After the type of vacuum system has been selected, tubing layout is the next step. This process may be accompanied by assistance from experienced tubing distributors, foresters, or Extension Educators.
The first step in tubing layout is to flag the proposed mainline locations in the sugarbush. Take into consideration the number and location of tappable sugar maples and the topography of the site. Mainlines may be located in a natural depression to facilitate sap flow from the lateral lines or run parallel with the slope of the sugarbush. Any brush or conifers that create shade of interfere with the mainline should be removed at this time.
Mainline should be supported every 50 feet by a tree or a support post. Ground lines are not recommended as they will be covered with snow, freeze quickly, and thaw more slowly. Maintenance of ground mainlines during the season is also more difficult and complete drainage is not guaranteed due to natural dips and low spots on the forest floor.
Using a hand level, flag the support trees at the point that indicates the grade and location of the mainline. Mainlines should maintain a slope drainage after every sap flow. A hand level is essential to maintain proper slope percent on hilly ground or flat terrain. On flat ground, a three percent slope is achieved by raising the end of the mainline three feet or more for every 100 feet of mainline.
The number of taps in the area dictates the size of the mainline. Today, maple producers and experienced tubing distributors are suggesting the use of larger mainline diameters. Although 1/2 inch mainline is available it is not recommended. A 3/4 inch to 1 inch mainline should have enough capacity to meet maximum sap flow requirements in a well designed system. Mainline sizes larger than 1 inch may be more difficult to sanitize when permanently installed in the sugarbush. Consult the following chart when considering the size of mainline required. (see table 1).
Table 1. Selecting mainline size (adapted from Morrow 1979)
Although sap collection directly at the sugarhouse is ideal, it is often not possible. In this case, collection tanks should be located at natural depressions in the sugarbush that are easily accessible for pumping or transportation of the sap to the sugarhouse. Collection tanks should allow at least two gallons of sap storage for each taphole. More storage capacity will be needed at the sugarhouse. Several types of collection tanks are available. When acquiring used tanks, be sure they are clean, free of rust, and have not previously contained toxic materials. Place the tanks on strong level platforms or cribbing. Tank covers protect the sap from precipitation and debris and should be light colored and designed to allow ventilation to keep the sap cool.