Thesis (M.F.)--Michigan. / eContent provider-neutral record in process. Description based on print version record.

Thesis (M.S.) in Ecology and Environmental Science--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 69-73).

Thesis (Ph. D.)--University of Chicago, 1915. / "Reprinted from the Botanical gazette, vol. LX, no. 6, 1915." "Contributions from the Hull botanical laboratory 210." "Literature cited": p. 470-471. Also available on the Internet.

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

No description available.

Thesis (M.Sc.), Memorial University of Newfoundland, 2000. / Restricted until June 2001. Bibliography: leaves 69-74.

Thesis (Ph. D.) in Forest Resources--University of Maine, 2000. / Includes vita. Includes bibliographical references (leaves 134-143).

The Christmas tree and greenery trade is a multi-million dollar industry in Atlantic Canada. Christmas trees grown in Nova Scotia are shipped internationally especially, to the United States. This thesis was set out to answer the over-arching hypothesis: pre- and post- harvest needle nutrient content influences post-harvest needle retention. Through a series of experiments it was shown that the pre-harvest needle P, Ca, Mg, Mn, Zn and B contents do not appear to be directly linked to post-harvest needle retention. Alternatively, the pre-harvest needle N, K, Cu and Fe contents significantly, but negatively influenced post-harvest needle retention. By maintaining needle N, K, Cu and Fe concentrations below 1.5 %, 0.55 %, 3.7 ppm and 35 ppm, respectively may extend needle retention in balsam fir. Xylem-fed nutrients negatively influenced needle retention. As well, foliar applications of calcium and zinc citrate did not promote needle retention at the concentrations used.

Thesis (M.Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 72-80.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Restricted until May 2005. Includes bibliographical references.