[PCA] NY Times Moss Article

Stephen Rae stephen.rae at gmail.com
Thu Dec 2 11:28:47 CST 2004


Most people are not aware of the extended times necessary for some
mosses to recolonize areas following removal.  There are bare spots on
trees and rocks where collections have been made over the years within
the Coast Ranges of California that have not been significantly
recolonized.  Some bare patches remain after twenty years.

As for mosses on trees and some that develop into carpets on the
forest floor, they may appear to recolonize quickly if only portions
of the plants are removed.  That is, some plants are large with
extended branching.  Leaving a portion of the plant behind provides a
jumpstart for filling in the void.  However, where plant sizes are
small, complete removal results in delays pending reestablishment of
new individual plants.

Some mosses do not readily reproduce from spores as capsule production
may be minimal.  Spores are produced within capsules.  But some of the
larger stature mosses on the forest floor and draping from trees may
only erratically produce capsules.  So, they reproduce vegetatively. 
Some reproduce by physically breaking apart, others by development of
new plants following the dispersal of special plant parts that break
off easily.  Keep in mind that these methods work best if there are
parent plants around to provide a source of vegetative material.

The bottom line is that there are several strategies used by mosses
for establishment and growth.  So, generalizing about their response
to removal is hazardous.

We do know that the commercial removal of moss in the Pacific
NorthWest has accelerated significantly over the past 10 years.  And,
there are few mechanisms for auditing the locations and rates of
removal.  In the absence of better understanding of moss species
response to removal I would suggest that the situation is not good. 
We could be differentially harvesting species that may be difficult to
recover within reasonable planning periods.  The USFS in the PNW has
started to address this issue.  There would be more incentive to
assess the problem if more citizens raised the question.

Stephen P. Rae
Plant Ecologist
California Registered Professional Forester
Bryologist




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