Today I cut wood. I used our Stihl MS 290 Farmboss chainsaw to fell an 18" diameter, 30' tall Douglas Fir that had died years ago and had seasoned itself vertically to our benefit. This tree was likely 80' tall before a wind blew the top out of it like a carrot being snapped in two. Over the past two or three years the Pileated Woodpecker native to our region has eaten two-inch holes up and down the trunk. But the Fir is in fair shape and will heat our 1,700 SF home for some time.
How much time exactly? Well, on average we heat the barn for 6 hours every night, and we burn a 16" length of an 18" diameter log in that 6 hours. This fuel is seasoned and dried for one year and is stored outdoors under a tarp. Assuming that we heat for 48 hours each week for a 24 week period (this is a conservative estimate, as we sometimes do not have to heat on oddly warm fall and spring nights) and knowing that each 16" length of log lasts 6 hours, we determined that we burn 11' of 18" tree trunk each week. That amounts to (3) 80' trees every year.
Taking this further...we know that 80' happy trees (Bob Ross reference? Yes!) in our timber stand exist on an average grid spacing of 15'x15' (1 tree in every 225 sq. ft.). If it takes 25 years to grow an 18" Douglas Fir, then we need to grow 75 trees to support ourselves continuously. These 75 trees take up 16,875 feet in our wood lot, or about four tenths of an acre. So, we have decided to dedicate one acre of woodlot on The Farmstead on which we will plant three and harvest three Douglas Fir trees each year. This additional six tenths of an acre will ensure that our heating fuel source is 100% sustainable and responsibly managed.
The further we go down our road, the more we realize how important and even cost effective it can be to practice sustainability. On top of that, I truly enjoy spending half a day covered in sawdust, staring up the tall trees, wondering which way they will fall.