most part, these piles are left in the forest to break down naturally under winter rain and snows, and are later burned. Because of strict air quality rules, forest managers have very small windows of opportunity to burn these piles, so they are often left on the landscape for many years, sometimes becoming a fire hazard themselves.
Forested communities are searching for ways to deal with this residual biomass that will improve the health of the forest ecosystem; improve and protect critical watersheds and wildlife habitat; reduce the amount of air pollution by removing the piles instead of burning them; and reduce the critical fire danger to their communities. The Placer County Biomass Program is taking up this challenge by chipping the slash piles and trucking the chips to a biomass facility to be converted into electricity.
Outside of Foresthill, Calif., the Tahoe National Forest American River Ranger District and the Sierra Nevada Adaptive Management Project (SNAMP) have been collaborating on a study of forest fuels reduction treatments carried out on national forests. The eight-year ‘Last Chance’ study involves independent third party research by University of California scientists of the integrated effects of forest thinning on fire hazard, forest health, wildlife, water quality and quantity, and public participation. The Placer County Biomass Program, in conjunction with the Tahoe National Forest, the Sierra Nevada Conservancy (SNC) and the Placer County Air Pollution Control District, proposes to remove some of the biomass waste from the Last Chance project to provide an alternative to open burning of the piles. Local contractors are hired to grind the material on-site, load the material into chip vans, and bring the material to market within 60 miles of the Last Chance site to create green, renewable electricity. Placer County estimates that roughly 3,000 Bone Dry Tons (BDTs) of biomass can be removed. According to UC researchers, one BDT burned in a typical commercial boiler fuel will produce 10,000 pounds of steam and 10,000 pounds of steam will produce about 1,000 horsepower or generate 1 megawatt hour (MWH) of electricity.
The economics of this project will be used as part of the assessment of locating a biomass energy facility in the Foresthill area. The removal of these biomass piles will greatly reduce the possibility of catastrophic fire to the local communities on the Foresthill Divide. The improved forest and watershed health will be noticed by the local community and the surrounding county which derives recreation and watershed benefits from the American River area. In addition, several tons of air pollutants will be avoided by removing the pile burns from this area which is currently a federal non-attainment basin that carries both business and health risks to the local population.
Though this project is of benefit to the Foresthill community, other communities in the wild-land urban interface aren’t as lucky. According to Brandon Collins, research scientist at the Pacific Southwest Research Station and UC Berkeley, the lack of funding to chip and remove slash piles and the lack of infrastructure or facilities to take the chips to, makes it impossible at this time to remove that biomass at a larger scale.
“There is so much woody material on the landscape as a result of fire exclusion, it could take decades to really get a handle on it," Collins said. "However, any effort to remove thinning residues from the forest and to also get a benefit from it, such as energy, is great and should be supported.”
- Author: Bill Stewart
- Posted by: Susie Kocher
By Bill Stewart, Co-Director, UC Center for Forestry, originally published at http://www.calforests.org/what-twenty-years-of-concerted-public-safety-oriented-forestry-looks-like/ on September 13, 2013
The 2013 Rim Fire that burned across large areas of the Stanislaus National Forest and Yosemite National Park brought national attention to the issue of how to increase the resiliency of forests to survive wildfires. There is considerable well-documented evidence that fuels are no longer limiting fires in the Western US and that they are getting larger and more expensive to manage (e.g. Miller et al. 2009, Miller et al. 2011). For example, a recent analysis concluded that “the percentage of high-severity fire in conifer-dominated forests was generally higher in areas dominated by smaller-diameter trees than in areas with larger-diameter trees.” (Miller et al. 2011). There is also considerable evidence that treatments that preferentially take out the smaller diameter trees (‘thin from below’) and focus on trees with signs of incipient mortality can significantly reduce the fire risk while still preserving most of the ecological characteristics of large tree dominated stands (e.g. Stephens et al. 2009, Moghaddas et al. 2010, Stephens et al. 2012a, Stephens et al. 2012b, Stephens et al. 2012c). In plain English, there is too much kindling in our forests and reducing fuel levels can extend the lifetimes of the big trees in forest stands.
While federal agencies often depend on prescribed fire and light thinning to increase fire resiliency, private and public land managers who produce sawlogs destined for renewable building products are interested in a wider range of approaches. Burning up trees that could have provided sustainable building products, renewable energy, and sufficient revenue to cover management costs is not a scenario favored by most forest landowners. Often lost in the discussion of the impact of the Rim Fire in Yosemite National Park is the opportunity to integrate fire risk reduction with sustainable and profitable forest management.
From our surveys of family forest owners we know that half of forest landowners want to do vegetation management to reduce fire risk (Ferranto et al. 2012). They want to work together with their neighbors and local fire districts. We noted that most of these landowners also value environmental attributes such as fish and wildlife habitats, native plants, and aesthetics in addition to the revenue generating potential of their lands. However, most of these owners are wary of using prescribed fire by itself or in combination with thinning treatments. Not surprisingly, landowners are also averse to losing money on any major resource management activity. They often reinvest timber revenues to reduce risks in areas but they will rarely borrow money from other assets they have and invest in fire risk reduction (Stewart et al. 2012, Stewart and Nakamura 2012).
The 4,270 acre Blodgett Forest Research Station is owned by the University of California and is managed to demonstrate the full range of management approaches that can be used by forest land managers and owners to accomplish their unique goals. We have worked hard to make the results on a wide variety of forest related themes available on our web sites, through publications, and with field trips for landowners, professionals and other interested parties. At Blodgett, one project that always gets considerable attention on field trips is our twenty year effort to create a fire resilient corridor into the office and residential area within the Blodgett Forest Research Station.
Figure 1: Blodgett manager Rob York explaining how the treatments to create the more open stand on the right reduced fire risk and still maintained a fast growing stand. The denser stand to the left of this photo has not been managed since it grew back a century ago.
Following extensive logging with railroads and steam engines from 1900 to 1933, the young stands at Blodgett were compartmentalized and assigned to a wide range of even-aged, uneven-aged, and reserve management. Harvest activity on the regenerating forest began in earnest in 1962 and has continued annually to the present. The wide range of treatments applied consistently over time, coupled with comprehensive permanent plots established beginning in 1974 has enabled the longest available empirical assessment of diverse forest management impacts and tradeoffs in productive forests of the Sierra Nevada.
An ever present challenge is the fact that in the high fire season we house up to 45 researchers in the middle of our forest. In the mid 90’s, we recognized the risk of having 45 non-fire fighters in the middle of a dense forest is risky and decided that public safety must trump research goals around the buildings and along the access road. We used a combination of commercial harvests coupled with surface fuel treatments and have now thinned these stands from below (keeping the large health trees) three times. Our detailed inventory data shows that we have been able to maintain high growth rates, large average tree size, high biomass volume per acre, and good separation between the crowns of the large trees. This will allow us to successfully evacuate if a wildfire ever swept through.
The comparison of the 1993 aerial view and the 2012 aerial view after three harvests clearly shows the four historical images with the project unit outlined in white at the end of this document show the progression of the fuelbreaks in between our other research treatments.
Figure 2: 1993 aerial view of Blodgett Forest and the main entrance road
Figure 3: 2012 aerial view of the fuel reduction corridor along the entrance road
From our detailed records of the forest conditions as well as what we harvested, we know that these treatments have paid for themselves. Even with a only 40, and now 30 large trees per acre, these stands are still capturing much of the growth potential as the large and healthy trees continue to put on girth and height.
While Blodgett was able to design the fuel breaks under a larger timber harvest plan (THP) that covered many other units, other landowners could be dissuaded from undertaking this public safety oriented actions due to the complexity of filing for a full blown THP. State and federal agencies often spend $500 to $1,500 per acre to reduce fire risks, but public funds are scarce and the task is large. Much greater sums can be spent putting out fires. As a public policy, making it easier for forest landowners to invest their own revenue in risk reduction and improving the quality of their stands to get larger trees, better habitat, and protected water quality makes sense.