Acquiring Logs & Bolts

 

EXPERT TIPS: Species Identification

“Tree species identification is a worth-while skill to hone as tree species are often easy to mix up. If you are unsure about what species you have, I recommend getting some verification... there are often forestry homeowner associations in all areas that can help.”

-Steve Sierigk, Hawk Meadow Farm

 

 

 

 

 

 

 

EXPERT OPINION: Tree Species and Taste

“Concerning the quality of shiitakes grown on different log substrates ... the longer I do this the more I notice differences on shiitakes grown on different woods, from taste, shape, how they pick.

One restaurant loves the spicy flavor that they detect in the bitternut hickory shiitakes so I often send these their way. Shiitakes grown on Carpinus (Musclewood) were the hands down least faorite in our group of 16 tasters with adjectives like “insipid” and “flavorless” coming up when compared to others.

Keep in mind that they all taste like shiitakes and are all perfectly acceptable and marketable. It is just fun to note and be aware of the differences... as our sense of taste is highly personal.”

-Steve Sierigk, Hawk Meadow Farm

Tree choice is very important; the species of tree used will affect the amount of mushrooms produced each flush, the amount of flushes you can expect from a single log, and even the taste and size of the mushrooms produced. See sidebar entitled, “Tree Species and Taste” for more information regarding how the tree species influences mushroom taste.

RESEARCH: How does log species influence mushroom taste?

Patrons at the Trumansburg Farmers Market, in Trumansburg, NY were not able to taste the difference between shiitake mushrooms grown on different tree species. This does not mean that there are not differences in the flavor of shiitakes grown on different tree species; it simply means that the differences, if there were any, were too subtle to be detected by the average consumer.

Culinary professionals, however, were able to generate a list of descriptive adjectives that differentiate the subtleties of flavor between shiitakes grown on different tree species. Mushrooms grown on sugar maple were described as having umami, smooth, mild, and clean flavors, mushrooms grown on red oak were described as having meaty, heavy, and hearty, while mushrooms grown on Carpinus were described as having flavors described as caramel, banana, and buckwheat pancakes.

(adapted from thesis research by B. Sobel (2013) of Cornell University)

 

Mushroom farmers have grown shiitake on many tree species in the Northeast, with varying degrees of success, and varying from one grower to the next. Oak has developed a reputation as the gold standard, but many growers have found that other species like sugar maple, beech and musclewood work as well as or better than oak. Conversely, red maple, poplar, black locust, fruit wood and ash are widely known to be less suitable.

 

In most cases, growers opt to use whatever hardwood species are available. In other situations, one may choose species with low timber value but which are good shiitake substrates like beech and musclewood; removing these trees can improve timber stand quality while producing a bumper crop of mushrooms.

 

Because different tree species respond differently to the set of conditions under which they are being cultivated, it is difficult to rank species from best to worst. Variables like the time of year, laying yard conditions, spawn strain, properties of the tree before it was cut down, and climate can all affect how well a certain species of log performs. Based on the input from research and professionals we’ve divided common northeast species into four tiers from excellent to poor. Species in a single tier generally have a similar performance but will outperform species in the preceding tier, but there are exceptions where a species in a lower tier may perform better than one in an upper tier. For example oak often out performs beech, but in our research site at the Arnot Forest, beech frequently out performs oak.

EXPERT TIPS: Acquiring Logs from Unique Sources

 

“Developing a connection with road clearing crews, local arborists, and tree companies can be an essential component of reducing the initial costs for a shiitake operation. A thorough description for the types and quality of logs must be made, and sometimes even inviting these people to your operation can be helpful so that a clear understanding for the quality and size of log is developed. Safety is essential when/if an arborist or state team is approached and a phone call asking for permission to access or work with their crew (when picking up logs) is typically mandatory.

 

State Forestry personnel sometimes allow state residents to apply for firewood permits, which for the state, the end purpose (firewood) of the logs is not necessarily the agenda, but rather thinning the logs from the forest is. A mushroom grower can use this opportunity to harvest trees at a reduced rate, or extend the life of their own forest if acreage is minimal.”

- Nicholas Laskovski, Dana Forest Farm

 

“Because oak is a valuable timber species, forest owners who include timber production as part of their woodland management goals may be reluctant to cut large amounts of young oak for shiitake cultivation. However, tops left after logging are often of an appropriate size to be used as bolts (logs) although timing of when the logs were cut might be less than optimal for mushroom production.

“Since I prefer oak I have put the word out to tree workers in our area that if they are ever taking down oak in our area let me know. This has been a great option as these folks better understand what I am after as what I have gotten from loggers has been less carefully handled. I encourage any of you who may want to source oak if you don’t have any in your woods to cultivate such relationships.”

-Steve Sierigk, Hawk Meadow Farm

A man leans on a pick-up truck with a trailer of logs hitched to it.
A man leans on a pick-up truck with a trailer of logs hitched to it. (Steve and Julie Rockcastle, Green Heron Growers)

Choice of Log Species

 

 

 

 

 

 

 

 

 

EXPERT TIPS: Musclewood or Ironwood

Musclewood (Carpinus) has rippled/ muscle-like smooth bark. the bark of ironwood (Ostrya), by comparison, is flaky.

 

 

 

 

 

 

EXPERT OPINION: Beech Bark Disease

“Beech Bark disease is a saprophytic fungus that attacks the vascular tissue of the tree and weakens the bark. The Nectria fungus won’t pose a direct competitive threat to shiitake mushroom mycelium. The issue is, once a bolt is inoculated, the wounds in the bark (caused by an outer tissue deficiency) will increase susceptibility to additional epiphytic fungal competition, increase moisture loss, and cause a reduction of available surface area for shiitake mycelia where sapwood has decayed. Mushroom growers who want to salvage beech can do so by using logs where beech bark disease has not yet become serious.”

- Allan Thompson, Consulting Forester

 

 

 

 

 

 

 

 

 

 

EXPERT OPINION: Species Choice

“I would encourage growers to try a mix of these woods to see firsthand what the performance is in their yard... we may all be surprised. For instance a grower I consulted with near Bainbridge N.Y. sent me some photos of her yard in its first flush. She had used red maples. I primed her to be disappointed and she was ready to be underwhelmed. However the photos she sent me showed logs nicely covered with shiitakes and when I took great care of my red maple logs mine never produced close to what she had... so what gives?“

-Steve Sierigk, Hawk Meadow Farm

 

 

 

 

 

 

 

 

 

 

 

 

 

Tier 1: Excellent Species

  • Oak (Quercus spp): Research at the Cornell University has shown that red and white oak exhibit similar performance as substrates for shiitake. Anecdotally, some growers claim that red oak is colonized more rapidly, less subject to competing fungus compared to white oak. Oak tends to be productive for more years than some other species, which means that you typically get more mushrooms for the initial amount of work. Shiitake mushrooms grown on oak tend to fruit within a short (weeklong) time-frame facilitating an easier harvest.

 

  • Sugar maple (Acer saccharum): Sugar maple is a reliable substrate, and a good choice for the Northeast where thinning of a sugarbush is a common practice to improve stands for maple syrup production. Lesser value trees can be thinned out and used for high-value Shiitake production. It is an excellent producer, the shiitakes taste wonderful, and are compatible with cold weather shiitake strains.

 

Tier 2. Very Good

  • American Hophornbeam / Ironwood (Ostrya virginiana): This species is highly productive; some growers have found it produces equally well if not better than oak.

 

  • American Hornbeam / Musclewood (Carpinus caroliniana): This species produces large impressive specimens, although some growers have found that shiitakes grown on musclewood have less desirable (although still adequate) flavor.

 

  • American Beech (Fagus grandifolia): Most people find that American beech is less productive than oak but will still produce an adequate harvest. However during research trials at Cornell, beech has consistently outperformed oak. Many landowners may have a surplus of beech as a consequence of beech bark disease infestation. See sidebar addressing beech bark disease for more information. Keep in mind that if you cut thin barked species like beech and red maple too late in the spring when the buds are breaking dormancy, the bark will separate from the wood and slide off very easily! This can be avoided by cutting in winter or early in the spring before bud swell.

RESEARCH: How does log species affect shiitake production?

Researchers at Cornell University measured the effect of tree species on shiitake mushroom production over 4 years. They achieved the greatest yields on Musclewood (Carpinus) and red oak. Means with different letters are significantly different (p<0.05).

Bar graph comparing the yields of different species of logs.
Bar graph comparing the yields of different species of logs (Cornell University).

Tier 3. Good

  • Sweet Birch / Black Birch / Yellow Birch (Betula spp): Both colonize well and make nice shiitakes.

 

  • Bitternut Hickory (Carya): Hickory seems slower to colonize than other species but once it gets going it makes some very high quality shiitakes. Growers have reported that the yield is close to at least fifty percent of red oak. They also grow fairly straight, which is a bonus when handling or inoculating logs.

 

  • Red Maple (Acer rubrum): Red maple is not regarded highly among commercial growers however it might be appropriate for hobby grower. Red maple has thin bark and tends to wear out sooner than the others species. Experienced growers claim that, from red oak logs, they expect 8 serviceable flushes; comparatively, when fruiting from red maple, growers expect only 4 or 5 flushes with smaller yields per flush. If you chose to use red maple, note that it is a softer wood, and tends to dry out sooner than others. Consequently, more maintenance soaks may be necessary, relative to other species. Also, be aware that if you cut red maple too late in the spring, the bark will separate from the wood and slide off very easily! In addition, a warm weather shiitake strain is recommended. -read more from Field and Forest on this topic.

 

Tier 4: Not Suitable

  • White Ash: White ash is generally sluggish and not very productive.
  • Elm: Not very productive.
  • Soft Hardwoods: We do not recommend using aspen or other soft hardwoods. These species might be appropriate for other types of mushroom production, such as oysters.
  • Evergreen Species: Do not use wood from any coniferous evergreen tree (pine, spruce, hemlock, etc.).
  • Fruit Wood: Apple, cherry and other fruit tree are not recommended.

 

Other Species

Further research is needed with chestnut, walnut, alder, elm, tupelo, and other hardwood species.

EXPERT TIPS: Sapwood:Heartwood Ratio

“I can have 2 similar 4-inch bolts of red oak... one that was open grown and has a great sapwood layer... vs. a slow-growing forest grown red oak that was struggling for growth rings with minimal sapwood. Both are 4-inch diameter bolts but I have found that I will expect perhaps to 4 to 6 times more shiitakes on the fast growing, fat sapwood layer bolts (through the eyeball data collection method... no hard data mind you).”

-Steve Sierigk, Hawk Meadow Farm

 

 

 

 

 

EXPERT TIPS & TRICKS: Safe Logging

The “Game of Logging” (GOL) is widely acknowledged as the premier chainsaw training program in the country, offering hands-on training in a competitive environment. Top instructors across the country combine demonstration with participation to teach safety, productivity, conservation and cutting techniques. To sign up for a course, go to http:// www.gameoflogging.com.

 

 

 

 

 

 

EXPERT OPINION: Winter Harvesting

“Late winter or very early spring inoculation can be successful. It is a smart time management technique, where the work gets done while the overall farm workload is less, before primary growing season farm tasks ensue. Some growers in the Northeast report the potential to have a late summer flush on logs inoculated very early that same year if conditions are right. The disadvantage of very early season inoculation is it can be unpleasant to work in cold, wet conditions. Working with Shiitake spawn in freezing conditions will not kill it off, but frozen spawn is difficult to handle.”

- Nick Laskovski, Dana Forest Farm

“Winter cut is best for many reasons... but as a grower sometimes you just get logs when you get them. The shiitake season has its time for different operations... it is just generally easier to deal with log acquisition in winter whether it is on your own land or sourced out. It is more straightforward to work in the woods when the foliage is off and perhaps a little snow is on the ground. Not much else is happening in the shiitake world that time of year.”

-Steve Sierigk, Hawk Meadow Farm

 

 

 

 

EXPERT TIP: Log Size Effects

“It has been shown over time that this size log will generally colonize at a specific rate which will allow for the fruiting of shiitake to happen in the following year. Larger logs may take longer to colonize with shiitake mycelium and may not be ready for production until 18 to 24 months.”

- Nick Laskovski, Dana Forest Farm

 

 

 

 

 

EXPERT TIP: Log Costs

“If you are doing all the labor 50 cents to $1 per bolt seems reasonable to me, although I always offer to thin woods for people and they benefit from the increased forest health/productivity (if a thinning is done well) - I take logs as my “pay” which is a fair trade. Also have offered to leave/split stems over 10 inches for landowner firewood as trade.”

-Steve Gabriel, Wellspring Forest Farm, Mecklenburg NY

Tree Section within a Forest

Only living healthy trees should be cut down. You cannot grow shiitake on dead wood, such as old logs in your yard or woodland, or firewood because existing local fungi have contaminated these logs and/or the logs have dried out.

 

The ratio of sapwood to heartwood within a log strongly impacts shiitake production. Shiitake mycelium colonize the sapwood section (the lighter colored outer layer) of a log. You can maximize the area available for myce- lium colonization by selecting vigorously growing trees with a fat ring of sapwood. See sidebar entitled, “Sapwood : Heartwood Ratio” for more infor- mation.

 

“Site index” is a forester’s means of estimating how suitable a particular site is for a given tree species. It depends on measurement of both tree age (increment borer) and tree height (clinometer) on your site. Site index tables have been published for many species of trees. So if your site has a high site index for red oak, it is more likely to have vigorously growing (fat sapwood) trees and will be a greater mushroom producer in the long run. Low site index trees are likely to be the slow growing oak that will likely be a dog for mushrooms.

Felling Trees

Mushroom growers who are forest owners (or have a working relationship with forest owners) should establish a management plan for their woodlot and have training in the safe use of a chain saw. See sidebar entitled, “Safe Logging” for more information.

 

Time of Year

Early spring, before the trees leaf out, is the season most often suggested for felling trees and inoculating bolts for mushroom production.

 

You may also cut trees during the winter months and store the logs for several months before inoculation in the spring. Farmers who tend to be very busy in the spring season may find this schedule more advantageous. If you are harvesting logs in the winter when the ground is still frozen, pile them up between some trees trying to keep them out of direct sun and wind in order to ensure they maintain high moisture levels. If it is practical, stack the logs off the ground to avoid them from becoming muddy during the spring thaw. Logs can be covered with clean snow to block out drying winter sun and wind. The melting snow keeps logs hydrated in spring before inoculation. For more information about winter harvest, see sidebar.

 

Inoculate the logs as early as possible to reduce contamination by other competitive fungi, and avoid logs drying out past the point where spawn will establish in the log. See research box on page 16 for more information.

 

Importance of Intact Bark

 

For a healthy mushroom log, the bark should be intact. Damaged bark allows for greater chance for invasion by ‘weed’ fungi species and increased moisture loss. Although the bark may become damaged over time, care should be taken to keep it on the bolts as long as possible. Sometimes damage to bark during the felling or skidding process is unavoidable. A good technique is to wax over damaged spots during inoculation to seal in moisture and block out competitive fungi.

 

Cutting time affects the likelihood of the bark falling off, or slipping. In the winter months of full dormancy, before bud swell, bark is tighter because the vascular cambium is dormant, and therefore cutting during these months may help in preserving bark integrity. Conversely, cutting in the late spring and summer months may lead to a greater incidence of bark slippage.

Ideal Bolt Size

Logs should typically be 4 to 6 inches in diameter, although when felling trees, there will often be larger logs available. Larger logs can be used but they are obviously more difficult to manage. The 4 to 6 inch diameter range is ideal because it optimizes the amount of sapwood per volume of log. The sapwood is the primary part of the log that the fungi will colonize. More research is needed to determine the rate and degree to which shiitake mycelium colonize heartwood. The sapwood to heartwood ratio is higher and preferable for cultivating shiitake in a tree that has been growing vigorously under optimal conditions compared to a less vigorous tree.

 

Length is not as important as diameter for health of the fungi, but a 3- to 4- foot-long is manageable for transport and individuals to carry. A common technique is to cut different lengths based on the diameter. Smaller diameters can be closer to 4-foot in length, while larger diameters up to 8 inches can be cut shorter so they can still be carried.

 

Heavier logs can also be inoculated using a cold weather strain that doesn’t necessitate shocking; these logs can remain in an A-frame stack for their useful life and won’t need frequent handling. (See section on Cold Weather strains)

Buying Bolts

You may also consider buying pre-cut lengths (at the time of this writing, loggers in the northeast were selling bolts to Shiitake growers for $1 to $2 per bolt). This is in line with what loggers would normally get for firewood. Buyers should try to purchase logs in good condition with the bark intact, and few places of rot or scarring. Be sure to ask when logs were cut and what the storage conditions prior to delivery or pick-up were. Remember that if the logs were stored in the sun, the moisture content is likely to be too low.

 

If you are doing all the labor, 50 cents per bolt is more reasonable. You can also offer to help the forest owner with thinning trees from an overcrowded stand, generally known as Timber Stand Improvement. They will benefit from the increased forest health/productivity (if a thinning is done well), and you can take the logs as “pay” - a pretty fair trade. Be sure to confirm that cutting trees fits in with the landowner’s forest management plan.

 

Acquiring bolts from local arborists may be an option for you, too. Be sure to inform yourself about local or regional restrictions on transporting “fire wood” (as shiitake bolts are considered, even if they are fresh cut) from one location to another, as a pest control measure. In most areas, it is illegal to transport firewood across state lines and transport from one area to another is highly discouraged. For more information about unique sources of low-cost bolts, “Acquiring Logs from Unique Sources” on page 10.

 

It’s important to ensure that whoever you buy wood from is managing the woodlots in a sustainable way. If they are not working with a forester, or have no background in forest ecology or management for health, it is advised to avoid purchasing logs from these individuals.

What will it take to create 100 bolts?

12 hours of labor

$45 worth of supplies

Chainsaw

Chainsaw oil

Gasoline

Tarps