I have been monitoring the maple chat sites and a many of the questions have been about tapping. Not when to tap but what is the best way to tap and where on the tree do it put my tap. Let’s start with the equipment. You need a sharp bit I recommend you buy a maple-tapping bit. Maple tapping bits are designed to drill fast, cut smoothly and pull the shavings out of the hole. There are several reason for following this suggestion. You want to drill as round a hole as possible. Slow down, two hands on the drill, accuracy counts. Oval holes leak, let in air and bacteria. You do not want shavings left in the hole because that is a good site for bacteria to grow. Bacteria closes the hole prematurely and is the number one cause of poor quality syrup. In a tubing, system shavings can cause problems. Shavings block tees and interfere with flow of sap. You would be surprised at how many shavings wash out with the first run. I do not worry about what comes out, as much as what remains, to block flow and support bacterial growth.
As you approach the tree that is at least 10 inches in diameter look at the bark. What you are looking for is old tap holes. Remember when you drill a hole a small portion of the wood adjacent to the hole will die. A common practice in the old days was to make all the taps at belt height all the way around the tree. This is not a good practice. To much deadwood in one area can lead to tree health problems. I would prefer that the tap is placed into area where there is an abundance of new wood. Over the years, you should stagger your taps as you move around the tree. Placed some high and some low. For hoby producers using tubing draining into a bucket gives you the most flexibility. You should drill your hole 1.5 to 2 inches into the tree. By doing this you will always be in the sapwood unless you hit dead wood. You will instantly know if you are into deadwood by the color of the shavings. The shavings from a good tap will always be light, almost white in color. Brown and extremely yellow shaving indicate dead or problematic wood, which results in limited sap flow. Unless you are tapping into frozen wood, your tap should start to drip immediately. If it does not, give it a few days, if it remains dry you are into deadwood. You can re-tap into another area if you are certain the first tap is dead. The only negative aspect of re-drilling is that you now have a dead hole where insects and disease can enter the tree.
Always use 5/16 or smaller taps because they are better for the health of the tree. 7/16 taps belong in a museum. When you set, the tap, drive it in snuggly, but do not over drive the spout. Over driven spouts will split the tree and cause leaks. The deeper you drive the spout the less sap you will get over the course of the season. A tap that is overdriven, to a depth of 1.5 to 2 inches can shut down a hole. When it comes to taping you only have one chance to do it right.
Let look at some of the myths of tapping. Always tap your tree on the sunny side or south side. Not true! As stated above you want to tap evenly around the tree, both high and low. With vacuum, you can even tap below the lateral line to obtain fresh healthy sapwood. Two Spouts are better than one! Not always! Remember it takes years for a tree to grow a new layer of sapwood that will cover up the wound deadwood. Work done at the Proctor Maple Research Center indicates that it takes at least 10 years for a tree 10 inches in diameter to grow back a new layer of sapwood. This is the basis for setting 10 inches as the minimum for a tap able tree. Because sap moves both vertically and horizontally in a maple tree, there is no advantage for two taps until you reach at least 20 to 24 inches. With buckets or gravity tubing many times a 2nd tap is desirable on bigger trees. When using vacuum it is a different story. In average size trees under high vacuum, you can obtain 80% of your production with one tap. The reality is you are not sacrificing production until you get above 24 inches in diameter. Depending on the tree you may or may not want to place a 2nd tap. If the tree is a yard tree that you are particularly fond of, one tap will do. Hope this answers some of your questions about tapping trees.