Monday, December 28, 2009

Organic Stump Removal

If you have ever had to have a stump removed, you know it is a long, difficult, often arduous or expensive process. There are many methods. You can use harsh chemicals, which slowly dissolve the stump over 4-6 weeks, while you try to keep the kids and pets at bay. Oh, and you will probably need to let the stump sit around for a year after you cut the tree down before this one will work. There are stump grinders, which are expensive and noisy, but produce a handy pile of wood shavings. Then there is the fun way: dynamite. It is kind of dangerous, though, and you had better have a hired expert and all kinds of permits.

If you aren’t in a big rush, though, you could just eat the stump. How’s that, you say? Well, it turns out that most trees have 1/3 to ½ of their total body mass under ground. Think about how much wood there is down there. It shouldn’t be too hard if you just cut up the top part of the tree. We are talking about hundreds or even thousands of pounds of wood. Now you and I can’t really get at all that wood, but there are other things that can. Many of the tastier gourmet mushrooms excel at stump removal. They will get in there and decompose that stump over several years, all while producing periodic clusters of tasty mushrooms. When they are done, any wood that is left over will be well decomposed and easy to dig out or bury. All that wood that is left over underground just gets turned into soil.

First, the cautions. There are two main difficulties with growing edible mushrooms on a stump. The first is contamination. You can put whatever edible mushroom on there that you want, but if some other mushroom beat you to it, you are just out of luck. Sometimes a wild mushroom will act like a mycorrhizal mushroom for the life of the tree. In doing so, it will grow its fibers throughout the wood of the tree. When the tree dies, it switches to saprophytic mode and begins decomposing the tree. When this is the case, it can be hard to supplant the original mushroom with the one you want growing there. Ditto with a parasitic mushroom that either killed the tree or was working on it when you cut it down. Also, tree roots have a LOT of surface area. That is their purpose. They contact the soil to get what they need out of it. That same soil can also have a lot of decomposers in it. When the tree dies and stops resisting the rot, it is just about guaranteed that something is waiting in the wings to move in, and there are lots of contact points for it do just that.

The second difficulty is related to the first. When you put an edible mushroom on your stump, you need to be able to identify it when it comes out of the ground. You need to know what it looks like and key features that distinguish it from other similar mushrooms. It is also an extremely good idea to be familiar with similar mushrooms and know which are poisonous. Joining a local mycological society is a good idea, or even finding a mycologist at your local university (assuming they are friendly and willing to help). Whatever you do, don't just eat whatever pops up on your stump. It is better to ignore the mushrooms and just have your stump removed than to get poisoned.

The first and most important step to stump removal with mushrooms is to pick the right mushroom for the job. The first thing to remember is that each species of mushroom has certain preferences for what types of wood it decomposes. If you put the wrong kind of mushroom on your stump, it will either fail to grow or not grow strong and be prone to competition from other kinds of mushrooms. The second thing to remember is that while certain types of mushrooms, such as shiitake and oyster, grow very well on logs, they may not be the best suited for growing on stumps. A stump is a unique and highly competitive environment. You are better off to pick a stump specialist. The third thing to consider is that, all else being equal, pick the mushroom that doesn't have any poisonous look-alikes. It will make identification easier.

Here are a few likely candidates:

Agrocybe aegerita (Black Poplar Mushroom or Pioppino Mushroom)
Flavor-wise, this is my personal favorite, being both mild and complex. It tends to prefer warmer, more humid environments and is native to the southeastern United States. It has a strong preference for members of the poplar family, so stumps of poplar, cottonwood, and aspen are good bets. It will also work nicely on willows and maples.

Hypholoma sublateritium (Brick Top Mushroom or Cinnamon Cap Mushroom)
This aggressive decomposer of wood can be pretty productive. I got a mushroom kit with this one on it several years ago and it has the distinction of having exceeded the theoretical maximum for mushroom production. The flavor is strong, but it made the best cream of mushroom soup I have ever had. Be careful, though, as there are look-alikes that are poisonous. It tends to prefer oak and chestnut stumps, but can probably be grown on many others.

Grifola frondosa (Hen-of-the-Woods Mushroom or Maitake)
G. frondosa is a strange one. It seems to be particularly good at not only keeping competitors at bay, but actually pushing out previous inhabitants of stumps it desires. It then seems to take its time in decomposing the stump. There are stories of majestic oaks whose stumps will produce seasonal clumps of these mushrooms for decades. It is a wonderful edible mushroom as well as a powerful medicinal mushroom and I have seen it selling at specialty stores for as much as $30/pound when fresh. It prefers oaks, but can also be grown on elms, honey locust, maples, and beech.

Laetiporus sulphureus (Chicken-of-the-Woods Mushroom or Sulphur Tuft Mushroom)
This orange mushroom is called the Chicken of the Woods because it supposedly has a texture and flavor so similar to chicken that it can be substituted for chicken in recipes. This mushroom is a bit less picky than some of the others and can be grown on a wide variety of woods, though it tends to prefer oaks. There is a closely related sister species called L. conifericola that prefers conifer trees, particularly hemlocks.

Trametes versicolor (Turkey Tail Mushroom)
This one isn't actually an edible mushroom, being too tough to chew. It is, however, a powerful medicinal mushroom, being the source of at least one of our common cancer fighting drugs. It makes a lovely and refreshing tea. I add this one to the list because it is the least picky of all of the types of mushrooms here. It can be grown on any type of hardwood and most kinds of conifers, including juniper, pine, fir, and spruce.

As far as method, it is actually pretty easy. The easiest way to inoculate a stump is with mushroom plug spawn. In essence, it is a small wooden dowel that has the particular mushroom you are looking for growing on it. You drill a hole in the log and pound it in, sealing the hole with wax when you are done. The more plugs you put in, the better, so one every few inches, especially in the outer rim of the wood, just inside the bark. A single stump can take over a hundred plugs. If you don't have access to plug spawn, you can also drill a larger hole and pack in some sawdust spawn. It becomes harder to protect, though, as many critters will get in and munch on your spawn. Earthworms and pillbugs particularly enjoy mushroom spawn. Another method is to cut off a round of the stump (assuming it is tall enough) and pack an inch or so of spawn on the open cut. Then nail the round back on top. A little burlap or wax around the edge should provide enough protection until the mushroom can become established.

Saturday, December 26, 2009

The Rational Method

Okay, let’s say that my method for calculating average monthly rainfall in my previous post just isn’t good enough for you. You are too detail-oriented for that little amount of information to be satisfying. You want to know how to calculate how much rain you are getting in a particular storm. Well, this post is for you. For the rest of you who came here looking for some interesting gardening information: may I show you to another lovely post? Just keep it in mind as a reference. At any rate, I’ll have another post up shortly. It is gonna get pretty math-y pretty quickly here.

The Rational Method is an old method that civil engineers use to determine how much water a particular storm even is going to deliver. So, if you are designing a culvert to carry the water from a 100 year storm, this one will do it. As technology and science have improved our accuracy for calculating runoff, the Rational Method hasn’t really gotten left behind. It is still considered pretty accurate up to about 600 acres or so and is often used as a check when more complex methods are used.

The beauty of the Rational Method is its simplicity. Here it is:


Q is the runoff in cubic feet per second (cfs)
C is the runoff coefficient
i is the rainfall intensity in inches/hour, and
A is the drainage basin area in acres

Starting with the easier ones, A is pretty easy to calculate. The only tricky part is measuring it. If you have a small area, you might be able to get it with a measuring tape or similar measuring device. If you have a larger drainage area, you might need to go to the USGS and find yourself a topo map of your area. Remember: water always flows perpendicular to the contour lines, so trace perpendicular to the contour lines until you can find the ridgeline. Then measure off and calculate your area. It is easiest for this sort of thing, unless you happen to have a planimeter, to just break it up into simple geometric shapes and calculate the areas individually. Then convert by the scale factor of the drawing and then convert to acres.

Your value for C is going to be based on observation. Take a look at the area that you are draining from. C gives you the percentage of water that is actually draining off. So impervious surfaces will give you a higher C value than a soft, fluffy forest floor. Here are some sample C values:

Paved areas, roof areas, impermeable areas: 0.95
Bare ground: 0.25
Lawn area: 0.20
Suburban areas: 0.35
Steep terrain: 0.70

The value for i is the tricky one. Basically, shorter storms tend to be more intense. However, when a drop of rain falls on the farthest reaches of your drainage basin, it takes a certain amount of time to reach your concentration point. If it takes 30 minutes for your raindrop to reach your concentration point and you calculate for the 10 minute storm, the storm will be over before the entire area is contributing to the runoff at the same time. However, for most areas that a homeowner would be dealing with, i.e. under a few acres, 10 minutes is a reasonable assumption, so use the 10 minute storm. To actually get the values for your area (in the United States), go to the NOAA site and get an intensity-duration-frequency chart for your area and use the column for a 10 minute storm. Just make sure that the final number you plug into the Rational Method is in inches/hour. If not, be sure to convert it beforehand.

Then you just plug the numbers in and calculate your flow. You can use that to tell you how quickly your basin will fill up in a particular storm, or multiply by the length of your storm to figure how much rain you will get.

I will offer one caution, though. A lot of what is involved in accurately determining the numbers to plug into the formula relies on expertise. If you don’t have the expertise, it is called guessing. If you really need this calculated accurately, which you will if you have flooding issues, or you are building it near your or anyone else’s building, or if you have a large drainage area near your house, to name a few, you should really have this calculation done professionally by a civil engineer.

To say it another way: The calculation above is for entertainment purposes only and should not be attempted by non-professionals for any purpose other than idle curiosity.