As management of forests and parks intensifies, pruning of
conifers becomes more common. Thus understanding the role of wounds
as possible entry courts for decay fungi is vital. In order to study
some aspects of this, three natural stands, one in New Brunswick and
two in Nova Scotia, which had been pruned 4 to 7 years earlier by
industrial or displaced workers, were examined. Five pruned and two
unpruned balsam fir (Abies balsamea (L.) Mill.) trees from each stand
were dissected; cultural isolations were taken from 207 knots where
pruning had caused little or no apparent damage to the bole, and from
169 blazes resulting from less careful prunings. All 15 pruned trees,
ranging in age from 23 to 42 years, had decay attributable to pruning
which averaged 1.7% of the stem volume. This incidence and volume of
decay exceeds that recorded in unpruned trees 40 to 60 years old in
New Brunswick.
Axe blazes were the major entry court for decay-causing fungis
basidiomycetes were associated with 12% of the blazes and with 5% of the
more carefully pruned knots. Neither stem nor butt decay was found in the
unpruned trees.
In a further study, 7 branches on each of 30 balsam fir trees
near Fredericton, N. B. were experimentally axe pruned; some carefully,
some carelessly; both during tree dormancy and during wet and dry periods of active growth. Thirty additional branches were saw pruned. At periods
of 2 to 3 weeks, 5 to 7 months and 17 to 19 months after pruning, cultures
were made in the field from 70 of the pruning wounds. Within 2 weeks of
the latter period, the trees were dissected, measured and further cultures
were made in the laboratory from the same 70 wounds.
Eighteen months after pruning, 28 of 30 trees had decay averaging
3.9% of stem volume and basidiomycetes were isolated from 22 (31%) of
70 wounds. In the controls butt decay only occurred in 4 of 10 trees.
These studies show: (l) that blazes into sapwood (careless
pruning) were more frequently infected than those where little or no
sapwood was exposed; (2) the incidence of infection was least in branches
pruned during the dry period and about equal for those pruned in the
wet-active and dormant periods; and (3) the successional pattern
began with imperfect fungi and bacteria, and terminated with decay fungi. / Forestry, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41855 |
| Date | January 1969 |
| Creators | Van Sickle, Gordon Allan |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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