Tree Planting/Mycorrhizae inoculation

truffler1635 at truffler1635 at
Sat Jan 8 12:16:40 EST 2000

It's about time to plant trees again. And also the best time to
inoculate with mycorrhizal fungi to get quick growth with minimal
fertilizing. In fact, if you inoculate with mycorrhizae, you probably
shouldn't fertilize.

Until recently, mycorrhizal fungi could not be reliably cultivated. But
there are several species and companies which now offer these tree
boosters in simple slurry inoculant form. One is located below.

Why are mycorrhizae important? Mycorrhizal fungi form vast networks of
underground threads which gather nutrients and water, which are shunted
to their host trees. Many true- and false-truffles are associated with
nitrogen-fixing bacteria. Some are believed to protect trees against
pathogenic root-rot fungi. A single square centimeter of soil can
contain over 1 km. of mycelial threads, which holds soils together,
decrease erosion, and assist nutrient recycling. Mycorrhizae can easily
extend hundreds of feet away, and act as water pumps to bring water to
trees from deep in the soil or far away to ridgetops.

Mycorrhizal fungi enhance tree growth. By providing nutrients and water
to growing trees, mycorrhizal fungi decrease stress on trees, such as
from overcrowding, transplantation, poor soils, drought and leaching
trace minerals from rock.

Mycorrhizal fungi therefore become a major component in both a healthy
tree stands and in biodiversity. For example, Douglas fir is believed to
form mycorrhizae with at least 3,000 fungal species. A single 1/2 cm
rootlet can host 7 different species of mycorrhizae. In terms of
biomass, mycorrhizal fungi make up perhaps 3 times the dry weight of
trees, but is rarely seen because the mycelium is so tiny the human eye
cannot see it unaided. That means that for ever tree you grow, mycelium
accounts for 3 times the amount of tree seen!

One of the easiest mycorrhizal fungi to grow are Rhizopogon sps. This
diverse family of underground fungi can fruit at almost any time of the
year. They are widely dispersed in the US, and are usually associated
with conifers, especially Pinus, Abies, Tsuga and Pseudotsuga.

Rhizopogon inoculation is simple when planting. A single Rhizopogon
contains enough spores to inoculate close to a million seedling trees in
a tree nursery, or at least several hundred thousand trees while
outplanting. The process is simple.

Take a dried Rhizopogon. Powder it or grind it find in a food processor
with a little water to create a thick sludge. Dilute the sludge into 5-
gallon buckets of water (about 1/100th the sludge per bucket). Dip the
seedling tree roots into the water just before planting.

You should expect much greater survival rates, healthier trees, and more
rapid growth (although increased growth may not show up for 2-3 years).

Mycorrhizal inoculation can also be introduced to existing trees, via a
backpack sprayer. A second or two of fine spray near the roots is
sufficient for inoculation.

Finally, mycorrhizal fungi are cheap to inoculate with. $50 will
inoculate 3 million trees, whether already planted or a new outplanting.
At 1,000 trees per acre, that amounts to 300 acres of inoculation, or
nearly half a square mile.

Can't access a site to inoculate it? No problem! Aerial application is
easy too.

Where to find sources for these fungi? See the website below.

Daniel B. Wheeler

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