Sapstreak disease is a potentially serious problem of sugarbushes and forest stands. It is caused by the fungus Ceratocystis virescens, which invades sapwood of roots and bases of stems through wounds created during logging, saphauling, or other activities. This report describes the results of observations and experiments to learn more about the patterns of disease development and the factors that affect them, within individual trees and within representative forests and sugarbushes.
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To properly classify or grade logs or trees, one must be able to correctly identify indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for sugar maple. Eleven types of external defect indicators and associated defects that are particularly difficult to evaluate are illustrated and described.
Many pests and other stresses affect maple trees growing in a sugarbush. Some pests can markedly reduce sap quantity; others, although conspicuous, are not important. Stresses can result from activities by people and from natural phenomena. Recognizing problems and understanding the factors that contribute to their occurrence, development, and significance are necessary to maintain tree health. This report brings together current information on the living agents and nonliving factors that can cause problems in sugarbushes. Insects, diseases, improper forest stand management, and unwise sugaring practices are illustrated. and ways to prevent or reduce their effects are described.
In March and April 1983, 289 and 196 young grafted sugar maple trees were tapped and evaluated for sap-sugar content. In April, sap was collected from taps both above and below the graft union. Diameter of all tapped trees at 18 inches above the ground was measured. Analysis of the data revealed that: (1) trees selected for high sugar yield cannot be reproduced by grafting on rootstock of unknown but varying sugar content without encountering large fluctuations in sap sweetness of the trees produced; (2) diameter is not correlated with sap sweetness of young grafted trees; (3) numerous sap-sugar readings over time may be necessary to identify the sap sugar characteristics of a candidate sweet tree; and (4) the cause of the variation in sap-sugar content of trees over time needs to be investigated more fully.
Our objectives were to develop time series of maple production costs and to observe the effects of changing technology, fuel price, interest rate, and sap sugar content on production cost. In addition, the relationships between major production cost items were examined.
A cost analysis of processing maple sap to syrup for three fuel types, oil-, wood-, and LP gas-fired evaporators, indicates that: (1) fuel, capital, and labor are the major cost components of processing sap to syrup; (2) woodfired evaporators show a slight cost advantage over oil- and LP gas-fired evaporators; however, as the cost of wood approaches $50 per cord, wood as a fuel would no longer have this cost advantage; (3) economies of scale exist in processing maple sap to syrup; (4) in 1977 the total cost of production, including both sap production costs and processing costs, for a medium-size (750) gallons of syrup) operation was $8.36 per gallon of syrup for oil-fired evaporators, $7.97 per gallon of syrup for wood-fired evaporators, and $8.37 per gallon for LP gas-fired evaporators.
The three grades of maple syrup and a commercial table syrup containing artificial flavor and 3 percent pure maple syrup were evaluated by 1,018 women in four cities. The results indicate that differences in preference for flavor are related to how close the respondents are to a maple syrup-production region. Differences in preference among grades of pure maple syrup were slight and in reverse order of the quality implied by the Federal grading standard. Outside of the region of maple syrup production, differences in preference between pure maple syrup and the commercial table syrup were marked, and favored the commercial syrup.
Maple syrup made from sap collected using improperly or carelessly installed plastic pipelines varied more in color from day to day, and was more often darker in color, than sap collected from either the property installed pipeline or clean, frequently emptied galvanized buckets. Use of both properly installed tubing and buckets, following recommended procedures, produced light colored syrup of equal quality throughout the entire maple syrup season.
A test of vapor compression distillers for processing maple syrup revealed that: (1) vapor compression equipment tested evaporated 1 pound of water with .047 pounds of steam equivalent (electrical energy); open-pan evaporators of similar capacity required 1.5 pounds of steam equivalent (oil energy) to produce 1 pound of water: (2) vapor compression evaporation produced a syrup equal in quality to that from a conventional open-pan evaporation plant; and (3) a central plant producing 8,000 gallons of syrup per year should yield a return of 16 percent on investment. Increasing annual product output should increase the return on investment.
A study of the engineering and economic effects of heat exchangers in conventional maple syrup evaporators indicated that: (1) Efficiency was increased by 15 to 17 percent with heat exchangers; (2) Syrup produced in evaporators with heat exchangers was similar to syrup produced in conventiona lsystems in flavor and in chemical and physical composition; and (3) Heat exchangers reduce per unit production costs, and can yield greater production and higher profits.