GardenBanter.co.uk - View Single Post

27-01-2003, 06:10 AM

(Jim Lewis) wrote in message news:001501c2c58d$5d65abc0$a5122cc7@pavilion...
Speaking of Mycorrhiza . . .

In the current issue of Arizona Highways (which is one of my
favorite magazines, but is NOT a scientific journal!), an article
about the Kaibab squirrel, found only in the Ponderosa pine
forest on the North Rim of the Grand Canyon (the CLOSELY related
Albert Squirrel is found in other Arizona Pondersoa forests),
says that these squirrels . . .

"relish truffles. . . .

"Together, in fact, the ponderosa pines, the truffles and the
squirrels enjoy a symbiotic relationship that ensures their
mutual survival.

"According to Joseph Hall in his book _Linea: Portrait of a
Kaibab Squirrel_, truffles attach themselves to ponderosa pine
rootlets with tiny, threadlike extensions. The fungi help
transfer nutrients and water from the soil to the tree, while
absorbing carbohydrates and amino acids from the tree's root
tissues. But beneath the forest floor, the fungi have no way to
disperse their spores. When a squirrel digs up and nibbles a
truffle, the fruiting body of the fungi, the spores pass through
the animal's digestive system to be scattered abouot the forest."

So here we have one way in which Mycorrhiza spores may get
transferred from point A to point B in nature (and in pots?
Assuming they're needed in pots ;-).

Anyway, all you Ponderosa Pine Bonsai fans might take note. Find
a Kaibab squirrel, then let him poop in your pot.

While you are correct that squirrel fecal pellets contain abundant
mycorrhizal fungi spores, it is unlikely some would get into bonsai
pots naturally. Squirrels don't normally access bonsai pots. And
bonsai in nature almost never come on contact with many
ectomycorrhizal fungi.

The same is true of nurseries and greenhouses, btw.

That's one reason why Dr. James Trappe did research on introducing
mycorrhizal fungi into tree nurseries here in Oregon.

Chris Maser has estimated a single squirrel fecal pellet may contain
upwards of 100,000 spores. It may take 1,000 spores (of the same
species) to establish the mycorrhizae for a new tree. It is also true
that spores tend to stay in the digestive tracks of squirrels for up
to a month after ingestion. So although 100,000 spores may sound like
a lot, they are often dispersed with lots of other mycorrhizal
species.

One of the mycorrhizal fungi sought out by squirrels are Rhizopogons.
These fungi are closely related to Suillus mushrooms, but grow for the
most part underground. Dr. Trappe has noted that a single
average-sized Rhizopogon (about 1 inch in diameter) is capable of
inoculating as many as 1 million tree seedlings.

But in nature, naturally occuring bonsai typically don't occur where
Rhizopogons are abundant. And one of the reasons bonsai growers
probably _don't_ want to have mycorrhizae such as Rhizopogons is that
the inoculated trees tend to grow _very_ rapidly: several feet per
year from seed is not unheard of.

Daniel B. Wheeler
www.oregonwhitetruffles.com