Timber Cruising

David using a prism

Every ten years Under Orion Farm must update its forest management plan to satisfy the requirements of the Use Value program as well as the management goals of the farm. The Use Value Program, or Current Use Program, lets farmers and foresters pay taxes based on their lands’ value as farm and forest land, in return for keeping it out of development. My farm has 240 acres – 140 acres of which is forest, including about 1400 trees in the sugar woods. Current Use is important to helping me keep this acreage in production.

David Birdsall is my forester. A few weeks ago, he and a colleague spent a day with me updating the plan – we finished up just before one of this winter’s storms arrived.

Planning starts with what I want to get out of my forests. In a nutshell, I want to grow a lot of big trees. This goal supports the natural progression in the forest where some trees grow big and die providing habit for animals and others are selectively harvested for my business. Most of the benefit from the bigger trees I won’t see in my lifetime. . . but it’s almost like having a savings account. For example, I’m trying to grow some veneer yellow birch logs and I know that if I need extra money or the price spikes on veneer yellow birch I can go in and cut my birch that I’ve been saving. There are some trees like spruce, hemlock and fir that need to be harvested a little smaller because they get unhealthy as they grow large. These smaller softwood trees are what I keep an inventory of for lumber. I have a self-service, honor system lumberyard stocked with dimension lumber and boards. Finally, some trees will come out early as I do thinning of hardwood lots to give high quality trees more space to grow. A lot of that wood goes into firewood for the house and evaporator.

We have a pretty diverse tree population. I mostly use pine, maple, ash, beech, birch, spruce, hemlock and fir. But there is also value in the species I use less, like little spots of tamarack (very rot resistant – I built part of my sugar house from it) and cedar. I look for trees that can supply specialty vendors: ash for boat and furniture building, spalted maple, basswood for wood carving, brown ash for baskets. I made gunnels for a 35 foot steamboat being built to cruise the Connecticut River and the salad bowls I use in my kitchen were made out of two cherry logs that I traded to a woodworker from Newfoundland.

After we’ve set goals, the forester starts surveying the woods. David takes plot samples using a prism. When you look at a tree through a prism held at arm’s length, the section in the prism looks offset – if the offset section overlaps the rest of the trunk the tree is in the plot, if it doesn’t overlap the tree is outside of the plot. Both the diameter of the tree and its distance from where you stand affect whether it’s “in” or “out”. The inventorying data from the plot is used to calculate the stocking density. Factoring in diameter using the prism makes the process go faster; because small trees have a small impact on the density measurements it makes sense to focus time on the trees with the greater diameter. Different intended uses and different tree species need different densities and I’ll have to thin to reach the right one. Trees are also categorized into saleable logs, pulp, firewood or junk based on factors like height, diameter, species and any damage to the wood – that information provides the value of the logs in the plot. All of these factors go into the final management plan.

Of course, right now the woods I’m thinking about are my sugar woods. We need ample space around each sugar maple so they can grow a big crown, an old rule of thumb is that you want 50 feet around each maple tree. You also want trees with the highest sugar content. A sap refractometer can tell you what the sugar content is from a drop of sap– then when you thin, you take out the trees with a lower sugar content. I’ll make those improvements in late fall when the ground is frozen.

My forestry plan helps me keep an overall view of the health of my forest and the most efficient utilization of its assets in lumber, syrup, firewood, wildlife habitat and recreation. And of course if you’re interested in buying any of these products let me know – wameden@gmail.com


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