In the existing systems of sap collecting for syrup production, large mature maple trees (e.g., typically having a diameter at breast height (dbh) of at least 8 inches) in naturally-regenerated hardwood stands are tapped in the spring using a drill bit and a spout inserted therein to channel the sap into a collecting system. In some older systems, the sap is collected from each tree with buckets, while in more modern systems sap is collected via a network of plastic tubing that connects each tree to one or more central collecting points. In the latter system, the flow of sap can be augmented by applying a vacuum to the spout via the tubing system.
Conventional sap collecting approaches typically require some level of crop management. This can range from minimal thinning to individual crop tree selection and tending on a periodic basis to encourage strong crown growth of dominant and co-dominant trees. The density of a typical managed stand of maple trees can range from about 40 to 120 trees/acre, with 80 maple crop trees/acre or greater being considered wellstocked.
Conventional sap-collecting systems place severe constraints on the potential productivity of maple syrup production operations. The large land area required for the tree stand results in relatively low productivity per unit land area, usually in the range from about 16 to about 40 gallons of syrup per acre annually. In addition, the need for a stand of mature trees with adequate spacing and other properties conducive to sap production limits the growth and expansion of the sap collecting operation due to the large land area lengthy time span required to establish the stand.
One way to increase the total sap (and thus syrup, sugar, or other desirable plant compound) output of existing sap collecting operations is to try to add new trees or by initiating new production operations. However, this requires a substantial investment to purchase or lease large tracts of forested land. And, there is a finite quantity of existing land that meets the appropriate criteria for syrup production, and maple syrup production in particular. Moreover, it typically requires at least 30 to 50 years for a maple tree to become mature enough before it can be tapped using conventional sap collecting techniques.
Moreover, current sap-collecting systems involve high operating costs to support and maintain a sap collecting infrastructure over a large forested area. The tubing collecting system not only requires large initial investments in supplies and labor for its creation and installation, but also poses high annual recurring costs for maintenance.