Why widespread tree mortality is not prevalent in coastal forests?

By Thembi Borras

During the last six months, since I have been producing articles, the most popular interest of readers has been causes and management of tree decline and mortality. Ironically, I left college believing that coastal forests were little afflicted by diseases and insects and that all of the serious problems were found in the Sierran and southern mountain ranges. While I continue to learn the numerous insects and diseases that cause decline and mortality of trees in coastal forests, coastal forests do not suffer the widespread tree mortality that shock certain communities, like Lake Tahoe and Lake Arrowhead. Why isn't widespread tree mortality prevalent in coastal forests?

Firstly, insect outbreaks become epidemic, causing widespread tree mortality, more often than disease outbreaks and insect outbreaks are more prevalent in dry regions as compared to outbreaks of disease, which are more prevalent in moist regions. Some insect genera emit pheromones, a potent chemical that attract other insects that can result in a population explosion, whereas the rate of spread of diseases is regulated by its vectors, such as wind and water, and is comparatively slower. Generally, in our coastal forests, trees die individually or in relatively small groups, resulting in little impact at the landscape level.

Secondly, single species forests are more prevalent in the Sierras. Single species forests are more susceptible to widespread mortality because a different tree species that may not be susceptible to a host specific insect is not present to break up the progression of the outbreak.

Thirdly, pines are more prevalent in the Sierran and southern mountain ranges and certain tree species, such as pine, are more susceptible to insect infestation. In fact, some of the most damaging forest epidemics are in pine forests.

Another reason that I did not learn as much about the diseases and insects that cause tree decline and mortality in coastal forests is because less is known about them. There is a comprehensive and accessible body of work about Sierran insects and diseases because the large amount of publicly owned land and visible widespread tree mortality in the Sierras has been a recipe for money, research and lands on which to do that research.

A portion of this production was gleaned from a conversation with Jack Marshall, Forest Pathologist at the California Department of Forestry and Fire Protection. If you have a local disease or insect question for Jack Marshall, he can be reached at Howard Forest in Willits at 707-459-7448.

Best Wood for Burning

By Thembi Borras

What is the best tree species for firewood? The answer is a function of abundance, availability, splitability, presence or lack thereof of messy sap, density and energy content.

The most abundant hardwood in the managed timberland on which I work is tanoak. The most available species for a low price or free are the less dense hardwoods and conifers, in fact I have found it hard to give pine and willow away. The most splitable woods are species that tend to have straight grain. Others have entangled fibers and can be very difficult to split. Some wood splits easiest when green such as live oak, madrone and tanoak and some split much easier when dry and brittle, such as fir and some pines. Obviously the conifers have the messy sap, and are not preferred because of their sap. Many people believe that burning sap will lead to excessive accumulations of creosote. However, if the wood burning system is functioning properly, above normal levels of creosote should not accumulate. The easiest and best fire is built by using a mixture of both softwoods and hardwoods. Softwoods start burning easily, and the hardwoods provide for long burning and good "coaling" qualities.

All wood, regardless of species, has about the same energy content per pound. The different species vary only in density. The higher the density, the higher the energy content per cord. A cord is 4' high by 4' deep and is 8' long. Energy content is often measured in British Thermal Units (BTUs). The following are the approximate number of BTUs produced per cord burned of local species: willow 18, redwood and grand fir 19, big leaf maple 22, western hemlock 23, California bay, black walnut and Douglas-fir 25, tanoak, white oak and black oak 27, madrone 30 and live oak 35.

Most folks will say madrone is the best tree species for firewood, but I encourage you to consider other species, which may be more available, less expensive and may be burnt regardless, in slash piles or wildland fires, without the benefit of heating your home. Ultimately, it is more important to have wood that is cut and split to the right size and properly dried than it is to get the most dense wood available.

For more information, visit the website http://www.woodheat.org/ and http://www.consumerenergycenter.org/homeandwork/homes/inside/heatandcool/fireplaces.html, from which this production was gleaned.

A Well Designed Wood Burning System

By Thembi Borras

A well-designed wood burning system embodies building a strong draft quickly, so a new fire is easy to start. When a fire is started, smoke should not spill into the room and excessive creosote should not accumulate. When a fire is not burning a cold draft should not come down the chimney. A well-designed wood burning system is a pleasure to use and the kind of system you want in your home.

There are ten design characteristics of a successful stove or fireplace system, they are:

1. The chimney runs inside the heated space of the home.
2. The chimney penetrates near the high point of the heated space.
3. The chimney is tall enough, beyond where it penetrates the roof, its top is clear of obstacles and it has a chimney cap.
4. The chimney flue is insulated and is the correct size for the appliance.
5. The conduit from the appliance runs straight up from the appliance and has no offsets.
6. The appliance and venting system are well sealed.
7. The stove or fireplace is EPA certified for safety and emissions.
8. If the system is installed in a tightly sealed house, the house has a balanced ventilation system.
9. If a large exhaust fan, such as a downdraft kitchen range exhaust, is present, it is electrically interlocked to a fan-forced make-up air system.
10. The appliance is operated by an informed user and regularly maintained.

These design characteristics function to keep the chimney gasses warmer than the heated space for as long as possible to keep the gases moving as quickly as possible, which facilitates beneficial draft and minimizes creosote buildup. These design characteristics also function to balance the air going out with the air coming in. This prevents the house from becoming depressurized, a symptom of which is smoke spillage and a cold draft from the chimney when there is no fire.

For more information, visit the website http://www.woodheat.org/, from which this production was gleaned.

Heating with Wood

By Thembi Borras

The following suggestions are provided to support firewood harvested sustainably, burned cleanly and efficiently, and its energy used.

1. Harvest your firewood sustainably, which includes not cutting wildlife trees, avoiding damage to remaining trees, using existing roads, matching the weather to the surface of the road, selecting trees with the future condition of the stand in mind and where appropriate giving removal preference to hardwoods overtopping or competing with conifers. If you buy your firewood, ask your supplier where the wood came from. Make it known you only want wood harvested sustainably. Also, be aware of diseases which may use your vehicle as a vector, such as Sudden Oak Death.

2. Design your wood burning system such that it burns wood cleanly and efficiently (more on this next week). The efficiency of the wood burning system you select can vary greatly, open fireplaces deliver between zero and 20% net efficiency, whereas the contemporary "hi-tech" air tight wood stove may deliver better than 75% net efficiency.

3. Install your indoor wood burning system per the manufacturer specifications and maintain it so that it remains working efficiently and safe. Maintenance includes cleaning the accumulation of creosote in the chimney, which is a flammable by-product of wood combustion. Most stove-related fires are attributable to installation, operation and maintenance, rather than product defects.

4. Your wood burning system can only operate with high efficiency and low emissions if your firewood is properly seasoned. Properly seasoned firewood has a moisture content of less than 20%. One way to properly season your firewood is to cut, split and stack the wood in the early spring and let it stand in the sun and wind all summer. Symptoms of poor performance related to wet firewood include, difficulty getting a fire going and keeping it burning, smoky fires with little flame, dirty glass, rapid creosote buildup in the chimney, low heat output, the smell of smoke in the house, short burn times, excessive fuel consumption and blue-gray smoke from the chimney.

5. Insulate your home to contain the heat you produce. Note open fireplaces may perform very badly in tight homes because the house is easily depressurized.

For more information, visit the website http://www.co.mendocino.ca.us/aqmd/, from which this production was gleaned. The article "Heating with Wood" by G. Nelson Wolfe was also used as a source.

Safe Debris Burning

By Thembi Borras

According to the Mendocino County Air Quality Management District, it is now winter burning season. Burning is allowed between the hours of 9am and 3pm only on permissive burn days. The burn forecast recording for Mendocino County is available 24-hours a day at 707-463-4391. It is not legal to burn anything except vegetative matter. A good rule of thumb is if it didn’t grow on your property, you may not burn it.

Burn permits are required for single piles in excess of 4' by 4'. They cost $10 and are available through the Mendocino County Air Quality Management District; the District can be reached at 707-463-4354.

In Mendocino County between 1994 and 2003, 18% of assigned fires were caused by escaped debris fires. The following are measures intended to minimize fire danger health issues and nuisance smoke:

1. Establish a 10-foot clearance from any combustible material.
2. Have shovel and water on hand until the fire is out.
3. Have a responsible adult present.
4. Consider a no-burn option. Composting and chipping may be feasible alternatives. Limbs and other debris may also be piled for wildlife habitat if located where they do not pose a fire hazard.
5. Burn one pile at a time.
6. Check the weather. It may be too windy to burn if trees are swaying, flags are extended, or waves appear on open water. It is not a good idea to burn on a day with a strong inversion because inversions trap pollutants at or near ground level and do not allow them to disperse. An inversion is when a layer of warm air traps a layer of cold air beneath it.

For more information, visit the website http://www.co.mendocino.ca.us/aqmd/. In Humboldt County, you can contact the North Coast Unified for burn information at 707-443-3093.

A portion of this production was gleaned from http://www.dnr.wa.gov/htdocs/rp/stewardship/bfs/WESTERN/safedebrisburning.html

Considering Wildlife Trees During Tree Marking

By Thembi Borras

Wildlife occupies every layer of a tree. In a light intensity single tree selection, during tree marking, you have the opportunity to evaluate each tree individually for wildlife value. Trees that provide preferred habitat to wildlife include goose pens, trees with broken tops and decadent trees.

Goose pen is the name given to a basal tree cavity, which during the homestead era could provide shelter for a goose or a gaggle of geese, depending on the size of the cavity. Goose pen is now used to describe any tree with a basal cavity, most often created by fire. Species that use goose pens include bats for roosting and birds for nesting.

Trees with broken tops facilitate fungal entry causing rot in the stem, which allows primary cavity nesters to begin excavation. Secondary cavity nesters follow. Flat tops provide nesting platforms and are preferred by several owl species if they are concave; meaning the top breaks off below the remaining canopy. Ospreys, a fish eating raptor, will nest in exposed flat tops. Portions of broken tops that stick above the rest of the canopy may be used by birds for roosting and perching.

Decadent trees, trees in a condition of decline, may possess oversized limbs and exfoliating bark, dense clusters of branches caused by a mistletoe infection and rotten cavities caused by some physical damage such as lightening or wind. Large limbs are platforms that support wildlife, the larger the limb the wider the range of species able to use the platform. Exfoliating bark is used by birds and bats to nest and roost. Dense clusters of branches may be used as cover or rest sites for animals including martens, fishers and squirrels. Northern spotted owls have used them as locations to nest. Decaying wood provides the medium in which woodpeckers forage and cavity nesters build nests.

Goose pens and decadent trees are not easily recreated given fire has been suppressed and stand age has been lowered. There is often an inverse relationship between the economic value and the wildlife value of a tree, which facilitates the decision to retain trees with high wildlife value and low economic value.

Marking to Improve Stand Structure

By Thembi Borras

Sustainable forestry is largely determined by how a forest management strategy is interpreted on the ground. Single tree selection does not imply sustainable forestry as it can easily be corrupted by high grading; taking the biggest and best trees. Tree marking, deciding which trees will be cut and which trees will be retained is the most important way a forester translates single tree selection on the ground. Although there are a hundred things to consider before marking a tree, the core criteria to improve stand structure, in descending order of priority, are:

1. Remove damaged, dying, or diseased trees. Generally, trees which may die prior to the next harvest. However, some dying trees may be retained to become snags, which are important to wildlife. This is a “sanitation” strategy.
2. Remove suppressed and intermediate crown class trees. These are trees that neither are presently contributing growth to the stand, nor are they expected to do so prior to the next harvest. This is a "thinning from below” strategy.
3. Remove selected larger trees that improve spacing for the higher quality trees, which will be retained. This is a “spacing improvement” strategy.

Target diameters also guide tree marking. For example, at age 50 the largest redwoods in the Jones Family Forest have not yet reached the target diameter of 36" specified in the long term management plan. Therefore, selection leans toward retaining the largest trees.

At age 80, the largest redwoods in the Jones Family Forest have reached the target diameter and selection leans toward removing them to benefit smaller diameter trees. However, not all trees that have reached the target diameter are cut. They are simply preferred if the situation warrants. In a situation where 18" to 24" redwood trees on the north side of the clump would benefit if the 36" tree on the south side were removed, then cutting the target diameter redwood may be warranted. If the removal of the target diameter tree will not benefit surrounding conifer trees because it is out on its own then retaining it may be warranted.

In conclusion, each harvest is used as an opportunity to upgrade overall stand quality by choosing which trees are retained and how they are spaced.

A portion of this production was gleaned from an unpublished paper by Craig Blencowe entitled, Craig Blencowe: Building up the Forest.

Increasing Timber Inventory to a Sustained Yield Goal

By Thembi Borras

Developing a sustained yield goal is in part based on site quality, which conveys the relative productivity of a land area. According to the Soil Survey Report for the western part of Mendocino County, the potential annual production from a fully stocked stand can be as low as 245 board feet (bf) per acre per year to as high as 2,050 bf/acre/year. Although different for each soil complex, often the potential annual production from a fully stocked stand of redwood and Douglas-fir is closer to 750 bf/acre/year. The sustained yield goal can be determined given the potential annual production and a selected long-term annual growth rate that can be maintained while protecting forest related values.

For example, if the potential annual production on the Jones Family Forest is 800 bf/acre/year and the Jones Family selects a long-term annual growth rate of 4%, the sustained yield goal is 20,000 bf/acre. This is determined by the following formula: 800 bf/acre/year = (.04/year)*X; X=20,000 bf/acre. The Jones Family Forest is 200 acres. Therefore, the sustained yield goal is 4,000,000 bf on the entire Jones Forest.

Critical to this exercise is to compare the sustained yield goal to the current standing volume and the current annual growth rate to the long term annual growth rate.

Continuing with this example, based on information from a timber cruise, the Jones Family Forest supports a current standing volume of 2,000,000 bf or 10,000 bf/acre. The Jones Family now knows the starting point, which is 2,000,000 bf, and the goal, which is 4,000,000 bf. At this point, a Potential Harvest Schedule can be developed, which will reflect how quickly this goal is reached based on the volume harvested at each entry, the responding growth rate and the frequency of entries.

By cutting less than growth over several cycles, the inventory of the stand will build and eventually the sustained yield goal will be attained, at which point, the periodic growth can be harvested without ever depleting the inventory.

The inventory can be viewed as “principle” and the growth as the “interest” earned on that principle. A truly sustainable forest allows the perpetual harvest of the interest without ever having to touch the principal.

The Soil Survey Report for the western part of Mendocino County is available at http://www.ca.nrcs.usda.gov/mlra02/wmendo.html. A portion of this production was gleaned from an unpublished paper by Craig Blencowe entitled, Craig Blencowe: Building up the Forest.

A Type of Forest Management

By Thembi Borras

I did not leave college knowing how to practice sustainable forestry on the ground. In fact, if I had depended solely on what I had learned in college I would not have thought the type of forest management I have learned and been privileged to implement for the last seven years was viable because, in part, economic return is not maximized. The type of forest management that I now use is quite simple. First, establish a long-range sustained yield goal based on the productive capacity of the site and a reasonable growth rate. After the long range sustained yield goal is established, build inventory by cutting less than growth until the goal is met. Once the goal is met, growth can be harvested. The other aspect of this approach is to improve stand structure by not cutting the biggest and best trees.

Although short-term profit is not maximized this approach provides a periodic income to the landowner and is an effective way to support forest related values. Pre harvest habitat is the same as post harvest habitat, so wildlife habitat does not decline. Aesthetics are bolstered by maintaining a continuous forest canopy and encouraging fewer large stems as opposed to many small stems. Also, this type of forest management can minimize adverse watershed effects through the low level of canopy removal. The lower the level of canopy removal the lower the increase in peak flow. Conversely, an increase in peak flows can mean an increase in sediment production.

Other arguments against this type of forest management, which can be described as a light intensity single tree selection, are natural regeneration suffers due to lack of adequate light and reentry every 10 to 15 years does not allow the land to rest. While these arguments have some validity, they are not insurmountable. Redwood sprouting is usually adequate post harvest but it is sometimes necessary to remove trees in small groups to encourage Douglas-fir seedlings. In addition, seedlings can be interplanted in openings created by the harvest to supplement natural regeneration. Finally, periodic entry every 10 to 15 years is an opportunity to improve a permanent truck road and skid trail network and correct accessible legacy problems.

A portion of this production was gleaned from an unpublished paper by Craig Blencowe entitled, Craig Blencowe: Building up the Forest.

Balancing Economics and Ecology

By Thembi Borras

Ask not what your forest can do for you instead ask what you can do for your forest. The reversal of this relationship is not mutually exclusive. Breaking forestland into ever smaller parcels, called forest fragmentation and converting forestland are widely considered "not good" for the forest. It is likely that the forest will benefit if forestland owners are able to withstand the lure of higher incomes from other uses. Forestland owners receiving income from forest management are better able to carry on, thus not fragmenting or converting forestland further.

If receiving income from forest management is key to keeping forestland intact so is forest management in which less than maximum profit is accepted to better support forest related values, including watershed, wildlife, aesthetics and recreation. Balancing economic return and ecosystem return is the challenge for foresters today. Mendocino County and Humboldt County forestland offer some examples of this balance.

Political Scientist William Obhuls stated, "Nature abhors a maximum." Following is Dr. Garrett Hardin's interpretation of this quote: What Obhuls meant by this: that if a you settle on a single measure of excellence, such as profit in a profit and loss system, and decide you're going to maximize the profit, no matter what, you can be quite sure that before you get through, you will have minimized some other value that you hadn't thought of, but which you really have high regard for. So the idea is, don't be so one-minded as to try to maximize any one thing. But instead, say here's a whole mixture of things I would like to have. Profit is one of them. Also, you would like to have beautiful scenery; you would like to have some wild animals, some wilderness areas, and so on; and you cannot maximize all at once.

Road Drainage

By Thembi Borras

Chances are you have seen the result of poor road drainage manifested in water that has been allowed to concentrate and reach a velocity that moves soil causing accelerated erosion. Addressing road drainage is central to meeting two of the road management goals, reducing chronic delivery of sediment and reducing maintenance.

There are three ways to drain a road. Insloping is where the roadbed is tipped toward the cutbank, water flows to the inside ditch where it mixes with flow intercepted from the hillslope. The water is then carried to a ditch relief culvert and underneath the road to the outside edge of the road. Outsloping is where the roadbed is tipped out; water is not concentrated and flows to the outside edge of the road. Rolling dips supplement outsloping by insuring water gets across the road. The third way to drain a road is crowning, 1/2 the roadbed is tipped out and 1/2 the roadbed is tipped in.

Any of these methods, installed well, will minimize chronic erosion. The key is to drain roads well and frequently onto stable surfaces.

After road improvement, chronic erosion will continue. However, improvements are intended to minimize and redirect the sediment generated to stable locations and filter strips, such that the sediment has a chance to drop out before reaching the waterway, thus disconnecting roads from streams.

For more information on road drainage reference the Handbook for Forest and Ranch Roads by Pacific Watershed Associates or the "Roads" video, adapted from the Handbook. Both are available through the Mendocino County Resource Conservation District (707-468-9223) and the Navarro River Resource Center (707-895-3230).

Stream Crossings

By Thembi Borras

Stream crossings exist where roads intersect watercourses, they include bridges, culverts, fords and rock armored fill crossings. One of the fundamentals of road management is that stream crossings be designed for large storm events. The currently accepted standard is for stream crossings to be designed for 100-year flood flows.

Stream crossings deserve considerable attention in road management because if a crossing fails the fill associated with the crossing will almost certainly enter the watercourse. Bridges with inadequately sized abutments, fords with steep dirt approaches and rock armored fill crossings with inadequately sized rock contribute sediment. However, in my experience, the highest risk of direct sediment delivery to a watercourse is from undersized, poorly designed and installed culverted stream crossings.

Culverted stream crossings have appropriately been described as a dam with a hole in it and are prone to plugging. The most common reason why culverts fail is the inlet becomes plugged with woody debris. The following design considerations will lower the risk of failure: 1) size the culvert to pass the 100-year flood flow and the wood and debris associated with that event, 2) align the culvert with the natural stream channel, 3) install the culvert at the grade of the original stream channel, 4) place the culvert in the bottom of the fill and compact the fill well, 5) install a trash rack and 6) install a diversion proof dip. The purpose of a diversion proof dip is, if the culvert should plug, the watercourse is directed back into the channel so that diversion is avoided. Finally, realize there are alternatives to culverted stream crossings that require less maintenance. For example, a rock armored fill crossing or a ford is a good alternative to a culverted stream crossing, where drivability allows.

There are a number of resources to aid you in stream crossing design and implementation. They include the Handbook for Forest and Ranch Roads by Pacific Watershed Associates and the February 2004 publication entitled Designing Watercourse Crossings for Passage of 100-year Flood Flows, Wood, and Sediment available through the California Department of Forestry and Fire Protection website. Click on Resource Management then click on Forest Practice or go directly to (http://www.fire.ca.gov/php/rsrc-mgt_forestpractice_pubsmemos.php).

Roads

By Thembi Borras

Roads facilitate travel to our homes and places of work. In fact, nearly every activity in a rural community requires getting in a car and traveling on a road somewhere. In a logging operation roads influence aesthetics, logging costs and environmental mitigation. I often find myself asking the question, can an existing problem road, located near a watercourse, be relocated to a ridge and diminish the environmental consequences at the same time facilitate logging method and be financially feasible? During my forestry fieldwork, second only to deciding what trees will be left and cut, is managing roads for improvement and aesthetics. I have yet to meet a road that did not need improvement. Why should you be concerned about roads? Because poorly constructed roads accelerate erosion, which increases stream sedimentation, and can be maintenance nightmares.

According to Danny Hagans of Pacific Watershed Associates the three goals of road improvement are to reduce the chance of sediment delivery as a result of episodic events, reduce chronic delivery of sediment and reduce maintenance. There are many ways to accomplish these goals. Addressing the following points in your road management decisions will insure the ultimate goal, of making roads as invisible on the landscape as possible, is met. Drain roads well and frequently onto stable surfaces, diversion proof crossings, design crossings to pass fish and design crossings for the large episodic event.

There are resources to aid you in road management decision making. A widely used publication is the Handbook for Forest and Ranch Roads by Pacific Watershed Associates. The concepts in the Handbook have been adapted into a "Roads" video. Both are available through the Mendocino County Resource Conservation District (707-468-9223) and the Navarro River Resource Center (707-895-3230). Also check out the website of the Navarro Watershed Working Group (http://www.nwwg.org/) and click on workshops. There you will find a comprehensive write-up from a 2003 Roads workshop.

Sudden Oak Death

By Thembi Borras

Sudden Oak Death (SOD) is a forest disease caused by a water mold fungus (Phytophthora ramorum). This fungus will cause SOD in hosts including tanoak, coast live oak and California black oak and a foliar/twig disease in other hosts including California bay laurel.

The most useful diagnostic symptom for Phytophthora ramorum in mature oaks and tanoak is cankers on the trunk from which dark black to red or amber sap exudes. Diagnosis of the disease is not always easy, for example, a tanoak tree may be infected but the symptoms do not show. The sudden browning of the tree crown, for which the "sudden" part of "sudden oak death" was derived, may occur several years after the onset of infection and not all trees end in a sudden browning, some have gradual leaf loss. Black charcoal bubbles, a fungus know as Hypoxylon decays sapwood and may move into a tree weakened by Phytophthora ramorum, but presence of Hypoxylon does not mean the tree has Phytophthora ramorum.

A common diagnostic symptom of Phytophthora ramorum in California bay laurel is dead areas on the leaves, where water collects. No bay laurel trees have reportedly died from this fungus. However, bay laurels are thought to be very important in spreading the disease as the fungus readily produces spores on moist bay leaves. The vectors of Phytophthora ramorum are wind and water.

By answering the following questions you can get an idea if a tree you suspect, is infected with Phytophthora ramorum: Is the tree a host species? Is it located in an infected area? Does it have the symptoms? The only way to be certain that a plant has Phytophthora ramorum is to have a tissue sample laboratory-tested. If you determine a tree is infected, what should you do? It depends, see " A Homeowner's Guide to Sudden Oak Death" at the website http://www.suddenoakdeath.org/. The fungus can be killed by burning infected wood or composting it very well. Moving infected wood can spread the fungus especially if conditions are wet. Remember, when leaving an infected area; disinfect your shoes or other wet muddy transport mechanisms.

The website http://www.suddenoakdeath.org/ is an excellent resource as are the County Agricultural Departments.

Redwood Top Die-back

By Thembi Borras

Throughout the redwood region redwood tops occasionally dieback. A green live top will turn brown, lose its needles and all that remains is a brown stem and lateral branches. The tree may or may not grow another top from this persistent weak spot. The dead top will sometimes break out and the tree becomes a flat top. Trees with dead tops are prevented from growing taller unless a new top grows, regardless the tree will continue to grow in diameter.

There are different causes of redwood top dieback, along the coast the harsh salt laden winds can cause tops, especially those that stick up more prominently, to lose their needles and dieback. Between Eureka and Crescent City, in the vicinity of the Drury Bypass, bear damage is apparent. Bears do not appear to get to the top, but will shred the bark, where the tree bole is larger. If the damage is extensive, the entire tree including the top will die. In Humboldt Redwoods Sate Park just south of Scotia, evident on the Eel River side of Highway 101 are old-growth redwood where nearly every tall tree has a dead top. In this case, the highway changed the water drainage pattern and increased the exposure of the treetops to increased air movement. Increased water stress combined with desiccation may have caused the tops to die.

The most common cause of redwood top dieback is animal damage by tree squirrels, wood rats and the occasional porcupine, which can chew the bark to the cambium. If enough area is affected the flow of nutrients is disrupted and the portion above the damaged area will die. The species of squirrels most likely causing the damage are Douglas' Squirrel (Tamiasciurus douglasii), also called "Red Tree Squirrel" or "Chickaree" and to a lesser extent the Western Gray Squirrel (Sciurus griseus), also called the "California Gray Squirrel". Dusky-footed Woodrats (Neotoma fuscipes) also cause damage, in younger redwood trees, trees less than 20 feet in height. In a clump of a dozen trees, the woodrat may advance a handful of tops to die. A handful more may be lightly chewed and the balance may escape being munched altogether. You may be able to catch the tree squirrels in action as they are active during the day, but it will be harder to catch woodrats in action as they are nocturnal.

Landowner Incentives to Increase Forest Net Carbon Stores

By Thembi Borras

This post explores the answer to the following question: What mechanisms encourage landowners to minimize forest loss, increase forested areas and temper forest harvest?

A market for ecosystem services, such as clean air, clean water and carbon storage is inevitable. The Chicago Climate Exchange (CCX) is one such infrastructure. CCX members agree to reduce their overall carbon dioxide emissions by 1 percent per year. Members who reduce their emissions by more than 1% per year can sell the difference as "carbon credits" to other members who pay a price to pollute.

Businesses based in the US have little incentive to join the voluntary cap and trade market, as they are not required to reduce emissions. Consequently, domestic prices remain as low as $4/ton of carbon. In Europe however companies required to reduce emissions per the, now in effect, Kyoto protocol are trading and carbon dioxide emissions credits have increased to $32/ton of carbon. European markets do not presently include the forest sector. However, it is feasible that, in the future, landowners could join the market by selling the carbon stored in their forest as an ecosystem service to companies that don't meet the carbon emissions reduction targets.

Apart from the slow pace the federal government is taking, within a couple of years, the State of California may adopt a market-based cap and trade strategy to implement Governor Schwarzenegger's greenhouse gas reduction goals for the State, within which the forest sector may be included.

The value per ton of carbon would need to reach $20 for landowners to be economically enticed to participate in the carbon market. If the value per ton of carbon reached $100, storing carbon would directly compete with returns from development and short rotation timber harvest.

Other economic mechanisms include consumer preference for forest products from well-managed forests (e.g. Forest Stewardship Council certified), land use laws (e.g. urban growth boundaries), education, performance-based regulation, global fair trade laws and a vibrant timber industry infrastructure (loggers, truckers, mills etc.).

More difficult to convert into economic terms are aesthetics and the deep connection to the land that many landowners exhibit which also inspires a well-managed forest that supports carbon storage and associated values.

A portion of this production was gleaned from Forest Carbon in the United States: Opportunities and Options for Private Lands a publication offered by The Pacific Forest Trust, a 08-01-05 article entitled Free Market, Cleaner Air written by Marianne Lavelle, Michelle Passero of the Pacific Forest Trust and a 08-01-05 article entitled Morgan Stanley, Citadel Chase Profit in Pollution-Rights Trade by Adam Levy.

The Relationship between Carbon Storage and Forest Disturbance

By Thembi Borras

Forests have tremendous potential to meter carbon dioxide emissions. Carbon is stored in forests until carbon is transferred back into the atmosphere through some sort of disturbance, such as forest loss, forest harvest or natural disturbance.

The scale of forest loss is more significant globally and nationally than it is regionally. Nonetheless forest loss is occurring regionally and has serious implications, 2% of existing forest and rangeland in the Klamath/ North Coast bioregion, which includes Mendocino County, will become, at a minimum, a rural residential neighborhood by the year 2040. If Mendocino County were considered individually, this figure would likely be higher given our proximity to the Bay Area. Statewide this figure is 10%. Part of the reason for this shift in land use is it can be more profitable to treat forestland as real estate than it can be to manage it. Shifting land use does not necessarily equate to forest loss but may lead to forest loss as it continues to do in Lake Arrowhead. In Lake Arrowhead, a Southern California forested neighborhood, bark beetle afflicted trees continue to be removed to reduce fire hazard and improve safety.

The amount of stored carbon is reduced at the time of harvest. When a tree is harvested, approximately 1/3 of the carbon is stored in the final product, for example, dimensional lumber and plywood. The remaining 2/3 is lost to the atmosphere, 1/3 of which is lost within 5 years, and the other 1/3 over time through decay. Stands at age 35 have 70 tons per acre of tree carbon. Stands at age 70 have more than double that, 194 tons per acre.

The amount of stored carbon is also reduced when harvest exceeds growth. Since the 1980's, growth in California has exceeded harvest. However, taken from 1996 data, nationally harvest exceeded growth.

Preventing forest loss, increasing forested area and forest management that increases forest age, increases growth relative to harvest, fosters a disease and fire resistant forest, has integrity, supports biodiversity and is economically sound can increase net carbon stores.

These strategies may be supported by performance based regulation, market incentives, land use laws, education, carbon credits, global fair trade laws and a functioning timber infrastructure.

A portion of this production was gleaned from The Changing California: Forest and Range 2003 Assessment for California from the California Department of Forestry and Fire Protection and Forest Carbon in the United States: Opportunities and Options for Private Lands a publication offered by The Pacific Forest Trust.

The Biology of Carbon Sequestration

By Thembi Borras

In response to the G8 meeting in Scotland of which global warming was one focus, I will explore the relationship between global warming and forests in the next several posts.

Greenhouse gases contribute to global warming, of these greenhouse gases, carbon dioxide is emitted in the greatest quantity. The bulk of the carbon dioxide is let into the atmosphere when fossil fuels are burned.

Carbon dioxide passes into the tree through the stomata, which are openings in the "skin" of the leaves and needles. Light energy, stored in chlorophyll, triggers photosynthesis, the reaction that changes inorganic carbon (carbon dioxide) into organic carbon (carbohydrate). Organic carbon is moved downward (translocated) in vascular tissue called phloem from a source, such as a mature leaf, to a sink such as roots, the tree bole, and developing fruits.

Organic carbon is used by the tree to increase biomass and provides the energy to build and maintain that biomass. To obtain this energy, trees respire consuming approximately 1/2 of the organic carbon assimilated during photosynthesis releasing carbon dioxide back into the atmosphere.

The carbon a tree gains is a function of the balance between carbon uptake by photosynthesis and carbon lost by respiration. Carbon sequestration is the term used for this net gain of organic carbon.

Although younger rapidly growing forests are more productive in terms of carbon dioxide uptake from the atmosphere and respiration is more efficient, the younger forest lacks the accumulated organic carbon from many decades of growth. When older forests are replaced by younger forests, they store less carbon. More influential is when forests are converted to non timber uses, such as roads, housing and agriculture and the capacity to store carbon is further decreased.

A portion of this post was gleaned from Introduction to Plant Physiology by William G. Hopkins and Forest Carbon in the United States: Opportunities and Options for Private Lands a publication offered by The Pacific Forest Trust.