Timber Grove

A timber grove is a stand of trees grown for the wood inside their trunks. Unlike a wood cut back again and again for fuel, it is felled once, decades after planting, and the value lies in a long straight trunk free of knots. A knot is the buried base of a branch, so the whole practice comes down to growing height without low limbs. The species chosen on planting day fixes the work for the life of the stand: a tree that sheds its own lower branches as it shades them needs far less pruning than one that holds them.

Three jobs recur. The first is choosing which trees to grow on - roughly 75 to 150 per hectare (30 to 60 per acre), with straight stems, strong growth and full healthy crowns - and cutting the neighbours crowding them from at least two sides. The second is thinning, triggered by a sign in the trees rather than by a date: when the living crown covers less than about a third of a tree's height it is crowded, and a thinning usually removes a third to half the stand. The third is pruning, done while the trees are bare, to whatever length of clear trunk is wanted, always leaving at least two thirds of the tree in living branches. Overdo any of them and the stand fails without looking like it: light striking a bare trunk wakes dormant buds into a rash of shoots that become the knots the pruning was meant to prevent.

Most groves that fail do so in the first three years, and deer are the usual reason - browsing seedlings is the greatest single obstacle to establishment, so young trees need protecting. A branch cut flush, or left as a stub rather than cut just outside the swollen collar at its base, rots in place and carries that rot into the log. Hardwood bark seals poorly over wounds, so machinery should enter rarely and by a planned route. Stock can graze beneath once the canopy is open enough for grass, somewhere around 25 to 40 percent cover, but not until the trees are tall enough that animals cannot reach the leading shoots and thick enough to survive being rubbed. Early thinnings and prunings are worth nothing as timber and come out as firewood.